--- a/jdk/src/share/classes/com/sun/jmx/remote/util/EventClientConnection.java Wed Oct 21 16:28:57 2009 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,469 +0,0 @@
-/*
- * Copyright 2007-2008 Sun Microsystems, Inc. All Rights Reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation. Sun designates this
- * particular file as subject to the "Classpath" exception as provided
- * by Sun in the LICENSE file that accompanied this code.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
- */
-
-package com.sun.jmx.remote.util;
-
-import com.sun.jmx.defaults.JmxProperties;
-import com.sun.jmx.event.EventClientFactory;
-
-import java.lang.reflect.InvocationHandler;
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
-import java.lang.reflect.Proxy;
-import java.util.Arrays;
-import java.util.concurrent.Callable;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReentrantLock;
-import java.util.logging.Level;
-import java.util.logging.Logger;
-
-import javax.management.MBeanServerConnection;
-import javax.management.NotificationFilter;
-import javax.management.NotificationListener;
-import javax.management.ObjectName;
-import javax.management.event.EventClient;
-import javax.management.event.EventClientDelegate;
-import javax.management.namespace.JMXNamespaces;
-
-/**
- * Class EventClientConnection - a {@link Proxy} that wraps an
- * {@link MBeanServerConnection} and an {@link EventClient}.
- * All methods are routed to the underlying {@code MBeanServerConnection},
- * except add/remove notification listeners which are routed to the
- * {@code EventClient}.
- * The caller only sees an {@code MBeanServerConnection} which uses an
- * {@code EventClient} behind the scenes.
- *
- * @author Sun Microsystems, Inc.
- */
-public class EventClientConnection implements InvocationHandler,
- EventClientFactory {
-
- /**
- * A logger for this class.
- **/
- private static final Logger LOG = JmxProperties.NOTIFICATION_LOGGER;
-
- private static final int NAMESPACE_SEPARATOR_LENGTH =
- JMXNamespaces.NAMESPACE_SEPARATOR.length();
-
- /**
- * Creates a new {@code EventClientConnection}.
- * @param connection The underlying MBeanServerConnection.
- */
- public EventClientConnection(MBeanServerConnection connection) {
- this(connection,null);
- }
-
- /**
- * Creates a new {@code EventClientConnection}.
- * @param connection The underlying MBeanServerConnection.
- * @param eventClientFactory a factory object that will be invoked
- * to create an {@link EventClient} when needed.
- * The {@code EventClient} is created lazily, when it is needed
- * for the first time. If null, a default factory will be used
- * (see {@link #createEventClient}).
- */
- public EventClientConnection(MBeanServerConnection connection,
- Callable<EventClient> eventClientFactory) {
-
- if (connection == null) {
- throw new IllegalArgumentException("Null connection");
- }
- this.connection = connection;
- if (eventClientFactory == null) {
- eventClientFactory = new Callable<EventClient>() {
- public final EventClient call() throws Exception {
- return createEventClient(EventClientConnection.this.connection);
- }
- };
- }
- this.eventClientFactory = eventClientFactory;
- this.lock = new ReentrantLock();
- }
-
- /**
- * <p>The MBean server connection through which the methods of
- * a proxy using this handler are forwarded.</p>
- *
- * @return the MBean server connection.
- *
- * @since 1.6
- */
- public MBeanServerConnection getMBeanServerConnection() {
- return connection;
- }
-
-
-
-
- /**
- * Creates a new EventClientConnection proxy instance.
- *
- * @param <T> The underlying {@code MBeanServerConnection} - which should
- * not be using the Event Service itself.
- * @param interfaceClass {@code MBeanServerConnection.class}, or a subclass.
- * @param eventClientFactory a factory used to create the EventClient.
- * If null, a default factory is used (see {@link
- * #createEventClient}).
- * @return the new proxy instance, which will route add/remove notification
- * listener calls through an {@code EventClient}.
- *
- */
- private static <T extends MBeanServerConnection> T
- newProxyInstance(T connection,
- Class<T> interfaceClass, Callable<EventClient> eventClientFactory) {
- final InvocationHandler handler =
- new EventClientConnection(connection,eventClientFactory);
- final Class<?>[] interfaces =
- new Class<?>[] {interfaceClass, EventClientFactory.class};
-
- Object proxy =
- Proxy.newProxyInstance(interfaceClass.getClassLoader(),
- interfaces,
- handler);
- return interfaceClass.cast(proxy);
- }
-
-
- public Object invoke(Object proxy, Method method, Object[] args)
- throws Throwable {
- final String methodName = method.getName();
-
- // add/remove notification listener are routed to the EventClient
- if (methodName.equals("addNotificationListener")
- || methodName.equals("removeNotificationListener")) {
- final Class<?>[] sig = method.getParameterTypes();
- if (sig.length>1 &&
- NotificationListener.class.isAssignableFrom(sig[1])) {
- return invokeBroadcasterMethod(proxy,method,args);
- }
- }
-
- // subscribe/unsubscribe are also routed to the EventClient.
- final Class<?> clazz = method.getDeclaringClass();
- if (clazz.equals(EventClientFactory.class)) {
- return invokeEventClientSubscriberMethod(proxy,method,args);
- }
-
- // local or not: equals, toString, hashCode
- if (shouldDoLocally(proxy, method))
- return doLocally(proxy, method, args);
-
- return call(connection,method,args);
- }
-
- // The purpose of this method is to unwrap InvocationTargetException,
- // in order to avoid throwing UndeclaredThrowableException for
- // declared exceptions.
- //
- // When calling method.invoke(), any exception thrown by the invoked
- // method will be wrapped in InvocationTargetException. If we don't
- // unwrap this exception, the proxy will always throw
- // UndeclaredThrowableException, even for runtime exceptions.
- //
- private Object call(final Object obj, final Method m,
- final Object[] args)
- throws Throwable {
- try {
- return m.invoke(obj,args);
- } catch (InvocationTargetException x) {
- final Throwable xx = x.getTargetException();
- if (xx == null) throw x;
- else throw xx;
- }
- }
-
- /**
- * Route add/remove notification listener to the event client.
- **/
- private Object invokeBroadcasterMethod(Object proxy, Method method,
- Object[] args) throws Exception {
- final String methodName = method.getName();
- final int nargs = (args == null) ? 0 : args.length;
-
- if (nargs < 1) {
- final String msg =
- "Bad arg count: " + nargs;
- throw new IllegalArgumentException(msg);
- }
-
- final ObjectName mbean = (ObjectName) args[0];
- final EventClient evtClient = getEventClient();
-
- // Fails if evtClient is null AND the MBean we try to listen to is
- // in a subnamespace. We fail here because we know this will not
- // work.
- //
- // Note that if the wrapped MBeanServerConnection points to a an
- // earlier agent (JDK 1.6 or earlier), then the EventClient will
- // be null (we can't use the event service with earlier JDKs).
- //
- // In principle a null evtClient indicates that the remote VM is of
- // an earlier version, in which case it shouldn't contain any namespace.
- //
- // So having a null evtClient AND an MBean contained in a namespace is
- // clearly an error case.
- //
- if (evtClient == null) {
- final String domain = mbean.getDomain();
- final int index = domain.indexOf(JMXNamespaces.NAMESPACE_SEPARATOR);
- if (index > -1 && index <
- (domain.length()-NAMESPACE_SEPARATOR_LENGTH)) {
- throw new UnsupportedOperationException(method.getName()+
- " on namespace "+domain.substring(0,index+
- NAMESPACE_SEPARATOR_LENGTH));
- }
- }
-
- if (methodName.equals("addNotificationListener")) {
- /* The various throws of IllegalArgumentException here
- should not happen, since we know what the methods in
- NotificationBroadcaster and NotificationEmitter
- are. */
- if (nargs != 4) {
- final String msg =
- "Bad arg count to addNotificationListener: " + nargs;
- throw new IllegalArgumentException(msg);
- }
- /* Other inconsistencies will produce ClassCastException
- below. */
-
- final NotificationListener listener = (NotificationListener) args[1];
- final NotificationFilter filter = (NotificationFilter) args[2];
- final Object handback = args[3];
-
- if (evtClient != null) {
- // general case
- evtClient.addNotificationListener(mbean,listener,filter,handback);
- } else {
- // deprecated case. Only works for mbean in local namespace.
- connection.addNotificationListener(mbean,listener,filter,
- handback);
- }
- return null;
-
- } else if (methodName.equals("removeNotificationListener")) {
-
- /* NullPointerException if method with no args, but that
- shouldn't happen because removeNL does have args. */
- NotificationListener listener = (NotificationListener) args[1];
-
- switch (nargs) {
- case 2:
- if (evtClient != null) {
- // general case
- evtClient.removeNotificationListener(mbean,listener);
- } else {
- // deprecated case. Only works for mbean in local namespace.
- connection.removeNotificationListener(mbean, listener);
- }
- return null;
-
- case 4:
- NotificationFilter filter = (NotificationFilter) args[2];
- Object handback = args[3];
- if (evtClient != null) {
- evtClient.removeNotificationListener(mbean,
- listener,
- filter,
- handback);
- } else {
- connection.removeNotificationListener(mbean,
- listener,
- filter,
- handback);
- }
- return null;
-
- default:
- final String msg =
- "Bad arg count to removeNotificationListener: " + nargs;
- throw new IllegalArgumentException(msg);
- }
-
- } else {
- throw new IllegalArgumentException("Bad method name: " +
- methodName);
- }
- }
-
- private boolean shouldDoLocally(Object proxy, Method method) {
- final String methodName = method.getName();
- if ((methodName.equals("hashCode") || methodName.equals("toString"))
- && method.getParameterTypes().length == 0
- && isLocal(proxy, method))
- return true;
- if (methodName.equals("equals")
- && Arrays.equals(method.getParameterTypes(),
- new Class<?>[] {Object.class})
- && isLocal(proxy, method))
- return true;
- return false;
- }
-
- private Object doLocally(Object proxy, Method method, Object[] args) {
- final String methodName = method.getName();
-
- if (methodName.equals("equals")) {
-
- if (this == args[0]) {
- return true;
- }
-
- if (!(args[0] instanceof Proxy)) {
- return false;
- }
-
- final InvocationHandler ihandler =
- Proxy.getInvocationHandler(args[0]);
-
- if (ihandler == null ||
- !(ihandler instanceof EventClientConnection)) {
- return false;
- }
-
- final EventClientConnection handler =
- (EventClientConnection)ihandler;
-
- return connection.equals(handler.connection) &&
- proxy.getClass().equals(args[0].getClass());
- } else if (methodName.equals("hashCode")) {
- return connection.hashCode();
- }
-
- throw new RuntimeException("Unexpected method name: " + methodName);
- }
-
- private static boolean isLocal(Object proxy, Method method) {
- final Class<?>[] interfaces = proxy.getClass().getInterfaces();
- if(interfaces == null) {
- return true;
- }
-
- final String methodName = method.getName();
- final Class<?>[] params = method.getParameterTypes();
- for (Class<?> intf : interfaces) {
- try {
- intf.getMethod(methodName, params);
- return false; // found method in one of our interfaces
- } catch (NoSuchMethodException nsme) {
- // OK.
- }
- }
-
- return true; // did not find in any interface
- }
-
- /**
- * Return the EventClient used by this object. Can be null if the
- * remote VM is of an earlier JDK version which doesn't have the
- * event service.<br>
- * This method will invoke the event client factory the first time
- * it is called.
- **/
- public final EventClient getEventClient() {
- if (initialized) return client;
- try {
- if (!lock.tryLock(TRYLOCK_TIMEOUT,TimeUnit.SECONDS))
- throw new IllegalStateException("can't acquire lock");
- try {
- client = eventClientFactory.call();
- initialized = true;
- } finally {
- lock.unlock();
- }
- } catch (RuntimeException x) {
- throw x;
- } catch (Exception x) {
- throw new IllegalStateException("Can't create EventClient: "+x,x);
- }
- return client;
- }
-
- /**
- * Returns an event client for the wrapped {@code MBeanServerConnection}.
- * This is the method invoked by the default event client factory.
- * @param connection the wrapped {@code MBeanServerConnection}.
- **/
- protected EventClient createEventClient(MBeanServerConnection connection)
- throws Exception {
- final ObjectName name =
- EventClientDelegate.OBJECT_NAME;
- if (connection.isRegistered(name)) {
- return new EventClient(connection);
- }
- return null;
- }
-
- /**
- * Creates a new {@link MBeanServerConnection} that goes through an
- * {@link EventClient} to receive/subscribe to notifications.
- * @param connection the underlying {@link MBeanServerConnection}.
- * The given <code>connection</code> shouldn't be already
- * using an {@code EventClient}.
- * @param eventClientFactory a factory object that will be invoked
- * to create an {@link EventClient} when needed.
- * The {@code EventClient} is created lazily, when it is needed
- * for the first time. If null, a default factory will be used
- * (see {@link #createEventClient}).
- * @return the MBeanServerConnection.
- **/
- public static MBeanServerConnection getEventConnectionFor(
- MBeanServerConnection connection,
- Callable<EventClient> eventClientFactory) {
- if (connection instanceof EventClientFactory
- && eventClientFactory != null)
- throw new IllegalArgumentException("connection already uses EventClient");
-
- if (connection instanceof EventClientFactory)
- return connection;
-
- // create a new proxy using an event client.
- //
- if (LOG.isLoggable(Level.FINE))
- LOG.fine("Creating EventClient for: "+connection);
- return newProxyInstance(connection,
- MBeanServerConnection.class,
- eventClientFactory);
- }
-
- private Object invokeEventClientSubscriberMethod(Object proxy,
- Method method, Object[] args) throws Throwable {
- return call(this,method,args);
- }
-
- // Maximum lock timeout in seconds. Obviously arbitrary.
- //
- private final static short TRYLOCK_TIMEOUT = 3;
-
- private final MBeanServerConnection connection;
- private final Callable<EventClient> eventClientFactory;
- private final Lock lock;
- private volatile EventClient client = null;
- private volatile boolean initialized = false;
-
-}