[jboss-cvs] JBossAS SVN: r74366 - projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US.
jboss-cvs-commits at lists.jboss.org
jboss-cvs-commits at lists.jboss.org
Tue Jun 10 23:55:10 EDT 2008
Author: irooskov at redhat.com
Date: 2008-06-10 23:55:10 -0400 (Tue, 10 Jun 2008)
New Revision: 74366
Modified:
projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/An_Introduction_to_the_JTA.xml
projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Configuring_JBossJTA.xml
projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Examples.xml
projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/JDBC_and_Transactions.xml
projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/The_Resource_Manager.xml
projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Transaction_Recovery.xml
projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Transactions.xml
projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Using_JBossJTA_in_Application_Servers.xml
Log:
conversion of *.doc to docbook xml for Transactions_JTA_Programmers_Guide is now completed
Modified: projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/An_Introduction_to_the_JTA.xml
===================================================================
--- projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/An_Introduction_to_the_JTA.xml 2008-06-11 01:35:24 UTC (rev 74365)
+++ projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/An_Introduction_to_the_JTA.xml 2008-06-11 03:55:10 UTC (rev 74366)
@@ -2,24 +2,52 @@
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
]>
-<chapter id="Transactions_JTA_Programmers_Guide-Test">
- <title>Test</title>
+<chapter id="Transactions_JTA_Programmers_Guide-An_Introduction_to_the_JTA">
+ <title>An Introduction to the JTA</title>
<para>
- This is a test paragraph
</para>
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_1_Test">
- <title>Section 1 Test</title>
+ <section id="Transactions_JTA_Programmers_Guide-An_Introduction_to_the_JTA-The_Java_Transaction_API">
+ <title>The Java Transaction API</title>
<para>
- Test of a section
+ The interfaces specified by the many transaction standards are typically too low-level for most application programmers. Therefore, Sun Microsystems has specified higher-level interfaces to assist in the development of distributed transactional applications. Note, these interfaces are still low-level, and require, for example, the programmer to be concerned with state management and concurrency for transactional application. In addition, they are geared more for applications which require XA resource integration capabilities, rather than the more general resources which the other APIs allow.
</para>
- </section>
-
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_2_Test">
- <title>Section 2 Test</title>
<para>
- Test of a section
+ With reference to [JTA99], distributed transaction services typically involve a number of participants:
</para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ Application server: which provides the infrastructure required to support the application run-time environment which includes transaction state management, for example, an EJB server.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Transaction manager: provides the services and management functions required to support transaction demarcation, transactional resource management, synchronisation and transaction context propagation.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Resource manager: (through a resource adapter<footnote>
+ <para>
+ A Resource Adapter is used by an application server or client to connect to a Resource Manager. JDBC drivers which are used to connect to relational databases are examples of Resource Adapters.
+ </para>
+ </footnote>) provides the application with access to resources. The resource manager participates in distributed transactions by implementing a transaction resource interface used by the transaction manager to communicate transaction association, transaction completion and recovery.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ A communication resource manager (CRM): supports transaction context propagation and access to the transaction service for incoming and outgoing requests.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <para>
+ From the transaction manager’s perspective, the actual implementation of the transaction services does not need to be exposed; only high-level interfaces need to be defined to allow transaction demarcation, resource enlistment, synchronization and recovery process to be driven from the users of the transaction services. The JTA is a high-level application interface that allows a transactional application to demarcate transaction boundaries, and contains also contains a mapping of the X/Open XA protocol.
+ </para>
+ <note>
+ <para>
+ The JTA support provided by JBossJTA is compliant with the 1.0.1 specification.
+ </para>
+ </note>
</section>
-
</chapter>
Modified: projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Configuring_JBossJTA.xml
===================================================================
--- projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Configuring_JBossJTA.xml 2008-06-11 01:35:24 UTC (rev 74365)
+++ projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Configuring_JBossJTA.xml 2008-06-11 03:55:10 UTC (rev 74366)
@@ -2,24 +2,58 @@
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
]>
-<chapter id="Transactions_JTA_Programmers_Guide-Test">
- <title>Test</title>
+<chapter id="Transactions_JTA_Programmers_Guide-Configuring_JBossJTA">
+ <title>Configuring JBossJTA</title>
<para>
- This is a test paragraph
</para>
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_1_Test">
- <title>Section 1 Test</title>
+ <section id="Transactions_JTA_Programmers_Guide-Configuring_JBossJTA-Configuring_options">
+ <title>Configuring options</title>
<para>
- Test of a section
+ The following table shows the configuration features, with default values shown in italics. For more detailed information, the relevant section numbers are provided.
</para>
+ <table frame='all'><title>JBossJTA configuration options.</title>
+ <tgroup cols='3'>
+ <thead>
+ <row>
+ <entry>Configuration Name</entry>
+ <entry>Possibile Values</entry>
+ <entry>Relevant Section</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>com.arjuna.ats.jta.supportSubtransactions</entry>
+ <entry>YES/NO</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>com.arjuna.ats.jta.jtaTMImplementation</entry>
+ <entry>com.arjuna.ats.internal.jta.transaction.arjunacore.TransactionManagerImple/com.arjuna.ats.internal.jta.transaction.jts.TransactionManagerImple</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>com.arjuna.ats.jta.jtaUTImplementation</entry>
+ <entry>com.arjuna.ats.internal.jta.transaction.arjunacore.UserTransactionImple/com.arjuna.ats.internal.jta.transaction.jts.UserTransactionImple</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>com.arjuna.ats.jta.xaBackoffPeriod</entry>
+ <entry></entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>com.arjuna.ats.jdbc.isolationLevel</entry>
+ <entry>Any supported JDBC isolation level.</entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>com.arjuna.ats.jta.xaTransactionTimetouEnabled</entry>
+ <entry>true/false</entry>
+ <entry>Chapter 3</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
</section>
-
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_2_Test">
- <title>Section 2 Test</title>
- <para>
- Test of a section
- </para>
- </section>
-
</chapter>
Modified: projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Examples.xml
===================================================================
--- projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Examples.xml 2008-06-11 01:35:24 UTC (rev 74365)
+++ projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Examples.xml 2008-06-11 03:55:10 UTC (rev 74366)
@@ -2,24 +2,356 @@
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
]>
-<chapter id="Transactions_JTA_Programmers_Guide-Test">
- <title>Test</title>
+<chapter id="Transactions_JTA_Programmers_Guide-Examples">
+ <title>Examples</title>
<para>
- This is a test paragraph
</para>
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_1_Test">
- <title>Section 1 Test</title>
+ <section id="Transactions_JTA_Programmers_Guide-Examples-JDBC_example">
+ <title>JDBC example</title>
<para>
- Test of a section
+ The following code illustrates many of the points described above (note that for simplicity, much error checking code has been remove). This example assumes that you are using the transactional JDBC driver provided with JBossTS. For details about how to configure and use this driver see the previous Chapter.
</para>
+<screen>
+public class JDBCTest
+{
+public static void main (String[] args)
+{
+ /*
+ */
+
+ Connection conn = null;
+ Connection conn2 = null;
+ Statement stmt = null; // non-tx statement
+ Statement stmtx = null; // will be a tx-statement
+ Properties dbProperties = new Properties();
+
+ try
+ {
+ System.out.println("\nCreating connection to database: "+url);
+
+ /*
+ * Create conn and conn2 so that they are bound to the JBossTS
+ * transactional JDBC driver. The details of how to do this will
+ * depend on your environment, the database you wish to use and
+ * whether or not you want to use the Direct or JNDI approach. See
+ * the appropriate chapter in the JTA Programmers Guide.
+ */
+
+ stmt = conn.createStatement(); // non-tx statement
+
+ try
+ {
+ stmt.executeUpdate("DROP TABLE test_table");
+ stmt.executeUpdate("DROP TABLE test_table2");
+ }
+ catch (Exception e)
+ {
+ // assume not in database.
+ }
+
+ try
+ {
+ stmt.executeUpdate("CREATE TABLE test_table (a INTEGER,b INTEGER)");
+ stmt.executeUpdate("CREATE TABLE test_table2 (a INTEGER,b INTEGER)");
+ }
+ catch (Exception e)
+ {
+ }
+
+ try
+ {
+ System.out.println("Starting top-level transaction.");
+
+ com.arjuna.ats.jta.UserTransaction.userTransaction().begin();
+
+ stmtx = conn.createStatement(); // will be a tx-statement
+
+ System.out.println("\nAdding entries to table 1.");
+
+ stmtx.executeUpdate("INSERT INTO test_table (a, b) VALUES (1,2)");
+
+ ResultSet res1 = null;
+
+ System.out.println("\nInspecting table 1.");
+
+ res1 = stmtx.executeQuery("SELECT * FROM test_table");
+ while (res1.next())
+ {
+ System.out.println("Column 1: "+res1.getInt(1));
+ System.out.println("Column 2: "+res1.getInt(2));
+ }
+
+ System.out.println("\nAdding entries to table 2.");
+
+ stmtx.executeUpdate("INSERT INTO test_table2 (a, b) VALUES (3,4)");
+
+ res1 = stmtx.executeQuery("SELECT * FROM test_table2");
+
+ System.out.println("\nInspecting table 2.");
+
+ while (res1.next())
+ {
+ System.out.println("Column 1: "+res1.getInt(1));
+ System.out.println("Column 2: "+res1.getInt(2));
+ }
+ System.out.print("\nNow attempting to rollback changes.");
+
+ com.arjuna.ats.jta.UserTransaction.userTransaction().rollback();
+
+ com.arjuna.ats.jta.UserTransaction.userTransaction().begin();
+
+ stmtx = conn.createStatement();
+ ResultSet res2 = null;
+
+ System.out.println("\nNow checking state of table 1.");
+
+ res2 = stmtx.executeQuery("SELECT * FROM test_table");
+ while (res2.next())
+ {
+ System.out.println("Column 1: "+res2.getInt(1));
+ System.out.println("Column 2: "+res2.getInt(2));
+ }
+
+ System.out.println("\nNow checking state of table 2.");
+
+ stmtx = conn.createStatement();
+ res2 = stmtx.executeQuery("SELECT * FROM test_table2");
+ while (res2.next())
+ {
+ System.out.println("Column 1: "+res2.getInt(1));
+ System.out.println("Column 2: "+res2.getInt(2));
+ }
+
+ com.arjuna.ats.jta.UserTransaction.userTransaction().commit(true);
+ }
+ catch (Exception ex)
+ {
+ ex.printStackTrace();
+ System.exit(0);
+ }
+ }
+ catch (Exception sysEx)
+ {
+ sysEx.printStackTrace();
+ System.exit(0);
+ }
+}
+</screen>
</section>
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_2_Test">
- <title>Section 2 Test</title>
+ <section id="Transactions_JTA_Programmers_Guide-Examples-Failure_recovery_example">
+ <title>Failure recovery example</title>
<para>
- Test of a section
+ This class implements the <interfacename>XAResourceRecovery</interfacename> interface for <code>XAResources</code>. The parameter supplied in setParameters can contain arbitrary information necessary to initialize the class once created. In this instance it contains the name of the property file in which the db connection information is specified, as well as the number of connections that this file contains information on (separated by ;).
</para>
+ <caution>
+ <para>
+ This is only an <emphasis>example</emphasis> of the sorts of things an <code>XAResourceRecovery</code> implementer could do. This implementation uses a property file that is assumed to contain sufficient information to recreate connections used during the normal run of an application so that we can perform recovery on them. It is not recommended that information such as user name and password appear in such a raw text format as it opens up a potential security hole.
+ </para>
+ </caution>
+ <para>
+ The db parameters specified in the property file are assumed to be in the format:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ DB_x_DatabaseURL=
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ DB_x_DatabaseUser=
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ DB_x_DatabasePassword=
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ DB_x_DatabaseDynamicClass=
+ </para>
+ </listitem>
+ </itemizedlist>
+ <para>
+ Where x is the number of the connection information.
+ </para>
+ <note>
+ <para>
+ Some error handling code has been removed from this text for ease of readability purposes.
+ </para>
+ </note>
+<screen>
+/*
+ * Some XAResourceRecovery implementations will do their startup work here,
+ * and then do little or nothing in setDetails. Since this one needs to know
+ * dynamic class name, the constructor does nothing.
+ */
+
+public BasicXARecovery () throws SQLException
+{
+ numberOfConnections = 1;
+ connectionIndex = 0;
+ props = null;
+}
+
+/*
+ * The recovery module will have chopped off this class name already. The
+ * parameter should specify a property file from which the url, user name,
+ * password, etc. can be read.
+ *
+ * @message com.arjuna.ats.internal.jdbc.recovery.initexp An exception
+ * occurred during initialisation.
+ */
+
+public boolean initialise (String parameter) throws SQLException
+{
+ if (parameter == null)
+ return true;
+
+ int breakPosition = parameter.indexOf(BREAKCHARACTER);
+ String fileName = parameter;
+
+ if (breakPosition != -1)
+ {
+ fileName = parameter.substring(0, breakPosition - 1);
+
+ try
+ {
+ numberOfConnections = Integer.parseInt(parameter.substring(breakPosition + 1));
+ }
+ catch (NumberFormatException e)
+ {
+ return false;
+ }
+ }
+
+ try
+ {
+ String uri = com.arjuna.common.util.FileLocator.locateFile(fileName);
+ jdbcPropertyManager.propertyManager.load(XMLFilePlugin.class.getName(), uri);
+
+ props = jdbcPropertyManager.propertyManager.getProperties();
+ }
+ catch (Exception e)
+ {
+ return false;
+ }
+
+ return true;
+}
+
+/*
+ * @message com.arjuna.ats.internal.jdbc.recovery.xarec {0} could not find
+ * information for connection!
+ */
+
+public synchronized XAResource getXAResource () throws SQLException
+{
+ JDBC2RecoveryConnection conn = null;
+
+ if (hasMoreResources())
+ {
+ connectionIndex++;
+
+ conn = getStandardConnection();
+
+ if (conn == null) conn = getJNDIConnection();
+ }
+
+ return conn.recoveryConnection().getConnection().getXAResource();
+}
+
+public synchronized boolean hasMoreResources ()
+{
+ if (connectionIndex == numberOfConnections)
+ return false;
+ else
+ return true;
+}
+
+private final JDBC2RecoveryConnection getStandardConnection ()
+ throws SQLException
+{
+ String number = new String("" + connectionIndex);
+ String url = new String(dbTag + number + urlTag);
+ String password = new String(dbTag + number + passwordTag);
+ String user = new String(dbTag + number + userTag);
+ String dynamicClass = new String(dbTag + number + dynamicClassTag);
+
+ Properties dbProperties = new Properties();
+
+ String theUser = props.getProperty(user);
+ String thePassword = props.getProperty(password);
+
+ if (theUser != null)
+ {
+ dbProperties.put(TransactionalDriver.userName, theUser);
+ dbProperties.put(TransactionalDriver.password, thePassword);
+
+ String dc = props.getProperty(dynamicClass);
+
+ if (dc != null)
+ dbProperties.put(TransactionalDriver.dynamicClass, dc);
+
+ return new JDBC2RecoveryConnection(url, dbProperties);
+ }
+ else
+ return null;
+}
+
+private final JDBC2RecoveryConnection getJNDIConnection ()
+ throws SQLException
+{
+ String number = new String("" + connectionIndex);
+ String url = new String(dbTag + jndiTag + number + urlTag);
+ String password = new String(dbTag + jndiTag + number + passwordTag);
+ String user = new String(dbTag + jndiTag + number + userTag);
+
+ Properties dbProperties = new Properties();
+
+ String theUser = props.getProperty(user);
+ String thePassword = props.getProperty(password);
+
+ if (theUser != null)
+ {
+ dbProperties.put(TransactionalDriver.userName, theUser);
+ dbProperties.put(TransactionalDriver.password, thePassword);
+
+ return new JDBC2RecoveryConnection(url, dbProperties);
+ }
+ else
+ return null;
+}
+
+private int numberOfConnections;
+private int connectionIndex;
+private Properties props;
+private static final String dbTag = "DB_";
+private static final String urlTag = "_DatabaseURL";
+private static final String passwordTag = "_DatabasePassword";
+private static final String userTag = "_DatabaseUser";
+private static final String dynamicClassTag = "_DatabaseDynamicClass";
+private static final String jndiTag = "JNDI_";
+
+/*
+ * Example:
+ *
+ * DB2_DatabaseURL=jdbc\:arjuna\:sequelink\://qa02\:20001
+ * DB2_DatabaseUser=tester2 DB2_DatabasePassword=tester
+ * DB2_DatabaseDynamicClass=com.arjuna.ats.internal.jdbc.drivers.sequelink_5_1
+ *
+ * DB_JNDI_DatabaseURL=jdbc\:arjuna\:jndi DB_JNDI_DatabaseUser=tester1
+ * DB_JNDI_DatabasePassword=tester DB_JNDI_DatabaseName=empay
+ * DB_JNDI_Host=qa02 DB_JNDI_Port=20000
+ */
+
+ private static final char BREAKCHARACTER = ';'; // delimiter for parameters
+</screen>
+ <para>
+ The class <classname>com.arjuna.ats.internal.jdbc.recovery.JDBC2RecoveryConnection</classname> may be used to create a new connection to the database using the same parameters that were used to create the initial connection.
+ </para>
</section>
-
</chapter>
Modified: projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/JDBC_and_Transactions.xml
===================================================================
--- projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/JDBC_and_Transactions.xml 2008-06-11 01:35:24 UTC (rev 74365)
+++ projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/JDBC_and_Transactions.xml 2008-06-11 03:55:10 UTC (rev 74366)
@@ -2,24 +2,332 @@
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
]>
-<chapter id="Transactions_JTA_Programmers_Guide-Test">
- <title>Test</title>
+<chapter id="Transactions_JTA_Programmers_Guide-JDBC_and_Transactions">
+ <title>JDBC and Transactions</title>
<para>
- This is a test paragraph
</para>
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_1_Test">
- <title>Section 1 Test</title>
+ <section id="Transactions_JTA_Programmers_Guide-JDBC_and_Transactions-Using_the_transactional_JDBC_driver">
+ <title>Using the transactional JDBC driver</title>
<para>
- Test of a section
+ JBossJTA supports the construction of both local and distributed transactional applications which access databases using the JDBC 2.0 APIs. JDBC 2.0 supports two-phase commit of transactions, and is similar to the XA X/Open standard. The JDBC 2.0 support is found in the com.arjuna.ats.jdbc package.
</para>
+ <para>
+ The JDBC 2.0 support has been tested with the following drivers and databases:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ Oracle 8.1.6/8.1.7, 9i and 10g thin driver.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ MS SQL Server 2000 native driver.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <para>
+ In the past we have qualified against:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ Merant’s Sequelink 5.1 with Oracle 8.1.6
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Cloudscape 3.6 with Cloudscape’s own database.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <para>
+ However, these drivers and databases are no longer part of our supported platforms. They may continue to work with JBossTS, but we cannot make that guarantee.
+ </para>
+ <formalpara>
+ <title>Managing transactions</title>
+ <para>
+ JBossJTA must be able to associate work performed on a JDBC connection with a specific transaction. Therefore, implicit transaction propagation and/or indirect transaction management must be used by applications, i.e., for each JDBC connection it must be possible for JBossJTA to determine the invoking thread’s current transaction context.
+ </para>
+ </formalpara>
+ <formalpara>
+ <title>Restrictions</title>
+ <para>
+ The following restrictions are imposed by limitations in the JDBC specifications and by JBossJTA to ensure that transactional interactions with JDBC databases can be correctly managed:
+ </para>
+ </formalpara>
+ <para>
+ Nested transactions are not supported by JDBC 2.0. If an attempt is made to use a JDBC connection within a subtransaction, JBossJTA will throw a suitable exception and no work will be allowed on that connection. However, if you wish to have nested transactions, then you can set the <property>com.arjuna.ats.jta.supportSubtransactions</property> property to YES.
+ </para>
</section>
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_2_Test">
- <title>Section 2 Test</title>
+ <section id="Transactions_JTA_Programmers_Guide-JDBC_and_Transactions-Transactional_drivers">
+ <title>Transactional drivers</title>
<para>
- Test of a section
+ The JBossJTA approach to incorporating JDBC connections within transactions is to provide transactional JDBC drivers through which all interactions occur. These drivers intercept all invocations and ensure that they are registered with, and driven by, appropriate transactions. There is a single type of transactional driver through which any JDBC driver can be driven; obviously if the database is not transactional then ACID properties cannot be guaranteed. This driver is <code>com.arjuna.ats.jdbc.TransactionalDriver</code>, which implements the <interfacename>java.sql.Driver</interfacename> interface.
</para>
+ <formalpara>
+ <title>Loading drivers</title>
+ <para>
+ The driver may be directly instantiated and used within an application. For example:
+ </para>
+ </formalpara>
+<screen>
+TransactionalDriver arjunaJDBC2Driver = new TransactionalDriver();
+</screen>
+ <para>
+ They can be registered with the JDBC driver manager (<code>java.sql.DriverManager</code>) by adding them to the Java system properties. The <property>jdbc.drivers</property> property contains a list of driver class names, separated by colons, that are loaded by the JDBC driver manager when it is initialized.
+ </para>
+<screen>
+/*
+ * Register the driver via the system properties variable
+ * "jdbc.drivers"
+ */
+
+Properties p = System.getProperties();
+
+switch (dbType)
+{
+case MYSQL:
+ p.put("jdbc.drivers", "org.gjt.mm.mysql.Driver");
+ break;
+case CLOUDSCAPE:
+ p.put("jdbc.drivers", "COM.cloudscape.core.JDBCDriver");
+ break;
+}
+
+System.setProperties(p);
+</screen>
+ <para>
+ Alternatively, the <methodname>Class.forName()</methodname> method may be used to load the driver or drivers:
+ </para>
+<screen>
+Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
+</screen>
+ <para>
+ Calling <methodname>Class.forName()</methodname> will automatically register the driver with the JDBC driver manager. It is also possible to explicitly create an instance of the JDBC driver:
+ </para>
+<screen>
+sun.jdbc.odbc.JdbcOdbcDriver drv = new sun.jdbc.odbc.JdbcOdbcDriver();
+
+DriverManager.registerDriver(drv);
+</screen>
+ <para>
+ When you have loaded a driver, it is available for making a connection with a DBMS.
+ </para>
</section>
-
+ <section id="Transactions_JTA_Programmers_Guide-JDBC_and_Transactions-Connections">
+ <title>Connections</title>
+ <para>
+ In this section we shall discuss the notion of transactional JDBC connections, how they are managed within JBossJTA and the implications on using them within an application.
+ </para>
+ <formalpara>
+ <title>Making the connection</title>
+ <para>
+ Because JDBC connectivity in JBossJTA works by simply providing a new JDBC driver, application code can remain relatively the same to that when not using transactions. Typically, the application programmer need only start and terminate transactions.
+ </para>
+ </formalpara>
+ <formalpara>
+ <title>JDBC 2.0</title>
+ <para>
+ Before describing the JDBC 2.0 support it is necessary to mention that the following properties can be set and passed to the JBossJTA driver (they are all located in the <classname>com.arjuna.ats.jdbc.TransactionalDriver</classname> class):
+ </para>
+ </formalpara>
+ <itemizedlist>
+ <listitem>
+ <para>
+ <property>userName</property>: the user name to use when attempting to connect to the database.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <property>password</property>: the password to use when attempting to connect to the database.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <property>createDb</property>: if set to true, the driver will attempt to create the database when it connects. This may not be supported by all JDBC 2.0 implementations.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <property>dynamicClass</property>: this specifies a class to instantiate to connect to the database, rather than using JNDI.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <formalpara>
+ <title>XADataSources</title>
+ <para>
+ JDBC 2.0 connections are created from appropriate DataSources. Those connections which must participate within distributed transactions are obtained from <code>XADataSources</code>. Therefore, when using a JDBC 2.0 driver, JBossJTA will use the appropriate DataSource whenever a connection to the database is made. It will then obtain <code>XAResources</code> and register them with the transaction via the JTA interfaces. It is these <code>XAResources</code> which the transaction service will use when the transaction terminates in order to drive the database to either commit or rollback the changes made via the JDBC connection.
+ </para>
+ </formalpara>
+ <para>
+ There are two ways in which the JBossJTA JDBC 2.0 support can obtain <code>XADataSources</code>. These will be explained in the following sections. Note, for simplicity we shall assume that the JDBC 2.0 driver is instantiated directly by the application.
+ </para>
+ <formalpara>
+ <title>Java Naming and Directory Interface (JNDI)</title>
+ <para>
+ In order to allow a JDBC driver to use arbitrary DataSources without having to know specific details about their implementations, DataSources are typically obtained from JNDI. A specific (XA)DataSource can be created and registered with an appropriate JNDI implementation, and the application (or JDBC driver) can later bind to and use it. Since JNDI only allows the application to see the (XA)DataSource as an instance of the interface (for example, <property>javax.sql.XADataSource</property>) rather than as an instance of the implementation class (for example, <property>com.mydb.myXADataSource</property>), the application is not tied at build time to only use a specific (XA)DataSource implementation.
+ </para>
+ </formalpara>
+ <para>
+ To get the <classname>TransactionalDriver</classname> class to use a JNDI registered <code>XADataSource</code> it is first necessary to create the <code>XADataSource</code> instance and store it in an appropriate JNDI implementation. Details of how to do this can be found in the JDBC 2.0 tutorial available at JavaSoft. An example is show below:
+ </para>
+<screen>
+XADataSource ds = MyXADataSource();
+Hashtable env = new Hashtable();
+String initialCtx = PropertyManager.getProperty("Context.INITIAL_CONTEXT_FACTORY");
+
+env.put(Context.INITIAL_CONTEXT_FACTORY, initialCtx);
+
+initialContext ctx = new InitialContext(env);
+
+ctx.bind("jdbc/foo", ds);
+</screen>
+ <para>
+ Where the <property>Context.INITIAL_CONTEXT_FACTORY</property> property is the JNDI way of specifying the type of JNDI implementation to use.
+ </para>
+ <para>
+ Then the application must pass an appropriate connection URL to the JDBC 2.0 driver:
+ </para>
+<screen>
+Properties dbProps = new Properties();
+
+dbProps.setProperty(TransactionalDriver.userName, "user");
+dbProps.setProperty(TransactionalDriver.password, "password");
+
+TransactionalDriver arjunaJDBC2Driver = new TransactionalDriver();
+Connection connection = arjunaJDBC2Driver.connect("jdbc:arjuna:jdbc/foo", dbProps);
+</screen>
+ <para>
+ The JNDI URL must be pre-pended with jdbc:arjuna: in order for the <code>ArjunaJDBC2Driver</code> to recognise that the DataSource must participate within transactions and be driven accordingly.
+ </para>
+ <formalpara>
+ <title>Dynamic class instantiation</title>
+ <para>
+ Many JDBC 2.0 implementations provide proprietary implementations of <interfacename>XADataSources</interfacename> that provide non-standard extensions to the specification. In order to allow the application to remain isolated from the actual JDBC 2.0 implementation it is using and yet continue to be able to use these extensions, JBossJTA hides the details of these proprietary implementations using dynamic class instantiation. In addition, the use of JNDI is not required when using this mechanism because the actual implementation of the <interfacename>XADataSource</interfacename> will be directly instantiated, albeit in a manner which will not tie an application or driver to a specific implementation. JBossJTA therefore has several classes which are for specific JDBC 2.0 implementations, and these can be selected at runtime by the application setting the <property>dynamicClass</property> property appropriately:
+ </para>
+ </formalpara>
+ <table frame='all'><title>Dynamic Class property values for specific databases</title>
+ <tgroup cols='2'>
+ <thead>
+ <row>
+ <entry>Database Type</entry>
+ <entry>Property Name</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Cloudscape 3.6</entry>
+ <entry>com.arjuna.ats.internal.jdbc.drivers.cloudscape_3_6</entry>
+ </row>
+ <row>
+ <entry>Sequelink 5.1</entry>
+ <entry>com.arjuna.ats.internal.jdbc.drivers.sequelink_5_1</entry>
+ </row>
+ <row>
+ <entry>Oracle 8.1.6</entry>
+ <entry>com.arjuna.ats.internal.jdbc.drivers.oracle_8_1_6</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ <note>
+ <para>
+ As mentioned earlier, JBossTS no longer supports Cloudscape or Sequelink as part of the qualified drivers. Furthermore, we recommend using JNDI to obtain JDBC classes rather than the direct method described here.
+ </para>
+ </note>
+ <para>
+ The application code must specify which dynamic class the <code>TransactionalDriver</code> should instantiate when setting up the connection:
+ </para>
+<screen>
+Properties dbProps = new Properties();
+
+dbProps.setProperty(TransactionalDriver.userName, "user");
+dbProps.setProperty(TransactionalDriver.password, "password");
+dbProps.setProperty(TransactionalDriver.dynamicClass,
+"com.arjuna.ats.internal.jdbc.drivers.sequelink_5_0");
+
+TransactionalDriver arjunaJDBC2Driver = new TransactionalDriver();
+Connection connection = arjunaJDBC2Driver.connect("jdbc:arjuna:sequelink://host:port;databaseName=foo",dbProperties);
+</screen>
+ <formalpara>
+ <title>Using the connection</title>
+ <para>
+ Once the connection has been established (for example, using the <methodname>java.sql.DriverManager.getConnection</methodname> method), all operations on the connection will be monitored by JBossJTA. Note, it is not necessary to use the transactional connection within transactions. If a transaction is not present when the connection is used, then operations will be performed directly on the database.
+ </para>
+ </formalpara>
+ <note>
+ <para>
+ JDBC does not support subtransactions.
+ </para>
+ </note>
+ <para>
+ Transaction timeouts can be used to automatically terminate transactions should the connection not be terminated within an appropriate period.
+ </para>
+ <para>
+ JBossJTA connections can be used within multiple different transactions simultaneously, for instance, different threads, with different notions of the current transaction, may use the same JDBC connection. JBossJTA does connection pooling for each transaction within the JDBC connection. So, although multiple threads may use the same instance of the JDBC connection, internally this may be using a different connection instance per transaction. With the exception of close, all operations performed on the connection at the application level will only be performed on this transaction-specific connection.
+ </para>
+ <para>
+ JBossJTA will automatically register the JDBC driver connection with the transaction via an appropriate resource . When the transaction terminates, this resource will be responsible for either committing or rolling back any changes made to the underlying database via appropriate calls on the JDBC driver.
+ </para>
+ <para>
+ Once created, the driver and any connection can be used in the same way as any other JDBC driver or connection.
+ </para>
+<screen>
+Statement stmt = conn.createStatement();
+
+try
+{
+ stmt.executeUpdate("CREATE TABLE test_table (a INTEGER,b INTEGER)");
+}
+catch (SQLException e)
+{
+ // table already exists
+}
+
+stmt.executeUpdate("INSERT INTO test_table (a, b) VALUES (1,2)");
+
+ResultSet res1 = stmt.executeQuery("SELECT * FROM test_table");
+</screen>
+ <formalpara>
+ <title>Connection pooling</title>
+ <para>
+ For each user name and password, JBossJTA will maintain a single instance of each connection for as long as that connection is in use. Subsequent requests for the same connection will get a reference to the originally created connection, rather than a new instance. Attempts to close the connection are allowed, but the connection will only actually be closed when all users (including transactions) have either finished with the connection, or issued close calls.
+ </para>
+ </formalpara>
+ <formalpara>
+ <title>Reusing connections</title>
+ <para>
+ Some JDBC drivers allow the reuse of a connection for multiple different transactions once a given transaction has completed. Unfortunately this is not a common feature, and other drivers require a new connection to be obtained for each new transaction. By default, the JBossJTA transactional driver will always obtain a new connection for each new transaction. However, if an existing connection is available and is currently unused, it is possible to make JBossJTA reuse this connection. In order to do this, the reuseconnection=true option must be specified on the JDBC URL. For example:
+ </para>
+ </formalpara>
+<screen>
+jdbc:arjuna:sequelink://host:port;databaseName=foo;reuseconnection=true
+</screen>
+ <formalpara>
+ <title>Terminating the transaction</title>
+ <para>
+ Whenever a transaction terminates (either explicitly by the application programmer, or implicitly when any associated transaction timeout expires) that has a JDBC connection registered with it, JBossJTA will drive the database (via the JDBC driver) to either commit or roll back any changes made to it. This happens transparently to the application.
+ </para>
+ </formalpara>
+ <formalpara>
+ <title>AutoCommit</title>
+ <para>
+ If <code>AutoCommit</code> of the <code>java.sql.Connection</code> is set to true for JDBC 1.0 then the execution of every SQL statement is a separate top-level transaction, and grouping multiple statements to be managed within a single OTS transaction is not possible. Therefore, JBossJTA will disable <code>AutoCommit</code> on JDBC 1.0 connections before they can be used. If auto commit is subsequently set to true by the application, JBossJTA will raise the <code>java.sql.SQLException</code>.
+ </para>
+ </formalpara>
+ <formalpara>
+ <title>Setting isolation levels</title>
+ <para>
+ When using the JBossJTA JDBC driver, it may be necessary to set the underlying transaction isolation level on the XA connection. By default, this is set to <code>TRANSACTION_SERIALIZABLE</code>, but you may want to set this to something more appropriate for your application. In order to do this, set the <property>com.arjuna.ats.jdbc.isolationLevel</property> property to the appropriate isolation level in string form, for example, <code>TRANSACTION_READ_COMMITTED</code>, or <code>TRANSACTION_REPEATABLE_READ</code>.
+ </para>
+ </formalpara>
+ <note>
+ <para>
+ At present this property applies to all XA connections created in the JVM.
+ </para>
+ </note>
+ </section>
</chapter>
Modified: projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/The_Resource_Manager.xml
===================================================================
--- projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/The_Resource_Manager.xml 2008-06-11 01:35:24 UTC (rev 74365)
+++ projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/The_Resource_Manager.xml 2008-06-11 03:55:10 UTC (rev 74366)
@@ -2,24 +2,255 @@
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
]>
-<chapter id="Transactions_JTA_Programmers_Guide-Test">
+<chapter id="Transactions_JTA_Programmers_Guide-The_Resource_Manager">
<title>Test</title>
<para>
This is a test paragraph
</para>
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_1_Test">
- <title>Section 1 Test</title>
+ <section id="Transactions_JTA_Programmers_Guide-The_Resource_Manager-The_XAResource_Interface">
+ <title>The XAResource Interface</title>
<para>
- Test of a section
+ Whereas some transaction specifications and systems define a generic resource which can be used to register arbitrary resources with a transaction, the JTA is much more XA specific. The <interfacename>javax.transaction.xa.XAResource</interfacename> interface is a Java mapping of the <interfacename>XA</interfacename> interface. The <interfacename>XAResource</interfacename> interface defines the contract between a Resource Manager and a Transaction Manager in a distributed transaction processing environment. A resource adapter for a resource manager implements the <interfacename>XAResource</interfacename> interface to support association of a top-level transaction to a resource such as a relational database.
</para>
+ <para>
+ The <interfacename>XAResource</interfacename> interface can be supported by any transactional resource adapter that is intended to be used in an environment where transactions are controlled by an external transaction manager, for example, a database management system. An application may access data through multiple database connections. Each database connection is associated with an <code>XAResource</code> object that serves as a proxy object to the underlying resource manager instance. The transaction manager obtains an <code>XAResource</code> for each resource manager participating in a top-level transaction. It uses the start method to associate the transaction with the resource, and it uses the end method to disassociate the transaction from the resource.
+ </para>
+ <para>
+ The resource manager is responsible for associating the transaction with all work performed on its data between the start and end invocations. At transaction commit time, these transactional resource managers are informed by the transaction manager to prepare, commit, or rollback the transaction according to the two-phase commit protocol.
+ </para>
+ <para>
+ In order to be better integrated with Java, the <interfacename>XAResource</interfacename> differs from the standard <interfacename>XA</interfacename> interface in the following ways:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ The resource manager initialization is done implicitly by the resource adapter when the resource (connection) is acquired. There is no <code>xa_open</code> equivalent.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <code>Rmid</code> is not passed as an argument. Each <code>Rmid</code> is represented by a separate <code>XAResource</code> object.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Asynchronous operations are not supported because Java supports multi-threaded processing and most databases do not support asynchronous operations.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Error return values that are caused by the transaction manager’s improper handling of the <code>XAResource</code> object are mapped to Java exceptions via the <classname>XAException</classname> class.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ The DTP concept of <emphasis>Thread of Control</emphasis> maps to all Java threads that are given access to the <code>XAResource</code> and <code>Connection</code> objects. For example, it is legal for two different threads to perform the start and end operations on the same <code>XAResource</code> object.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <formalpara>
+ <title>Extended XAResource control</title>
+ <para>
+ By default, whenever an <code>XAResource</code> object is registered with a JTA compliant transaction service, you have no control over the order in which it will be invoked during the two-phase commit protocol, with respect to other <code>XAResource</code> objects. In JBossTS, however, there is support for controlling the order via the two interfaces <interfacename>com.arjuna.ats.jta.resources.StartXAResource</interfacename> and <interfacename>com.arjuna.ats.jta.resources.EndXAResource</interfacename>. By inheriting your <code>XAResource</code> instance from either of these interfaces, you control whether an instance of your class will be invoked first or last, respectively.
+ </para>
+ </formalpara>
+ <note>
+ <para>
+ Only one instance of each interface type may be registered with a specific transaction.
+ </para>
+ </note>
+ <para>
+ In the TxCore manual we discussed the Last Resource Commit optimization (LRCO), whereby a single resource that is only one-phase aware (does not support prepare), can be enlisted with a transaction that is manipulating two-phase aware participants. This optimization is also supported within the JTA aspects of JBossTS.
+ </para>
+ <para>
+ In order to use the LRCO, your <interfacename>XAResource</interfacename> implementation must extend the <interfacename>com.arjuna.ats.jta.resources.LastResourceCommitOptimisation</interfacename> marker interface (it provides no methods). When enlisting the resource via Transaction.enlistResource, JBossTS will ensure that only a single instance of this type of participant is used within each transaction. Your resource will be driven last in the commit protocol: no invocation of prepare will occur.
+ </para>
+ <note>
+ <para>
+ By default an attempt to enlist more than one instance of a <classname>LastResourceCommitOptimisation</classname> class will fail and false will be returned from <methodname>Transaction.enlistResource</methodname>. This behaviour can be overridden by setting the <property>com.arjuna.ats.jta.allowMultipleLastResources</property> to true. However, before doing so you should read the Section on enlisting multiple one-phase aware resources.
+ </para>
+ </note>
+ <para>
+ In order to utilize the LRCO in a distributed environment, it is necessary to disable interposition support. It is still possible to use implicit context propagation.
+ </para>
+ <formalpara>
+ <title>Enlisting multiple one-phase aware resources</title>
+ <para>
+ As discussed in the Transaction Core documentation, in order to guarantee consistency (atomicity) of outcome between multiple participants (resources) within the same transaction, the two-phase commit protocol is used with a durable transaction log. In the case of possessing a single one-phase aware resource, it is still possible to achieve an atomic (all of nothing) outcome across resources by utilizing the Last Resource Commit Optimization, as explained earlier.
+ </para>
+ </formalpara>
+ <para>
+ However, there may be situations where multiple one-phase aware resources are enlisted within the same transaction. For example, a legacy database running within the same transaction as a legacy JMS implementation. In these situations it is not possible to achieve atomicity of transaction outcome across multiple resources because none of them enter the prepare (waiting for final outcome) state: they commit or rollback immediately when instructed by the transaction coordinator, without knowledge of other resource states and without any way of undoing should subsequent resources make a different choice. This can result in data corruption or heuristic outcomes.
+ </para>
+ <para>
+ In these situations we recommend one of the following approaches:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ Wrap the resources in compensating transactions. See the Web Services transactions guides for further details.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Migrate the legacy implementations to two-phase aware equivalents.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <para>
+ In the cases where neither of these options are viable, JBossTS does support the enlistment of multiple one-phase aware resources within the same transaction. In order to do this, see the section on the Last Resource Commit Optimization.
+ </para>
+ <caution>
+ <para>
+ Even when this support is enabled, JBossTS will issue warnings when it detects that the option has been enabled ("You have chosen to enable multiple last resources in the transaction manager. This is transactionally unsafe and should not be relied upon.”) and when multiple one-phase resources are enlisted within the transaction (“This is transactionally unsafe and should not be relied on.”).
+ </para>
+ </caution>
</section>
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_2_Test">
- <title>Section 2 Test</title>
+ <section id="Transactions_JTA_Programmers_Guide-The_Resource_Manager-Opening_a_Resource_Manager">
+ <title>Opening a Resource Manager</title>
<para>
- Test of a section
+ The X/Open <interfacename>XA</interfacename> interface requires that the transaction manager initialize a resource manager (xa_open) prior to any other xa_ calls. JTA requires initialization of a resource manager to be embedded within the resource adapter that represents the resource manager. The transaction manager does not need to know how to initialize a resource manager; it is only responsible for informing the resource manager about when to start and end work associated with a transaction and when to complete the transaction. The resource adapter is responsible for opening (initializing) the resource manager when the connection to the resource manager is established.
</para>
</section>
-
+ <section id="Transactions_JTA_Programmers_Guide-The_Resource_Manager-Closing_a_Resource_Manager">
+ <title>Closing a Resource Manager</title>
+ <para>
+ A resource manager is closed by the resource adapter as a result of destroying the transactional resource. A transaction resource at the resource adapter level is comprised of two separate objects:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ An <code>XAResource</code> object that allows the transaction manager to start and end the transaction association with the resource in use and to coordinate transaction completion process.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ A connection object that allows the application to perform operations on the underlying resource (for example, JDBC operations on an RDBMS).
+ </para>
+ </listitem>
+ </itemizedlist>
+ <para>
+ Once opened, the resource manager is kept open until the resource is released (closed) explicitly. When the application invokes the connection’s close method, the resource adapter invalidates the connection object reference that was held by the application and notifies the application server about the close. The transaction manager should invoke the <methodname>XAResource.end</methodname> method to disassociate the transaction from that connection.
+ </para>
+ <para>
+ The close notification allows the application server to perform any necessary cleanup work and to mark the physical XA connection as free for reuse, if connection pooling is in place.
+ </para>
+ </section>
+ <section id="Transactions_JTA_Programmers_Guide-The_Resource_Manager-Threads_of_control">
+ <title>Threads of control</title>
+ <para>
+ The X/Open <interfacename>XA</interfacename> interface specifies that the transaction association related xa calls must be invoked from the same thread context. This thread-of-control requirement is not applicable to the object-oriented component-based application run-time environment, in which application threads are dispatched dynamically at method invocation time. Different threads may be using the same connection resource to access the resource manager if the connection spans multiple method invocation. Depending on the implementation of the application server, different threads may be involved with the same <code>XAResource</code> object. The resource context and the transaction context may be operated independent of thread context. This means that it is possible for different threads to be invoking the start and end methods.
+ </para>
+ <para>
+ If the application server allows multiple threads to use a single <code>XAResource</code> object and the associated connection to the resource manager, it is the responsibility of the application server to ensure that there is only one transaction context associated with the resource at any point of time. Thus the <interfacename>XAResource</interfacename> interface requires that the resource managers be able to support the two-phase commit protocol from any thread context.
+ </para>
+ </section>
+ <section id="Transactions_JTA_Programmers_Guide-The_Resource_Manager-Transaction_association">
+ <title>Transaction association</title>
+ <para>
+ Transactions are associated with a transactional resource via the start method, and disassociated from the resource via the <methodname>end</methodname> method. The resource adapter is responsible for internally maintaining an association between the resource connection object and the <code>XAResource</code> object. At any given time, a connection is associated with a single transaction, or it is not associated with any transaction at all. Because JTA does not support nested transactions it is an error for the start method to be invoked on a connection that is currently associated with a different transaction.
+ </para>
+ <para>
+ Interleaving multiple transaction contexts using the same resource may be done by the transaction manager as long as start and end are invoked properly for each transaction context switch. Each time the resource is used with a different transaction, the method end must be invoked for the previous transaction that was associated with the resource, and start must be invoked for the current transaction context.
+ </para>
+ </section>
+ <section id="Transactions_JTA_Programmers_Guide-The_Resource_Manager-Externally_controlled_connections">
+ <title>Externally controlled connections</title>
+ <para>
+ For transactional application whose transaction states are managed by an application server, its resources must also be managed by the application server so that transaction association is performed properly. If an application is associated with a transaction, it is an error for the application to perform transactional work through the connection without having the connection’s resource object already associated with the global transaction. The application server must ensure that the <code>XAResource</code> object in use is associated with the transaction. This is done by invoking the <methodname>Transaction.enlistResource</methodname> method.
+ </para>
+ <para>
+ If a server side transactional application retains its database connection across multiple client requests, the application server must ensure that before dispatching a client request to the application thread, the resource is enlisted with the application’s current transaction context. This implies that the application server manages the connection resource usage status across multiple method invocations.
+ </para>
+ </section>
+ <section id="Transactions_JTA_Programmers_Guide-The_Resource_Manager-Resource_sharing">
+ <title>Resource sharing</title>
+ <para>
+ When the same transactional resource is used to interleave multiple transactions, it is the responsibility of the application server to ensure that only one transaction is enlisted with the resource at any given time. To initiate the transaction commit process, the transaction manager is allowed to use any of the resource objects connected to the same resource manager instance. The resource object used for the two-phase commit protocol does not need to have been involved with the transaction being completed.
+ </para>
+ <para>
+ The resource adapter must be able to handle multiple threads invoking the <interfacename>XAResource</interfacename> methods concurrently for transaction commit processing. For example, with reference to the code below, suppose we have a transactional resource <code>r1</code>. Global transaction <code>xid1</code> was started and ended with <code>r1</code>. Then a different global transaction <code>xid2</code> is associated with <code>r1</code>. In the meanwhile, the transaction manager may start the two phase commit process for <code>xid1</code> using <code>r1</code> or any other transactional resource connected to the same resource manager. The resource adapter needs to allow the commit process to be executed while the resource is currently associated with a different global transaction.
+ </para>
+<screen>
+XAResource xares = r1.getXAResource();
+
+xares.start(xid1); // associate xid1 to the connection
+
+..
+xares.end(xid1); // disassociate xid1 to the connection
+..
+xares.start(xid2); // associate xid2 to the connection
+..
+// While the connection is associated with xid2,
+// the TM starts the commit process for xid1
+status = xares.prepare(xid1);
+..
+xares.commit(xid1, false);
+</screen>
+ </section>
+ <section id="Transactions_JTA_Programmers_Guide-The_Resource_Manager-Local_and_global_transactions">
+ <title>Local and global transactions</title>
+ <para>
+ The resource adapter must support the usage of both local and global transactions within the same transactional connection. Local transactions are transactions that are started and coordinated by the resource manager internally. The <interfacename>XAResource</interfacename> interface is not used for local transactions. When using the same connection to perform both local and global transactions, the following rules apply:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ The local transaction must be committed (or rolled back) before starting a global transaction in the connection.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ The global transaction must be disassociated from the connection before any local transaction is started.
+ </para>
+ </listitem>
+ </itemizedlist>
+ </section>
+ <section id="Transactions_JTA_Programmers_Guide-The_Resource_Manager-Transaction_timeouts">
+ <title>Transaction timeouts</title>
+ <para>
+ Timeout values can be associated with transactions in order to control their lifetime. If a transaction has not terminated (committed or rolled back) before the timeout value elapses, the transaction system will automatically roll it back. The <interfacename>XAResource</interfacename> interface supports a operation, which allows the timeout associated with the current transaction to be propagated to the resource manager and if supported, will override any default timeout associated with the resource manager. This can be useful when long running transactions may have lifetimes that would exceed the default and in which case, if the timeout were not altered, the resource manager would rollback before the transaction terminated and subsequently cause the transaction to roll back as well.
+ </para>
+ <para>
+ If no timeout value is explicitly set for a transaction, or a value of 0 is specified, then an implementation specific default value may be used. In the case of JBossTS, how this default value is set depends upon which JTA implementation you are using.
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ Local JTA: use the <property>com.arjuna.ats.arjuna.coordinator.defaultTimeout</property> property value and give a timeout in seconds. The default value is 60 seconds.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ JTS: use the <property>com.arjuna.ats.jts.defaultTimeout</property> property value and give a timeout in seconds. The default value is 0, for instance, transactions do not timeout.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <para>
+ Unfortunately there are situations where imposing the same timeout as the transaction on a resource manager may not be appropriate. For example, if the system administrator wishes to have control over the lifetimes on resource managers and does not want to (or cannot) allow that control to be passed to some external entity. At present JBossTS supports an all-or-nothing approach to whether or not <methodname>setTransactionTimeout</methodname> is called on <interfacename>XAResource</interfacename> instances.
+ </para>
+ <para>
+ If the <property>com.arjuna.ats.jta.xaTransactionTimeoutEnabled</property> property is set to true (the default) then it will be called on all instances. Alternatively, the <methodname>setXATransactionTimeoutEnabled</methodname> method of <classname>com.arjuna.ats.jta.common.Configuration</classname> can be used.
+ </para>
+ </section>
+ <section id="Transactions_JTA_Programmers_Guide-The_Resource_Manager-Dynamic_Registration">
+ <title>Dynamic Registration</title>
+ <para>
+ Dynamic registration is not supported in <interfacename>XAResource</interfacename> because of the following reasons:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ In the Java component-based application server environment, connections to the resource manager are acquired dynamically when the application explicitly requests a connection. These resources are enlisted with the transaction manager on a needed basis.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ If a resource manager requires a way to dynamically register its work to the global transaction, the implementation can be done at the resource adapter level via a private interface between the resource adapter and the underlying resource manager.
+ </para>
+ </listitem>
+ </itemizedlist>
+ </section>
</chapter>
Modified: projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Transaction_Recovery.xml
===================================================================
--- projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Transaction_Recovery.xml 2008-06-11 01:35:24 UTC (rev 74365)
+++ projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Transaction_Recovery.xml 2008-06-11 03:55:10 UTC (rev 74366)
@@ -2,24 +2,150 @@
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
]>
-<chapter id="Transactions_JTA_Programmers_Guide-Test">
- <title>Test</title>
+<chapter id="Transactions_JTA_Programmers_Guide-Transaction_Recovery">
+ <title>Transaction Recovery</title>
<para>
- This is a test paragraph
</para>
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_1_Test">
- <title>Section 1 Test</title>
+ <section id="Transactions_JTA_Programmers_Guide-Transaction_Recovery-Failure_recovery">
+ <title>Failure recovery</title>
<para>
- Test of a section
+ During recovery, the Transaction Manager needs to be able to communicate to all resource managers that are in use by the applications in the system. For each resource manager, the Transaction Manager uses the <methodname>XAResource.recover</methodname> method to retrieve the list of transactions that are currently in a prepared or heuristically completed state. Typically, the system administrator configures all transactional resource factories that are used by the applications deployed on the system. An example of such a resource factory is the JDBC <code>XADataSource</code> object, which is a factory for the JDBC <code>XAConnection</code> objects.
</para>
+ <para>
+ Because <code>XAResource</code> objects are not persistent across system failures, the Transaction Manager needs to have some way to acquire the <code>XAResource</code> objects that represent the resource managers which might have participated in the transactions prior to the system failure. For example, a Transaction Manager might, through the use of JNDI lookup mechanism, acquire a connection from each of the transactional resource factories, and then obtain the corresponding <code>XAResource</code> object for each connection. The Transaction Manager then invokes the <methodname>XAResource.recover</methodname> method to ask each resource manager to return the transactions that are currently in a prepared or heuristically completed state.
+ </para>
+ <note>
+ <para>
+ When running XA recovery it is necessary to tell JBossTS which types of Xid it can recover. Each Xid that JBossTS creates has a unique node identifier encoded within it and JBossTS will only recover transactions and states that match a specified node identifier. The node identifier to use should be provided to JBossTS via a property that starts with the name <property>com.arjuna.ats.jta.xaRecoveryNode</property>; multiple values may be provided. A value of ‘*’ will force JBossTS to recover (and possibly rollback) all transactions irrespective of their node identifier and should be used with caution.
+ </para>
+ </note>
+ <para>
+ If using the JBossJTA JDBC 2.0 driver, then JBossJTA will take care of all <interfacename>XAResource</interfacename> crash recovery automatically. Otherwise one of the following recovery mechanisms will be used:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ If the <code>XAResource</code> is serializable, then the serialized form will be saved during transaction commitment, and used during recovery. It is assumed that the recreated <code>XAResource</code> is valid and can be used to drive recovery on the associated database.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ The <interfacename>com.arjuna.ats.jta.recovery.XAResourceRecovery</interfacename>, <interfacename>com.arjuna.ats.jta.recovery.XARecoveryResourceManager</interfacename> and <interfacename>com.arjuna.ats.jta.recovery.XARecoveryResource</interfacename> interfaces are used. These are documented in the JDBC chapters on failure recovery.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <note>
+ <para>
+ In JBossTS 3.3 the interface <interfacename>XAConnectionRecovery</interfacename> was deprecated in favor of <interfacename>XAResourceRecovery</interfacename>. Users are encouraged to move to his new interface.
+ </para>
+ </note>
</section>
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_2_Test">
- <title>Section 2 Test</title>
+ <section id="Transactions_JTA_Programmers_Guide-Transaction_Recovery-Recovering_XAConnections">
+ <title>Recovering XAConnections</title>
<para>
- Test of a section
+ When recovering from failures, JBossJTA requires the ability to reconnect to databases that were in use prior to the failures in order to resolve any outstanding transactions. Most connection information will be saved by the transaction service during its normal execution, and can be used during recovery to recreate the connection. However, it is possible that not all such information will have been saved prior to a failure (for example, a failure occurs before such information can be saved, but after the database connection is used). In order to recreate those connections it is necessary to provide implementations of the following JBossJTA interface <interfacename>com.arjuna.ats.jta.recovery.XAResourceRecovery</interfacename>, one for each database that may be used by an application.
</para>
+ <note>
+ <para>
+ If using the transactional JDBC 2.0 driver provided with JBossJTA, then no additional work is necessary in order to ensure that recovery occurs.
+ </para>
+ </note>
+ <para>
+ To inform the recovery system about each of the <code>XAResourceRecovery</code> instances, it is necessary to specify their class names through property variables. Any property variable found in the properties file, or registered at runtime, which starts with the name <property>com.arjuna.ats.jta.recovery.XAResourceRecovery</property> will be assumed to represent one of these instances, and its value should be the class name. For example:
+ </para>
+<screen>
+com.arjuna.ats.jta.recovery.XAResourceRecoveryOracle=com.foo.barRecovery
+</screen>
+ <para>
+ Additional information that will be passed to the instance when it is created may be specified after a semicolon:
+ </para>
+<screen>
+com.arjuna.ats.jta.recovery.XAResourceRecoveryOracle=com.foo.barRecovery;myData=hello
+</screen>
+ <note>
+ <para>
+ These properties need to go into the JTA section of the property file.
+ </para>
+ </note>
+ <para>
+ Any errors will be reported during recovery.
+ </para>
+<screen>
+public interface XAResourceRecovery
+{
+ public XAResource getXAResource () throws SQLException;
+
+ public boolean initialise (String p);
+
+ public boolean hasMoreResources ();
+};
+</screen>
+ <para>
+ Each method should return the following information:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ <methodname>initialise</methodname>: once the instance has been created, any additional information which occurred on the property value (anything found after the first semi-colon) will be passed to the object. The object can then use this information in an implementation specific manner to initialise itself, for example.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <methodname>hasMoreResources</methodname>: each <code>XAResourceRecovery</code> implementation may provide multiple <code>XAResource</code> instances. Before any call to <methodname>getXAResource</methodname> is made, <methodname>hasMoreResources</methodname> is called to determine whether there are any further connections to be obtained. If this returns false, <methodname>getXAResource</methodname> will not be called again during this recovery sweep and the instance will not be used further until the next recovery scan.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <methodname>getXAResource</methodname>: returns an instance of the <code>XAResource</code> object. How this is created (and how the parameters to its constructors are obtained) is up to the <code>XAResourceRecovery</code> implementation. The parameters to the constructors of this class should be similar to those used when creating the initial driver or data source, and should obviously be sufficient to create new <code>XAResources</code> that can be used to drive recovery.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <note>
+ <para>
+ If you want your <code>XAResourceRecovery</code> instance to be called during each sweep of the recovery manager then you should ensure that once <methodname>hasMoreResources</methodname> returns false to indicate the end of work for the current scan it then returns true for the next recovery scan.
+ </para>
+ </note>
</section>
-
+ <section id="Transactions_JTA_Programmers_Guide-Transaction_Recovery-Shipped_XAResourceRecovery_implementations">
+ <title>Shipped XAResourceRecovery implementations</title>
+ <para>
+ Recovery of <interfacename>XA</interfacename> datasources can sometimes be implementation dependant, requiring developers to provide their own <interfacename>XAResourceRecovery</interfacename> instances. However, JBossTS ships with several out-of-the-box implementations that may be useful.
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ <interfacename>com.arjuna.ats.internal.jdbc.recovery.OracleXARecovery</interfacename>: this expects an XML property file to be specified upon creation and from which it will read the database URL, username and password. For example:
+ </para>
+<screen>
+<?xml version="1.0" encoding="UTF-8"?>
+
+<transaction-service>
+ <properties name="jdbc" type="system">
+ <property name="DatabaseURL" value="jdbc:oracle:thin:@hostname:1521:sid"/>
+ <property name="UserName" value="username"/>
+ <property name="Password" value="password"/>
+ </properties>
+</transaction-service>
+</screen>
+ </listitem>
+ <listitem>
+ <para>
+ <interfacename>com.arjuna.ats.internal.jdbc.recovery.JDBCXARecovery</interfacename>: this recovery implementation should work on any datasource that is exposed via JNDI. It expects an XML property file to be specified upon creation and from which it will read the database JNDI name, username and password. For example:
+ </para>
+<screen>
+<?xml version="1.0" encoding="UTF-8"?>
+
+<transaction-service>
+ <properties name="jdbc" type="system">
+ <property name="DatabaseJNDIName" value="java:ExampleDS"/>
+ <property name="UserName" value="username"/>
+ <property name="Password" value="password"/>
+ </properties>
+</transaction-service>
+</screen>
+ </listitem>
+ </itemizedlist>
+ </section>
</chapter>
Modified: projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Transactions.xml
===================================================================
--- projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Transactions.xml 2008-06-11 01:35:24 UTC (rev 74365)
+++ projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Transactions.xml 2008-06-11 03:55:10 UTC (rev 74366)
@@ -2,24 +2,187 @@
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
]>
-<chapter id="Transactions_JTA_Programmers_Guide-Test">
- <title>Test</title>
+<chapter id="Transactions_JTA_Programmers_Guide-Transactions">
+ <title>Transactions</title>
<para>
- This is a test paragraph
</para>
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_1_Test">
- <title>Section 1 Test</title>
+ <section id="Transactions_JTA_Programmers_Guide-Transactions-The_API">
+ <title>The API</title>
<para>
- Test of a section
+ The Java Transaction API consists of three elements: a high-level application transaction demarcation interface, a high-level transaction manager interface intended for application server, and a standard Java mapping of the X/Open XA protocol intended for transactional resource manager. All of the JTA classes and interfaces occur within the <package>javax.transaction</package> package, and the corresponding JBossJTA implementations within the <package>com.arjuna.ats.jta</package> package.
</para>
- </section>
-
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_2_Test">
- <title>Section 2 Test</title>
+ <caution>
+ <para>
+ Each Xid that JBossTS creates must have a unique node identifier encoded within it and JBossTS will only recover transactions and states that match a specified node identifier. The node identifier to use should be provided to JBossTS via the <property>com.arjuna.ats.arjuna.xa.nodeIdentifier</property> property. You must make sure this value is unique across your JBossTS instances. If you do not provide a value, then JBossTS will fabricate one and report the value via the logging infrastructure. The contents of this should be alphanumeric.
+ </para>
+ </caution>
+ <formalpara>
+ <title>UserTransaction</title>
+ <para>
+ The <interfacename>UserTransaction</interfacename> interface provides applications with the ability to control transaction boundaries. It has methods for beginning, committing, and rolling back top-level transactions: nested transactions are not supported, and begin throws the <code>NotSupportedException</code> when the calling thread is already associated with a transaction. <interfacename>UserTransaction</interfacename> automatically associates newly created transactions with the invoking thread.
+ </para>
+ </formalpara>
+ <note>
+ <para>
+ In JBossJTA, UserTransactions can be obtained from the static <methodname>com.arjuna.ats.jta.UserTransaction.userTransaction()</methodname> method.
+ </para>
+ </note>
<para>
- Test of a section
+ In order to select the local JTA implementation it is necessary to perform the following steps:
</para>
+ <orderedlist>
+ <listitem>
+ <para>
+ make sure the property <property>com.arjuna.ats.jta.jtaTMImplementation</property> is set to <property>com.arjuna.ats.internal.jta.transaction.arjunacore.TransactionManagerImple</property>.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ 1.make sure the property <property>com.arjuna.ats.jta.jtaUTImplementation</property> is set to <property>com.arjuna.ats.internal.jta.transaction.arjunacore.UserTransactionImple</property>.
+ </para>
+ </listitem>
+ </orderedlist>
+ <formalpara>
+ <title>TransactionManager</title>
+ <para>
+ The <interfacename>TransactionManager</interfacename> interface allows the application server to control transaction boundaries on behalf of the application being managed.
+ </para>
+ </formalpara>
+ <note>
+ <para>
+ In JBossJTA, transaction manager implementations can be obtained from the static <methodname>com.arjuna.ats.jta.TransactionManager.transactionManager</methodname> method.
+ </para>
+ </note>
+ <para>
+ The Transaction Manager maintains the transaction context association with threads as part of its internal data structure. A thread’s transaction context is either null or it refers to a specific global transaction. Multiple threads may be associated with the same global transaction. As noted above, nested transactions are not supported.
+ </para>
+ <para>
+ Each transaction context is encapsulated by a Transaction object, which can be used to perform operations which are specific to the target transaction, regardless of the calling thread’s transaction context.
+ </para>
+ <para>
+ The <methodname>begin</methodname> method of <interfacename>TransactionManager</interfacename> starts a new top-level transaction and associates the transaction context with the calling thread. If the calling thread is already associated with a transaction then it throws the <code>NotSupportedException</code>.
+ </para>
+ <para>
+ The <methodname>getTransaction</methodname> method returns the Transaction object that represents the transaction context currently associated with the calling thread. This object can be used to perform various operations on the target transaction, described later.
+ </para>
+ <para>
+ The commit method is used to complete the transaction currently associated with the calling thread. After it returns, the calling thread is associated with no transaction. If commit is called when the thread is not associated with any transaction context, the TM throws an exception. In some implementation, the commit operation is restricted to the transaction originator only. If the calling thread is not allowed to commit the transaction, the TM throws an exception. JBossJTA does not currently impose any restriction on the ability of threads to terminate transactions.
+ </para>
+ <para>
+ The <methodname>rollback</methodname> method is used to rollback the transaction associated with the current thread. After the <methodname>rollback</methodname> method completes, the thread is associated with no transaction.
+ </para>
+ <note>
+ <para>
+ In a multi-threaded environment it is possible that multiple threads are active within the same transaction. If checked transaction semantics have been disabled, or the transaction times out, then it is possible for a transaction to be terminated by a thread other than the one that created it. In this case, it is often important that this information is communicated to the creator. JBossTS does this during commit or rollback by throwing <code>IllegalStateException</code>.
+ </para>
+ </note>
+ <formalpara>
+ <title>Suspending and resuming a transaction</title>
+ <para>
+ The JTA supports the concept of a thread temporarily suspending and resuming transactions to enable it to perform non-transactional work. The suspend method is called to temporarily suspend the current transaction that is associated with the calling thread, i.e., so that the thread is no longer operating within its scope. If the thread is not associated with any transaction, a null object reference is returned; otherwise, a valid <code>Transaction</code> object is returned. The <code>Transaction</code> object can later be passed to the resume method to reinstate the transaction context.
+ </para>
+ </formalpara>
+ <para>
+ The <methodname>resume</methodname> method associates the specified transaction context with the calling thread. If the transaction specified is a valid transaction, the transaction context is associated with the calling thread; otherwise, the thread is associated with no transaction.
+ </para>
+ <note>
+ <para>
+ If <methodname>resume</methodname> is invoked when the calling thread is already associated with another transaction, the Transaction Manager throws the <code>IllegalStateException</code> exception.
+ </para>
+ </note>
+<screen>
+Transaction tobj = TransactionManager.suspend();
+ ..
+TransactionManager.resume(tobj);
+</screen>
+ <note>
+ <para>
+ Some Transaction Manager implementations allow a suspended transaction to be resumed by a different thread. This feature is not required by JTA, but JBossJTA does support this.
+ </para>
+ </note>
+ <para>
+ When a transaction is suspended the application server must ensure that the resources in use by the application are no longer registered with the suspended transaction. When a resource is de-listed this triggers the Transaction Manager to inform the resource manager to disassociate the transaction from the specified resource object. When the application’s transaction context is resumed, the application server must ensure that the resources in use by the application are again enlisted with the transaction. Enlisting a resource as a result of resuming a transaction triggers the Transaction Manager to inform the resource manager to re-associate the resource object with the resumed transaction.
+ </para>
+ <formalpara>
+ <title>The Transaction interface</title>
+ <para>
+ The <interfacename>Transaction</interfacename> interface allows operations to be performed on the transaction associated with the target object. Every top-level transaction is associated with one <code>Transaction</code> object when the transaction is created. The <code>Transaction</code> object can be used to:
+ </para>
+ </formalpara>
+ <itemizedlist>
+ <listitem>
+ <para>
+ Enlist the transactional resources in use by the application.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Register for transaction synchronization call backs.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Commit or rollback the transaction.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Obtain the status of the transaction.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <para>
+ The <methodname>commit</methodname> and <methodname>rollback</methodname> methods allow the target object to be committed or rolled back. The calling thread is not required to have the same transaction associated with the thread. If the calling thread is not allowed to commit the transaction, the transaction manager throws an exception. At present JBossJTA does not impose restrictions on threads terminating transactions.
+ </para>
+ <formalpara>
+ <title>Resource enlistment</title>
+ <para>
+ Transactional resources such as database connections are typically managed by the application server in conjunction with some resource adapter and optionally with connection pooling optimization. In order for an external transaction manager to co-ordinate transactional work performed by the resource managers, the application server must enlist and de-list the resources used in the transaction. These resources (participants) are enlisted with the transaction so that they can be informed when the transaction terminates, for example, are driven through the two-phase commit protocol.
+ </para>
+ </formalpara>
+ <para>
+ As stated previously, the JTA is much more closely integrated with the XA concept of resources than the arbitrary objects. For each resource in-use by the application, the application server invokes the <methodname>enlistResource</methodname> method with an <code>XAResource</code> object which identifies the resource in use. See for details on how the implementation of the <code>XAResource</code> can affect recovery in the event of a failure.
+ </para>
+ <para>
+ The enlistment request results in the transaction manager informing the resource manager to start associating the transaction with the work performed through the corresponding resource. The transaction manager is responsible for passing the appropriate flag in its <methodname>XAResource.start</methodname> method call to the resource manager.
+ </para>
+ <para>
+ The <methodname>delistResource</methodname> method is used to disassociate the specified resource from the transaction context in the target object. The application server invokes the method with the two parameters: the <code>XAResource</code> object that represents the resource, and a flag to indicate whether the operation is due to the transaction being suspended (TMSUSPEND), a portion of the work has failed (TMFAIL), or a normal resource release by the application (TMSUCCESS).
+ </para>
+ <para>
+ The de-list request results in the transaction manager informing the resource manager to end the association of the transaction with the target <code>XAResource</code>. The flag value allows the application server to indicate whether it intends to come back to the same resource whereby the resource states must be kept intact. The transaction manager passes the appropriate flag value in its <methodname>XAResource.end</methodname> method call to the underlying resource manager.
+ </para>
+ <formalpara>
+ <title>Transaction synchronization</title>
+ <para>
+ Transaction synchronization allows the application server to be notified before and after the transaction completes. For each transaction started, the application server may optionally register a Synchronization call back object to be invoked by the transaction manager:
+ </para>
+ </formalpara>
+ <itemizedlist>
+ <listitem>
+ <para>
+ The <methodname>beforeCompletion</methodname> method is called prior to the start of the two-phase transaction complete process. This call is executed in the same transaction context of the caller who initiates the <methodname>TransactionManager.commit</methodname> or the call is executed with no transaction context if <methodname>Transaction.commit</methodname> is used.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ The <methodname>afterCompletion</methodname> method is called after the transaction has completed. The status of the transaction is supplied in the parameter. This method is executed without a transaction context.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <formalpara>
+ <title>Transaction equality</title>
+ <para>
+ The transaction manager implements the Transaction object’s equals method to allow comparison between the target object and another Transaction object. The equals method should return true if the target object and the parameter object both refer to the same global transaction.
+ </para>
+ </formalpara>
+<screen>
+Transaction txObj = TransactionManager.getTransaction();
+Transaction someOtherTxObj = ..
+ ..
+
+boolean isSame = txObj.equals(someOtherTxObj);
+</screen>
</section>
-
</chapter>
Modified: projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Using_JBossJTA_in_Application_Servers.xml
===================================================================
--- projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Using_JBossJTA_in_Application_Servers.xml 2008-06-11 01:35:24 UTC (rev 74365)
+++ projects/docs/enterprise/4.3/Transactions/Transactions_JTA_Programmers_Guide/en-US/Using_JBossJTA_in_Application_Servers.xml 2008-06-11 03:55:10 UTC (rev 74366)
@@ -2,24 +2,91 @@
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
]>
-<chapter id="Transactions_JTA_Programmers_Guide-Test">
- <title>Test</title>
+<chapter id="Transactions_JTA_Programmers_Guide-Using_JBossJTA_in_Application_Servers">
+ <title>Using JBossJTA in Application Servers</title>
<para>
- This is a test paragraph
</para>
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_1_Test">
- <title>Section 1 Test</title>
+ <section id="Transactions_JTA_Programmers_Guide-Using_JBossJTA_in_Application_Servers-JBoss_Application_Server">
+ <title>JBoss Application Server</title>
+ <formalpara>
+ <title>Service Configuration</title>
+ <para>
+ The JBoss Transaction Service is configured primarily via the XML files stored in the etc directory, but when run as a JBOSS service there are a number of configurable attributes available. They are as follows:
+ </para>
+ </formalpara>
+ <itemizedlist>
+ <listitem>
+ <para>
+ TransactionTimeout – The default transaction timeout to be used for new transactions. Specified as an integer in seconds.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ StatisticsEnabled – This determines whether or not the transaction service should gather statistical information. This information can then be viewed using the PerformanceStatistics MBean. Specified as a Boolean. The default is to not gather this information.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ PropagateFullContext – This determines whether a full transactional context is propagated by context importer/exporter. If set to false only the current transaction context is propagated. If set to true the full transaction context (including parent transactions) is propagated.
+ </para>
+ </listitem>
+ </itemizedlist>
<para>
- Test of a section
+ These attributes are specified as MBean attributes in the jboss-service.xml file located in the server/all/conf directory, for example:
</para>
- </section>
-
- <section id="Transactions_JTA_Programmers_Guide-Test-Section_2_Test">
- <title>Section 2 Test</title>
+<screen>
+<mbean code="com.arjuna.ats.jbossatx.jts.TransactionManagerService" name="jboss:service=TransactionManager">
+
+<attribute name="TransactionTimeout">300</attribute>
+<attribute name="StatisticsEnabled>true</attribute>>
+
+</mbean>
+</screen>
<para>
- Test of a section
+ The transaction service is configurable also via the standard JBoss Transaction Service property files. These are located in the JBossTS install location under the etc sub-directory.
</para>
+ <para>
+ These files can be edited manually or through JMX. Each property file is exposed via an object with the name <code>com.arjuna.ts.properties</code> and an attribute of module where module is equal to the name of the module to be configured, for example, <code>com.arjuna.ts.properties:module=arjuna</code>.
+ </para>
+ <formalpara>
+ <title>Logging</title>
+ <para>
+ In order to make JBossTS logging semantically consistent with JBossAS, the TransactionManagerService modifies the level of some log messages. This is achieved by overriding the value of the <property>com.arjuna.common.util.logger</property> property given in the <filename>jbossjta-properties.xml</filename> file. Therefore, the value of this property will have no effect on the logging behaviour when running embedded in JBossAS. By forcing use of the log4j_releveler logger, the TransactionManagerService causes all INFO level messages in the transaction code to be modified to behave as DEBUG messages. Therefore, these messages will not appear in log files if the filter level is INFO. All other log messages behave as normal.
+ </para>
+ </formalpara>
+ <formalpara>
+ <title>The services</title>
+ <para>
+ There is currently one service offered by the JBOSS integration called TransactionManagerService. Here we shall discuss what this service does.
+ </para>
+ </formalpara>
+ <para>
+ The transaction manager service’s main purpose is to ensure the recovery manager is started. It also binds the JBossTS JTA transaction manager to java:/TransactionManager name with the JNDI provider. This service depends upon the existence of the CORBA ORB Service and it must be using JacORB as the underlying ORB implementation.
+ </para>
+ <para>
+ There are two instances of this service:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ distributed: this uses the JTS enabled transaction manager implementation and hence supports distributed transactions and recovery. To configure this use the <classname>com.arjuna.ats.jbossatx.jts.TransactionManagerService</classname> class. This is the default configuration.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ local: this uses the purely local JTA implementation. To configure this use the <classname>com.arjuna.ats.jbossatx.jta.TransactionManagerService</classname> class.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <formalpara>
+ <title>Ensuring Transactional Context is Propagated to the Server</title>
+ <para>
+ It is possible to coordinate transactions from a coordinator which is not located within the JBoss server (e.g. using transactions created by an external OTS server). To ensure the transaction context is propagated via JRMP invocations to the server, the transaction propagation context factory needs to be explicitly set for the JRMP invoker proxy. This is done as follows:
+ </para>
+ </formalpara>
+<screen>
+JRMPInvokerProxy.setTPCFactory( new com.arjuna.ats.internal.jbossatx.jts.PropagationContextManager() );
+</screen>
</section>
-
</chapter>
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