Java tutorial
/** * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.codehaus.stomp.jms; import java.io.IOException; import java.util.Map; import javax.jms.JMSException; import javax.jms.Message; import javax.jms.MessageConsumer; import javax.jms.MessageListener; import javax.naming.NamingException; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.codehaus.stomp.ProtocolException; import org.codehaus.stomp.Stomp; import org.codehaus.stomp.StompFrame; /** * Represents an individual Stomp subscription */ public class StompSubscription implements MessageListener { public static final String AUTO_ACK = Stomp.Headers.Subscribe.AckModeValues.AUTO; public static final String CLIENT_ACK = Stomp.Headers.Subscribe.AckModeValues.CLIENT; private static final transient Log log = LogFactory.getLog(StompSubscription.class); private final StompSession session; private final String subscriptionId; private MessageConsumer consumer; private Map<String, Object> headers; public StompSubscription(StompSession session, String subscriptionId, StompFrame frame) throws JMSException, ProtocolException, NamingException { this.subscriptionId = subscriptionId; this.session = session; this.headers = frame.getHeaders(); this.consumer = session.createConsumer(headers); this.consumer.setMessageListener(this); } public void close() throws JMSException { log.debug("Closing: " + (String) headers.get(Stomp.Headers.Subscribe.DESTINATION)); consumer.close(); resume(); } public void resume() { log.debug("Resuming: " + (String) headers.get(Stomp.Headers.Subscribe.DESTINATION)); synchronized (session) { session.notify(); } } public void onMessage(Message message) { String destinationName = (String) headers.get(Stomp.Headers.Subscribe.DESTINATION); try { log.debug("Received from HQ: " + message.getJMSMessageID()); log.debug("received: " + destinationName + " for: " + message.getObjectProperty("messagereplyto")); } catch (JMSException e) { log.warn("received: " + destinationName + " with trouble getting the message properties"); } if (message != null) { log.debug("Locking session to send a message"); // Lock the session so that the connection cannot be started before // the acknowledge is done synchronized (session) { // Send the message to the server log.debug("Sending message: " + session); try { session.sendToStomp(message, subscriptionId); try { session.wait(); } catch (InterruptedException e) { log.error("Could not wait to be woken", e); } // Acknowledge the message for this connection as we know // the server has received it now try { log.debug("Acking message: " + message.getJMSMessageID()); message.acknowledge(); log.debug("Acked message: " + message.getJMSMessageID()); } catch (JMSException e) { log.error("Could not acknowledge the message: " + e, e); } } catch (IOException e) { log.warn("Could not send to stomp: " + e, e); try { session.recover(); } catch (JMSException e1) { log.fatal("Could not recover the session, possible lost message: " + e, e); } } catch (JMSException e) { log.warn("Could not convert message to send to stomp: " + e, e); try { session.recover(); } catch (JMSException e1) { log.fatal("Could not recover the session, possible lost message: " + e, e); } } } } } }