actiond.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.
//
// Modifications:
//
// 2003 Jan 31: Cleaned up some unused imports.
//
// Original code base 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]>
//      http://www.opennms.org/
//      http://www.opennms.com/
//
// Tab Size = 8
//

package org.opennms.netmgt.actiond;

import java.io.IOException;
import java.lang.reflect.UndeclaredThrowableException;

import org.apache.log4j.Category;
import org.exolab.castor.xml.MarshalException;
import org.exolab.castor.xml.ValidationException;
import org.opennms.core.fiber.PausableFiber;
import org.opennms.core.queue.FifoQueue;
import org.opennms.core.queue.FifoQueueImpl;
import org.opennms.core.utils.ThreadCategory;
import org.opennms.netmgt.config.ActiondConfigFactory;

/**
 * This class is used to represent the auto action execution service. When an
 * event is received by this service that has one of either a notification,
 * trouble ticket, or auto action then a process is launched to execute the
 * appropriate commands.
 * 
 * @author <a href="mailto:[e-mail]">Mike Davidson </a>
 * @author <a href="mailto:[e-mail]">Brian Weaver </a>
 * @author <a href="http://www.opennms.org/">OpenNMS.org </a>
 * 
 */
public final class Actiond implements PausableFiber {
    /**
     * The log4j category used to log debug messsages and statements.
     */
    private static final String LOG4J_CATEGORY = "OpenNMS.Actiond";

    /**
     * The singleton instance.
     */
    private static final Actiond m_singleton = new Actiond();

    /**
     * The execution launcher and reaper
     */
    private Executor m_execution;

    /**
     * The broadcast event receiver.
     */
    private BroadcastEventProcessor m_eventReader;

    /**
     * The current status of this fiber
     */
    private int m_status;

    /**
     * Constructs a new Action execution daemon.
     */
    private Actiond() {
        m_execution = null;
        m_eventReader = null;
        m_status = START_PENDING;
    }

    public synchronized void init() {
        ThreadCategory.setPrefix(LOG4J_CATEGORY);
        Category log = ThreadCategory.getInstance();

        // Load the configuration informatin
        //
        ActiondConfigFactory aFactory = null;
        try {
            ActiondConfigFactory.reload();
            aFactory = ActiondConfigFactory.getInstance();
        } catch (MarshalException ex) {
            log.error("Failed to load actiond configuration", ex);
            throw new UndeclaredThrowableException(ex);
        } catch (ValidationException ex) {
            log.error("Failed to load actiond configuration", ex);
            throw new UndeclaredThrowableException(ex);
        } catch (IOException ex) {
            log.error("Failed to load actiond configuration", ex);
            throw new UndeclaredThrowableException(ex);
        }

        // A queue for execution
        //
        FifoQueue execQ = new FifoQueueImpl();

        // start the event reader
        //
        try {
            m_eventReader = new BroadcastEventProcessor(execQ);
        } catch (Exception ex) {
            log.error("Failed to setup event reader", ex);
            throw new UndeclaredThrowableException(ex);
        }

        m_execution = new Executor(execQ, aFactory.getMaxProcessTime(), aFactory.getMaxOutstandingActions());
    }

    /**
     * Starts the <em>Actiond</em> service. The process of starting the
     * service involves reading the configuration data, starting an event
     * receiver, and creating an execution fiber. If the services is already
     * running then an exception is thrown.
     * 
     * @throws java.lang.IllegalStateException
     *             Thrown if the service is already running.
     */
    public synchronized void start() {
        ThreadCategory.setPrefix(LOG4J_CATEGORY);
        Category log = ThreadCategory.getInstance();

        if (m_status == START_PENDING) {
            m_status = STARTING;
            if (m_execution == null) {
                init();
            }

            m_execution.start();
            m_status = RUNNING;

            log.info("Actiond running");
        } else if (m_execution != null && m_execution.getStatus() != STOPPED) {
            // Service is already running?
            throw new IllegalStateException("The actiond service is already running");
        }
    }

    /**
     * Stops the currently running service. If the service is not running then
     * the command is silently discarded.
     * 
     */
    public synchronized void stop() {
        m_status = STOP_PENDING;

        try {
            if (m_execution != null) {
                m_execution.stop();
            }
        } catch (Exception e) {
        }

        if (m_eventReader != null) {
            m_eventReader.close();
        }

        m_eventReader = null;
        m_execution = null;
        m_status = STOPPED;
    }

    /**
     * Returns the current status of the service.
     * 
     * @return The service's status.
     */
    public synchronized int getStatus() {
        return m_status;
    }

    /**
     * Returns the name of the service.
     * 
     * @return The service's name.
     */
    public String getName() {
        return "OpenNMS.Actiond";
    }

    /**
     * Pauses the service if its currently running
     */
    public synchronized void pause() {
        if (m_status != RUNNING) {
            return;
        }

        m_status = PAUSE_PENDING;

        m_execution.pause();
        m_status = PAUSED;
    }

    /**
     * Resumes the service if its currently paused
     */
    public synchronized void resume() {
        if (m_status != PAUSED) {
            return;
        }

        m_status = RESUME_PENDING;

        m_execution.resume();
        m_status = RUNNING;
    }

    /**
     * Returns the singular instance of the actiond daemon. There can be only
     * one instance of this service per virtual machine.
     */
    public static Actiond getInstance() {
        return m_singleton;
    }
}