/*
* Copyright (C) The MX4J Contributors.
* All rights reserved.
*
* This software is distributed under the terms of the MX4J License version 1.0.
* See the terms of the MX4J License in the documentation provided with this software.
*/
package mx4j.server.interceptor;
import java.util.ArrayList;
import javax.management.MBeanException;
import javax.management.MBeanServer;
import javax.management.ObjectName;
import mx4j.ImplementationException;
/**
* MBean that configures the MBeanServer --> MBean interceptor chain.
*
* @version $Revision: 1.9 $
*/
public class MBeanServerInterceptorConfigurator implements MBeanServerInterceptorConfiguratorMBean
{
public static final String OBJECT_NAME = "JMImplementation:type=MBeanServerInterceptorConfigurator";
private final MBeanServer server;
private final ArrayList preInterceptors = new ArrayList();
private final ArrayList postInterceptors = new ArrayList();
private final ArrayList clientInterceptors = new ArrayList();
private volatile boolean running;
private boolean chainModified;
private MBeanServerInterceptor head;
/**
* Creates an instance of this configurator, for the given MBeanServer
*/
public MBeanServerInterceptorConfigurator(MBeanServer server)
{
this.server = server;
chainModified = true;
}
/**
* Appends the given interceptor, provided by the client, to the existing interceptor chain.
*
* @see #registerInterceptor
*/
public void addInterceptor(MBeanServerInterceptor interceptor)
{
synchronized (clientInterceptors)
{
clientInterceptors.add(interceptor);
chainModified = true;
}
}
/**
* Appends the given interceptor, provided by the client, to the existing interceptor chain and registers it as MBean.
*
* @see #addInterceptor
*/
public void registerInterceptor(MBeanServerInterceptor interceptor, ObjectName name) throws MBeanException
{
// First, try register this interceptor. The call will use the old interceptor chain
try
{
server.registerMBean(interceptor, name);
addInterceptor(interceptor);
}
catch (Exception x)
{
throw new MBeanException(x, "Could not register interceptor with name " + name);
}
}
/**
* Removes all the interceptors added via {@link #addInterceptor(MBeanServerInterceptor interceptor)}.
*
* @see #addInterceptor
*/
public void clearInterceptors()
{
synchronized (clientInterceptors)
{
clientInterceptors.clear();
chainModified = true;
}
}
/**
* Adds the given interceptor at the beginning of the interceptor chain, before the custom interceptors that may be added
* via {@link #addInterceptor}.
* This method is called by the MBeanServer during initialization, to configure the interceptors needed to work properly.
*/
public void addPreInterceptor(MBeanServerInterceptor interceptor)
{
if (isRunning()) throw new ImplementationException();
preInterceptors.add(interceptor);
}
/**
* Adds the given interceptor at the end of the interceptor chain, after the custom interceptors that may be added
* via {@link #addInterceptor}.
* This method is called by the MBeanServer during initialization, to configure the interceptors needed to work properly.
*/
public void addPostInterceptor(MBeanServerInterceptor interceptor)
{
if (isRunning()) throw new ImplementationException();
postInterceptors.add(interceptor);
}
/**
* Returns the head interceptor of the interceptor chain.
* The head interceptor is always present.
*/
public MBeanServerInterceptor getHeadInterceptor()
{
if (!isRunning()) return null;
if (chainModified) setupChain();
return head;
}
private void setupChain()
{
chainModified = false;
int size = clientInterceptors.size();
ArrayList chain = new ArrayList(preInterceptors.size() + size + postInterceptors.size());
chain.addAll(preInterceptors);
if (size > 0)
{
synchronized (clientInterceptors)
{
chain.addAll(clientInterceptors);
}
}
chain.addAll(postInterceptors);
// Set the chain on the first interceptor
MBeanServerInterceptor first = (MBeanServerInterceptor)chain.get(0);
first.setChain(chain);
head = first;
}
/**
* Starts this configurator, so that the MBeanServer is now able to accept incoming calls.
*
* @see #stop
* @see #isRunning
*/
public void start()
{
if (!isRunning())
{
running = true;
}
}
/**
* Stops this configurator, so that the MBeanServer is not able to accept incoming calls.
*
* @see #start
*/
public void stop()
{
if (isRunning())
{
running = false;
}
}
/**
* Returns whether this configurator is running and thus if the MBeanServer can accept incoming calls
*
* @see #start
*/
public boolean isRunning()
{
return running;
}
}