AbstractServiceDaemon.java

/*******************************************************************************
 * This file is part of OpenNMS(R).
 *
 * Copyright (C) 2008-2011 The OpenNMS Group, Inc.
 * OpenNMS(R) is Copyright (C) 1999-2011 The OpenNMS Group, Inc.
 *
 * OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.
 *
 * OpenNMS(R) 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 3 of the License,
 * or (at your option) any later version.
 *
 * OpenNMS(R) 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 OpenNMS(R).  If not, see:
 *      http://www.gnu.org/licenses/
 *
 * For more information contact:
 *     OpenNMS(R) Licensing <license@opennms.org>
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 *******************************************************************************/


package org.opennms.netmgt.daemon;

import org.opennms.core.utils.ThreadCategory;
import org.opennms.netmgt.model.ServiceDaemon;

/**
 * <p>Abstract AbstractServiceDaemon class.</p>
 *
 * @author <a href="mailto:brozow@opennms.org">Mathew Brozowski</a>
 * @author <a href="mailto:dj@opennms.org">DJ Gregor</a>
 */
public abstract class AbstractServiceDaemon implements ServiceDaemon, SpringServiceDaemon {
    /**
     * <p>afterPropertiesSet</p>
     *
     * @throws java.lang.Exception if any.
     */
    @Override
    public final void afterPropertiesSet() throws Exception {
        init();
    }

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

    private String m_name;
    
    private Object m_statusLock = new Object();

    /**
     * <p>onInit</p>
     */
    abstract protected void onInit();

    /**
     * <p>onPause</p>
     */
    protected void onPause() {}

    /**
     * <p>onResume</p>
     */
    protected void onResume() {}

    /**
     * <p>onStart</p>
     */
    protected void onStart() {}

    /**
     * <p>onStop</p>
     */
    protected void onStop() {}

    /**
     * <p>getName</p>
     *
     * @return a {@link java.lang.String} object.
     */
    @Override
    final public String getName() { return m_name; }

    /**
     * <p>Constructor for AbstractServiceDaemon.</p>
     *
     * @param name a {@link java.lang.String} object.
     */
    protected AbstractServiceDaemon(final String name) {
        m_name = name;
        setStatus(START_PENDING);
    }

    /**
     * <p>setStatus</p>
     *
     * @param status a int.
     */
    protected final void setStatus(final int status) {
        synchronized (m_statusLock) {
            m_status = status;
            m_statusLock.notifyAll();
        }
    }
    
    /**
     * <p>waitForStatus</p>
     *
     * @param status a int.
     * @param timeout a long.
     * @throws java.lang.InterruptedException if any.
     */
    protected final void waitForStatus(final int status, final long timeout) throws InterruptedException {
        synchronized (m_statusLock) {
            
            final long last = System.currentTimeMillis();
            long waitTime = timeout;
            while (status != m_status && waitTime > 0) {
                m_statusLock.wait(waitTime);
                long now = System.currentTimeMillis();
                waitTime -= (now - last);
            }
        
        }
    }

    /**
     * <p>waitForStatus</p>
     *
     * @param status a int.
     * @throws java.lang.InterruptedException if any.
     */
    protected final void waitForStatus(final int status) throws InterruptedException {
        synchronized (m_statusLock) {
            while (status != m_status) {
                m_statusLock.wait();
            }
        }
    }

    /**
     * <p>getStatus</p>
     *
     * @return a int.
     */
    @Override
    public int getStatus() {
        synchronized (m_statusLock) {
            return m_status;
        }
    }

    /**
     * <p>getStatusText</p>
     *
     * @return a {@link java.lang.String} object.
     */
    @Override
    public String getStatusText() {
        return STATUS_NAMES[getStatus()];
    }

    /**
     * <p>status</p>
     *
     * @return a {@link java.lang.String} object.
     * 
     * @deprecated Use {@link #getStatusText()} instead. This field is only for 
     * backwards compatibility with JMX operations.
     */
    public String status() {
        return getStatusText();
    }

    /**
     * <p>isRunning</p>
     *
     * @return a boolean.
     */
    protected synchronized boolean isRunning() {
        return getStatus() == RUNNING;
    }

    /**
     * <p>isPaused</p>
     *
     * @return a boolean.
     */
    protected synchronized boolean isPaused() {
        return getStatus() == PAUSED;
    }

    /**
     * <p>isStarting</p>
     *
     * @return a boolean.
     */
    protected synchronized boolean isStarting() {
        return getStatus() == STARTING;
    }

    /**
     * <p>log</p>
     *
     * @return a {@link org.opennms.core.utils.ThreadCategory} object.
     */
    protected ThreadCategory log() {
        return ThreadCategory.getInstance(getClass());
    }
    
    /**
     * <p>fatalf</p>
     *
     * @param format a {@link java.lang.String} object.
     * @param args a {@link java.lang.Object} object.
     */
    protected void fatalf(final String format, final Object... args) {
        log().fatal(String.format(format, args));
    }

    /**
     * <p>fatalf</p>
     *
     * @param t a {@link java.lang.Throwable} object.
     * @param format a {@link java.lang.String} object.
     * @param args a {@link java.lang.Object} object.
     */
    protected void fatalf(final Throwable t, final String format, final Object... args) {
        log().fatal(String.format(format, args), t);
    }

    /**
     * <p>errorf</p>
     *
     * @param format a {@link java.lang.String} object.
     * @param args a {@link java.lang.Object} object.
     */
    protected void errorf(final String format, final Object... args) {
        log().error(String.format(format, args));
    }

    /**
     * <p>errorf</p>
     *
     * @param t a {@link java.lang.Throwable} object.
     * @param format a {@link java.lang.String} object.
     * @param args a {@link java.lang.Object} object.
     */
    protected void errorf(final Throwable t, final String format, final Object... args) {
        log().error(String.format(format, args), t);
    }

    /**
     * <p>warnf</p>
     *
     * @param format a {@link java.lang.String} object.
     * @param args a {@link java.lang.Object} object.
     */
    protected void warnf(final String format, final Object... args) {
        log().warn(String.format(format, args));
    }

    /**
     * <p>warnf</p>
     *
     * @param t a {@link java.lang.Throwable} object.
     * @param format a {@link java.lang.String} object.
     * @param args a {@link java.lang.Object} object.
     */
    protected void warnf(final Throwable t, final String format, final Object... args) {
        log().warn(String.format(format, args), t);
    }

    /**
     * <p>infof</p>
     *
     * @param format a {@link java.lang.String} object.
     * @param args a {@link java.lang.Object} object.
     */
    protected void infof(final String format, final Object... args) {
        if (log().isInfoEnabled()) {
            log().info(String.format(format, args));
        }
    }

    /**
     * <p>infof</p>
     *
     * @param t a {@link java.lang.Throwable} object.
     * @param format a {@link java.lang.String} object.
     * @param args a {@link java.lang.Object} object.
     */
    protected void infof(final Throwable t, final String format, final Object... args) {
        if (log().isInfoEnabled()) {
            log().info(String.format(format, args), t);
        }
    }

    /**
     * <p>debugf</p>
     *
     * @param format a {@link java.lang.String} object.
     * @param args a {@link java.lang.Object} object.
     */
    protected void debugf(final String format, final Object... args) {
        if (log().isDebugEnabled()) {
            log().debug(String.format(format, args));
        }
    }

    /**
     * <p>debugf</p>
     *
     * @param t a {@link java.lang.Throwable} object.
     * @param format a {@link java.lang.String} object.
     * @param args a {@link java.lang.Object} object.
     */
    protected void debugf(final Throwable t, final String format, final Object... args) {
        if (log().isDebugEnabled()) {
            log().debug(String.format(format, args), t);
        }
    }

    /**
     * <p>init</p>
     */
    final public void init() {
        final String prefix = ThreadCategory.getPrefix();
        try {
            
            ThreadCategory.setPrefix(getName());
            log().info(getName()+" initializing.");

            onInit();

            log().info(getName()+" initialization complete.");
        } finally {
            ThreadCategory.setPrefix(prefix);
        }
    }



    /**
     * <p>pause</p>
     */
    @Override
    final public void pause() {
        final String prefix = ThreadCategory.getPrefix();
        try {
            ThreadCategory.setPrefix(getName());

            if (!isRunning()) return;

            log().info(getName()+" pausing.");

            setStatus(PAUSE_PENDING);
            onPause();
            setStatus(PAUSED);

            log().info(getName()+" paused.");

        } finally {
            ThreadCategory.setPrefix(prefix);
        }
    }

    /**
     * <p>resume</p>
     */
    @Override
    final public void resume() {
        final String prefix = ThreadCategory.getPrefix();
        try {
            ThreadCategory.setPrefix(getName());
            if (!isPaused()) return;

            log().info(getName()+" resuming.");

            setStatus(RESUME_PENDING);
            onResume();
            setStatus(RUNNING);

            log().info(getName()+" resumed.");
        } finally {
            ThreadCategory.setPrefix(prefix);
        }
    }

    /**
     * <p>start</p>
     */
    @Override
    final public synchronized void start() {
        final String prefix = ThreadCategory.getPrefix();
        try {
            ThreadCategory.setPrefix(getName());
            log().info(getName()+" starting.");

            setStatus(STARTING);
            onStart();
            setStatus(RUNNING);

            log().info(getName()+" started.");
        } finally {
            ThreadCategory.setPrefix(prefix);
        }

    }

    /**
     * Stops the currently running service. If the service is not running then
     * the command is silently discarded.
     */
    @Override
    final public synchronized void stop() {
        final String prefix = ThreadCategory.getPrefix();
        try {
            ThreadCategory.setPrefix(getName());
            log().info(getName()+" stopping.");

            setStatus(STOP_PENDING);
            onStop();
            setStatus(STOPPED);

            log().info(getName()+" stopped.");
        } finally {
            ThreadCategory.setPrefix(prefix);
        }
    }

    /**
     * Destroys the current service.
     */
    @Override
    final public void destroy() {
        stop();
    }

}