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Diffstat (limited to 'trunk/qpid/java/client/example/src/main/java/org/apache/qpid/example/jmsexample/pubsub/Listener.java')
| -rw-r--r-- | trunk/qpid/java/client/example/src/main/java/org/apache/qpid/example/jmsexample/pubsub/Listener.java | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/trunk/qpid/java/client/example/src/main/java/org/apache/qpid/example/jmsexample/pubsub/Listener.java b/trunk/qpid/java/client/example/src/main/java/org/apache/qpid/example/jmsexample/pubsub/Listener.java new file mode 100644 index 0000000000..1a3d40041d --- /dev/null +++ b/trunk/qpid/java/client/example/src/main/java/org/apache/qpid/example/jmsexample/pubsub/Listener.java @@ -0,0 +1,214 @@ +/* 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.apache.qpid.example.jmsexample.pubsub; + +import java.util.Properties; + +import javax.jms.BytesMessage; +import javax.jms.ConnectionFactory; +import javax.jms.ExceptionListener; +import javax.jms.JMSException; +import javax.jms.Message; +import javax.jms.MessageListener; +import javax.jms.Session; +import javax.jms.TextMessage; +import javax.jms.Topic; +import javax.jms.TopicConnection; +import javax.jms.TopicSession; +import javax.naming.Context; +import javax.naming.InitialContext; + +/** + * The example creates a TopicSubscriber on the specified + * Topic and uses a MessageListener with this TopicSubscriber + * in order to enable asynchronous delivery. + */ +public class Listener +{ + /* Used in log output. */ + private static final String CLASS="Listener"; + + /* An object to synchronize on. */ + private final static Object _lock=new Object(); + + /* A boolean to indicate a clean finish. */ + private static int _finished=0; + + /* A boolean to indicate an unsuccesful finish. */ + private static boolean _failed=false; + + /** + * Run the message consumer example. + * + * @param args Command line arguments. + */ + public static void main(String[] args) + { + Listener listener=new Listener(); + listener.runTest(); + } + + private void createListener(Context ctx,TopicSession session,String topicName) throws Exception{ + // lookup the topic usa + Topic topic=(Topic) ctx.lookup(topicName); + // Create a Message Subscriber + System.out.println(CLASS + ": Creating a Message Subscriber for topic " + topicName); + javax.jms.TopicSubscriber messageSubscriber=session.createSubscriber(topic); + + // Set a message listener on the messageConsumer + messageSubscriber.setMessageListener(new MyMessageListener(topicName)); + + } + + /** + * Start the example. + */ + private void runTest() + { + try + { + Properties properties=new Properties(); + properties.load(this.getClass().getResourceAsStream("pubsub.properties")); + + //Create the initial context + Context ctx=new InitialContext(properties); + + // Declare the connection + ConnectionFactory conFac=(ConnectionFactory) ctx.lookup("qpidConnectionfactory"); + TopicConnection connection=(TopicConnection) conFac.createConnection(); + + // As this application is using a TopicSubscriber we need to set an ExceptionListener on the connection + // so that errors raised within the JMS client library can be reported to the application + System.out.println( + CLASS + ": Setting an ExceptionListener on the connection as sample uses a TopicSubscriber"); + + connection.setExceptionListener(new ExceptionListener() + { + public void onException(JMSException jmse) + { + // The connection may have broken invoke reconnect code if available. + System.err.println(CLASS + ": The sample received an exception through the ExceptionListener"); + System.exit(0); + } + }); + + // Create a session on the connection + // This session is a default choice of non-transacted and uses + // the auto acknowledge feature of a session. + System.out.println(CLASS + ": Creating a non-transacted, auto-acknowledged session"); + TopicSession session=connection.createTopicSession(false, Session.AUTO_ACKNOWLEDGE); + + createListener(ctx,session,"usa"); + createListener(ctx,session,"europe"); + createListener(ctx,session,"news"); + createListener(ctx,session,"weather"); + + // Now the messageConsumer is set up we can start the connection + System.out.println(CLASS + ": Starting connection so TopicSubscriber can receive messages"); + connection.start(); + + // Wait for the messageConsumer to have received all the messages it needs + synchronized (_lock) + { + while (_finished < 4 && !_failed) + { + _lock.wait(); + } + } + + // If the MessageListener abruptly failed (probably due to receiving a non-text message) + if (_failed) + { + System.out.println(CLASS + ": This sample failed as it received unexpected messages"); + } + + // Close the connection to the server + System.out.println(CLASS + ": Closing connection"); + connection.close(); + + // Close the JNDI reference + System.out.println(CLASS + ": Closing JNDI context"); + ctx.close(); + } + catch (Exception exp) + { + exp.printStackTrace(); + System.err.println(CLASS + ": Caught an Exception: " + exp); + } + } + + private class MyMessageListener implements MessageListener + { + /* The topic this subscriber is subscribing to */ + private String _topicName; + + public MyMessageListener(String topicName) + { + _topicName=topicName; + } + + /** + * This method is required by the <CODE>MessageListener</CODE> interface. It + * will be invoked when messages are available. + * After receiving the final message it releases a lock so that the + * main program may continue. + * + * @param message The message. + */ + public void onMessage(Message message) + { + try + { + String text; + if (message instanceof TextMessage) + { + text=((TextMessage) message).getText(); + } + else + { + byte[] body=new byte[(int) ((BytesMessage) message).getBodyLength()]; + ((BytesMessage) message).readBytes(body); + text=new String(body); + } + if (text.equals("That's all, folks!")) + { + System.out.println(CLASS + ": Shutting down listener for " + _topicName); + synchronized (_lock) + { + _finished++; + _lock.notifyAll(); + } + } + else + { + System.out.println(CLASS + ": Received message for topic: " + _topicName + ": " + text); + } + } + catch (JMSException exp) + { + System.out.println(CLASS + ": Caught an exception handling a received message"); + exp.printStackTrace(); + synchronized (_lock) + { + _failed=true; + _lock.notifyAll(); + } + } + } + } +} |