multiplexedmanagedconnection.java

OpenJMS是一个开源的Java Message Service API 1.0.2 规范的实现,它包含有以下特性： *. 它既支持点到点（point-to-point）（PTP）模型和发布/订

/**
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 * 4. Products derived from this Software may not be called "Exolab"
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 * 5. Due credit should be given to the Exolab Project
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 *
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 * Copyright 2004-2005 (C) Exoffice Technologies Inc. All Rights Reserved.
 *
 * $Id: MultiplexedManagedConnection.java,v 1.10 2006/12/16 12:37:17 tanderson Exp $
 */
package org.exolab.jms.net.multiplexer;

import java.io.IOException;
import java.security.Principal;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.exolab.jms.net.connector.AbstractManagedConnection;
import org.exolab.jms.net.connector.Authenticator;
import org.exolab.jms.net.connector.Caller;
import org.exolab.jms.net.connector.CallerImpl;
import org.exolab.jms.net.connector.ConnectException;
import org.exolab.jms.net.connector.Connection;
import org.exolab.jms.net.connector.IllegalStateException;
import org.exolab.jms.net.connector.InvocationHandler;
import org.exolab.jms.net.connector.Request;
import org.exolab.jms.net.connector.ResourceException;
import org.exolab.jms.net.connector.Response;
import org.exolab.jms.net.connector.SecurityException;
import org.exolab.jms.net.connector.ManagedConnectionListener;
import org.exolab.jms.net.uri.URI;


/**
 * A <code>ManagedConnection</code> that uses a {@link Multiplexer} to multiplex
 * data over an {@link Endpoint}
 *
 * @author <a href="mailto:[e-mail]">Tim Anderson</a>
 * @version $Revision: 1.10 $ $Date: 2006/12/16 12:37:17 $
 */
public abstract class MultiplexedManagedConnection
        extends AbstractManagedConnection
        implements MultiplexerListener {

    /**
     * The multiplexer.
     */
    private Multiplexer _multiplexer;

    /**
     * The thread used to run {@link #_multiplexer}.
     */
    private Thread _multiplexThread;

    /**
     * The endpoint to multiplex data over.
     */
    private Endpoint _endpoint;

    /**
     * The invocation handler.
     */
    private InvocationHandler _invoker;

    /**
     * The security principal.
     */
    private Principal _principal;

    /**
     * The connection authenticator, for server side instances.
     */
    private Authenticator _authenticator;

    /**
     * Cached caller instance. Non-null if this is a server-side instance.
     */
    private Caller _caller;

    /**
     * The thread group to associate any allocated threads with.
     */
    private ThreadGroup _group;

    /**
     * The logger.
     */
    private static final Log _log =
            LogFactory.getLog(MultiplexedManagedConnection.class);


    /**
     * Construct a new client <code>MultiplexedManagedConnection</code>.
     *
     * @param principal the security principal. May be <code>null</code>
     */
    public MultiplexedManagedConnection(Principal principal) {
        _principal = principal;
    }

    /**
     * Construct a new server <code>MultiplexedManagedConnection</code>.
     *
     * @param authenticator the connection authenticator
     */
    public MultiplexedManagedConnection(Authenticator authenticator) {
        if (authenticator == null) {
            throw new IllegalArgumentException(
                    "Argument 'authenticator' is null");
        }
        _authenticator = authenticator;
    }

    /**
     * Registers a handler for handling invocations on objects exported via this
     * connection. Once a handler is registered, it cannot be de-registered.
     *
     * @param handler the invocation handler
     * @throws IllegalStateException if a handler is already registered
     * @throws ResourceException     for any error
     */
    public void setInvocationHandler(InvocationHandler handler)
            throws ResourceException {
        if (_invoker != null) {
            throw new IllegalStateException(
                    "An invocation handler is already registered");
        }
        _invoker = handler;
        try {
            _endpoint = createEndpoint();
            if (isClient()) {
                _multiplexer = createMultiplexer(_endpoint, _principal);
            } else {
                _multiplexer = createMultiplexer(_endpoint, _authenticator);
                _principal = _multiplexer.getPrincipal();
                _caller = new CallerImpl(getRemoteURI(), getLocalURI());
            }
            String name = getDisplayName() + "-Multiplexer";
            _multiplexThread = new Thread(getThreadGroup(), _multiplexer,
                                          name);
            _multiplexThread.start();
        } catch (IOException exception) {
            throw new ConnectException("Failed to start multiplexer",
                                       exception);
        }
    }

    /**
     * Creates a new connection handle for the underlying physical connection.
     *
     * @return a new connection handle
     * @throws IllegalStateException if an invocation handler hasn't been
     *                               registered
     */
    public synchronized Connection getConnection()
            throws IllegalStateException {
        if (_invoker == null) {
            throw new IllegalStateException("No InvocationHandler registered");
        }
        return new MultiplexedConnection(this);
    }

    /**
     * Ping the connection. The connection event listener will be notified
     * if the ping succeeds.
     *
     * @throws IllegalStateException if a connection is not established
     * @throws ResourceException for any error
     */
    public void ping() throws ResourceException {
        Multiplexer multiplexer;
        synchronized (this) {
            multiplexer = _multiplexer;
        }
        if (multiplexer != null) {
            try {
                multiplexer.ping(0);
            } catch (IOException exception) {
                throw new ResourceException(exception.getMessage(), exception);
            }
        } else {
            throw new IllegalStateException("Connection not established");
        }
    }

    /**
     * Destroys the physical connection.
     *
     * @throws ResourceException for any error
     */
    public void destroy() throws ResourceException {
        Multiplexer multiplexer;
        Thread thread;
        Endpoint endpoint;

        synchronized (this) {
            multiplexer = _multiplexer;
            thread = _multiplexThread;
            endpoint = _endpoint;
        }
        try {
            if (multiplexer != null) {