Metacat

package edu.ucsb.nceas.metacat.dataone;

import org.apache.log4j.Logger;

import org.dataone.cn.index.messaging.IndexTaskMessagingClient;

import org.dataone.cn.index.messaging.IndexTaskMessagingClientFactory;

/**

 * This class will guarantee to get a single IndexTaskMesagingClient by the singleton pattern 

 * @author tao

 *

 */

public class IndexTaskMessagingClientManager {

    private IndexTaskMessagingClient indexTaskClient = null;

    private static IndexTaskMessagingClientManager manager = null;

    private static Logger logMetacat = Logger.getLogger(IndexTaskMessagingClientManager.class);

    /**

     * A thread safe method to get the instance of the manager

     * @return

     * @throws InstantiationException

     * @throws IllegalAccessException

     * @throws ClassNotFoundException

     */

    public static IndexTaskMessagingClientManager getInstance() throws InstantiationException, IllegalAccessException, ClassNotFoundException {

        if(manager == null) {

            synchronized (IndexTaskMessagingClientManager.class) {

                if(manager == null) {

                    manager = new IndexTaskMessagingClientManager();

                }

            }

        }

        return manager;

    }

    /**

     * Default private constructor

     * @throws InstantiationException

     * @throws IllegalAccessException

     * @throws ClassNotFoundException

     */

    private IndexTaskMessagingClientManager() throws InstantiationException, IllegalAccessException, ClassNotFoundException {

        initIndexTaskClient();

    }

    /*

     * Method to get the index tasks client.

     */

    private void initIndexTaskClient() throws InstantiationException, IllegalAccessException, ClassNotFoundException {

        if(indexTaskClient == null) {

            indexTaskClient = IndexTaskMessagingClientFactory.getClient();

            logMetacat.info("IndexTaskMessagingClientManager.initIndexTaskClient - after generating the client .......................");

        }

    }

    /**

     * Get the client object which can submit the index tasks.

     * @return

     */

    public IndexTaskMessagingClient getMessagingClient() {

        return indexTaskClient;

    }

}