eventipcmanagerfactory.java

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//
// This file is part of the OpenNMS(R) Application.
//
// OpenNMS(R) is Copyright (C) 2002-2003 The OpenNMS Group, Inc.  All rights reserved.
// OpenNMS(R) is a derivative work, containing both original code, included code and modified
// code that was published under the GNU General Public License. Copyrights for modified 
// and included code are below.
//
// OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.
//
// Copyright (C) 1999-2001 Oculan Corp.  All rights reserved.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program 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 General Public License for more details.                                                            
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//       
// For more information contact: 
//      OpenNMS Licensing       <[e-mail]>
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//      http://www.opennms.com/
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package org.opennms.netmgt.eventd;

/**
 * 
 * @author <A HREF="mailto:[e-mail]">Sowmya Nataraj </A>
 * @author <A HREF="http://www.opennms.org">OpenNMS.org </A>
 */
public class EventIpcManagerFactory {
    /**
     * The singleton instance of this factory
     */
    private static EventIpcManagerFactory m_singleton = null;

    /**
     * This member is set to true if init() has been called
     */
    private static boolean m_loaded = false;

    /**
     * The default EventIpcManager
     */
    private EventIpcManagerDefaultImpl m_defIpcManager;

    /**
     * Private constructor
     */
    private EventIpcManagerFactory() {
        m_defIpcManager = new EventIpcManagerDefaultImpl();
    }

    /**
     * Create the singleton instance of this factory
     */
    public static synchronized void init() {
        if (m_loaded) {
            // init already called - return
            return;
        }

        m_singleton = new EventIpcManagerFactory();

        m_loaded = true;
    }

    /**
     * Return the singleton instance of this factory.
     * 
     * @return The current factory instance.
     * 
     * @throws java.lang.IllegalStateException
     *             Thrown if the factory has not yet been initialized.
     */
    public static synchronized EventIpcManagerFactory getInstance() {
        if (!m_loaded)
            throw new IllegalStateException("The factory has not been initialized");

        return m_singleton;
    }

    /**
     * Returns an implementation of the default EventIpcManager class
     */
    public EventIpcManagerDefaultImpl getManager() {
        return m_defIpcManager;
    }

    //
    // Will eventually have methods to get instances of managers to
    // communicate across VMs
    //

}