8:22 a.m.
Author: dan.j.allen
Date: 2008-12-04 02:22:51 -0500 (Thu, 04 Dec 2008)
New Revision: 9712
Added:
trunk/src/main/org/jboss/seam/jmx/
trunk/src/main/org/jboss/seam/jmx/JBossClusterMonitor.java
Modified:
trunk/src/main/org/jboss/seam/servlet/SeamListener.java
Log:
JBSEAM-3172
Added: trunk/src/main/org/jboss/seam/jmx/JBossClusterMonitor.java
===================================================================
--- trunk/src/main/org/jboss/seam/jmx/JBossClusterMonitor.java
(rev 0)
+++ trunk/src/main/org/jboss/seam/jmx/JBossClusterMonitor.java 2008-12-04 07:22:51 UTC
(rev 9712)
@@ -0,0 +1,149 @@
+package org.jboss.seam.jmx;
+
+import static org.jboss.seam.ScopeType.APPLICATION;
+import static org.jboss.seam.annotations.Install.BUILT_IN;
+
+import java.util.Iterator;
+import java.util.Vector;
+
+import javax.management.MBeanServer;
+import javax.management.MBeanServerFactory;
+import javax.management.MalformedObjectNameException;
+import javax.management.ObjectName;
+import javax.servlet.ServletContext;
+
+import org.jboss.seam.Seam;
+import org.jboss.seam.annotations.Create;
+import org.jboss.seam.annotations.Install;
+import org.jboss.seam.annotations.Name;
+import org.jboss.seam.annotations.Scope;
+import org.jboss.seam.annotations.Startup;
+import org.jboss.seam.annotations.intercept.BypassInterceptors;
+import org.jboss.seam.log.Log;
+import org.jboss.seam.log.Logging;
+
+(a)Name("org.jboss.seam.jmx.jbossClusterMonitor")
+@BypassInterceptors
+@Scope(APPLICATION)
+@Startup
+@Install(precedence=BUILT_IN,
classDependencies="org.jgroups.MembershipListener")
+public class JBossClusterMonitor
+{
+ private static Log log = Logging.getLog(JBossClusterMonitor.class);
+
+ private MBeanServer jbossMBeanServer;
+
+ private boolean clustered;
+
+ private ObjectName clusteringCacheObjectName;
+
+ private ObjectName serverObjectName;
+
+ @Create
+ public void create()
+ {
+ jbossMBeanServer = locateJBoss();
+
+ if (!isJBoss())
+ {
+ return;
+ }
+
+ try
+ {
+ clusteringCacheObjectName = new
ObjectName("jboss.cache:service=TomcatClusteringCache");
+ serverObjectName = new ObjectName("jboss.system:type=Server");
+ }
+ catch (MalformedObjectNameException e)
+ {
+ log.warn("Invalid JMX name: " + e.getMessage());
+ }
+
+ try
+ {
+ jbossMBeanServer.getMBeanInfo(clusteringCacheObjectName);
+ clustered = true;
+ log.info("JBoss cluster detected");
+ }
+ catch (Exception e) {}
+ }
+
+ public boolean isClustered()
+ {
+ return clustered;
+ }
+
+ /**
+ * Consults the jboss.system:type=Server MBean to determine if this instance
+ * of JBoss AS is currently being shutdown. Note that the flag only returns
+ * true if the shutdown() method on this MBean is used. It does not detect a
+ * force halt via a process signal (i.e., CTRL-C).
+ */
+ public boolean nodeIsShuttingDown()
+ {
+ if (!isJBoss())
+ {
+ return false;
+ }
+
+ try
+ {
+ return (Boolean) jbossMBeanServer.getAttribute(serverObjectName,
"InShutdown");
+ }
+ catch (Exception e)
+ {
+ return false;
+ }
+ }
+
+ public boolean isLastNode()
+ {
+ if (!clustered)
+ {
+ return true;
+ }
+
+ // other options
+ // object name => jboss.jgroups:cluster=DefaultPartition,type=channel
+ // object name => jboss.jgroups:cluster=Tomcat-Cluster,type=channel
+ // attribute => NumberOfTasksInTimer
+
+ try
+ {
+ return ((Vector) jbossMBeanServer.getAttribute(clusteringCacheObjectName,
"Members")).size() == 1;
+ }
+ catch (Exception e) {
+ log.warn("Could not determine number of members in cluster", e);
+ return true;
+ }
+ }
+
+ public boolean failover()
+ {
+ return isClustered() && nodeIsShuttingDown() && !isLastNode();
+ }
+
+ public boolean isJBoss()
+ {
+ return jbossMBeanServer != null;
+ }
+
+ protected MBeanServer locateJBoss()
+ {
+ for (Iterator i = MBeanServerFactory.findMBeanServer(null).iterator(); i.hasNext();
)
+ {
+ MBeanServer server = (MBeanServer) i.next();
+ if (server.getDefaultDomain().equals("jboss"))
+ {
+ return server;
+ }
+ }
+ return null;
+ }
+
+ // FIXME my sense is that this could lookup could be more elegant or conforming
+ public static JBossClusterMonitor getInstance(ServletContext ctx)
+ {
+ return (JBossClusterMonitor)
ctx.getAttribute(Seam.getComponentName(JBossClusterMonitor.class));
+ }
+}
Modified: trunk/src/main/org/jboss/seam/servlet/SeamListener.java
===================================================================
--- trunk/src/main/org/jboss/seam/servlet/SeamListener.java 2008-12-04 03:42:05 UTC (rev
9711)
+++ trunk/src/main/org/jboss/seam/servlet/SeamListener.java 2008-12-04 07:22:51 UTC (rev
9712)
@@ -14,6 +14,7 @@
import org.jboss.seam.Seam;
import org.jboss.seam.contexts.ServletLifecycle;
import org.jboss.seam.init.Initialization;
+import org.jboss.seam.jmx.JBossClusterMonitor;
import org.jboss.seam.log.LogProvider;
import org.jboss.seam.log.Logging;
@@ -46,7 +47,16 @@
public void sessionDestroyed(HttpSessionEvent event)
{
- ServletLifecycle.endSession( event.getSession() );
+ JBossClusterMonitor monitor =
JBossClusterMonitor.getInstance(event.getSession().getServletContext());
+ if (monitor != null && monitor.failover())
+ {
+ // If application is unfarmed or all nodes shutdown simultaneously, cluster
cache may still fail to retrieve SFSBs to destroy
+ log.info("Detected fail-over, not destroying session context");
+ }
+ else
+ {
+ ServletLifecycle.endSession( event.getSession() );
+ }
}
}