Link.java :  » JMS » Open-Message-Queue » com » sun » messaging » jmq » transport » httptunnel » Java Open Source

/*
 * The contents of this file are subject to the terms
 * of the Common Development and Distribution License
 * (the "License").  You may not use this file except
 * in compliance with the License.
 *
 * You can obtain a copy of the license at
 * https://glassfish.dev.java.net/public/CDDLv1.0.html.
 * See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL
 * HEADER in each file and include the License file at
 * https://glassfish.dev.java.net/public/CDDLv1.0.html.  
 *
 * If applicable add the following below this CDDL HEADER,
 * with the fields enclosed by brackets "[]" replaced with 
 * your own identifying information: Portions Copyright 
 * [year] [name of copyright owner]
 */

/*
 * @(#)Link.java  1.9 05/02/06
 *
 * Copyright 2006 Sun Microsystems, Inc.  All Rights Reserved.
 */ 

package com.sun.messaging.jmq.transport.httptunnel;

import java.io.InputStream;
import java.io.OutputStream;

import java.util.logging.Level;
import java.util.logging.Logger;


/**
 * This class provides a common mechanism for establishing / maintaining
 * and consuming packets from a TCP connection.
 */
public abstract class Link extends Thread {
    private static boolean DEBUG = Boolean.getBoolean("httptunnel.debug");
    private boolean connected = false;
    protected boolean done = false;
    protected InputStream is = null;
    protected OutputStream os = null;
    private Logger logger = Logger.getLogger("Http Tunneling");

    /**
     * Establish the connection. This method blocks and keeps trying
     * until a connection is established.
     */
    protected abstract void createLink();

    /**
     * Consume a packet received over this connection.
     */
    protected abstract void receivePacket(HttpTunnelPacket p);

    /**
     * Handle connection error.
     */
    protected abstract void handleLinkDown();

    /**
     * Send a packet over this connection.
     */
    public synchronized void sendPacket(HttpTunnelPacket p) {
        if (DEBUG) {
            log("Sending packet : " + p);
        }

        try {
            p.writePacket(os);
        } catch (Exception e) {
            if (DEBUG) {
                log(e);
            }

            linkDown();
        }
    }

    protected void linkDown() {
        try {
            is.close();
            os.close();
            handleLinkDown();
        } catch (Exception e) {
        }

        connected = false;
    }

    public void shutdown() {
        done = true;
    }

    public void run() {
        while (!done) {
            try {
                if (connected == false) {
                    createLink();
                    connected = true;
                }

                HttpTunnelPacket p = new HttpTunnelPacket();
                p.readPacket(is);
                receivePacket(p);
            } catch (IllegalStateException e) {
                if (DEBUG) {
                    log(e);
                }

                done = true;
            } catch (Exception e) {
                if (DEBUG) {
                    log(e);
                }

                linkDown();
            }
        }
    }

    protected void log(String msg) {
        logger.log(Level.INFO, msg);
    }

    protected void log(Exception ex) {
      logger.log(Level.INFO, "Http Tunneling", ex);
    }
}

/*
 * EOF
 */