org.apache.stratos.autoscaler.integration.TopicPublisher.java Source code

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Here is the source code for org.apache.stratos.autoscaler.integration.TopicPublisher.java

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/*
 * 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.stratos.autoscaler.integration;

import com.google.gson.Gson;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.stratos.messaging.event.Event;
import org.apache.stratos.messaging.util.Constants;

import javax.jms.*;
import javax.naming.InitialContext;
import javax.naming.NamingException;

import java.io.IOException;
import java.io.Serializable;
import java.util.Properties;

public class TopicPublisher {
    private static final Log log = LogFactory.getLog(TopicPublisher.class);
    private TopicConnection topicConnection;
    private TopicSession topicSession;
    private Topic topic;
    private String topicName;

    public TopicPublisher(String topicName) {
        this.topicName = topicName;
    }

    public void connect() throws NamingException, JMSException, IOException {
        // Prepare JNDI properties
        Properties properties = new Properties();
        properties.put("java.naming.provider.url", "tcp://localhost:61616");
        properties.put("java.naming.factory.initial", "org.apache.activemq.jndi.ActiveMQInitialContextFactory");
        properties.put("connectionfactoryName", "ConnectionFactory");
        properties.put("java.naming.security.principal", "admin");
        properties.put("java.naming.security.credentials", "admin");
        InitialContext ctx = new InitialContext(properties);

        // Lookup connection factory
        String connectionFactoryName = properties.get("connectionfactoryName").toString();
        TopicConnectionFactory connectionFactory = (TopicConnectionFactory) ctx.lookup(connectionFactoryName);
        topicConnection = connectionFactory.createTopicConnection();
        topicConnection.start();
        topicSession = topicConnection.createTopicSession(false, QueueSession.AUTO_ACKNOWLEDGE);

        // Create topic
        topic = topicSession.createTopic(topicName);
    }

    public void publish(Event event) throws NamingException, JMSException, IOException {
        Gson gson = new Gson();
        String json = gson.toJson(event);
        publish(json, event.getClass().getName());
    }

    private void publish(Object message, String eventClassName) throws NamingException, JMSException, IOException {
        // Send message
        if (message instanceof String) {
            TextMessage textMessage = topicSession.createTextMessage((String) message);
            textMessage.setStringProperty(Constants.EVENT_CLASS_NAME, eventClassName);
            javax.jms.TopicPublisher topicPublisher = topicSession.createPublisher(topic);
            topicPublisher.publish(textMessage);
            log.info("Text message sent: " + (String) message);
        } else if (message instanceof Serializable) {
            ObjectMessage objectMessage = topicSession.createObjectMessage((Serializable) message);
            javax.jms.TopicPublisher topicPublisher = topicSession.createPublisher(topic);
            topicPublisher.publish(objectMessage);
            log.info("Object message sent: " + ((Serializable) message).toString());
        } else {
            throw new RuntimeException("Unknown message type");
        }
    }

    public void close() throws JMSException {
        // Clean up resources
        if (topicSession != null)
            topicSession.close();
        if (topicConnection != null)
            topicConnection.close();
    }
}