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.apache.servicemix.wsn.jms; import java.io.StringReader; import java.io.StringWriter; import java.util.ArrayList; import java.util.List; import javax.jms.Connection; import javax.jms.JMSException; import javax.jms.Message; import javax.jms.MessageConsumer; import javax.jms.MessageProducer; import javax.jms.Queue; import javax.jms.Session; import javax.jms.TextMessage; import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBException; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.servicemix.wsn.AbstractPullPoint; import org.oasis_open.docs.wsn.b_2.NotificationMessageHolderType; import org.oasis_open.docs.wsn.b_2.Notify; import org.oasis_open.docs.wsn.b_2.UnableToGetMessagesFaultType; import org.oasis_open.docs.wsn.bw_2.UnableToGetMessagesFault; import org.oasis_open.docs.wsrf.rw_2.ResourceUnknownFault; public class JmsPullPoint extends AbstractPullPoint { private static Log log = LogFactory.getLog(JmsPullPoint.class); private JAXBContext jaxbContext; private Connection connection; private Session session; private Queue queue; private MessageProducer producer; private MessageConsumer consumer; public JmsPullPoint(String name) { super(name); try { jaxbContext = JAXBContext.newInstance(Notify.class); } catch (JAXBException e) { throw new RuntimeException("Could not create PullEndpoint", e); } } protected void initSession() throws JMSException { if (session == null) { session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE); queue = session.createQueue(getName()); producer = session.createProducer(queue); consumer = session.createConsumer(queue); } } @Override protected synchronized void store(NotificationMessageHolderType messageHolder) { try { initSession(); Notify notify = new Notify(); notify.getNotificationMessage().add(messageHolder); StringWriter writer = new StringWriter(); jaxbContext.createMarshaller().marshal(notify, writer); Message message = session.createTextMessage(writer.toString()); producer.send(message); } catch (JMSException e) { log.warn("Error storing message", e); if (session != null) { try { session.close(); } catch (JMSException inner) { log.debug("Error closing session", inner); } finally { session = null; } } } catch (JAXBException e) { log.warn("Error storing message", e); } } @Override protected synchronized List<NotificationMessageHolderType> getMessages(int max) throws ResourceUnknownFault, UnableToGetMessagesFault { try { if (max == 0) { max = 256; } initSession(); List<NotificationMessageHolderType> messages = new ArrayList<NotificationMessageHolderType>(); for (int i = 0; i < max; i++) { Message msg = consumer.receiveNoWait(); if (msg == null) { break; } TextMessage txtMsg = (TextMessage) msg; StringReader reader = new StringReader(txtMsg.getText()); Notify notify = (Notify) jaxbContext.createUnmarshaller().unmarshal(reader); messages.addAll(notify.getNotificationMessage()); } return messages; } catch (JMSException e) { log.info("Error retrieving messages", e); if (session != null) { try { session.close(); } catch (JMSException inner) { log.debug("Error closing session", inner); } finally { session = null; } } UnableToGetMessagesFaultType fault = new UnableToGetMessagesFaultType(); throw new UnableToGetMessagesFault("Unable to retrieve messages", fault, e); } catch (JAXBException e) { log.info("Error retrieving messages", e); UnableToGetMessagesFaultType fault = new UnableToGetMessagesFaultType(); throw new UnableToGetMessagesFault("Unable to retrieve messages", fault, e); } } public Connection getConnection() { return connection; } public void setConnection(Connection connection) { this.connection = connection; } }