JobScheduler.java

/*
 jBilling - The Enterprise Open Source Billing System
 Copyright (C) 2003-2011 Enterprise jBilling Software Ltd. and Emiliano Conde

 This file is part of jbilling.

 jbilling is free software: you can redistribute it and/or modify
 it under the terms of the GNU Affero General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 jbilling is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Affero General Public License for more details.

 You should have received a copy of the GNU Affero General Public License
 along with jbilling.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.sapienter.jbilling.client.process;

import org.apache.log4j.Logger;
import org.quartz.Scheduler;
import org.quartz.SchedulerException;
import org.quartz.SchedulerFactory;
import org.quartz.impl.StdSchedulerFactory;

/**
 * Singleton wrapper to provide easy access to the Quartz Scheduler. Used to schedule
 * all of jBilling's batch processes and {@link com.sapienter.jbilling.server.process.task.IScheduledTask}
 * plug-ins.
 *
 * @author Brian Cowdery
 * @since 02-02-2010
 */
public class JobScheduler {
    private static final Logger LOG = Logger.getLogger(JobScheduler.class);

    private static JobScheduler instance = null;
    private SchedulerFactory factory = null;
    private Scheduler scheduler = null;

    private JobScheduler() {
        factory = new StdSchedulerFactory();
    }

    public static JobScheduler getInstance() {
        if (instance == null)
            instance = new JobScheduler();
        return instance;
    }

    public Scheduler getScheduler() {
        if (scheduler == null) {
            try {
                scheduler = factory.getScheduler();
            } catch (SchedulerException e) {
                LOG.error("Exception occurred retrieving the scheduler instance.", e);
            }
        }
        return scheduler;
    }

    public void start() {
        try {
            getScheduler().start();
        } catch (SchedulerException e) {
            LOG.error("Exception occurred starting the scheduler.", e);
        }
    }

    public void shutdown() {
        try {
            getScheduler().shutdown();
        } catch (SchedulerException e) {
            // swallow
        }
    }
}