001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.activemq.transport.http;
018
019import java.net.URI;
020import javax.servlet.ServletException;
021
022import org.apache.activemq.broker.BrokerService;
023import org.apache.activemq.transport.TransportAcceptListener;
024
025/**
026 * This servlet embeds an ActiveMQ broker inside a servlet engine which is ideal
027 * for deploying ActiveMQ inside a WAR and using this servlet as a HTTP tunnel.
028 * 
029 * 
030 */
031public class HttpEmbeddedTunnelServlet extends HttpTunnelServlet {
032    private static final long serialVersionUID = -3705734740251302361L;
033
034    protected BrokerService broker;
035    protected HttpTransportServer transportConnector;
036
037    public synchronized void init() throws ServletException {
038        // lets initialize the ActiveMQ broker
039        try {
040            if (broker == null) {
041                broker = createBroker();
042
043                // Add the servlet connector
044                String url = getConnectorURL();
045                HttpTransportFactory factory = new HttpTransportFactory();
046                transportConnector = (HttpTransportServer) factory.doBind(new URI(url));
047                broker.addConnector(transportConnector);
048
049                String brokerURL = getServletContext().getInitParameter("org.apache.activemq.brokerURL");
050                if (brokerURL != null) {
051                    log("Listening for internal communication on: " + brokerURL);
052                }
053            }
054            broker.start();
055        } catch (Exception e) {
056            throw new ServletException("Failed to start embedded broker: " + e, e);
057        }
058        // now lets register the listener
059        TransportAcceptListener listener = transportConnector.getAcceptListener();
060        getServletContext().setAttribute("transportChannelListener", listener);
061        super.init();
062    }
063
064    /**
065     * Factory method to create a new broker
066     * 
067     * @throws Exception
068     */
069    protected BrokerService createBroker() throws Exception {
070        BrokerService answer = new BrokerService();
071        return answer;
072    }
073
074    protected String getConnectorURL() {
075        return "http://localhost/" + getServletContext().getServletContextName();
076    }
077}