SyslogProcessor.java

//
// 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 <license@opennms.org>
// http://www.opennms.org/
// http://www.opennms.com/
//

package org.infosec.ismp.syslogd;

import java.net.InetAddress;
import java.net.UnknownHostException;

import org.infosec.ismp.eventd.EventIpcManagerFactory;
import org.infosec.ismp.model.event.Event;
import org.infosec.ismp.util.ThreadCategory;

/**
 * This class encapsulates the execution context for processing syslog messsages
 * received via UDP from remote agents. This is a separate event context to
 * allow the event receiver to do minimum work to avoid dropping packets from
 * the agents.
 *
 * @author <a href="mailto:weave@oculan.com">Brian Weaver </a>
 * @author <a href="http://www.oculan.com">Oculan Corporation </a>
 */
final class SyslogProcessor implements Runnable {

	@SuppressWarnings("unused")
	private BroadcastEventProcessor m_eventReader;

	/**
	 * The UDP receiver thread.
	 */
	private Thread m_context;

	/**
	 * The stop flag
	 */
	private volatile boolean m_stop;

	/**
	 * The log prefix
	 */
	private String m_logPrefix;

	private String m_localAddr;

	public static void setSyslogConfig(SyslogdConfig syslogdConfig) {
		@SuppressWarnings("unused")
		SyslogdConfig m_syslogdConfig = syslogdConfig;
	}

	SyslogProcessor(UeiList ueiList) {
		m_context = null;
		m_stop = false;

		m_logPrefix = Syslogd.LOG4J_CATEGORY;

		try {
			m_localAddr = InetAddress.getLocalHost().getHostName();
		} catch (UnknownHostException uhE) {
			ThreadCategory log = ThreadCategory.getInstance(getClass());

			m_localAddr = "localhost";
			log.error("Error looking up local hostname; using 'localhost'", uhE);
		}

	}

	/**
	 * Returns true if the thread is still alive
	 */
	boolean isAlive() {
		return (m_context != null && m_context.isAlive());
	}

	/**
	 * Stops the current context
	 */
	void stop() throws InterruptedException {
		m_stop = true;
		if (m_context != null) {
			ThreadCategory log = ThreadCategory.getInstance(getClass());
			if (log.isDebugEnabled())
				log.debug("Stopping and joining thread context "
						+ m_context.getName());

			m_context.interrupt();
			m_context.join();

			log.debug("Thread context stopped and joined");
		}
	}

	/**
	 * The event processing execution context.
	 */
	@Override
	public void run() {
		// The runnable context
		m_context = Thread.currentThread();

		// get a logger
		ThreadCategory.setPrefix(m_logPrefix);
		ThreadCategory log = ThreadCategory.getInstance(getClass());
		boolean isTracing = log.isEnabledFor(ThreadCategory.Level.TRACE);

		if (m_stop) {
			if (isTracing)
				log.trace("Stop flag set before thread started, exiting");
			return;
		} else if (isTracing)
			log.trace("Thread context started");

		while (!m_stop) {

			Event event = null;

			event = SyslogHandler.queueManager.getFromQueue();

			if (event != null) {
				try {
					if (isTracing) {
						log.trace("Processing a syslog to event dispatch"
								+ event.toString());
						// TODO 记录事件的详细信息，便于调试
						log.trace("}");
					}

					EventIpcManagerFactory.getIpcManager().sendNow(event);

				} catch (Throwable t) {
					log.error(
							"Unexpected error processing SyslogMessage - Could not send",
							t);
				}
			}

		}

	}

	void setLogPrefix(String prefix) {
		m_logPrefix = prefix;
	}

}