trace.java

java1.6众多例子参考

/*
 * @(#)Trace.java	1.20 05/11/17
 * 
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.jmx.trace;

// java import
//
import java.util.Properties;
import java.util.ArrayList;
import java.util.HashMap;
import java.io.IOException;

/**
 * Sends trace to a pluggable destination.
 *
 * @since 1.5
 * @since.unbundled JMX RI 1.2
 */
public final class Trace implements TraceTags {

    private static TraceDestination out = initDestination();
    // private static TraceDestination out = 
    // TraceImplementation.newDestination(2);

    // private constructor defined to "hide" the default public constructor
    private Trace() {
	
    }

    // Method used to test if the implementation of TraceDestination which relies
    // on the java.util.logging API (com.sun.jmx.trace.TraceManager) can be used
    // to initialize the trace destination. This is the case iff. we are running 
    // J2SE 1.4 or higher. Otherwise, the trace destination is null, and needs to
    // be later initialized if we want to see traces !
    //
    private static TraceDestination initDestination()
    {
      // Attempt to locate class java.util.logging.LogManager
      //
      try
      {
        Class.forName("java.util.logging.LogManager");
        
        // Class could be loaded, use a new instance of TraceManager as the trace
        // destination 
        //
        return new TraceManager();
      }
      catch (ClassNotFoundException e)
      {
        // Class could not be loaded, means that we are running J2SE 1.3 or below.
        //
        return null;
      }
    }

    // --------------
    // public methods
    // --------------

    /**
     * Set the trace destination.
     **/
    public static synchronized void setDestination(TraceDestination output) {
	out = output;
    }

    /**
     * Verify whether the specified info level and the info type are 
     * selected by a listener.
     *
     * <P>It is strongly recommended to call this method before sending
     * an information to this Trace class.
     *
     * @param level the level of trace information.
     * @param type the type of the trace information.
     */
    public static boolean isSelected(int level, int type) {
	final TraceDestination output = out();
	if (output != null) return output.isSelected(level,type);
	return false;
    }


    /**
     * Send a new information to this Trace class
     *
     * @param level the level of trace information to be sent.
     * @param type the type of trace information to be sent.
     * @param className the name of the class from which the trace 
     *        information is from.
     * @param methodName the name of the method from which the trace 
     *        information is from.
     * @param info the trace information to be sent.
     * @return false if the level and the type are not selected.
     */
    public static boolean send(int level,
			       int type,
			       String className,
			       String methodName,
			       String info) {

	final TraceDestination output = out();
	if (output == null) return false;
	if (!(output.isSelected(level, type))) return false;
	return output.send(level,type,className,methodName,info);
    }

   /**
     * Send an exception to this Trace class.
     *
     * @param level the level of trace information to be sent.
     * @param type the type of trace information to be sent.
     * @param className the name of the class from which the trace 
     *        information is from.
     * @param methodName the name of the method from which the trace 
     *        information is from.
     * @param exception exception sent as the trace information.
     */
    public static boolean send(int level,
			       int type,
			       String className,
			       String methodName,
			       Throwable exception) {
	final TraceDestination output = out();
	if (output == null) return false;
	if (!(output.isSelected(level, type))) return false;
	return output.send(level,type,className,methodName,exception);
    }

    /**
     * Logs a warning message.
     * This is equivalent to 
     * <code>Logger.getLogger(loggerName).warning(msg);</code>
     * This method is a hack for backward compatibility with J2SE 1.3.
     *
     * @since.unbundled JMX RI 1.2.1
     **/
    public static void warning(String loggerName, String msg) {
	final TraceDestination output = out();
	if (output instanceof TraceManager)
	    // Log a warning message
	    ((TraceManager)output).warning(loggerName,msg);
	else if (output != null) 
	    // Best effort
	    output.send(LEVEL_TRACE,INFO_MISC,null,null,msg);
    }

    /**
     * Logs a fine message.
     * This is equivalent to 
     * <code>Logger.getLogger(loggerName).fine(msg);</code>
     * This method is a hack for backward compatibility with J2SE 1.3.
     *
     * @since.unbundled JMX RI 1.2.1
     **/
    public static void fine(String loggerName, String msg) {
	final TraceDestination output = out();
	if (output instanceof TraceManager)
	    // Log a fine message
	    ((TraceManager)output).fine(loggerName,msg);
	else if (output != null) 
	    // Best effort
	    output.send(LEVEL_TRACE,INFO_MISC,null,null,msg);
    }

    /**
     * Return the trace destination.
     **/
    private static synchronized TraceDestination out() {
	return out;
    }

}