[jboss-cvs] JBossAS SVN: r94463 - in projects/jboss-osgi/projects/bundles/common/trunk: src/main/java/org and 4 other directories.
jboss-cvs-commits at lists.jboss.org
jboss-cvs-commits at lists.jboss.org
Wed Oct 7 10:51:13 EDT 2009
Author: thomas.diesler at jboss.com
Date: 2009-10-07 10:51:13 -0400 (Wed, 07 Oct 2009)
New Revision: 94463
Added:
projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/
projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/
projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/
projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/Log.java
projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/LogConfigurationException.java
projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/LogFactory.java
projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/impl/
projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/impl/Log4JLogger.java
projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/impl/LogFactoryImpl.java
Modified:
projects/jboss-osgi/projects/bundles/common/trunk/pom.xml
Log:
[JBOSGI-161] Cannot use commons-logging
Modified: projects/jboss-osgi/projects/bundles/common/trunk/pom.xml
===================================================================
--- projects/jboss-osgi/projects/bundles/common/trunk/pom.xml 2009-10-07 14:50:27 UTC (rev 94462)
+++ projects/jboss-osgi/projects/bundles/common/trunk/pom.xml 2009-10-07 14:51:13 UTC (rev 94463)
@@ -27,11 +27,12 @@
<parent>
<groupId>org.jboss.osgi</groupId>
<artifactId>jboss-osgi-parent</artifactId>
- <version>1.0.2</version>
+ <version>1.0.3-SNAPSHOT</version>
</parent>
<properties>
- <version.jboss.osgi.spi>1.0.1</version.jboss.osgi.spi>
+ <version.jboss.osgi.spi>1.0.2-SNAPSHOT</version.jboss.osgi.spi>
+ <version.log4j>1.2.14</version.log4j>
<version.osgi>r4v42</version.osgi>
</properties>
@@ -43,8 +44,14 @@
<version>${version.jboss.osgi.spi}</version>
</dependency>
- <!-- OSGi Dependencies -->
+ <!-- Provided Dependencies -->
<dependency>
+ <groupId>log4j</groupId>
+ <artifactId>log4j</artifactId>
+ <version>${version.log4j}</version>
+ <scope>provided</scope>
+ </dependency>
+ <dependency>
<groupId>org.osgi</groupId>
<artifactId>org.osgi.core</artifactId>
<version>${version.osgi}</version>
@@ -69,13 +76,16 @@
<Bundle-SymbolicName>${artifactId}</Bundle-SymbolicName>
<Bundle-Activator>org.jboss.osgi.common.internal.CommonServicesActivator</Bundle-Activator>
<Export-Package>
+ org.apache.commons.logging;version=1.1.1,
org.jboss.osgi.common.log;version=${version}
</Export-Package>
<Private-Package>
+ org.apache.commons.logging.impl,
org.jboss.osgi.common.internal
</Private-Package>
<Import-Package>
- javax.management,
+ javax.management,
+ org.apache.log4j;resolution=optional,
org.jboss.logging,
org.jboss.osgi.spi.management;version="1.0",
org.jboss.osgi.spi.logging;version="1.0",
Added: projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/Log.java
===================================================================
--- projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/Log.java (rev 0)
+++ projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/Log.java 2009-10-07 14:51:13 UTC (rev 94463)
@@ -0,0 +1,246 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package org.apache.commons.logging;
+
+/**
+ * <p>A simple logging interface abstracting logging APIs. In order to be
+ * instantiated successfully by {@link LogFactory}, classes that implement
+ * this interface must have a constructor that takes a single String
+ * parameter representing the "name" of this Log.</p>
+ *
+ * <p> The six logging levels used by <code>Log</code> are (in order):
+ * <ol>
+ * <li>trace (the least serious)</li>
+ * <li>debug</li>
+ * <li>info</li>
+ * <li>warn</li>
+ * <li>error</li>
+ * <li>fatal (the most serious)</li>
+ * </ol>
+ * The mapping of these log levels to the concepts used by the underlying
+ * logging system is implementation dependent.
+ * The implemention should ensure, though, that this ordering behaves
+ * as expected.</p>
+ *
+ * <p>Performance is often a logging concern.
+ * By examining the appropriate property,
+ * a component can avoid expensive operations (producing information
+ * to be logged).</p>
+ *
+ * <p> For example,
+ * <code><pre>
+ * if (log.isDebugEnabled()) {
+ * ... do something expensive ...
+ * log.debug(theResult);
+ * }
+ * </pre></code>
+ * </p>
+ *
+ * <p>Configuration of the underlying logging system will generally be done
+ * external to the Logging APIs, through whatever mechanism is supported by
+ * that system.</p>
+ *
+ * @author <a href="mailto:sanders at apache.org">Scott Sanders</a>
+ * @author Rod Waldhoff
+ * @version $Id: Log.java 424107 2006-07-20 23:15:42Z skitching $
+ */
+public interface Log {
+
+
+ // ----------------------------------------------------- Logging Properties
+
+
+ /**
+ * <p> Is debug logging currently enabled? </p>
+ *
+ * <p> Call this method to prevent having to perform expensive operations
+ * (for example, <code>String</code> concatenation)
+ * when the log level is more than debug. </p>
+ *
+ * @return true if debug is enabled in the underlying logger.
+ */
+ public boolean isDebugEnabled();
+
+
+ /**
+ * <p> Is error logging currently enabled? </p>
+ *
+ * <p> Call this method to prevent having to perform expensive operations
+ * (for example, <code>String</code> concatenation)
+ * when the log level is more than error. </p>
+ *
+ * @return true if error is enabled in the underlying logger.
+ */
+ public boolean isErrorEnabled();
+
+
+ /**
+ * <p> Is fatal logging currently enabled? </p>
+ *
+ * <p> Call this method to prevent having to perform expensive operations
+ * (for example, <code>String</code> concatenation)
+ * when the log level is more than fatal. </p>
+ *
+ * @return true if fatal is enabled in the underlying logger.
+ */
+ public boolean isFatalEnabled();
+
+
+ /**
+ * <p> Is info logging currently enabled? </p>
+ *
+ * <p> Call this method to prevent having to perform expensive operations
+ * (for example, <code>String</code> concatenation)
+ * when the log level is more than info. </p>
+ *
+ * @return true if info is enabled in the underlying logger.
+ */
+ public boolean isInfoEnabled();
+
+
+ /**
+ * <p> Is trace logging currently enabled? </p>
+ *
+ * <p> Call this method to prevent having to perform expensive operations
+ * (for example, <code>String</code> concatenation)
+ * when the log level is more than trace. </p>
+ *
+ * @return true if trace is enabled in the underlying logger.
+ */
+ public boolean isTraceEnabled();
+
+
+ /**
+ * <p> Is warn logging currently enabled? </p>
+ *
+ * <p> Call this method to prevent having to perform expensive operations
+ * (for example, <code>String</code> concatenation)
+ * when the log level is more than warn. </p>
+ *
+ * @return true if warn is enabled in the underlying logger.
+ */
+ public boolean isWarnEnabled();
+
+
+ // -------------------------------------------------------- Logging Methods
+
+
+ /**
+ * <p> Log a message with trace log level. </p>
+ *
+ * @param message log this message
+ */
+ public void trace(Object message);
+
+
+ /**
+ * <p> Log an error with trace log level. </p>
+ *
+ * @param message log this message
+ * @param t log this cause
+ */
+ public void trace(Object message, Throwable t);
+
+
+ /**
+ * <p> Log a message with debug log level. </p>
+ *
+ * @param message log this message
+ */
+ public void debug(Object message);
+
+
+ /**
+ * <p> Log an error with debug log level. </p>
+ *
+ * @param message log this message
+ * @param t log this cause
+ */
+ public void debug(Object message, Throwable t);
+
+
+ /**
+ * <p> Log a message with info log level. </p>
+ *
+ * @param message log this message
+ */
+ public void info(Object message);
+
+
+ /**
+ * <p> Log an error with info log level. </p>
+ *
+ * @param message log this message
+ * @param t log this cause
+ */
+ public void info(Object message, Throwable t);
+
+
+ /**
+ * <p> Log a message with warn log level. </p>
+ *
+ * @param message log this message
+ */
+ public void warn(Object message);
+
+
+ /**
+ * <p> Log an error with warn log level. </p>
+ *
+ * @param message log this message
+ * @param t log this cause
+ */
+ public void warn(Object message, Throwable t);
+
+
+ /**
+ * <p> Log a message with error log level. </p>
+ *
+ * @param message log this message
+ */
+ public void error(Object message);
+
+
+ /**
+ * <p> Log an error with error log level. </p>
+ *
+ * @param message log this message
+ * @param t log this cause
+ */
+ public void error(Object message, Throwable t);
+
+
+ /**
+ * <p> Log a message with fatal log level. </p>
+ *
+ * @param message log this message
+ */
+ public void fatal(Object message);
+
+
+ /**
+ * <p> Log an error with fatal log level. </p>
+ *
+ * @param message log this message
+ * @param t log this cause
+ */
+ public void fatal(Object message, Throwable t);
+
+
+}
Added: projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/LogConfigurationException.java
===================================================================
--- projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/LogConfigurationException.java (rev 0)
+++ projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/LogConfigurationException.java 2009-10-07 14:51:13 UTC (rev 94463)
@@ -0,0 +1,98 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.logging;
+
+
+/**
+ * <p>An exception that is thrown only if a suitable <code>LogFactory</code>
+ * or <code>Log</code> instance cannot be created by the corresponding
+ * factory methods.</p>
+ *
+ * @author Craig R. McClanahan
+ * @version $Revision: 424107 $ $Date: 2006-07-21 01:15:42 +0200 (fr, 21 jul 2006) $
+ */
+
+public class LogConfigurationException extends RuntimeException {
+
+
+ /**
+ * Construct a new exception with <code>null</code> as its detail message.
+ */
+ public LogConfigurationException() {
+
+ super();
+
+ }
+
+
+ /**
+ * Construct a new exception with the specified detail message.
+ *
+ * @param message The detail message
+ */
+ public LogConfigurationException(String message) {
+
+ super(message);
+
+ }
+
+
+ /**
+ * Construct a new exception with the specified cause and a derived
+ * detail message.
+ *
+ * @param cause The underlying cause
+ */
+ public LogConfigurationException(Throwable cause) {
+
+ this((cause == null) ? null : cause.toString(), cause);
+
+ }
+
+
+ /**
+ * Construct a new exception with the specified detail message and cause.
+ *
+ * @param message The detail message
+ * @param cause The underlying cause
+ */
+ public LogConfigurationException(String message, Throwable cause) {
+
+ super(message + " (Caused by " + cause + ")");
+ this.cause = cause; // Two-argument version requires JDK 1.4 or later
+
+ }
+
+
+ /**
+ * The underlying cause of this exception.
+ */
+ protected Throwable cause = null;
+
+
+ /**
+ * Return the underlying cause of this exception (if any).
+ */
+ public Throwable getCause() {
+
+ return (this.cause);
+
+ }
+
+
+}
Added: projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/LogFactory.java
===================================================================
--- projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/LogFactory.java (rev 0)
+++ projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/LogFactory.java 2009-10-07 14:51:13 UTC (rev 94463)
@@ -0,0 +1,1824 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.logging;
+
+
+import java.io.BufferedReader;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.PrintStream;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.net.URL;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.Enumeration;
+import java.util.Hashtable;
+import java.util.Properties;
+
+
+/**
+ * <p>Factory for creating {@link Log} instances, with discovery and
+ * configuration features similar to that employed by standard Java APIs
+ * such as JAXP.</p>
+ *
+ * <p><strong>IMPLEMENTATION NOTE</strong> - This implementation is heavily
+ * based on the SAXParserFactory and DocumentBuilderFactory implementations
+ * (corresponding to the JAXP pluggability APIs) found in Apache Xerces.</p>
+ *
+ * @author Craig R. McClanahan
+ * @author Costin Manolache
+ * @author Richard A. Sitze
+ * @version $Revision: 593798 $ $Date: 2007-11-10 18:40:43 +0100 $
+ */
+
+public abstract class LogFactory {
+ // Implementation note re AccessController usage
+ //
+ // It is important to keep code invoked via an AccessController to small
+ // auditable blocks. Such code must carefully evaluate all user input
+ // (parameters, system properties, config file contents, etc). As an
+ // example, a Log implementation should not write to its logfile
+ // with an AccessController anywhere in the call stack, otherwise an
+ // insecure application could configure the log implementation to write
+ // to a protected file using the privileges granted to JCL rather than
+ // to the calling application.
+ //
+ // Under no circumstance should a non-private method return data that is
+ // retrieved via an AccessController. That would allow an insecure app
+ // to invoke that method and obtain data that it is not permitted to have.
+ //
+ // Invoking user-supplied code with an AccessController set is not a major
+ // issue (eg invoking the constructor of the class specified by
+ // HASHTABLE_IMPLEMENTATION_PROPERTY). That class will be in a different
+ // trust domain, and therefore must have permissions to do whatever it
+ // is trying to do regardless of the permissions granted to JCL. There is
+ // a slight issue in that untrusted code may point that environment var
+ // to another trusted library, in which case the code runs if both that
+ // lib and JCL have the necessary permissions even when the untrusted
+ // caller does not. That's a pretty hard route to exploit though.
+
+
+ // ----------------------------------------------------- Manifest Constants
+
+ /**
+ * The name (<code>priority</code>) of the key in the config file used to
+ * specify the priority of that particular config file. The associated value
+ * is a floating-point number; higher values take priority over lower values.
+ */
+ public static final String PRIORITY_KEY = "priority";
+
+ /**
+ * The name (<code>use_tccl</code>) of the key in the config file used
+ * to specify whether logging classes should be loaded via the thread
+ * context class loader (TCCL), or not. By default, the TCCL is used.
+ */
+ public static final String TCCL_KEY = "use_tccl";
+
+ /**
+ * The name (<code>org.apache.commons.logging.LogFactory</code>) of the property
+ * used to identify the LogFactory implementation
+ * class name. This can be used as a system property, or as an entry in a
+ * configuration properties file.
+ */
+ public static final String FACTORY_PROPERTY =
+ "org.apache.commons.logging.LogFactory";
+
+ /**
+ * The fully qualified class name of the fallback <code>LogFactory</code>
+ * implementation class to use, if no other can be found.
+ */
+ public static final String FACTORY_DEFAULT =
+ "org.apache.commons.logging.impl.LogFactoryImpl";
+
+ /**
+ * The name (<code>commons-logging.properties</code>) of the properties file to search for.
+ */
+ public static final String FACTORY_PROPERTIES =
+ "commons-logging.properties";
+
+ /**
+ * JDK1.3+ <a href="http://java.sun.com/j2se/1.3/docs/guide/jar/jar.html#Service%20Provider">
+ * 'Service Provider' specification</a>.
+ *
+ */
+ protected static final String SERVICE_ID =
+ "META-INF/services/org.apache.commons.logging.LogFactory";
+
+ /**
+ * The name (<code>org.apache.commons.logging.diagnostics.dest</code>)
+ * of the property used to enable internal commons-logging
+ * diagnostic output, in order to get information on what logging
+ * implementations are being discovered, what classloaders they
+ * are loaded through, etc.
+ * <p>
+ * If a system property of this name is set then the value is
+ * assumed to be the name of a file. The special strings
+ * STDOUT or STDERR (case-sensitive) indicate output to
+ * System.out and System.err respectively.
+ * <p>
+ * Diagnostic logging should be used only to debug problematic
+ * configurations and should not be set in normal production use.
+ */
+ public static final String DIAGNOSTICS_DEST_PROPERTY =
+ "org.apache.commons.logging.diagnostics.dest";
+
+ /**
+ * When null (the usual case), no diagnostic output will be
+ * generated by LogFactory or LogFactoryImpl. When non-null,
+ * interesting events will be written to the specified object.
+ */
+ private static PrintStream diagnosticsStream = null;
+
+ /**
+ * A string that gets prefixed to every message output by the
+ * logDiagnostic method, so that users can clearly see which
+ * LogFactory class is generating the output.
+ */
+ private static String diagnosticPrefix;
+
+ /**
+ * <p>Setting this system property
+ * (<code>org.apache.commons.logging.LogFactory.HashtableImpl</code>)
+ * value allows the <code>Hashtable</code> used to store
+ * classloaders to be substituted by an alternative implementation.
+ * </p>
+ * <p>
+ * <strong>Note:</strong> <code>LogFactory</code> will print:
+ * <code><pre>
+ * [ERROR] LogFactory: Load of custom hashtable failed</em>
+ * </pre></code>
+ * to system error and then continue using a standard Hashtable.
+ * </p>
+ * <p>
+ * <strong>Usage:</strong> Set this property when Java is invoked
+ * and <code>LogFactory</code> will attempt to load a new instance
+ * of the given implementation class.
+ * For example, running the following ant scriplet:
+ * <code><pre>
+ * <java classname="${test.runner}" fork="yes" failonerror="${test.failonerror}">
+ * ...
+ * <sysproperty
+ * key="org.apache.commons.logging.LogFactory.HashtableImpl"
+ * value="org.apache.commons.logging.AltHashtable"/>
+ * </java>
+ * </pre></code>
+ * will mean that <code>LogFactory</code> will load an instance of
+ * <code>org.apache.commons.logging.AltHashtable</code>.
+ * </p>
+ * <p>
+ * A typical use case is to allow a custom
+ * Hashtable implementation using weak references to be substituted.
+ * This will allow classloaders to be garbage collected without
+ * the need to release them (on 1.3+ JVMs only, of course ;)
+ * </p>
+ */
+ public static final String HASHTABLE_IMPLEMENTATION_PROPERTY =
+ "org.apache.commons.logging.LogFactory.HashtableImpl";
+ /** Name used to load the weak hashtable implementation by names */
+ private static final String WEAK_HASHTABLE_CLASSNAME =
+ "org.apache.commons.logging.impl.WeakHashtable";
+
+ /**
+ * A reference to the classloader that loaded this class. This is the
+ * same as LogFactory.class.getClassLoader(). However computing this
+ * value isn't quite as simple as that, as we potentially need to use
+ * AccessControllers etc. It's more efficient to compute it once and
+ * cache it here.
+ */
+ private static ClassLoader thisClassLoader;
+
+ // ----------------------------------------------------------- Constructors
+
+
+ /**
+ * Protected constructor that is not available for public use.
+ */
+ protected LogFactory() {
+ }
+
+ // --------------------------------------------------------- Public Methods
+
+
+ /**
+ * Return the configuration attribute with the specified name (if any),
+ * or <code>null</code> if there is no such attribute.
+ *
+ * @param name Name of the attribute to return
+ */
+ public abstract Object getAttribute(String name);
+
+
+ /**
+ * Return an array containing the names of all currently defined
+ * configuration attributes. If there are no such attributes, a zero
+ * length array is returned.
+ */
+ public abstract String[] getAttributeNames();
+
+
+ /**
+ * Convenience method to derive a name from the specified class and
+ * call <code>getInstance(String)</code> with it.
+ *
+ * @param clazz Class for which a suitable Log name will be derived
+ *
+ * @exception LogConfigurationException if a suitable <code>Log</code>
+ * instance cannot be returned
+ */
+ public abstract Log getInstance(Class clazz)
+ throws LogConfigurationException;
+
+
+ /**
+ * <p>Construct (if necessary) and return a <code>Log</code> instance,
+ * using the factory's current set of configuration attributes.</p>
+ *
+ * <p><strong>NOTE</strong> - Depending upon the implementation of
+ * the <code>LogFactory</code> you are using, the <code>Log</code>
+ * instance you are returned may or may not be local to the current
+ * application, and may or may not be returned again on a subsequent
+ * call with the same name argument.</p>
+ *
+ * @param name Logical name of the <code>Log</code> instance to be
+ * returned (the meaning of this name is only known to the underlying
+ * logging implementation that is being wrapped)
+ *
+ * @exception LogConfigurationException if a suitable <code>Log</code>
+ * instance cannot be returned
+ */
+ public abstract Log getInstance(String name)
+ throws LogConfigurationException;
+
+
+ /**
+ * Release any internal references to previously created {@link Log}
+ * instances returned by this factory. This is useful in environments
+ * like servlet containers, which implement application reloading by
+ * throwing away a ClassLoader. Dangling references to objects in that
+ * class loader would prevent garbage collection.
+ */
+ public abstract void release();
+
+
+ /**
+ * Remove any configuration attribute associated with the specified name.
+ * If there is no such attribute, no action is taken.
+ *
+ * @param name Name of the attribute to remove
+ */
+ public abstract void removeAttribute(String name);
+
+
+ /**
+ * Set the configuration attribute with the specified name. Calling
+ * this with a <code>null</code> value is equivalent to calling
+ * <code>removeAttribute(name)</code>.
+ *
+ * @param name Name of the attribute to set
+ * @param value Value of the attribute to set, or <code>null</code>
+ * to remove any setting for this attribute
+ */
+ public abstract void setAttribute(String name, Object value);
+
+
+ // ------------------------------------------------------- Static Variables
+
+
+ /**
+ * The previously constructed <code>LogFactory</code> instances, keyed by
+ * the <code>ClassLoader</code> with which it was created.
+ */
+ protected static Hashtable factories = null;
+
+ /**
+ * Prevously constructed <code>LogFactory</code> instance as in the
+ * <code>factories</code> map, but for the case where
+ * <code>getClassLoader</code> returns <code>null</code>.
+ * This can happen when:
+ * <ul>
+ * <li>using JDK1.1 and the calling code is loaded via the system
+ * classloader (very common)</li>
+ * <li>using JDK1.2+ and the calling code is loaded via the boot
+ * classloader (only likely for embedded systems work).</li>
+ * </ul>
+ * Note that <code>factories</code> is a <i>Hashtable</i> (not a HashMap),
+ * and hashtables don't allow null as a key.
+ */
+ protected static LogFactory nullClassLoaderFactory = null;
+
+ /**
+ * Create the hashtable which will be used to store a map of
+ * (context-classloader -> logfactory-object). Version 1.2+ of Java
+ * supports "weak references", allowing a custom Hashtable class
+ * to be used which uses only weak references to its keys. Using weak
+ * references can fix memory leaks on webapp unload in some cases (though
+ * not all). Version 1.1 of Java does not support weak references, so we
+ * must dynamically determine which we are using. And just for fun, this
+ * code also supports the ability for a system property to specify an
+ * arbitrary Hashtable implementation name.
+ * <p>
+ * Note that the correct way to ensure no memory leaks occur is to ensure
+ * that LogFactory.release(contextClassLoader) is called whenever a
+ * webapp is undeployed.
+ */
+ private static final Hashtable createFactoryStore() {
+ Hashtable result = null;
+ String storeImplementationClass;
+ try {
+ storeImplementationClass = getSystemProperty(HASHTABLE_IMPLEMENTATION_PROPERTY, null);
+ } catch(SecurityException ex) {
+ // Permissions don't allow this to be accessed. Default to the "modern"
+ // weak hashtable implementation if it is available.
+ storeImplementationClass = null;
+ }
+
+ if (storeImplementationClass == null) {
+ storeImplementationClass = WEAK_HASHTABLE_CLASSNAME;
+ }
+ try {
+ Class implementationClass = Class.forName(storeImplementationClass);
+ result = (Hashtable) implementationClass.newInstance();
+
+ } catch (Throwable t) {
+ // ignore
+ if (!WEAK_HASHTABLE_CLASSNAME.equals(storeImplementationClass)) {
+ // if the user's trying to set up a custom implementation, give a clue
+ if (isDiagnosticsEnabled()) {
+ // use internal logging to issue the warning
+ logDiagnostic("[ERROR] LogFactory: Load of custom hashtable failed");
+ } else {
+ // we *really* want this output, even if diagnostics weren't
+ // explicitly enabled by the user.
+ System.err.println("[ERROR] LogFactory: Load of custom hashtable failed");
+ }
+ }
+ }
+ if (result == null) {
+ result = new Hashtable();
+ }
+ return result;
+ }
+
+
+ // --------------------------------------------------------- Static Methods
+
+ /** Utility method to safely trim a string. */
+ private static String trim(String src) {
+ if (src == null) {
+ return null;
+ }
+ return src.trim();
+ }
+
+ /**
+ * <p>Construct (if necessary) and return a <code>LogFactory</code>
+ * instance, using the following ordered lookup procedure to determine
+ * the name of the implementation class to be loaded.</p>
+ * <ul>
+ * <li>The <code>org.apache.commons.logging.LogFactory</code> system
+ * property.</li>
+ * <li>The JDK 1.3 Service Discovery mechanism</li>
+ * <li>Use the properties file <code>commons-logging.properties</code>
+ * file, if found in the class path of this class. The configuration
+ * file is in standard <code>java.util.Properties</code> format and
+ * contains the fully qualified name of the implementation class
+ * with the key being the system property defined above.</li>
+ * <li>Fall back to a default implementation class
+ * (<code>org.apache.commons.logging.impl.LogFactoryImpl</code>).</li>
+ * </ul>
+ *
+ * <p><em>NOTE</em> - If the properties file method of identifying the
+ * <code>LogFactory</code> implementation class is utilized, all of the
+ * properties defined in this file will be set as configuration attributes
+ * on the corresponding <code>LogFactory</code> instance.</p>
+ *
+ * <p><em>NOTE</em> - In a multithreaded environment it is possible
+ * that two different instances will be returned for the same
+ * classloader environment.
+ * </p>
+ *
+ * @exception LogConfigurationException if the implementation class is not
+ * available or cannot be instantiated.
+ */
+ public static LogFactory getFactory() throws LogConfigurationException {
+ // Identify the class loader we will be using
+ ClassLoader contextClassLoader = getContextClassLoaderInternal();
+
+ if (contextClassLoader == null) {
+ // This is an odd enough situation to report about. This
+ // output will be a nuisance on JDK1.1, as the system
+ // classloader is null in that environment.
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Context classloader is null.");
+ }
+ }
+
+ // Return any previously registered factory for this class loader
+ LogFactory factory = getCachedFactory(contextClassLoader);
+ if (factory != null) {
+ return factory;
+ }
+
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] LogFactory implementation requested for the first time for context classloader "
+ + objectId(contextClassLoader));
+ logHierarchy("[LOOKUP] ", contextClassLoader);
+ }
+
+ // Load properties file.
+ //
+ // If the properties file exists, then its contents are used as
+ // "attributes" on the LogFactory implementation class. One particular
+ // property may also control which LogFactory concrete subclass is
+ // used, but only if other discovery mechanisms fail..
+ //
+ // As the properties file (if it exists) will be used one way or
+ // another in the end we may as well look for it first.
+
+ Properties props = getConfigurationFile(contextClassLoader, FACTORY_PROPERTIES);
+
+ // Determine whether we will be using the thread context class loader to
+ // load logging classes or not by checking the loaded properties file (if any).
+ ClassLoader baseClassLoader = contextClassLoader;
+ if (props != null) {
+ String useTCCLStr = props.getProperty(TCCL_KEY);
+ if (useTCCLStr != null) {
+ // The Boolean.valueOf(useTCCLStr).booleanValue() formulation
+ // is required for Java 1.2 compatability.
+ if (Boolean.valueOf(useTCCLStr).booleanValue() == false) {
+ // Don't use current context classloader when locating any
+ // LogFactory or Log classes, just use the class that loaded
+ // this abstract class. When this class is deployed in a shared
+ // classpath of a container, it means webapps cannot deploy their
+ // own logging implementations. It also means that it is up to the
+ // implementation whether to load library-specific config files
+ // from the TCCL or not.
+ baseClassLoader = thisClassLoader;
+ }
+ }
+ }
+
+ // Determine which concrete LogFactory subclass to use.
+ // First, try a global system property
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] Looking for system property [" + FACTORY_PROPERTY
+ + "] to define the LogFactory subclass to use...");
+ }
+
+ try {
+ String factoryClass = getSystemProperty(FACTORY_PROPERTY, null);
+ if (factoryClass != null) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] Creating an instance of LogFactory class '" + factoryClass
+ + "' as specified by system property " + FACTORY_PROPERTY);
+ }
+
+ factory = newFactory(factoryClass, baseClassLoader, contextClassLoader);
+ } else {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] No system property [" + FACTORY_PROPERTY
+ + "] defined.");
+ }
+ }
+ } catch (SecurityException e) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] A security exception occurred while trying to create an"
+ + " instance of the custom factory class"
+ + ": [" + trim(e.getMessage())
+ + "]. Trying alternative implementations...");
+ }
+ ; // ignore
+ } catch(RuntimeException e) {
+ // This is not consistent with the behaviour when a bad LogFactory class is
+ // specified in a services file.
+ //
+ // One possible exception that can occur here is a ClassCastException when
+ // the specified class wasn't castable to this LogFactory type.
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] An exception occurred while trying to create an"
+ + " instance of the custom factory class"
+ + ": [" + trim(e.getMessage())
+ + "] as specified by a system property.");
+ }
+ throw e;
+ }
+
+
+ // Second, try to find a service by using the JDK1.3 class
+ // discovery mechanism, which involves putting a file with the name
+ // of an interface class in the META-INF/services directory, where the
+ // contents of the file is a single line specifying a concrete class
+ // that implements the desired interface.
+
+ if (factory == null) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] Looking for a resource file of name [" + SERVICE_ID
+ + "] to define the LogFactory subclass to use...");
+ }
+ try {
+ InputStream is = getResourceAsStream(contextClassLoader,
+ SERVICE_ID);
+
+ if( is != null ) {
+ // This code is needed by EBCDIC and other strange systems.
+ // It's a fix for bugs reported in xerces
+ BufferedReader rd;
+ try {
+ rd = new BufferedReader(new InputStreamReader(is, "UTF-8"));
+ } catch (java.io.UnsupportedEncodingException e) {
+ rd = new BufferedReader(new InputStreamReader(is));
+ }
+
+ String factoryClassName = rd.readLine();
+ rd.close();
+
+ if (factoryClassName != null &&
+ ! "".equals(factoryClassName)) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] Creating an instance of LogFactory class " + factoryClassName
+ + " as specified by file '" + SERVICE_ID
+ + "' which was present in the path of the context"
+ + " classloader.");
+ }
+ factory = newFactory(factoryClassName, baseClassLoader, contextClassLoader );
+ }
+ } else {
+ // is == null
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] No resource file with name '" + SERVICE_ID
+ + "' found.");
+ }
+ }
+ } catch( Exception ex ) {
+ // note: if the specified LogFactory class wasn't compatible with LogFactory
+ // for some reason, a ClassCastException will be caught here, and attempts will
+ // continue to find a compatible class.
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] A security exception occurred while trying to create an"
+ + " instance of the custom factory class"
+ + ": [" + trim(ex.getMessage())
+ + "]. Trying alternative implementations...");
+ }
+ ; // ignore
+ }
+ }
+
+
+ // Third try looking into the properties file read earlier (if found)
+
+ if (factory == null) {
+ if (props != null) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] Looking in properties file for entry with key '"
+ + FACTORY_PROPERTY
+ + "' to define the LogFactory subclass to use...");
+ }
+ String factoryClass = props.getProperty(FACTORY_PROPERTY);
+ if (factoryClass != null) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] Properties file specifies LogFactory subclass '"
+ + factoryClass + "'");
+ }
+ factory = newFactory(factoryClass, baseClassLoader, contextClassLoader);
+
+ // TODO: think about whether we need to handle exceptions from newFactory
+ } else {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] Properties file has no entry specifying LogFactory subclass.");
+ }
+ }
+ } else {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] No properties file available to determine"
+ + " LogFactory subclass from..");
+ }
+ }
+ }
+
+
+ // Fourth, try the fallback implementation class
+
+ if (factory == null) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] Loading the default LogFactory implementation '" + FACTORY_DEFAULT
+ + "' via the same classloader that loaded this LogFactory"
+ + " class (ie not looking in the context classloader).");
+ }
+
+ // Note: unlike the above code which can try to load custom LogFactory
+ // implementations via the TCCL, we don't try to load the default LogFactory
+ // implementation via the context classloader because:
+ // * that can cause problems (see comments in newFactory method)
+ // * no-one should be customising the code of the default class
+ // Yes, we do give up the ability for the child to ship a newer
+ // version of the LogFactoryImpl class and have it used dynamically
+ // by an old LogFactory class in the parent, but that isn't
+ // necessarily a good idea anyway.
+ factory = newFactory(FACTORY_DEFAULT, thisClassLoader, contextClassLoader);
+ }
+
+ if (factory != null) {
+ /**
+ * Always cache using context class loader.
+ */
+ cacheFactory(contextClassLoader, factory);
+
+ if( props!=null ) {
+ Enumeration names = props.propertyNames();
+ while (names.hasMoreElements()) {
+ String name = (String) names.nextElement();
+ String value = props.getProperty(name);
+ factory.setAttribute(name, value);
+ }
+ }
+ }
+
+ return factory;
+ }
+
+
+ /**
+ * Convenience method to return a named logger, without the application
+ * having to care about factories.
+ *
+ * @param clazz Class from which a log name will be derived
+ *
+ * @exception LogConfigurationException if a suitable <code>Log</code>
+ * instance cannot be returned
+ */
+ public static Log getLog(Class clazz)
+ throws LogConfigurationException {
+
+ return (getFactory().getInstance(clazz));
+
+ }
+
+
+ /**
+ * Convenience method to return a named logger, without the application
+ * having to care about factories.
+ *
+ * @param name Logical name of the <code>Log</code> instance to be
+ * returned (the meaning of this name is only known to the underlying
+ * logging implementation that is being wrapped)
+ *
+ * @exception LogConfigurationException if a suitable <code>Log</code>
+ * instance cannot be returned
+ */
+ public static Log getLog(String name)
+ throws LogConfigurationException {
+
+ return (getFactory().getInstance(name));
+
+ }
+
+
+ /**
+ * Release any internal references to previously created {@link LogFactory}
+ * instances that have been associated with the specified class loader
+ * (if any), after calling the instance method <code>release()</code> on
+ * each of them.
+ *
+ * @param classLoader ClassLoader for which to release the LogFactory
+ */
+ public static void release(ClassLoader classLoader) {
+
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Releasing factory for classloader " + objectId(classLoader));
+ }
+ synchronized (factories) {
+ if (classLoader == null) {
+ if (nullClassLoaderFactory != null) {
+ nullClassLoaderFactory.release();
+ nullClassLoaderFactory = null;
+ }
+ } else {
+ LogFactory factory = (LogFactory) factories.get(classLoader);
+ if (factory != null) {
+ factory.release();
+ factories.remove(classLoader);
+ }
+ }
+ }
+
+ }
+
+
+ /**
+ * Release any internal references to previously created {@link LogFactory}
+ * instances, after calling the instance method <code>release()</code> on
+ * each of them. This is useful in environments like servlet containers,
+ * which implement application reloading by throwing away a ClassLoader.
+ * Dangling references to objects in that class loader would prevent
+ * garbage collection.
+ */
+ public static void releaseAll() {
+
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Releasing factory for all classloaders.");
+ }
+ synchronized (factories) {
+ Enumeration elements = factories.elements();
+ while (elements.hasMoreElements()) {
+ LogFactory element = (LogFactory) elements.nextElement();
+ element.release();
+ }
+ factories.clear();
+
+ if (nullClassLoaderFactory != null) {
+ nullClassLoaderFactory.release();
+ nullClassLoaderFactory = null;
+ }
+ }
+
+ }
+
+
+ // ------------------------------------------------------ Protected Methods
+
+ /**
+ * Safely get access to the classloader for the specified class.
+ * <p>
+ * Theoretically, calling getClassLoader can throw a security exception,
+ * and so should be done under an AccessController in order to provide
+ * maximum flexibility. However in practice people don't appear to use
+ * security policies that forbid getClassLoader calls. So for the moment
+ * all code is written to call this method rather than Class.getClassLoader,
+ * so that we could put AccessController stuff in this method without any
+ * disruption later if we need to.
+ * <p>
+ * Even when using an AccessController, however, this method can still
+ * throw SecurityException. Commons-logging basically relies on the
+ * ability to access classloaders, ie a policy that forbids all
+ * classloader access will also prevent commons-logging from working:
+ * currently this method will throw an exception preventing the entire app
+ * from starting up. Maybe it would be good to detect this situation and
+ * just disable all commons-logging? Not high priority though - as stated
+ * above, security policies that prevent classloader access aren't common.
+ * <p>
+ * Note that returning an object fetched via an AccessController would
+ * technically be a security flaw anyway; untrusted code that has access
+ * to a trusted JCL library could use it to fetch the classloader for
+ * a class even when forbidden to do so directly.
+ *
+ * @since 1.1
+ */
+ protected static ClassLoader getClassLoader(Class clazz) {
+ try {
+ return clazz.getClassLoader();
+ } catch(SecurityException ex) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "Unable to get classloader for class '" + clazz
+ + "' due to security restrictions - " + ex.getMessage());
+ }
+ throw ex;
+ }
+ }
+
+ /**
+ * Returns the current context classloader.
+ * <p>
+ * In versions prior to 1.1, this method did not use an AccessController.
+ * In version 1.1, an AccessController wrapper was incorrectly added to
+ * this method, causing a minor security flaw.
+ * <p>
+ * In version 1.1.1 this change was reverted; this method no longer uses
+ * an AccessController. User code wishing to obtain the context classloader
+ * must invoke this method via AccessController.doPrivileged if it needs
+ * support for that.
+ *
+ * @return the context classloader associated with the current thread,
+ * or null if security doesn't allow it.
+ *
+ * @throws LogConfigurationException if there was some weird error while
+ * attempting to get the context classloader.
+ *
+ * @throws SecurityException if the current java security policy doesn't
+ * allow this class to access the context classloader.
+ */
+ protected static ClassLoader getContextClassLoader()
+ throws LogConfigurationException {
+
+ return directGetContextClassLoader();
+ }
+
+ /**
+ * Calls LogFactory.directGetContextClassLoader under the control of an
+ * AccessController class. This means that java code running under a
+ * security manager that forbids access to ClassLoaders will still work
+ * if this class is given appropriate privileges, even when the caller
+ * doesn't have such privileges. Without using an AccessController, the
+ * the entire call stack must have the privilege before the call is
+ * allowed.
+ *
+ * @return the context classloader associated with the current thread,
+ * or null if security doesn't allow it.
+ *
+ * @throws LogConfigurationException if there was some weird error while
+ * attempting to get the context classloader.
+ *
+ * @throws SecurityException if the current java security policy doesn't
+ * allow this class to access the context classloader.
+ */
+ private static ClassLoader getContextClassLoaderInternal()
+ throws LogConfigurationException {
+ return (ClassLoader)AccessController.doPrivileged(
+ new PrivilegedAction() {
+ public Object run() {
+ return directGetContextClassLoader();
+ }
+ });
+ }
+
+ /**
+ * Return the thread context class loader if available; otherwise return
+ * null.
+ * <p>
+ * Most/all code should call getContextClassLoaderInternal rather than
+ * calling this method directly.
+ * <p>
+ * The thread context class loader is available for JDK 1.2
+ * or later, if certain security conditions are met.
+ * <p>
+ * Note that no internal logging is done within this method because
+ * this method is called every time LogFactory.getLogger() is called,
+ * and we don't want too much output generated here.
+ *
+ * @exception LogConfigurationException if a suitable class loader
+ * cannot be identified.
+ *
+ * @exception SecurityException if the java security policy forbids
+ * access to the context classloader from one of the classes in the
+ * current call stack.
+ * @since 1.1
+ */
+ protected static ClassLoader directGetContextClassLoader()
+ throws LogConfigurationException
+ {
+ ClassLoader classLoader = null;
+
+ try {
+ // Are we running on a JDK 1.2 or later system?
+ Method method = Thread.class.getMethod("getContextClassLoader",
+ (Class[]) null);
+
+ // Get the thread context class loader (if there is one)
+ try {
+ classLoader = (ClassLoader)method.invoke(Thread.currentThread(),
+ (Object[]) null);
+ } catch (IllegalAccessException e) {
+ throw new LogConfigurationException
+ ("Unexpected IllegalAccessException", e);
+ } catch (InvocationTargetException e) {
+ /**
+ * InvocationTargetException is thrown by 'invoke' when
+ * the method being invoked (getContextClassLoader) throws
+ * an exception.
+ *
+ * getContextClassLoader() throws SecurityException when
+ * the context class loader isn't an ancestor of the
+ * calling class's class loader, or if security
+ * permissions are restricted.
+ *
+ * In the first case (not related), we want to ignore and
+ * keep going. We cannot help but also ignore the second
+ * with the logic below, but other calls elsewhere (to
+ * obtain a class loader) will trigger this exception where
+ * we can make a distinction.
+ */
+ if (e.getTargetException() instanceof SecurityException) {
+ ; // ignore
+ } else {
+ // Capture 'e.getTargetException()' exception for details
+ // alternate: log 'e.getTargetException()', and pass back 'e'.
+ throw new LogConfigurationException
+ ("Unexpected InvocationTargetException", e.getTargetException());
+ }
+ }
+ } catch (NoSuchMethodException e) {
+ // Assume we are running on JDK 1.1
+ classLoader = getClassLoader(LogFactory.class);
+
+ // We deliberately don't log a message here to outputStream;
+ // this message would be output for every call to LogFactory.getLog()
+ // when running on JDK1.1
+ //
+ // if (outputStream != null) {
+ // outputStream.println(
+ // "Method Thread.getContextClassLoader does not exist;"
+ // + " assuming this is JDK 1.1, and that the context"
+ // + " classloader is the same as the class that loaded"
+ // + " the concrete LogFactory class.");
+ // }
+
+ }
+
+ // Return the selected class loader
+ return classLoader;
+ }
+
+ /**
+ * Check cached factories (keyed by contextClassLoader)
+ *
+ * @param contextClassLoader is the context classloader associated
+ * with the current thread. This allows separate LogFactory objects
+ * per component within a container, provided each component has
+ * a distinct context classloader set. This parameter may be null
+ * in JDK1.1, and in embedded systems where jcl-using code is
+ * placed in the bootclasspath.
+ *
+ * @return the factory associated with the specified classloader if
+ * one has previously been created, or null if this is the first time
+ * we have seen this particular classloader.
+ */
+ private static LogFactory getCachedFactory(ClassLoader contextClassLoader)
+ {
+ LogFactory factory = null;
+
+ if (contextClassLoader == null) {
+ // We have to handle this specially, as factories is a Hashtable
+ // and those don't accept null as a key value.
+ //
+ // nb: nullClassLoaderFactory might be null. That's ok.
+ factory = nullClassLoaderFactory;
+ } else {
+ factory = (LogFactory) factories.get(contextClassLoader);
+ }
+
+ return factory;
+ }
+
+ /**
+ * Remember this factory, so later calls to LogFactory.getCachedFactory
+ * can return the previously created object (together with all its
+ * cached Log objects).
+ *
+ * @param classLoader should be the current context classloader. Note that
+ * this can be null under some circumstances; this is ok.
+ *
+ * @param factory should be the factory to cache. This should never be null.
+ */
+ private static void cacheFactory(ClassLoader classLoader, LogFactory factory)
+ {
+ // Ideally we would assert(factory != null) here. However reporting
+ // errors from within a logging implementation is a little tricky!
+
+ if (factory != null) {
+ if (classLoader == null) {
+ nullClassLoaderFactory = factory;
+ } else {
+ factories.put(classLoader, factory);
+ }
+ }
+ }
+
+ /**
+ * Return a new instance of the specified <code>LogFactory</code>
+ * implementation class, loaded by the specified class loader.
+ * If that fails, try the class loader used to load this
+ * (abstract) LogFactory.
+ * <p>
+ * <h2>ClassLoader conflicts</h2>
+ * Note that there can be problems if the specified ClassLoader is not the
+ * same as the classloader that loaded this class, ie when loading a
+ * concrete LogFactory subclass via a context classloader.
+ * <p>
+ * The problem is the same one that can occur when loading a concrete Log
+ * subclass via a context classloader.
+ * <p>
+ * The problem occurs when code running in the context classloader calls
+ * class X which was loaded via a parent classloader, and class X then calls
+ * LogFactory.getFactory (either directly or via LogFactory.getLog). Because
+ * class X was loaded via the parent, it binds to LogFactory loaded via
+ * the parent. When the code in this method finds some LogFactoryYYYY
+ * class in the child (context) classloader, and there also happens to be a
+ * LogFactory class defined in the child classloader, then LogFactoryYYYY
+ * will be bound to LogFactory at childloader. It cannot be cast to
+ * LogFactory at parentloader, ie this method cannot return the object as
+ * the desired type. Note that it doesn't matter if the LogFactory class
+ * in the child classloader is identical to the LogFactory class in the
+ * parent classloader, they are not compatible.
+ * <p>
+ * The solution taken here is to simply print out an error message when
+ * this occurs then throw an exception. The deployer of the application
+ * must ensure they remove all occurrences of the LogFactory class from
+ * the child classloader in order to resolve the issue. Note that they
+ * do not have to move the custom LogFactory subclass; that is ok as
+ * long as the only LogFactory class it can find to bind to is in the
+ * parent classloader.
+ * <p>
+ * @param factoryClass Fully qualified name of the <code>LogFactory</code>
+ * implementation class
+ * @param classLoader ClassLoader from which to load this class
+ * @param contextClassLoader is the context that this new factory will
+ * manage logging for.
+ *
+ * @exception LogConfigurationException if a suitable instance
+ * cannot be created
+ * @since 1.1
+ */
+ protected static LogFactory newFactory(final String factoryClass,
+ final ClassLoader classLoader,
+ final ClassLoader contextClassLoader)
+ throws LogConfigurationException
+ {
+ // Note that any unchecked exceptions thrown by the createFactory
+ // method will propagate out of this method; in particular a
+ // ClassCastException can be thrown.
+ Object result = AccessController.doPrivileged(
+ new PrivilegedAction() {
+ public Object run() {
+ return createFactory(factoryClass, classLoader);
+ }
+ });
+
+ if (result instanceof LogConfigurationException) {
+ LogConfigurationException ex = (LogConfigurationException) result;
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "An error occurred while loading the factory class:"
+ + ex.getMessage());
+ }
+ throw ex;
+ }
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "Created object " + objectId(result)
+ + " to manage classloader " + objectId(contextClassLoader));
+ }
+ return (LogFactory)result;
+ }
+
+ /**
+ * Method provided for backwards compatibility; see newFactory version that
+ * takes 3 parameters.
+ * <p>
+ * This method would only ever be called in some rather odd situation.
+ * Note that this method is static, so overriding in a subclass doesn't
+ * have any effect unless this method is called from a method in that
+ * subclass. However this method only makes sense to use from the
+ * getFactory method, and as that is almost always invoked via
+ * LogFactory.getFactory, any custom definition in a subclass would be
+ * pointless. Only a class with a custom getFactory method, then invoked
+ * directly via CustomFactoryImpl.getFactory or similar would ever call
+ * this. Anyway, it's here just in case, though the "managed class loader"
+ * value output to the diagnostics will not report the correct value.
+ */
+ protected static LogFactory newFactory(final String factoryClass,
+ final ClassLoader classLoader) {
+ return newFactory(factoryClass, classLoader, null);
+ }
+
+ /**
+ * Implements the operations described in the javadoc for newFactory.
+ *
+ * @param factoryClass
+ *
+ * @param classLoader used to load the specified factory class. This is
+ * expected to be either the TCCL or the classloader which loaded this
+ * class. Note that the classloader which loaded this class might be
+ * "null" (ie the bootloader) for embedded systems.
+ *
+ * @return either a LogFactory object or a LogConfigurationException object.
+ * @since 1.1
+ */
+ protected static Object createFactory(String factoryClass, ClassLoader classLoader) {
+
+ // This will be used to diagnose bad configurations
+ // and allow a useful message to be sent to the user
+ Class logFactoryClass = null;
+ try {
+ if (classLoader != null) {
+ try {
+ // First the given class loader param (thread class loader)
+
+ // Warning: must typecast here & allow exception
+ // to be generated/caught & recast properly.
+ logFactoryClass = classLoader.loadClass(factoryClass);
+ if (LogFactory.class.isAssignableFrom(logFactoryClass)) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "Loaded class " + logFactoryClass.getName()
+ + " from classloader " + objectId(classLoader));
+ }
+ } else {
+ //
+ // This indicates a problem with the ClassLoader tree.
+ // An incompatible ClassLoader was used to load the
+ // implementation.
+ // As the same classes
+ // must be available in multiple class loaders,
+ // it is very likely that multiple JCL jars are present.
+ // The most likely fix for this
+ // problem is to remove the extra JCL jars from the
+ // ClassLoader hierarchy.
+ //
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "Factory class " + logFactoryClass.getName()
+ + " loaded from classloader " + objectId(logFactoryClass.getClassLoader())
+ + " does not extend '" + LogFactory.class.getName()
+ + "' as loaded by this classloader.");
+ logHierarchy("[BAD CL TREE] ", classLoader);
+ }
+ }
+
+ return (LogFactory) logFactoryClass.newInstance();
+
+ } catch (ClassNotFoundException ex) {
+ if (classLoader == thisClassLoader) {
+ // Nothing more to try, onwards.
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "Unable to locate any class called '" + factoryClass
+ + "' via classloader " + objectId(classLoader));
+ }
+ throw ex;
+ }
+ // ignore exception, continue
+ } catch (NoClassDefFoundError e) {
+ if (classLoader == thisClassLoader) {
+ // Nothing more to try, onwards.
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "Class '" + factoryClass + "' cannot be loaded"
+ + " via classloader " + objectId(classLoader)
+ + " - it depends on some other class that cannot"
+ + " be found.");
+ }
+ throw e;
+ }
+ // ignore exception, continue
+ } catch(ClassCastException e) {
+ if (classLoader == thisClassLoader) {
+ // There's no point in falling through to the code below that
+ // tries again with thisClassLoader, because we've just tried
+ // loading with that loader (not the TCCL). Just throw an
+ // appropriate exception here.
+
+ final boolean implementsLogFactory = implementsLogFactory(logFactoryClass);
+
+ //
+ // Construct a good message: users may not actual expect that a custom implementation
+ // has been specified. Several well known containers use this mechanism to adapt JCL
+ // to their native logging system.
+ //
+ String msg =
+ "The application has specified that a custom LogFactory implementation should be used but " +
+ "Class '" + factoryClass + "' cannot be converted to '"
+ + LogFactory.class.getName() + "'. ";
+ if (implementsLogFactory) {
+ msg = msg + "The conflict is caused by the presence of multiple LogFactory classes in incompatible classloaders. " +
+ "Background can be found in http://commons.apache.org/logging/tech.html. " +
+ "If you have not explicitly specified a custom LogFactory then it is likely that " +
+ "the container has set one without your knowledge. " +
+ "In this case, consider using the commons-logging-adapters.jar file or " +
+ "specifying the standard LogFactory from the command line. ";
+ } else {
+ msg = msg + "Please check the custom implementation. ";
+ }
+ msg = msg + "Help can be found @http://commons.apache.org/logging/troubleshooting.html.";
+
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(msg);
+ }
+
+ ClassCastException ex = new ClassCastException(msg);
+ throw ex;
+ }
+
+ // Ignore exception, continue. Presumably the classloader was the
+ // TCCL; the code below will try to load the class via thisClassLoader.
+ // This will handle the case where the original calling class is in
+ // a shared classpath but the TCCL has a copy of LogFactory and the
+ // specified LogFactory implementation; we will fall back to using the
+ // LogFactory implementation from the same classloader as this class.
+ //
+ // Issue: this doesn't handle the reverse case, where this LogFactory
+ // is in the webapp, and the specified LogFactory implementation is
+ // in a shared classpath. In that case:
+ // (a) the class really does implement LogFactory (bad log msg above)
+ // (b) the fallback code will result in exactly the same problem.
+ }
+ }
+
+ /* At this point, either classLoader == null, OR
+ * classLoader was unable to load factoryClass.
+ *
+ * In either case, we call Class.forName, which is equivalent
+ * to LogFactory.class.getClassLoader().load(name), ie we ignore
+ * the classloader parameter the caller passed, and fall back
+ * to trying the classloader associated with this class. See the
+ * javadoc for the newFactory method for more info on the
+ * consequences of this.
+ *
+ * Notes:
+ * * LogFactory.class.getClassLoader() may return 'null'
+ * if LogFactory is loaded by the bootstrap classloader.
+ */
+ // Warning: must typecast here & allow exception
+ // to be generated/caught & recast properly.
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "Unable to load factory class via classloader "
+ + objectId(classLoader)
+ + " - trying the classloader associated with this LogFactory.");
+ }
+ logFactoryClass = Class.forName(factoryClass);
+ return (LogFactory) logFactoryClass.newInstance();
+ } catch (Exception e) {
+ // Check to see if we've got a bad configuration
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Unable to create LogFactory instance.");
+ }
+ if (logFactoryClass != null
+ && !LogFactory.class.isAssignableFrom(logFactoryClass)) {
+
+ return new LogConfigurationException(
+ "The chosen LogFactory implementation does not extend LogFactory."
+ + " Please check your configuration.",
+ e);
+ }
+ return new LogConfigurationException(e);
+ }
+ }
+
+ /**
+ * Determines whether the given class actually implements <code>LogFactory</code>.
+ * Diagnostic information is also logged.
+ * <p>
+ * <strong>Usage:</strong> to diagnose whether a classloader conflict is the cause
+ * of incompatibility. The test used is whether the class is assignable from
+ * the <code>LogFactory</code> class loaded by the class's classloader.
+ * @param logFactoryClass <code>Class</code> which may implement <code>LogFactory</code>
+ * @return true if the <code>logFactoryClass</code> does extend
+ * <code>LogFactory</code> when that class is loaded via the same
+ * classloader that loaded the <code>logFactoryClass</code>.
+ */
+ private static boolean implementsLogFactory(Class logFactoryClass) {
+ boolean implementsLogFactory = false;
+ if (logFactoryClass != null) {
+ try {
+ ClassLoader logFactoryClassLoader = logFactoryClass.getClassLoader();
+ if (logFactoryClassLoader == null) {
+ logDiagnostic("[CUSTOM LOG FACTORY] was loaded by the boot classloader");
+ } else {
+ logHierarchy("[CUSTOM LOG FACTORY] ", logFactoryClassLoader);
+ Class factoryFromCustomLoader
+ = Class.forName("org.apache.commons.logging.LogFactory", false, logFactoryClassLoader);
+ implementsLogFactory = factoryFromCustomLoader.isAssignableFrom(logFactoryClass);
+ if (implementsLogFactory) {
+ logDiagnostic("[CUSTOM LOG FACTORY] " + logFactoryClass.getName()
+ + " implements LogFactory but was loaded by an incompatible classloader.");
+ } else {
+ logDiagnostic("[CUSTOM LOG FACTORY] " + logFactoryClass.getName()
+ + " does not implement LogFactory.");
+ }
+ }
+ } catch (SecurityException e) {
+ //
+ // The application is running within a hostile security environment.
+ // This will make it very hard to diagnose issues with JCL.
+ // Consider running less securely whilst debugging this issue.
+ //
+ logDiagnostic("[CUSTOM LOG FACTORY] SecurityException thrown whilst trying to determine whether " +
+ "the compatibility was caused by a classloader conflict: "
+ + e.getMessage());
+ } catch (LinkageError e) {
+ //
+ // This should be an unusual circumstance.
+ // LinkageError's usually indicate that a dependent class has incompatibly changed.
+ // Another possibility may be an exception thrown by an initializer.
+ // Time for a clean rebuild?
+ //
+ logDiagnostic("[CUSTOM LOG FACTORY] LinkageError thrown whilst trying to determine whether " +
+ "the compatibility was caused by a classloader conflict: "
+ + e.getMessage());
+ } catch (ClassNotFoundException e) {
+ //
+ // LogFactory cannot be loaded by the classloader which loaded the custom factory implementation.
+ // The custom implementation is not viable until this is corrected.
+ // Ensure that the JCL jar and the custom class are available from the same classloader.
+ // Running with diagnostics on should give information about the classloaders used
+ // to load the custom factory.
+ //
+ logDiagnostic("[CUSTOM LOG FACTORY] LogFactory class cannot be loaded by classloader which loaded the " +
+ "custom LogFactory implementation. Is the custom factory in the right classloader?");
+ }
+ }
+ return implementsLogFactory;
+ }
+
+ /**
+ * Applets may run in an environment where accessing resources of a loader is
+ * a secure operation, but where the commons-logging library has explicitly
+ * been granted permission for that operation. In this case, we need to
+ * run the operation using an AccessController.
+ */
+ private static InputStream getResourceAsStream(final ClassLoader loader,
+ final String name)
+ {
+ return (InputStream)AccessController.doPrivileged(
+ new PrivilegedAction() {
+ public Object run() {
+ if (loader != null) {
+ return loader.getResourceAsStream(name);
+ } else {
+ return ClassLoader.getSystemResourceAsStream(name);
+ }
+ }
+ });
+ }
+
+ /**
+ * Given a filename, return an enumeration of URLs pointing to
+ * all the occurrences of that filename in the classpath.
+ * <p>
+ * This is just like ClassLoader.getResources except that the
+ * operation is done under an AccessController so that this method will
+ * succeed when this jarfile is privileged but the caller is not.
+ * This method must therefore remain private to avoid security issues.
+ * <p>
+ * If no instances are found, an Enumeration is returned whose
+ * hasMoreElements method returns false (ie an "empty" enumeration).
+ * If resources could not be listed for some reason, null is returned.
+ */
+ private static Enumeration getResources(final ClassLoader loader,
+ final String name)
+ {
+ PrivilegedAction action =
+ new PrivilegedAction() {
+ public Object run() {
+ try {
+ if (loader != null) {
+ return loader.getResources(name);
+ } else {
+ return ClassLoader.getSystemResources(name);
+ }
+ } catch(IOException e) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "Exception while trying to find configuration file "
+ + name + ":" + e.getMessage());
+ }
+ return null;
+ } catch(NoSuchMethodError e) {
+ // we must be running on a 1.1 JVM which doesn't support
+ // ClassLoader.getSystemResources; just return null in
+ // this case.
+ return null;
+ }
+ }
+ };
+ Object result = AccessController.doPrivileged(action);
+ return (Enumeration) result;
+ }
+
+ /**
+ * Given a URL that refers to a .properties file, load that file.
+ * This is done under an AccessController so that this method will
+ * succeed when this jarfile is privileged but the caller is not.
+ * This method must therefore remain private to avoid security issues.
+ * <p>
+ * Null is returned if the URL cannot be opened.
+ */
+ private static Properties getProperties(final URL url) {
+ PrivilegedAction action =
+ new PrivilegedAction() {
+ public Object run() {
+ try {
+ InputStream stream = url.openStream();
+ if (stream != null) {
+ Properties props = new Properties();
+ props.load(stream);
+ stream.close();
+ return props;
+ }
+ } catch(IOException e) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Unable to read URL " + url);
+ }
+ }
+
+ return null;
+ }
+ };
+ return (Properties) AccessController.doPrivileged(action);
+ }
+
+ /**
+ * Locate a user-provided configuration file.
+ * <p>
+ * The classpath of the specified classLoader (usually the context classloader)
+ * is searched for properties files of the specified name. If none is found,
+ * null is returned. If more than one is found, then the file with the greatest
+ * value for its PRIORITY property is returned. If multiple files have the
+ * same PRIORITY value then the first in the classpath is returned.
+ * <p>
+ * This differs from the 1.0.x releases; those always use the first one found.
+ * However as the priority is a new field, this change is backwards compatible.
+ * <p>
+ * The purpose of the priority field is to allow a webserver administrator to
+ * override logging settings in all webapps by placing a commons-logging.properties
+ * file in a shared classpath location with a priority > 0; this overrides any
+ * commons-logging.properties files without priorities which are in the
+ * webapps. Webapps can also use explicit priorities to override a configuration
+ * file in the shared classpath if needed.
+ */
+ private static final Properties getConfigurationFile(
+ ClassLoader classLoader, String fileName) {
+
+ Properties props = null;
+ double priority = 0.0;
+ URL propsUrl = null;
+ try {
+ Enumeration urls = getResources(classLoader, fileName);
+
+ if (urls == null) {
+ return null;
+ }
+
+ while (urls.hasMoreElements()) {
+ URL url = (URL) urls.nextElement();
+
+ Properties newProps = getProperties(url);
+ if (newProps != null) {
+ if (props == null) {
+ propsUrl = url;
+ props = newProps;
+ String priorityStr = props.getProperty(PRIORITY_KEY);
+ priority = 0.0;
+ if (priorityStr != null) {
+ priority = Double.parseDouble(priorityStr);
+ }
+
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] Properties file found at '" + url + "'"
+ + " with priority " + priority);
+ }
+ } else {
+ String newPriorityStr = newProps.getProperty(PRIORITY_KEY);
+ double newPriority = 0.0;
+ if (newPriorityStr != null) {
+ newPriority = Double.parseDouble(newPriorityStr);
+ }
+
+ if (newPriority > priority) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] Properties file at '" + url + "'"
+ + " with priority " + newPriority
+ + " overrides file at '" + propsUrl + "'"
+ + " with priority " + priority);
+ }
+
+ propsUrl = url;
+ props = newProps;
+ priority = newPriority;
+ } else {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[LOOKUP] Properties file at '" + url + "'"
+ + " with priority " + newPriority
+ + " does not override file at '" + propsUrl + "'"
+ + " with priority " + priority);
+ }
+ }
+ }
+
+ }
+ }
+ } catch (SecurityException e) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("SecurityException thrown while trying to find/read config files.");
+ }
+ }
+
+ if (isDiagnosticsEnabled()) {
+ if (props == null) {
+ logDiagnostic(
+ "[LOOKUP] No properties file of name '" + fileName
+ + "' found.");
+ } else {
+ logDiagnostic(
+ "[LOOKUP] Properties file of name '" + fileName
+ + "' found at '" + propsUrl + '"');
+ }
+ }
+
+ return props;
+ }
+
+ /**
+ * Read the specified system property, using an AccessController so that
+ * the property can be read if JCL has been granted the appropriate
+ * security rights even if the calling code has not.
+ * <p>
+ * Take care not to expose the value returned by this method to the
+ * calling application in any way; otherwise the calling app can use that
+ * info to access data that should not be available to it.
+ */
+ private static String getSystemProperty(final String key, final String def)
+ throws SecurityException {
+ return (String) AccessController.doPrivileged(
+ new PrivilegedAction() {
+ public Object run() {
+ return System.getProperty(key, def);
+ }
+ });
+ }
+
+ /**
+ * Determines whether the user wants internal diagnostic output. If so,
+ * returns an appropriate writer object. Users can enable diagnostic
+ * output by setting the system property named {@link #DIAGNOSTICS_DEST_PROPERTY} to
+ * a filename, or the special values STDOUT or STDERR.
+ */
+ private static void initDiagnostics() {
+ String dest;
+ try {
+ dest = getSystemProperty(DIAGNOSTICS_DEST_PROPERTY, null);
+ if (dest == null) {
+ return;
+ }
+ } catch(SecurityException ex) {
+ // We must be running in some very secure environment.
+ // We just have to assume output is not wanted..
+ return;
+ }
+
+ if (dest.equals("STDOUT")) {
+ diagnosticsStream = System.out;
+ } else if (dest.equals("STDERR")) {
+ diagnosticsStream = System.err;
+ } else {
+ try {
+ // open the file in append mode
+ FileOutputStream fos = new FileOutputStream(dest, true);
+ diagnosticsStream = new PrintStream(fos);
+ } catch(IOException ex) {
+ // We should report this to the user - but how?
+ return;
+ }
+ }
+
+ // In order to avoid confusion where multiple instances of JCL are
+ // being used via different classloaders within the same app, we
+ // ensure each logged message has a prefix of form
+ // [LogFactory from classloader OID]
+ //
+ // Note that this prefix should be kept consistent with that
+ // in LogFactoryImpl. However here we don't need to output info
+ // about the actual *instance* of LogFactory, as all methods that
+ // output diagnostics from this class are static.
+ String classLoaderName;
+ try {
+ ClassLoader classLoader = thisClassLoader;
+ if (thisClassLoader == null) {
+ classLoaderName = "BOOTLOADER";
+ } else {
+ classLoaderName = objectId(classLoader);
+ }
+ } catch(SecurityException e) {
+ classLoaderName = "UNKNOWN";
+ }
+ diagnosticPrefix = "[LogFactory from " + classLoaderName + "] ";
+ }
+
+ /**
+ * Indicates true if the user has enabled internal logging.
+ * <p>
+ * By the way, sorry for the incorrect grammar, but calling this method
+ * areDiagnosticsEnabled just isn't java beans style.
+ *
+ * @return true if calls to logDiagnostic will have any effect.
+ * @since 1.1
+ */
+ protected static boolean isDiagnosticsEnabled() {
+ return diagnosticsStream != null;
+ }
+
+ /**
+ * Write the specified message to the internal logging destination.
+ * <p>
+ * Note that this method is private; concrete subclasses of this class
+ * should not call it because the diagnosticPrefix string this
+ * method puts in front of all its messages is LogFactory at ....,
+ * while subclasses should put SomeSubClass at ...
+ * <p>
+ * Subclasses should instead compute their own prefix, then call
+ * logRawDiagnostic. Note that calling isDiagnosticsEnabled is
+ * fine for subclasses.
+ * <p>
+ * Note that it is safe to call this method before initDiagnostics
+ * is called; any output will just be ignored (as isDiagnosticsEnabled
+ * will return false).
+ *
+ * @param msg is the diagnostic message to be output.
+ */
+ private static final void logDiagnostic(String msg) {
+ if (diagnosticsStream != null) {
+ diagnosticsStream.print(diagnosticPrefix);
+ diagnosticsStream.println(msg);
+ diagnosticsStream.flush();
+ }
+ }
+
+ /**
+ * Write the specified message to the internal logging destination.
+ *
+ * @param msg is the diagnostic message to be output.
+ * @since 1.1
+ */
+ protected static final void logRawDiagnostic(String msg) {
+ if (diagnosticsStream != null) {
+ diagnosticsStream.println(msg);
+ diagnosticsStream.flush();
+ }
+ }
+
+ /**
+ * Generate useful diagnostics regarding the classloader tree for
+ * the specified class.
+ * <p>
+ * As an example, if the specified class was loaded via a webapp's
+ * classloader, then you may get the following output:
+ * <pre>
+ * Class com.acme.Foo was loaded via classloader 11111
+ * ClassLoader tree: 11111 -> 22222 (SYSTEM) -> 33333 -> BOOT
+ * </pre>
+ * <p>
+ * This method returns immediately if isDiagnosticsEnabled()
+ * returns false.
+ *
+ * @param clazz is the class whose classloader + tree are to be
+ * output.
+ */
+ private static void logClassLoaderEnvironment(Class clazz) {
+ if (!isDiagnosticsEnabled()) {
+ return;
+ }
+
+ try {
+ // Deliberately use System.getProperty here instead of getSystemProperty; if
+ // the overall security policy for the calling application forbids access to
+ // these variables then we do not want to output them to the diagnostic stream.
+ logDiagnostic("[ENV] Extension directories (java.ext.dir): " + System.getProperty("java.ext.dir"));
+ logDiagnostic("[ENV] Application classpath (java.class.path): " + System.getProperty("java.class.path"));
+ } catch(SecurityException ex) {
+ logDiagnostic("[ENV] Security setting prevent interrogation of system classpaths.");
+ }
+
+ String className = clazz.getName();
+ ClassLoader classLoader;
+
+ try {
+ classLoader = getClassLoader(clazz);
+ } catch(SecurityException ex) {
+ // not much useful diagnostics we can print here!
+ logDiagnostic(
+ "[ENV] Security forbids determining the classloader for " + className);
+ return;
+ }
+
+ logDiagnostic(
+ "[ENV] Class " + className + " was loaded via classloader "
+ + objectId(classLoader));
+ logHierarchy("[ENV] Ancestry of classloader which loaded " + className + " is ", classLoader);
+ }
+
+ /**
+ * Logs diagnostic messages about the given classloader
+ * and it's hierarchy. The prefix is prepended to the message
+ * and is intended to make it easier to understand the logs.
+ * @param prefix
+ * @param classLoader
+ */
+ private static void logHierarchy(String prefix, ClassLoader classLoader) {
+ if (!isDiagnosticsEnabled()) {
+ return;
+ }
+ ClassLoader systemClassLoader;
+ if (classLoader != null) {
+ final String classLoaderString = classLoader.toString();
+ logDiagnostic(prefix + objectId(classLoader) + " == '" + classLoaderString + "'");
+ }
+
+ try {
+ systemClassLoader = ClassLoader.getSystemClassLoader();
+ } catch(SecurityException ex) {
+ logDiagnostic(
+ prefix + "Security forbids determining the system classloader.");
+ return;
+ }
+ if (classLoader != null) {
+ StringBuffer buf = new StringBuffer(prefix + "ClassLoader tree:");
+ for(;;) {
+ buf.append(objectId(classLoader));
+ if (classLoader == systemClassLoader) {
+ buf.append(" (SYSTEM) ");
+ }
+
+ try {
+ classLoader = classLoader.getParent();
+ } catch(SecurityException ex) {
+ buf.append(" --> SECRET");
+ break;
+ }
+
+ buf.append(" --> ");
+ if (classLoader == null) {
+ buf.append("BOOT");
+ break;
+ }
+ }
+ logDiagnostic(buf.toString());
+ }
+ }
+
+ /**
+ * Returns a string that uniquely identifies the specified object, including
+ * its class.
+ * <p>
+ * The returned string is of form "classname at hashcode", ie is the same as
+ * the return value of the Object.toString() method, but works even when
+ * the specified object's class has overidden the toString method.
+ *
+ * @param o may be null.
+ * @return a string of form classname at hashcode, or "null" if param o is null.
+ * @since 1.1
+ */
+ public static String objectId(Object o) {
+ if (o == null) {
+ return "null";
+ } else {
+ return o.getClass().getName() + "@" + System.identityHashCode(o);
+ }
+ }
+
+ // ----------------------------------------------------------------------
+ // Static initialiser block to perform initialisation at class load time.
+ //
+ // We can't do this in the class constructor, as there are many
+ // static methods on this class that can be called before any
+ // LogFactory instances are created, and they depend upon this
+ // stuff having been set up.
+ //
+ // Note that this block must come after any variable declarations used
+ // by any methods called from this block, as we want any static initialiser
+ // associated with the variable to run first. If static initialisers for
+ // variables run after this code, then (a) their value might be needed
+ // by methods called from here, and (b) they might *override* any value
+ // computed here!
+ //
+ // So the wisest thing to do is just to place this code at the very end
+ // of the class file.
+ // ----------------------------------------------------------------------
+
+ static {
+ // note: it's safe to call methods before initDiagnostics (though
+ // diagnostic output gets discarded).
+ thisClassLoader = getClassLoader(LogFactory.class);
+ initDiagnostics();
+ logClassLoaderEnvironment(LogFactory.class);
+ factories = createFactoryStore();
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("BOOTSTRAP COMPLETED");
+ }
+ }
+}
Added: projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/impl/Log4JLogger.java
===================================================================
--- projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/impl/Log4JLogger.java (rev 0)
+++ projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/impl/Log4JLogger.java 2009-10-07 14:51:13 UTC (rev 94463)
@@ -0,0 +1,343 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package org.apache.commons.logging.impl;
+
+import java.io.Serializable;
+import org.apache.commons.logging.Log;
+import org.apache.log4j.Logger;
+import org.apache.log4j.Priority;
+import org.apache.log4j.Level;
+
+/**
+ * Implementation of {@link Log} that maps directly to a
+ * <strong>Logger</strong> for log4J version 1.2.
+ * <p>
+ * Initial configuration of the corresponding Logger instances should be done
+ * in the usual manner, as outlined in the Log4J documentation.
+ * <p>
+ * The reason this logger is distinct from the 1.3 logger is that in version 1.2
+ * of Log4J:
+ * <ul>
+ * <li>class Logger takes Priority parameters not Level parameters.
+ * <li>class Level extends Priority
+ * </ul>
+ * Log4J1.3 is expected to change Level so it no longer extends Priority, which is
+ * a non-binary-compatible change. The class generated by compiling this code against
+ * log4j 1.2 will therefore not run against log4j 1.3.
+ *
+ * @author <a href="mailto:sanders at apache.org">Scott Sanders</a>
+ * @author Rod Waldhoff
+ * @author Robert Burrell Donkin
+ * @version $Id: Log4JLogger.java 479747 2006-11-27 20:15:01Z dennisl $
+ */
+
+ at SuppressWarnings("deprecation")
+public class Log4JLogger implements Log, Serializable {
+
+ // ------------------------------------------------------------- Attributes
+
+ /** The fully qualified name of the Log4JLogger class. */
+ private static final String FQCN = Log4JLogger.class.getName();
+
+ /** Log to this logger */
+ private transient Logger logger = null;
+
+ /** Logger name */
+ private String name = null;
+
+ private static Priority traceLevel;
+
+ // ------------------------------------------------------------
+ // Static Initializer.
+ //
+ // Note that this must come after the static variable declarations
+ // otherwise initialiser expressions associated with those variables
+ // will override any settings done here.
+ //
+ // Verify that log4j is available, and that it is version 1.2.
+ // If an ExceptionInInitializerError is generated, then LogFactoryImpl
+ // will treat that as meaning that the appropriate underlying logging
+ // library is just not present - if discovery is in progress then
+ // discovery will continue.
+ // ------------------------------------------------------------
+
+ static {
+ if (!Priority.class.isAssignableFrom(Level.class)) {
+ // nope, this is log4j 1.3, so force an ExceptionInInitializerError
+ throw new InstantiationError("Log4J 1.2 not available");
+ }
+
+ // Releases of log4j1.2 >= 1.2.12 have Priority.TRACE available, earlier
+ // versions do not. If TRACE is not available, then we have to map
+ // calls to Log.trace(...) onto the DEBUG level.
+
+ try {
+ traceLevel = (Priority) Level.class.getDeclaredField("TRACE").get(null);
+ } catch(Exception ex) {
+ // ok, trace not available
+ traceLevel = Priority.DEBUG;
+ }
+ }
+
+
+ // ------------------------------------------------------------ Constructor
+
+ public Log4JLogger() {
+ }
+
+
+ /**
+ * Base constructor.
+ */
+ public Log4JLogger(String name) {
+ this.name = name;
+ this.logger = getLogger();
+ }
+
+ /**
+ * For use with a log4j factory.
+ */
+ public Log4JLogger(Logger logger ) {
+ if (logger == null) {
+ throw new IllegalArgumentException(
+ "Warning - null logger in constructor; possible log4j misconfiguration.");
+ }
+ this.name = logger.getName();
+ this.logger=logger;
+ }
+
+
+ // ---------------------------------------------------------
+ // Implementation
+ //
+ // Note that in the methods below the Priority class is used to define
+ // levels even though the Level class is supported in 1.2. This is done
+ // so that at compile time the call definitely resolves to a call to
+ // a method that takes a Priority rather than one that takes a Level.
+ //
+ // The Category class (and hence its subclass Logger) in version 1.2 only
+ // has methods that take Priority objects. The Category class (and hence
+ // Logger class) in version 1.3 has methods that take both Priority and
+ // Level objects. This means that if we use Level here, and compile
+ // against log4j 1.3 then calls would be bound to the versions of
+ // methods taking Level objects and then would fail to run against
+ // version 1.2 of log4j.
+ // ---------------------------------------------------------
+
+
+ /**
+ * Logs a message with <code>org.apache.log4j.Priority.TRACE</code>.
+ * When using a log4j version that does not support the <code>TRACE</code>
+ * level, the message will be logged at the <code>DEBUG</code> level.
+ *
+ * @param message to log
+ * @see org.apache.commons.logging.Log#trace(Object)
+ */
+ public void trace(Object message) {
+ getLogger().log(FQCN, traceLevel, message, null );
+ }
+
+
+ /**
+ * Logs a message with <code>org.apache.log4j.Priority.TRACE</code>.
+ * When using a log4j version that does not support the <code>TRACE</code>
+ * level, the message will be logged at the <code>DEBUG</code> level.
+ *
+ * @param message to log
+ * @param t log this cause
+ * @see org.apache.commons.logging.Log#trace(Object, Throwable)
+ */
+ public void trace(Object message, Throwable t) {
+ getLogger().log(FQCN, traceLevel, message, t );
+ }
+
+
+ /**
+ * Logs a message with <code>org.apache.log4j.Priority.DEBUG</code>.
+ *
+ * @param message to log
+ * @see org.apache.commons.logging.Log#debug(Object)
+ */
+ public void debug(Object message) {
+ getLogger().log(FQCN, Priority.DEBUG, message, null );
+ }
+
+ /**
+ * Logs a message with <code>org.apache.log4j.Priority.DEBUG</code>.
+ *
+ * @param message to log
+ * @param t log this cause
+ * @see org.apache.commons.logging.Log#debug(Object, Throwable)
+ */
+ public void debug(Object message, Throwable t) {
+ getLogger().log(FQCN, Priority.DEBUG, message, t );
+ }
+
+
+ /**
+ * Logs a message with <code>org.apache.log4j.Priority.INFO</code>.
+ *
+ * @param message to log
+ * @see org.apache.commons.logging.Log#info(Object)
+ */
+ public void info(Object message) {
+ getLogger().log(FQCN, Priority.INFO, message, null );
+ }
+
+
+ /**
+ * Logs a message with <code>org.apache.log4j.Priority.INFO</code>.
+ *
+ * @param message to log
+ * @param t log this cause
+ * @see org.apache.commons.logging.Log#info(Object, Throwable)
+ */
+ public void info(Object message, Throwable t) {
+ getLogger().log(FQCN, Priority.INFO, message, t );
+ }
+
+
+ /**
+ * Logs a message with <code>org.apache.log4j.Priority.WARN</code>.
+ *
+ * @param message to log
+ * @see org.apache.commons.logging.Log#warn(Object)
+ */
+ public void warn(Object message) {
+ getLogger().log(FQCN, Priority.WARN, message, null );
+ }
+
+
+ /**
+ * Logs a message with <code>org.apache.log4j.Priority.WARN</code>.
+ *
+ * @param message to log
+ * @param t log this cause
+ * @see org.apache.commons.logging.Log#warn(Object, Throwable)
+ */
+ public void warn(Object message, Throwable t) {
+ getLogger().log(FQCN, Priority.WARN, message, t );
+ }
+
+
+ /**
+ * Logs a message with <code>org.apache.log4j.Priority.ERROR</code>.
+ *
+ * @param message to log
+ * @see org.apache.commons.logging.Log#error(Object)
+ */
+ public void error(Object message) {
+ getLogger().log(FQCN, Priority.ERROR, message, null );
+ }
+
+
+ /**
+ * Logs a message with <code>org.apache.log4j.Priority.ERROR</code>.
+ *
+ * @param message to log
+ * @param t log this cause
+ * @see org.apache.commons.logging.Log#error(Object, Throwable)
+ */
+ public void error(Object message, Throwable t) {
+ getLogger().log(FQCN, Priority.ERROR, message, t );
+ }
+
+
+ /**
+ * Logs a message with <code>org.apache.log4j.Priority.FATAL</code>.
+ *
+ * @param message to log
+ * @see org.apache.commons.logging.Log#fatal(Object)
+ */
+ public void fatal(Object message) {
+ getLogger().log(FQCN, Priority.FATAL, message, null );
+ }
+
+
+ /**
+ * Logs a message with <code>org.apache.log4j.Priority.FATAL</code>.
+ *
+ * @param message to log
+ * @param t log this cause
+ * @see org.apache.commons.logging.Log#fatal(Object, Throwable)
+ */
+ public void fatal(Object message, Throwable t) {
+ getLogger().log(FQCN, Priority.FATAL, message, t );
+ }
+
+
+ /**
+ * Return the native Logger instance we are using.
+ */
+ public Logger getLogger() {
+ if (logger == null) {
+ logger = Logger.getLogger(name);
+ }
+ return (this.logger);
+ }
+
+
+ /**
+ * Check whether the Log4j Logger used is enabled for <code>DEBUG</code> priority.
+ */
+ public boolean isDebugEnabled() {
+ return getLogger().isDebugEnabled();
+ }
+
+
+ /**
+ * Check whether the Log4j Logger used is enabled for <code>ERROR</code> priority.
+ */
+ public boolean isErrorEnabled() {
+ return getLogger().isEnabledFor(Priority.ERROR);
+ }
+
+
+ /**
+ * Check whether the Log4j Logger used is enabled for <code>FATAL</code> priority.
+ */
+ public boolean isFatalEnabled() {
+ return getLogger().isEnabledFor(Priority.FATAL);
+ }
+
+
+ /**
+ * Check whether the Log4j Logger used is enabled for <code>INFO</code> priority.
+ */
+ public boolean isInfoEnabled() {
+ return getLogger().isInfoEnabled();
+ }
+
+
+ /**
+ * Check whether the Log4j Logger used is enabled for <code>TRACE</code> priority.
+ * When using a log4j version that does not support the TRACE level, this call
+ * will report whether <code>DEBUG</code> is enabled or not.
+ */
+ public boolean isTraceEnabled() {
+ return getLogger().isEnabledFor(traceLevel);
+ }
+
+ /**
+ * Check whether the Log4j Logger used is enabled for <code>WARN</code> priority.
+ */
+ public boolean isWarnEnabled() {
+ return getLogger().isEnabledFor(Priority.WARN);
+ }
+}
Added: projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/impl/LogFactoryImpl.java
===================================================================
--- projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/impl/LogFactoryImpl.java (rev 0)
+++ projects/jboss-osgi/projects/bundles/common/trunk/src/main/java/org/apache/commons/logging/impl/LogFactoryImpl.java 2009-10-07 14:51:13 UTC (rev 94463)
@@ -0,0 +1,1500 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.logging.impl;
+
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.net.URL;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.Enumeration;
+import java.util.Hashtable;
+import java.util.Vector;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogConfigurationException;
+import org.apache.commons.logging.LogFactory;
+
+
+/**
+ * <p>Concrete subclass of {@link LogFactory} that implements the
+ * following algorithm to dynamically select a logging implementation
+ * class to instantiate a wrapper for.</p>
+ * <ul>
+ * <li>Use a factory configuration attribute named
+ * <code>org.apache.commons.logging.Log</code> to identify the
+ * requested implementation class.</li>
+ * <li>Use the <code>org.apache.commons.logging.Log</code> system property
+ * to identify the requested implementation class.</li>
+ * <li>If <em>Log4J</em> is available, return an instance of
+ * <code>org.apache.commons.logging.impl.Log4JLogger</code>.</li>
+ * <li>If <em>JDK 1.4 or later</em> is available, return an instance of
+ * <code>org.apache.commons.logging.impl.Jdk14Logger</code>.</li>
+ * <li>Otherwise, return an instance of
+ * <code>org.apache.commons.logging.impl.SimpleLog</code>.</li>
+ * </ul>
+ *
+ * <p>If the selected {@link Log} implementation class has a
+ * <code>setLogFactory()</code> method that accepts a {@link LogFactory}
+ * parameter, this method will be called on each newly created instance
+ * to identify the associated factory. This makes factory configuration
+ * attributes available to the Log instance, if it so desires.</p>
+ *
+ * <p>This factory will remember previously created <code>Log</code> instances
+ * for the same name, and will return them on repeated requests to the
+ * <code>getInstance()</code> method.</p>
+ *
+ * @author Rod Waldhoff
+ * @author Craig R. McClanahan
+ * @author Richard A. Sitze
+ * @author Brian Stansberry
+ * @version $Revision: 581090 $ $Date: 2007-10-02 00:01:06 +0200 (ti, 02 okt 2007) $
+ */
+
+public class LogFactoryImpl extends LogFactory {
+
+
+ /** Log4JLogger class name */
+ private static final String LOGGING_IMPL_LOG4J_LOGGER = "org.apache.commons.logging.impl.Log4JLogger";
+ /** Jdk14Logger class name */
+ private static final String LOGGING_IMPL_JDK14_LOGGER = "org.apache.commons.logging.impl.Jdk14Logger";
+ /** Jdk13LumberjackLogger class name */
+ private static final String LOGGING_IMPL_LUMBERJACK_LOGGER = "org.apache.commons.logging.impl.Jdk13LumberjackLogger";
+ /** SimpleLog class name */
+ private static final String LOGGING_IMPL_SIMPLE_LOGGER = "org.apache.commons.logging.impl.SimpleLog";
+
+ private static final String PKG_IMPL="org.apache.commons.logging.impl.";
+ private static final int PKG_LEN = PKG_IMPL.length();
+
+ // ----------------------------------------------------------- Constructors
+
+
+
+ /**
+ * Public no-arguments constructor required by the lookup mechanism.
+ */
+ public LogFactoryImpl() {
+ super();
+ initDiagnostics(); // method on this object
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Instance created.");
+ }
+ }
+
+
+ // ----------------------------------------------------- Manifest Constants
+
+
+ /**
+ * The name (<code>org.apache.commons.logging.Log</code>) of the system
+ * property identifying our {@link Log} implementation class.
+ */
+ public static final String LOG_PROPERTY =
+ "org.apache.commons.logging.Log";
+
+
+ /**
+ * The deprecated system property used for backwards compatibility with
+ * old versions of JCL.
+ */
+ protected static final String LOG_PROPERTY_OLD =
+ "org.apache.commons.logging.log";
+
+ /**
+ * The name (<code>org.apache.commons.logging.Log.allowFlawedContext</code>)
+ * of the system property which can be set true/false to
+ * determine system behaviour when a bad context-classloader is encountered.
+ * When set to false, a LogConfigurationException is thrown if
+ * LogFactoryImpl is loaded via a child classloader of the TCCL (this
+ * should never happen in sane systems).
+ *
+ * Default behaviour: true (tolerates bad context classloaders)
+ *
+ * See also method setAttribute.
+ */
+ public static final String ALLOW_FLAWED_CONTEXT_PROPERTY =
+ "org.apache.commons.logging.Log.allowFlawedContext";
+
+ /**
+ * The name (<code>org.apache.commons.logging.Log.allowFlawedDiscovery</code>)
+ * of the system property which can be set true/false to
+ * determine system behaviour when a bad logging adapter class is
+ * encountered during logging discovery. When set to false, an
+ * exception will be thrown and the app will fail to start. When set
+ * to true, discovery will continue (though the user might end up
+ * with a different logging implementation than they expected).
+ *
+ * Default behaviour: true (tolerates bad logging adapters)
+ *
+ * See also method setAttribute.
+ */
+ public static final String ALLOW_FLAWED_DISCOVERY_PROPERTY =
+ "org.apache.commons.logging.Log.allowFlawedDiscovery";
+
+ /**
+ * The name (<code>org.apache.commons.logging.Log.allowFlawedHierarchy</code>)
+ * of the system property which can be set true/false to
+ * determine system behaviour when a logging adapter class is
+ * encountered which has bound to the wrong Log class implementation.
+ * When set to false, an exception will be thrown and the app will fail
+ * to start. When set to true, discovery will continue (though the user
+ * might end up with a different logging implementation than they expected).
+ *
+ * Default behaviour: true (tolerates bad Log class hierarchy)
+ *
+ * See also method setAttribute.
+ */
+ public static final String ALLOW_FLAWED_HIERARCHY_PROPERTY =
+ "org.apache.commons.logging.Log.allowFlawedHierarchy";
+
+
+ /**
+ * The names of classes that will be tried (in order) as logging
+ * adapters. Each class is expected to implement the Log interface,
+ * and to throw NoClassDefFound or ExceptionInInitializerError when
+ * loaded if the underlying logging library is not available. Any
+ * other error indicates that the underlying logging library is available
+ * but broken/unusable for some reason.
+ */
+ private static final String[] classesToDiscover = {
+ LOGGING_IMPL_LOG4J_LOGGER,
+ "org.apache.commons.logging.impl.Jdk14Logger",
+ "org.apache.commons.logging.impl.Jdk13LumberjackLogger",
+ "org.apache.commons.logging.impl.SimpleLog"
+ };
+
+
+ // ----------------------------------------------------- Instance Variables
+
+ /**
+ * Determines whether logging classes should be loaded using the thread-context
+ * classloader, or via the classloader that loaded this LogFactoryImpl class.
+ */
+ private boolean useTCCL = true;
+
+ /**
+ * The string prefixed to every message output by the logDiagnostic method.
+ */
+ private String diagnosticPrefix;
+
+
+ /**
+ * Configuration attributes.
+ */
+ protected Hashtable attributes = new Hashtable();
+
+
+ /**
+ * The {@link org.apache.commons.logging.Log} instances that have
+ * already been created, keyed by logger name.
+ */
+ protected Hashtable instances = new Hashtable();
+
+
+ /**
+ * Name of the class implementing the Log interface.
+ */
+ private String logClassName;
+
+
+ /**
+ * The one-argument constructor of the
+ * {@link org.apache.commons.logging.Log}
+ * implementation class that will be used to create new instances.
+ * This value is initialized by <code>getLogConstructor()</code>,
+ * and then returned repeatedly.
+ */
+ protected Constructor logConstructor = null;
+
+
+ /**
+ * The signature of the Constructor to be used.
+ */
+ protected Class logConstructorSignature[] =
+ { java.lang.String.class };
+
+
+ /**
+ * The one-argument <code>setLogFactory</code> method of the selected
+ * {@link org.apache.commons.logging.Log} method, if it exists.
+ */
+ protected Method logMethod = null;
+
+
+ /**
+ * The signature of the <code>setLogFactory</code> method to be used.
+ */
+ protected Class logMethodSignature[] =
+ { LogFactory.class };
+
+ /**
+ * See getBaseClassLoader and initConfiguration.
+ */
+ private boolean allowFlawedContext;
+
+ /**
+ * See handleFlawedDiscovery and initConfiguration.
+ */
+ private boolean allowFlawedDiscovery;
+
+ /**
+ * See handleFlawedHierarchy and initConfiguration.
+ */
+ private boolean allowFlawedHierarchy;
+
+ // --------------------------------------------------------- Public Methods
+
+
+ /**
+ * Return the configuration attribute with the specified name (if any),
+ * or <code>null</code> if there is no such attribute.
+ *
+ * @param name Name of the attribute to return
+ */
+ public Object getAttribute(String name) {
+
+ return (attributes.get(name));
+
+ }
+
+
+ /**
+ * Return an array containing the names of all currently defined
+ * configuration attributes. If there are no such attributes, a zero
+ * length array is returned.
+ */
+ public String[] getAttributeNames() {
+
+ Vector names = new Vector();
+ Enumeration keys = attributes.keys();
+ while (keys.hasMoreElements()) {
+ names.addElement((String) keys.nextElement());
+ }
+ String results[] = new String[names.size()];
+ for (int i = 0; i < results.length; i++) {
+ results[i] = (String) names.elementAt(i);
+ }
+ return (results);
+
+ }
+
+
+ /**
+ * Convenience method to derive a name from the specified class and
+ * call <code>getInstance(String)</code> with it.
+ *
+ * @param clazz Class for which a suitable Log name will be derived
+ *
+ * @exception LogConfigurationException if a suitable <code>Log</code>
+ * instance cannot be returned
+ */
+ public Log getInstance(Class clazz) throws LogConfigurationException {
+
+ return (getInstance(clazz.getName()));
+
+ }
+
+
+ /**
+ * <p>Construct (if necessary) and return a <code>Log</code> instance,
+ * using the factory's current set of configuration attributes.</p>
+ *
+ * <p><strong>NOTE</strong> - Depending upon the implementation of
+ * the <code>LogFactory</code> you are using, the <code>Log</code>
+ * instance you are returned may or may not be local to the current
+ * application, and may or may not be returned again on a subsequent
+ * call with the same name argument.</p>
+ *
+ * @param name Logical name of the <code>Log</code> instance to be
+ * returned (the meaning of this name is only known to the underlying
+ * logging implementation that is being wrapped)
+ *
+ * @exception LogConfigurationException if a suitable <code>Log</code>
+ * instance cannot be returned
+ */
+ public Log getInstance(String name) throws LogConfigurationException {
+
+ Log instance = (Log) instances.get(name);
+ if (instance == null) {
+ instance = newInstance(name);
+ instances.put(name, instance);
+ }
+ return (instance);
+
+ }
+
+
+ /**
+ * Release any internal references to previously created
+ * {@link org.apache.commons.logging.Log}
+ * instances returned by this factory. This is useful in environments
+ * like servlet containers, which implement application reloading by
+ * throwing away a ClassLoader. Dangling references to objects in that
+ * class loader would prevent garbage collection.
+ */
+ public void release() {
+
+ logDiagnostic("Releasing all known loggers");
+ instances.clear();
+ }
+
+
+ /**
+ * Remove any configuration attribute associated with the specified name.
+ * If there is no such attribute, no action is taken.
+ *
+ * @param name Name of the attribute to remove
+ */
+ public void removeAttribute(String name) {
+
+ attributes.remove(name);
+
+ }
+
+
+ /**
+ * Set the configuration attribute with the specified name. Calling
+ * this with a <code>null</code> value is equivalent to calling
+ * <code>removeAttribute(name)</code>.
+ * <p>
+ * This method can be used to set logging configuration programmatically
+ * rather than via system properties. It can also be used in code running
+ * within a container (such as a webapp) to configure behaviour on a
+ * per-component level instead of globally as system properties would do.
+ * To use this method instead of a system property, call
+ * <pre>
+ * LogFactory.getFactory().setAttribute(...)
+ * </pre>
+ * This must be done before the first Log object is created; configuration
+ * changes after that point will be ignored.
+ * <p>
+ * This method is also called automatically if LogFactory detects a
+ * commons-logging.properties file; every entry in that file is set
+ * automatically as an attribute here.
+ *
+ * @param name Name of the attribute to set
+ * @param value Value of the attribute to set, or <code>null</code>
+ * to remove any setting for this attribute
+ */
+ public void setAttribute(String name, Object value) {
+
+ if (logConstructor != null) {
+ logDiagnostic("setAttribute: call too late; configuration already performed.");
+ }
+
+ if (value == null) {
+ attributes.remove(name);
+ } else {
+ attributes.put(name, value);
+ }
+
+ if (name.equals(TCCL_KEY)) {
+ useTCCL = Boolean.valueOf(value.toString()).booleanValue();
+ }
+
+ }
+
+
+ // ------------------------------------------------------
+ // Static Methods
+ //
+ // These methods only defined as workarounds for a java 1.2 bug;
+ // theoretically none of these are needed.
+ // ------------------------------------------------------
+
+ /**
+ * Gets the context classloader.
+ * This method is a workaround for a java 1.2 compiler bug.
+ * @since 1.1
+ */
+ protected static ClassLoader getContextClassLoader() throws LogConfigurationException {
+ return LogFactory.getContextClassLoader();
+ }
+
+
+ /**
+ * Workaround for bug in Java1.2; in theory this method is not needed.
+ * See LogFactory.isDiagnosticsEnabled.
+ */
+ protected static boolean isDiagnosticsEnabled() {
+ return LogFactory.isDiagnosticsEnabled();
+ }
+
+
+ /**
+ * Workaround for bug in Java1.2; in theory this method is not needed.
+ * See LogFactory.getClassLoader.
+ * @since 1.1
+ */
+ protected static ClassLoader getClassLoader(Class clazz) {
+ return LogFactory.getClassLoader(clazz);
+ }
+
+
+ // ------------------------------------------------------ Protected Methods
+
+ /**
+ * Calculate and cache a string that uniquely identifies this instance,
+ * including which classloader the object was loaded from.
+ * <p>
+ * This string will later be prefixed to each "internal logging" message
+ * emitted, so that users can clearly see any unexpected behaviour.
+ * <p>
+ * Note that this method does not detect whether internal logging is
+ * enabled or not, nor where to output stuff if it is; that is all
+ * handled by the parent LogFactory class. This method just computes
+ * its own unique prefix for log messages.
+ */
+ private void initDiagnostics() {
+ // It would be nice to include an identifier of the context classloader
+ // that this LogFactoryImpl object is responsible for. However that
+ // isn't possible as that information isn't available. It is possible
+ // to figure this out by looking at the logging from LogFactory to
+ // see the context & impl ids from when this object was instantiated,
+ // in order to link the impl id output as this object's prefix back to
+ // the context it is intended to manage.
+ // Note that this prefix should be kept consistent with that
+ // in LogFactory.
+ Class clazz = this.getClass();
+ ClassLoader classLoader = getClassLoader(clazz);
+ String classLoaderName;
+ try {
+ if (classLoader == null) {
+ classLoaderName = "BOOTLOADER";
+ } else {
+ classLoaderName = objectId(classLoader);
+ }
+ } catch(SecurityException e) {
+ classLoaderName = "UNKNOWN";
+ }
+ diagnosticPrefix = "[LogFactoryImpl@" + System.identityHashCode(this) + " from " + classLoaderName + "] ";
+ }
+
+
+ /**
+ * Output a diagnostic message to a user-specified destination (if the
+ * user has enabled diagnostic logging).
+ *
+ * @param msg diagnostic message
+ * @since 1.1
+ */
+ protected void logDiagnostic(String msg) {
+ if (isDiagnosticsEnabled()) {
+ logRawDiagnostic(diagnosticPrefix + msg);
+ }
+ }
+
+ /**
+ * Return the fully qualified Java classname of the {@link Log}
+ * implementation we will be using.
+ *
+ * @deprecated Never invoked by this class; subclasses should not assume
+ * it will be.
+ */
+ protected String getLogClassName() {
+
+ if (logClassName == null) {
+ discoverLogImplementation(getClass().getName());
+ }
+
+ return logClassName;
+ }
+
+
+ /**
+ * <p>Return the <code>Constructor</code> that can be called to instantiate
+ * new {@link org.apache.commons.logging.Log} instances.</p>
+ *
+ * <p><strong>IMPLEMENTATION NOTE</strong> - Race conditions caused by
+ * calling this method from more than one thread are ignored, because
+ * the same <code>Constructor</code> instance will ultimately be derived
+ * in all circumstances.</p>
+ *
+ * @exception LogConfigurationException if a suitable constructor
+ * cannot be returned
+ *
+ * @deprecated Never invoked by this class; subclasses should not assume
+ * it will be.
+ */
+ protected Constructor getLogConstructor()
+ throws LogConfigurationException {
+
+ // Return the previously identified Constructor (if any)
+ if (logConstructor == null) {
+ discoverLogImplementation(getClass().getName());
+ }
+
+ return logConstructor;
+ }
+
+
+ /**
+ * Is <em>JDK 1.3 with Lumberjack</em> logging available?
+ *
+ * @deprecated Never invoked by this class; subclasses should not assume
+ * it will be.
+ */
+ protected boolean isJdk13LumberjackAvailable() {
+ return isLogLibraryAvailable(
+ "Jdk13Lumberjack",
+ "org.apache.commons.logging.impl.Jdk13LumberjackLogger");
+ }
+
+
+ /**
+ * <p>Return <code>true</code> if <em>JDK 1.4 or later</em> logging
+ * is available. Also checks that the <code>Throwable</code> class
+ * supports <code>getStackTrace()</code>, which is required by
+ * Jdk14Logger.</p>
+ *
+ * @deprecated Never invoked by this class; subclasses should not assume
+ * it will be.
+ */
+ protected boolean isJdk14Available() {
+ return isLogLibraryAvailable(
+ "Jdk14",
+ "org.apache.commons.logging.impl.Jdk14Logger");
+ }
+
+
+ /**
+ * Is a <em>Log4J</em> implementation available?
+ *
+ * @deprecated Never invoked by this class; subclasses should not assume
+ * it will be.
+ */
+ protected boolean isLog4JAvailable() {
+ return isLogLibraryAvailable(
+ "Log4J",
+ LOGGING_IMPL_LOG4J_LOGGER);
+ }
+
+
+ /**
+ * Create and return a new {@link org.apache.commons.logging.Log}
+ * instance for the specified name.
+ *
+ * @param name Name of the new logger
+ *
+ * @exception LogConfigurationException if a new instance cannot
+ * be created
+ */
+ protected Log newInstance(String name) throws LogConfigurationException {
+
+ Log instance = null;
+ try {
+ if (logConstructor == null) {
+ instance = discoverLogImplementation(name);
+ }
+ else {
+ Object params[] = { name };
+ instance = (Log) logConstructor.newInstance(params);
+ }
+
+ if (logMethod != null) {
+ Object params[] = { this };
+ logMethod.invoke(instance, params);
+ }
+
+ return (instance);
+
+ } catch (LogConfigurationException lce) {
+
+ // this type of exception means there was a problem in discovery
+ // and we've already output diagnostics about the issue, etc.;
+ // just pass it on
+ throw (LogConfigurationException) lce;
+
+ } catch (InvocationTargetException e) {
+ // A problem occurred invoking the Constructor or Method
+ // previously discovered
+ Throwable c = e.getTargetException();
+ if (c != null) {
+ throw new LogConfigurationException(c);
+ } else {
+ throw new LogConfigurationException(e);
+ }
+ } catch (Throwable t) {
+ // A problem occurred invoking the Constructor or Method
+ // previously discovered
+ throw new LogConfigurationException(t);
+ }
+ }
+
+
+ // ------------------------------------------------------ Private Methods
+
+ /**
+ * Calls LogFactory.directGetContextClassLoader under the control of an
+ * AccessController class. This means that java code running under a
+ * security manager that forbids access to ClassLoaders will still work
+ * if this class is given appropriate privileges, even when the caller
+ * doesn't have such privileges. Without using an AccessController, the
+ * the entire call stack must have the privilege before the call is
+ * allowed.
+ *
+ * @return the context classloader associated with the current thread,
+ * or null if security doesn't allow it.
+ *
+ * @throws LogConfigurationException if there was some weird error while
+ * attempting to get the context classloader.
+ *
+ * @throws SecurityException if the current java security policy doesn't
+ * allow this class to access the context classloader.
+ */
+ private static ClassLoader getContextClassLoaderInternal()
+ throws LogConfigurationException {
+ return (ClassLoader)AccessController.doPrivileged(
+ new PrivilegedAction() {
+ public Object run() {
+ return LogFactory.directGetContextClassLoader();
+ }
+ });
+ }
+
+ /**
+ * Read the specified system property, using an AccessController so that
+ * the property can be read if JCL has been granted the appropriate
+ * security rights even if the calling code has not.
+ * <p>
+ * Take care not to expose the value returned by this method to the
+ * calling application in any way; otherwise the calling app can use that
+ * info to access data that should not be available to it.
+ */
+ private static String getSystemProperty(final String key, final String def)
+ throws SecurityException {
+ return (String) AccessController.doPrivileged(
+ new PrivilegedAction() {
+ public Object run() {
+ return System.getProperty(key, def);
+ }
+ });
+ }
+
+ /**
+ * Fetch the parent classloader of a specified classloader.
+ * <p>
+ * If a SecurityException occurs, null is returned.
+ * <p>
+ * Note that this method is non-static merely so logDiagnostic is available.
+ */
+ private ClassLoader getParentClassLoader(final ClassLoader cl) {
+ try {
+ return (ClassLoader)AccessController.doPrivileged(
+ new PrivilegedAction() {
+ public Object run() {
+ return cl.getParent();
+ }
+ });
+ } catch(SecurityException ex) {
+ logDiagnostic("[SECURITY] Unable to obtain parent classloader");
+ return null;
+ }
+
+ }
+
+ /**
+ * Utility method to check whether a particular logging library is
+ * present and available for use. Note that this does <i>not</i>
+ * affect the future behaviour of this class.
+ */
+ private boolean isLogLibraryAvailable(String name, String classname) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Checking for '" + name + "'.");
+ }
+ try {
+ Log log = createLogFromClass(
+ classname,
+ this.getClass().getName(), // dummy category
+ false);
+
+ if (log == null) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Did not find '" + name + "'.");
+ }
+ return false;
+ } else {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Found '" + name + "'.");
+ }
+ return true;
+ }
+ } catch(LogConfigurationException e) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Logging system '" + name + "' is available but not useable.");
+ }
+ return false;
+ }
+ }
+
+ /**
+ * Attempt to find an attribute (see method setAttribute) or a
+ * system property with the provided name and return its value.
+ * <p>
+ * The attributes associated with this object are checked before
+ * system properties in case someone has explicitly called setAttribute,
+ * or a configuration property has been set in a commons-logging.properties
+ * file.
+ *
+ * @return the value associated with the property, or null.
+ */
+ private String getConfigurationValue(String property) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("[ENV] Trying to get configuration for item " + property);
+ }
+
+ Object valueObj = getAttribute(property);
+ if (valueObj != null) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("[ENV] Found LogFactory attribute [" + valueObj + "] for " + property);
+ }
+ return valueObj.toString();
+ }
+
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("[ENV] No LogFactory attribute found for " + property);
+ }
+
+ try {
+ // warning: minor security hole here, in that we potentially read a system
+ // property that the caller cannot, then output it in readable form as a
+ // diagnostic message. However it's only ever JCL-specific properties
+ // involved here, so the harm is truly trivial.
+ String value = getSystemProperty(property, null);
+ if (value != null) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("[ENV] Found system property [" + value + "] for " + property);
+ }
+ return value;
+ }
+
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("[ENV] No system property found for property " + property);
+ }
+ } catch (SecurityException e) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("[ENV] Security prevented reading system property " + property);
+ }
+ }
+
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("[ENV] No configuration defined for item " + property);
+ }
+
+ return null;
+ }
+
+ /**
+ * Get the setting for the user-configurable behaviour specified by key.
+ * If nothing has explicitly been set, then return dflt.
+ */
+ private boolean getBooleanConfiguration(String key, boolean dflt) {
+ String val = getConfigurationValue(key);
+ if (val == null)
+ return dflt;
+ return Boolean.valueOf(val).booleanValue();
+ }
+
+ /**
+ * Initialize a number of variables that control the behaviour of this
+ * class and that can be tweaked by the user. This is done when the first
+ * logger is created, not in the constructor of this class, because we
+ * need to give the user a chance to call method setAttribute in order to
+ * configure this object.
+ */
+ private void initConfiguration() {
+ allowFlawedContext = getBooleanConfiguration(ALLOW_FLAWED_CONTEXT_PROPERTY, true);
+ allowFlawedDiscovery = getBooleanConfiguration(ALLOW_FLAWED_DISCOVERY_PROPERTY, true);
+ allowFlawedHierarchy = getBooleanConfiguration(ALLOW_FLAWED_HIERARCHY_PROPERTY, true);
+ }
+
+
+ /**
+ * Attempts to create a Log instance for the given category name.
+ * Follows the discovery process described in the class javadoc.
+ *
+ * @param logCategory the name of the log category
+ *
+ * @throws LogConfigurationException if an error in discovery occurs,
+ * or if no adapter at all can be instantiated
+ */
+ private Log discoverLogImplementation(String logCategory)
+ throws LogConfigurationException
+ {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Discovering a Log implementation...");
+ }
+
+ initConfiguration();
+
+ Log result = null;
+
+ // See if the user specified the Log implementation to use
+ String specifiedLogClassName = findUserSpecifiedLogClassName();
+
+ if (specifiedLogClassName != null) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Attempting to load user-specified log class '" +
+ specifiedLogClassName + "'...");
+ }
+
+ result = createLogFromClass(specifiedLogClassName,
+ logCategory,
+ true);
+ if (result == null) {
+ StringBuffer messageBuffer = new StringBuffer("User-specified log class '");
+ messageBuffer.append(specifiedLogClassName);
+ messageBuffer.append("' cannot be found or is not useable.");
+
+ // Mistyping or misspelling names is a common fault.
+ // Construct a good error message, if we can
+ if (specifiedLogClassName != null) {
+ informUponSimilarName(messageBuffer, specifiedLogClassName, LOGGING_IMPL_LOG4J_LOGGER);
+ informUponSimilarName(messageBuffer, specifiedLogClassName, LOGGING_IMPL_JDK14_LOGGER);
+ informUponSimilarName(messageBuffer, specifiedLogClassName, LOGGING_IMPL_LUMBERJACK_LOGGER);
+ informUponSimilarName(messageBuffer, specifiedLogClassName, LOGGING_IMPL_SIMPLE_LOGGER);
+ }
+ throw new LogConfigurationException(messageBuffer.toString());
+ }
+
+ return result;
+ }
+
+ // No user specified log; try to discover what's on the classpath
+ //
+ // Note that we deliberately loop here over classesToDiscover and
+ // expect method createLogFromClass to loop over the possible source
+ // classloaders. The effect is:
+ // for each discoverable log adapter
+ // for each possible classloader
+ // see if it works
+ //
+ // It appears reasonable at first glance to do the opposite:
+ // for each possible classloader
+ // for each discoverable log adapter
+ // see if it works
+ //
+ // The latter certainly has advantages for user-installable logging
+ // libraries such as log4j; in a webapp for example this code should
+ // first check whether the user has provided any of the possible
+ // logging libraries before looking in the parent classloader.
+ // Unfortunately, however, Jdk14Logger will always work in jvm>=1.4,
+ // and SimpleLog will always work in any JVM. So the loop would never
+ // ever look for logging libraries in the parent classpath. Yet many
+ // users would expect that putting log4j there would cause it to be
+ // detected (and this is the historical JCL behaviour). So we go with
+ // the first approach. A user that has bundled a specific logging lib
+ // in a webapp should use a commons-logging.properties file or a
+ // service file in META-INF to force use of that logging lib anyway,
+ // rather than relying on discovery.
+
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "No user-specified Log implementation; performing discovery" +
+ " using the standard supported logging implementations...");
+ }
+ for(int i=0; (i<classesToDiscover.length) && (result == null); ++i) {
+ result = createLogFromClass(classesToDiscover[i], logCategory, true);
+ }
+
+ if (result == null) {
+ throw new LogConfigurationException
+ ("No suitable Log implementation");
+ }
+
+ return result;
+ }
+
+
+ /**
+ * Appends message if the given name is similar to the candidate.
+ * @param messageBuffer <code>StringBuffer</code> the message should be appended to,
+ * not null
+ * @param name the (trimmed) name to be test against the candidate, not null
+ * @param candidate the candidate name (not null)
+ */
+ private void informUponSimilarName(final StringBuffer messageBuffer, final String name,
+ final String candidate) {
+ if (name.equals(candidate)) {
+ // Don't suggest a name that is exactly the same as the one the
+ // user tried...
+ return;
+ }
+
+ // If the user provides a name that is in the right package, and gets
+ // the first 5 characters of the adapter class right (ignoring case),
+ // then suggest the candidate adapter class name.
+ if (name.regionMatches(true, 0, candidate, 0, PKG_LEN + 5)) {
+ messageBuffer.append(" Did you mean '");
+ messageBuffer.append(candidate);
+ messageBuffer.append("'?");
+ }
+ }
+
+
+ /**
+ * Checks system properties and the attribute map for
+ * a Log implementation specified by the user under the
+ * property names {@link #LOG_PROPERTY} or {@link #LOG_PROPERTY_OLD}.
+ *
+ * @return classname specified by the user, or <code>null</code>
+ */
+ private String findUserSpecifiedLogClassName()
+ {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Trying to get log class from attribute '" + LOG_PROPERTY + "'");
+ }
+ String specifiedClass = (String) getAttribute(LOG_PROPERTY);
+
+ if (specifiedClass == null) { // @deprecated
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Trying to get log class from attribute '" +
+ LOG_PROPERTY_OLD + "'");
+ }
+ specifiedClass = (String) getAttribute(LOG_PROPERTY_OLD);
+ }
+
+ if (specifiedClass == null) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Trying to get log class from system property '" +
+ LOG_PROPERTY + "'");
+ }
+ try {
+ specifiedClass = getSystemProperty(LOG_PROPERTY, null);
+ } catch (SecurityException e) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("No access allowed to system property '" +
+ LOG_PROPERTY + "' - " + e.getMessage());
+ }
+ }
+ }
+
+ if (specifiedClass == null) { // @deprecated
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Trying to get log class from system property '" +
+ LOG_PROPERTY_OLD + "'");
+ }
+ try {
+ specifiedClass = getSystemProperty(LOG_PROPERTY_OLD, null);
+ } catch (SecurityException e) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("No access allowed to system property '" +
+ LOG_PROPERTY_OLD + "' - " + e.getMessage());
+ }
+ }
+ }
+
+ // Remove any whitespace; it's never valid in a classname so its
+ // presence just means a user mistake. As we know what they meant,
+ // we may as well strip the spaces.
+ if (specifiedClass != null) {
+ specifiedClass = specifiedClass.trim();
+ }
+
+ return specifiedClass;
+ }
+
+
+ /**
+ * Attempts to load the given class, find a suitable constructor,
+ * and instantiate an instance of Log.
+ *
+ * @param logAdapterClassName classname of the Log implementation
+ *
+ * @param logCategory argument to pass to the Log implementation's
+ * constructor
+ *
+ * @param affectState <code>true</code> if this object's state should
+ * be affected by this method call, <code>false</code> otherwise.
+ *
+ * @return an instance of the given class, or null if the logging
+ * library associated with the specified adapter is not available.
+ *
+ * @throws LogConfigurationException if there was a serious error with
+ * configuration and the handleFlawedDiscovery method decided this
+ * problem was fatal.
+ */
+ private Log createLogFromClass(String logAdapterClassName,
+ String logCategory,
+ boolean affectState)
+ throws LogConfigurationException {
+
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Attempting to instantiate '" + logAdapterClassName + "'");
+ }
+
+ Object[] params = { logCategory };
+ Log logAdapter = null;
+ Constructor constructor = null;
+
+ Class logAdapterClass = null;
+ ClassLoader currentCL = getBaseClassLoader();
+
+ for(;;) {
+ // Loop through the classloader hierarchy trying to find
+ // a viable classloader.
+ logDiagnostic(
+ "Trying to load '"
+ + logAdapterClassName
+ + "' from classloader "
+ + objectId(currentCL));
+ try {
+ if (isDiagnosticsEnabled()) {
+ // Show the location of the first occurrence of the .class file
+ // in the classpath. This is the location that ClassLoader.loadClass
+ // will load the class from -- unless the classloader is doing
+ // something weird.
+ URL url;
+ String resourceName = logAdapterClassName.replace('.', '/') + ".class";
+ if (currentCL != null) {
+ url = currentCL.getResource(resourceName );
+ } else {
+ url = ClassLoader.getSystemResource(resourceName + ".class");
+ }
+
+ if (url == null) {
+ logDiagnostic("Class '" + logAdapterClassName + "' [" + resourceName + "] cannot be found.");
+ } else {
+ logDiagnostic("Class '" + logAdapterClassName + "' was found at '" + url + "'");
+ }
+ }
+
+ Class c = null;
+ try {
+ c = Class.forName(logAdapterClassName, true, currentCL);
+ } catch (ClassNotFoundException originalClassNotFoundException) {
+ // The current classloader was unable to find the log adapter
+ // in this or any ancestor classloader. There's no point in
+ // trying higher up in the hierarchy in this case..
+ String msg = "" + originalClassNotFoundException.getMessage();
+ logDiagnostic(
+ "The log adapter '"
+ + logAdapterClassName
+ + "' is not available via classloader "
+ + objectId(currentCL)
+ + ": "
+ + msg.trim());
+ try {
+ // Try the class classloader.
+ // This may work in cases where the TCCL
+ // does not contain the code executed or JCL.
+ // This behaviour indicates that the application
+ // classloading strategy is not consistent with the
+ // Java 1.2 classloading guidelines but JCL can
+ // and so should handle this case.
+ c = Class.forName(logAdapterClassName);
+ } catch (ClassNotFoundException secondaryClassNotFoundException) {
+ // no point continuing: this adapter isn't available
+ msg = "" + secondaryClassNotFoundException.getMessage();
+ logDiagnostic(
+ "The log adapter '"
+ + logAdapterClassName
+ + "' is not available via the LogFactoryImpl class classloader: "
+ + msg.trim());
+ break;
+ }
+ }
+
+ constructor = c.getConstructor(logConstructorSignature);
+ Object o = constructor.newInstance(params);
+
+ // Note that we do this test after trying to create an instance
+ // [rather than testing Log.class.isAssignableFrom(c)] so that
+ // we don't complain about Log hierarchy problems when the
+ // adapter couldn't be instantiated anyway.
+ if (o instanceof Log) {
+ logAdapterClass = c;
+ logAdapter = (Log) o;
+ break;
+ }
+
+ // Oops, we have a potential problem here. An adapter class
+ // has been found and its underlying lib is present too, but
+ // there are multiple Log interface classes available making it
+ // impossible to cast to the type the caller wanted. We
+ // certainly can't use this logger, but we need to know whether
+ // to keep on discovering or terminate now.
+ //
+ // The handleFlawedHierarchy method will throw
+ // LogConfigurationException if it regards this problem as
+ // fatal, and just return if not.
+ handleFlawedHierarchy(currentCL, c);
+ } catch (NoClassDefFoundError e) {
+ // We were able to load the adapter but it had references to
+ // other classes that could not be found. This simply means that
+ // the underlying logger library is not present in this or any
+ // ancestor classloader. There's no point in trying higher up
+ // in the hierarchy in this case..
+ String msg = "" + e.getMessage();
+ logDiagnostic(
+ "The log adapter '"
+ + logAdapterClassName
+ + "' is missing dependencies when loaded via classloader "
+ + objectId(currentCL)
+ + ": "
+ + msg.trim());
+ break;
+ } catch (ExceptionInInitializerError e) {
+ // A static initializer block or the initializer code associated
+ // with a static variable on the log adapter class has thrown
+ // an exception.
+ //
+ // We treat this as meaning the adapter's underlying logging
+ // library could not be found.
+ String msg = "" + e.getMessage();
+ logDiagnostic(
+ "The log adapter '"
+ + logAdapterClassName
+ + "' is unable to initialize itself when loaded via classloader "
+ + objectId(currentCL)
+ + ": "
+ + msg.trim());
+ break;
+ } catch(LogConfigurationException e) {
+ // call to handleFlawedHierarchy above must have thrown
+ // a LogConfigurationException, so just throw it on
+ throw e;
+ } catch(Throwable t) {
+ // handleFlawedDiscovery will determine whether this is a fatal
+ // problem or not. If it is fatal, then a LogConfigurationException
+ // will be thrown.
+ handleFlawedDiscovery(logAdapterClassName, currentCL, t);
+ }
+
+ if (currentCL == null) {
+ break;
+ }
+
+ // try the parent classloader
+ // currentCL = currentCL.getParent();
+ currentCL = getParentClassLoader(currentCL);
+ }
+
+ if ((logAdapter != null) && affectState) {
+ // We've succeeded, so set instance fields
+ this.logClassName = logAdapterClassName;
+ this.logConstructor = constructor;
+
+ // Identify the <code>setLogFactory</code> method (if there is one)
+ try {
+ this.logMethod = logAdapterClass.getMethod("setLogFactory",
+ logMethodSignature);
+ logDiagnostic("Found method setLogFactory(LogFactory) in '"
+ + logAdapterClassName + "'");
+ } catch (Throwable t) {
+ this.logMethod = null;
+ logDiagnostic(
+ "[INFO] '" + logAdapterClassName
+ + "' from classloader " + objectId(currentCL)
+ + " does not declare optional method "
+ + "setLogFactory(LogFactory)");
+ }
+
+ logDiagnostic(
+ "Log adapter '" + logAdapterClassName
+ + "' from classloader " + objectId(logAdapterClass.getClassLoader())
+ + " has been selected for use.");
+ }
+
+ return logAdapter;
+ }
+
+
+ /**
+ * Return the classloader from which we should try to load the logging
+ * adapter classes.
+ * <p>
+ * This method usually returns the context classloader. However if it
+ * is discovered that the classloader which loaded this class is a child
+ * of the context classloader <i>and</i> the allowFlawedContext option
+ * has been set then the classloader which loaded this class is returned
+ * instead.
+ * <p>
+ * The only time when the classloader which loaded this class is a
+ * descendant (rather than the same as or an ancestor of the context
+ * classloader) is when an app has created custom classloaders but
+ * failed to correctly set the context classloader. This is a bug in
+ * the calling application; however we provide the option for JCL to
+ * simply generate a warning rather than fail outright.
+ *
+ */
+ private ClassLoader getBaseClassLoader() throws LogConfigurationException {
+ ClassLoader thisClassLoader = getClassLoader(LogFactoryImpl.class);
+
+ if (useTCCL == false) {
+ return thisClassLoader;
+ }
+
+ ClassLoader contextClassLoader = getContextClassLoaderInternal();
+
+ ClassLoader baseClassLoader = getLowestClassLoader(
+ contextClassLoader, thisClassLoader);
+
+ if (baseClassLoader == null) {
+ // The two classloaders are not part of a parent child relationship.
+ // In some classloading setups (e.g. JBoss with its
+ // UnifiedLoaderRepository) this can still work, so if user hasn't
+ // forbidden it, just return the contextClassLoader.
+ if (allowFlawedContext) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "[WARNING] the context classloader is not part of a"
+ + " parent-child relationship with the classloader that"
+ + " loaded LogFactoryImpl.");
+ }
+ // If contextClassLoader were null, getLowestClassLoader() would
+ // have returned thisClassLoader. The fact we are here means
+ // contextClassLoader is not null, so we can just return it.
+ return contextClassLoader;
+ }
+ else {
+ throw new LogConfigurationException(
+ "Bad classloader hierarchy; LogFactoryImpl was loaded via"
+ + " a classloader that is not related to the current context"
+ + " classloader.");
+ }
+ }
+
+ if (baseClassLoader != contextClassLoader) {
+ // We really should just use the contextClassLoader as the starting
+ // point for scanning for log adapter classes. However it is expected
+ // that there are a number of broken systems out there which create
+ // custom classloaders but fail to set the context classloader so
+ // we handle those flawed systems anyway.
+ if (allowFlawedContext) {
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(
+ "Warning: the context classloader is an ancestor of the"
+ + " classloader that loaded LogFactoryImpl; it should be"
+ + " the same or a descendant. The application using"
+ + " commons-logging should ensure the context classloader"
+ + " is used correctly.");
+ }
+ } else {
+ throw new LogConfigurationException(
+ "Bad classloader hierarchy; LogFactoryImpl was loaded via"
+ + " a classloader that is not related to the current context"
+ + " classloader.");
+ }
+ }
+
+ return baseClassLoader;
+ }
+
+ /**
+ * Given two related classloaders, return the one which is a child of
+ * the other.
+ * <p>
+ * @param c1 is a classloader (including the null classloader)
+ * @param c2 is a classloader (including the null classloader)
+ *
+ * @return c1 if it has c2 as an ancestor, c2 if it has c1 as an ancestor,
+ * and null if neither is an ancestor of the other.
+ */
+ private ClassLoader getLowestClassLoader(ClassLoader c1, ClassLoader c2) {
+ // TODO: use AccessController when dealing with classloaders here
+
+ if (c1 == null)
+ return c2;
+
+ if (c2 == null)
+ return c1;
+
+ ClassLoader current;
+
+ // scan c1's ancestors to find c2
+ current = c1;
+ while (current != null) {
+ if (current == c2)
+ return c1;
+ current = current.getParent();
+ }
+
+ // scan c2's ancestors to find c1
+ current = c2;
+ while (current != null) {
+ if (current == c1)
+ return c2;
+ current = current.getParent();
+ }
+
+ return null;
+ }
+
+ /**
+ * Generates an internal diagnostic logging of the discovery failure and
+ * then throws a <code>LogConfigurationException</code> that wraps
+ * the passed <code>Throwable</code>.
+ *
+ * @param logAdapterClassName is the class name of the Log implementation
+ * that could not be instantiated. Cannot be <code>null</code>.
+ *
+ * @param classLoader is the classloader that we were trying to load the
+ * logAdapterClassName from when the exception occurred.
+ *
+ * @param discoveryFlaw is the Throwable created by the classloader
+ *
+ * @throws LogConfigurationException ALWAYS
+ */
+ private void handleFlawedDiscovery(String logAdapterClassName,
+ ClassLoader classLoader,
+ Throwable discoveryFlaw) {
+
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic("Could not instantiate Log '"
+ + logAdapterClassName + "' -- "
+ + discoveryFlaw.getClass().getName() + ": "
+ + discoveryFlaw.getLocalizedMessage());
+
+ if (discoveryFlaw instanceof InvocationTargetException ) {
+ // Ok, the lib is there but while trying to create a real underlying
+ // logger something failed in the underlying lib; display info about
+ // that if possible.
+ InvocationTargetException ite = (InvocationTargetException)discoveryFlaw;
+ Throwable cause = ite.getTargetException();
+ if (cause != null) {
+ logDiagnostic("... InvocationTargetException: " +
+ cause.getClass().getName() + ": " +
+ cause.getLocalizedMessage());
+
+ if (cause instanceof ExceptionInInitializerError) {
+ ExceptionInInitializerError eiie = (ExceptionInInitializerError)cause;
+ Throwable cause2 = eiie.getException();
+ if (cause2 != null) {
+ logDiagnostic("... ExceptionInInitializerError: " +
+ cause2.getClass().getName() + ": " +
+ cause2.getLocalizedMessage());
+ }
+ }
+ }
+ }
+ }
+
+ if (!allowFlawedDiscovery) {
+ throw new LogConfigurationException(discoveryFlaw);
+ }
+ }
+
+
+ /**
+ * Report a problem loading the log adapter, then either return
+ * (if the situation is considered recoverable) or throw a
+ * LogConfigurationException.
+ * <p>
+ * There are two possible reasons why we successfully loaded the
+ * specified log adapter class then failed to cast it to a Log object:
+ * <ol>
+ * <li>the specific class just doesn't implement the Log interface
+ * (user screwed up), or
+ * <li> the specified class has bound to a Log class loaded by some other
+ * classloader; Log at classloaderX cannot be cast to Log at classloaderY.
+ * </ol>
+ * <p>
+ * Here we try to figure out which case has occurred so we can give the
+ * user some reasonable feedback.
+ *
+ * @param badClassLoader is the classloader we loaded the problem class from,
+ * ie it is equivalent to badClass.getClassLoader().
+ *
+ * @param badClass is a Class object with the desired name, but which
+ * does not implement Log correctly.
+ *
+ * @throws LogConfigurationException when the situation
+ * should not be recovered from.
+ */
+ private void handleFlawedHierarchy(ClassLoader badClassLoader, Class badClass)
+ throws LogConfigurationException {
+
+ boolean implementsLog = false;
+ String logInterfaceName = Log.class.getName();
+ Class interfaces[] = badClass.getInterfaces();
+ for (int i = 0; i < interfaces.length; i++) {
+ if (logInterfaceName.equals(interfaces[i].getName())) {
+ implementsLog = true;
+ break;
+ }
+ }
+
+ if (implementsLog) {
+ // the class does implement an interface called Log, but
+ // it is in the wrong classloader
+ if (isDiagnosticsEnabled()) {
+ try {
+ ClassLoader logInterfaceClassLoader = getClassLoader(Log.class);
+ logDiagnostic(
+ "Class '" + badClass.getName()
+ + "' was found in classloader "
+ + objectId(badClassLoader)
+ + ". It is bound to a Log interface which is not"
+ + " the one loaded from classloader "
+ + objectId(logInterfaceClassLoader));
+ } catch (Throwable t) {
+ logDiagnostic(
+ "Error while trying to output diagnostics about"
+ + " bad class '" + badClass + "'");
+ }
+ }
+
+ if (!allowFlawedHierarchy) {
+ StringBuffer msg = new StringBuffer();
+ msg.append("Terminating logging for this context ");
+ msg.append("due to bad log hierarchy. ");
+ msg.append("You have more than one version of '");
+ msg.append(Log.class.getName());
+ msg.append("' visible.");
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(msg.toString());
+ }
+ throw new LogConfigurationException(msg.toString());
+ }
+
+ if (isDiagnosticsEnabled()) {
+ StringBuffer msg = new StringBuffer();
+ msg.append("Warning: bad log hierarchy. ");
+ msg.append("You have more than one version of '");
+ msg.append(Log.class.getName());
+ msg.append("' visible.");
+ logDiagnostic(msg.toString());
+ }
+ } else {
+ // this is just a bad adapter class
+ if (!allowFlawedDiscovery) {
+ StringBuffer msg = new StringBuffer();
+ msg.append("Terminating logging for this context. ");
+ msg.append("Log class '");
+ msg.append(badClass.getName());
+ msg.append("' does not implement the Log interface.");
+ if (isDiagnosticsEnabled()) {
+ logDiagnostic(msg.toString());
+ }
+
+ throw new LogConfigurationException(msg.toString());
+ }
+
+ if (isDiagnosticsEnabled()) {
+ StringBuffer msg = new StringBuffer();
+ msg.append("[WARNING] Log class '");
+ msg.append(badClass.getName());
+ msg.append("' does not implement the Log interface.");
+ logDiagnostic(msg.toString());
+ }
+ }
+ }
+}
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