org.nebulaframework.grid.cluster.manager.services.jobs.remote.RemoteJobRequestMessageConverter.java Source code

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Here is the source code for org.nebulaframework.grid.cluster.manager.services.jobs.remote.RemoteJobRequestMessageConverter.java

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/*
 * Copyright (C) 2008 Yohan Liyanage. 
 * 
 * Licensed 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.nebulaframework.grid.cluster.manager.services.jobs.remote;

import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.Session;

import org.springframework.jms.support.converter.MessageConversionException;
import org.springframework.jms.support.converter.SimpleMessageConverter;
import org.springframework.remoting.support.RemoteInvocation;

/**
 * A JMS {@code MessageConverter} which appends meta-data to
 * {@code RemoteClusterJobService} messages. This converter
 * attaches a property to each JMS Message sent by the service
 * to indicate the target Cluster ID. This ensures that the
 * message is dispatched to the intended cluster's RemoteJobService
 * only.
 * <p>
 * <i>Spring Managed</i>
 * 
 * @author Yohan Liyanage
 * @version 1.0
 */
class RemoteJobRequestMessageConverter extends SimpleMessageConverter {

    /**
     * {@inheritDoc}
     */
    @Override
    public Object fromMessage(Message message) throws JMSException, MessageConversionException {

        // No Special Operation
        return super.fromMessage(message);
    }

    /**
     * Attaches a String property to the JMS Messages which
     * indicates the target cluster's Cluster ID.
     * 
     * @param object Object to be converted
     * @param JMS Session
     * 
     * @return JMS Message
     */
    @Override
    public Message toMessage(Object object, Session session) throws JMSException, MessageConversionException {

        Message m = super.toMessage(object, session);

        if (object instanceof RemoteInvocation) {
            RemoteInvocation invocation = (RemoteInvocation) object;

            // If its a invocation of remoteJobRequest
            if (invocation.getMethodName().equals("remoteJobRequest")) {

                // Attach Target ClusterID
                m.setStringProperty("targetClusterId", parseClusterId((String) invocation.getArguments()[0]));
            }
        }

        return m;
    }

    /**
     * Returns the ClusterID of a given JobID.
     * <p>
     * Note that JobID format specifies that
     * a job ID should be,
     * <pre>
     *     <i>ClusterId</i>.<i>NodeId</i>.<i>RandomUUID</i>
     * </pre>
     * 
     * @param jobId JobId
     * @return ClusterId
     * @throws MessageConversionException if JobId is invalid
     */
    private String parseClusterId(String jobId) throws MessageConversionException {
        try {
            return jobId.split("\\.")[0];
        } catch (Exception e) {
            throw new MessageConversionException("Exception while parsing ClusterId", e);
        }
    }
}