Importing upstream Jetty jetty-9.2.1.v20140609

[gigi.git] / lib / jetty / org / eclipse / jetty / servlet / listener / ELContextCleaner.java

diff --git a/lib/jetty/org/eclipse/jetty/servlet/listener/ELContextCleaner.java b/lib/jetty/org/eclipse/jetty/servlet/listener/ELContextCleaner.java
new file mode 100644 (file)
index 0000000..81b7528
--- /dev/null
+++ b/lib/jetty/org/eclipse/jetty/servlet/listener/ELContextCleaner.java
@@ -0,0 +1,126 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.servlet.listener;
+
+import java.lang.reflect.Field;
+import java.util.Iterator;
+import java.util.concurrent.ConcurrentHashMap;
+
+import javax.servlet.ServletContextEvent;
+import javax.servlet.ServletContextListener;
+
+import org.eclipse.jetty.util.Loader;
+import org.eclipse.jetty.util.log.Log;
+import org.eclipse.jetty.util.log.Logger;
+
+/**
+ * ELContextCleaner
+ *
+ * Clean up BeanELResolver when the context is going out
+ * of service:
+ *
+ * See http://java.net/jira/browse/GLASSFISH-1649
+ * See https://bugs.eclipse.org/bugs/show_bug.cgi?id=353095
+ */
+public class ELContextCleaner implements ServletContextListener
+{
+    private static final Logger LOG = Log.getLogger(ELContextCleaner.class);
+
+
+    public void contextInitialized(ServletContextEvent sce)
+    {
+    }
+
+    public void contextDestroyed(ServletContextEvent sce)
+    {
+        try
+        {
+            //Check that the BeanELResolver class is on the classpath
+            Class beanELResolver = Loader.loadClass(this.getClass(), "javax.el.BeanELResolver");
+
+            //Get a reference via reflection to the properties field which is holding class references
+            Field field = getField(beanELResolver);
+
+            //Get rid of references
+            purgeEntries(field);
+
+            LOG.debug("javax.el.BeanELResolver purged");
+        }
+
+        catch (ClassNotFoundException e)
+        {
+            //BeanELResolver not on classpath, ignore
+        }
+        catch (SecurityException e)
+        {
+            LOG.warn("Cannot purge classes from javax.el.BeanELResolver", e);
+        }
+        catch (IllegalArgumentException e)
+        {
+            LOG.warn("Cannot purge classes from javax.el.BeanELResolver", e);
+        }
+        catch (IllegalAccessException e)
+        {
+            LOG.warn("Cannot purge classes from javax.el.BeanELResolver", e);
+        }
+        catch (NoSuchFieldException e)
+        {
+            LOG.debug("Not cleaning cached beans: no such field javax.el.BeanELResolver.properties");
+        }
+
+    }
+
+
+    protected Field getField (Class beanELResolver)
+    throws SecurityException, NoSuchFieldException
+    {
+        if (beanELResolver == null)
+            return  null;
+
+        return beanELResolver.getDeclaredField("properties");
+    }
+
+    protected void purgeEntries (Field properties)
+    throws IllegalArgumentException, IllegalAccessException
+    {
+        if (properties == null)
+            return;
+
+        if (!properties.isAccessible())
+            properties.setAccessible(true);
+
+        ConcurrentHashMap map = (ConcurrentHashMap) properties.get(null);
+        if (map == null)
+            return;
+
+        Iterator<Class> itor = map.keySet().iterator();
+        while (itor.hasNext())
+        {
+            Class clazz = itor.next();
+            LOG.debug("Clazz: "+clazz+" loaded by "+clazz.getClassLoader());
+            if (Thread.currentThread().getContextClassLoader().equals(clazz.getClassLoader()))
+            {
+                itor.remove();
+                LOG.debug("removed");
+            }
+            else
+                LOG.debug("not removed: "+"contextclassloader="+Thread.currentThread().getContextClassLoader()+"clazz's classloader="+clazz.getClassLoader());
+        }
+    }
+}