logrecord.java

JAVA基本类源代码,大家可以学习学习!

/*
 * @(#)LogRecord.java	1.18 03/01/13
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.util.logging;
import java.util.*;
import java.io.*;

/**
 * LogRecord objects are used to pass logging requests between
 * the logging framework and individual log Handlers.
 * <p>
 * When a LogRecord is passed into the logging framework it 
 * logically belongs to the framework and should no longer be
 * used or updated by the client application.
 * <p>
 * Note that if the client application has not specified an
 * explicit source method name and source class name, then the
 * LogRecord class will infer them automatically when they are
 * first accessed (due to a call on getSourceMethodName or
 * getSourceClassName) by analyzing the call stack.  Therefore,
 * if a logging Handler wants to pass off a LogRecord to another
 * thread, or to transmit it over RMI, and if it wishes to subsequently
 * obtain method name or class name information it should call
 * one of getSourceClassName or getSourceMethodName to force
 * the values to be filled in.
 * <p>
 * <b> Serialization notes:</b>
 * <ul>
 * <li>The LogRecord class is serializable.
 *
 * <li> Because objects in the parameters array may not be serializable,
 * during serialization all objects in the parameters array are
 * written as the corresponding Strings (using Object.toString).
 *
 * <li> The ResourceBundle is not transmitted as part of the serialized
 * form, but the resource bundle name is, and the recipient object's
 * readObject method will attempt to locate a suitable resource bundle.
 *
 * </ul>
 *
 * @version 1.18, 01/13/03
 * @since 1.4
 */

public class LogRecord implements java.io.Serializable {
    private static long globalSequenceNumber;
    private static int nextThreadId=10;
    private static ThreadLocal threadIds = new ThreadLocal();

    /**
     * @serial Logging message level
     */
    private Level level;

    /**
     * @serial Sequence number
     */
    private long sequenceNumber;

    /**
     * @serial Class that issued logging call
     */
    private String sourceClassName;

    /**
     * @serial Method that issued logging call
     */
    private String sourceMethodName;

    /**
     * @serial Non-localized raw message text
     */
    private String message;

    /**
     * @serial Thread ID for thread that issued logging call.
     */
    private int threadID;

    /**
     * @serial Event time in milliseconds since 1970
     */
    private long millis;

    /**
     * @serial The Throwable (if any) associated with log message
     */
    private Throwable thrown;

    /**
     * @serial Name of the source Logger.
     */
    private String loggerName;

    /**
     * @serial Resource bundle name to localized log message.
     */
    private String resourceBundleName;

    private transient boolean needToInferCaller;
    private transient Object parameters[];
    private transient ResourceBundle resourceBundle;

    /**
     * Construct a LogRecord with the given level and message values.
     * <p>
     * The sequence property will be initialized with a new unique value.
     * These sequence values are allocated in increasing order within a VM.
     * <p>
     * The millis property will be initialized to the current time.
     * <p>
     * The thread ID property will be initialized with a unique ID for
     * the current thread.
     * <p>
     * All other properties will be initialized to "null". 
     * 
     * @param level  a logging level value
     * @param msg  the raw non-localized logging message
     */
    public LogRecord(Level level, String msg) {
	// Make sure level isn't null, by calling random method.
	level.getClass();
	this.level = level;
	message = msg;
	// Assign a thread ID and a unique sequence number.
	synchronized (LogRecord.class) {
	    sequenceNumber = globalSequenceNumber++;
	    Integer id = (Integer)threadIds.get();
	    if (id == null) {
		id = new Integer(nextThreadId++);
		threadIds.set(id);
	    }
	    threadID = id.intValue();
	}
	millis = System.currentTimeMillis(); 
	needToInferCaller = true;
   }

    /**
     * Get the source Logger name's
     *
     * @return source logger name (may be null)
     */
    public String getLoggerName() {
	return loggerName;
    }
   
    /**
     * Set the source Logger name.
     *
     * @param name   the source logger name (may be null)
     */
    public void setLoggerName(String name) {
	loggerName = name;
    }
   
    /**
     * Get the localization resource bundle
     * <p>
     * This is the ResourceBundle that should be used to localize
     * the message string before formatting it.  The result may
     * be null if the message is not localizable, or if no suitable
     * ResourceBundle is available.
     */
    public ResourceBundle getResourceBundle() {
	return resourceBundle;
    }
   
    /**
     * Set the localization resource bundle.
     *
     * @param bundle  localization bundle (may be null)
     */
    public void setResourceBundle(ResourceBundle bundle) {
	resourceBundle = bundle;
    }
   
    /**
     * Get the localization resource bundle name
     * <p>
     * This is the name for the ResourceBundle that should be
     * used to localize the message string before formatting it.
     * The result may be null if the message is not localizable.
     */
    public String getResourceBundleName() {
	return resourceBundleName;
    }
   
    /**
     * Set the localization resource bundle name.
     *
     * @param name  localization bundle name (may be null)
     */
    public void setResourceBundleName(String name) {
	resourceBundleName = name;
    }
   
    /**
     * Get the logging message level, for example Level.SEVERE.
     * @return the logging message level
     */  
    public Level getLevel() {
	return level;
    }

    /**
     * Set the logging message level, for example Level.SEVERE.
     * @param level the logging message level
     */  
    public void setLevel(Level level) {
	if (level == null) {
	    throw new NullPointerException();
	}
	this.level = level;
    }

    /** 
     * Get the sequence number.
     * <p>
     * Sequence numbers are normally assigned in the LogRecord
     * constructor, which assignes unique sequence numbers to
     * each new LogRecord in increasing order.
     * @return the sequence number
     */
    public long getSequenceNumber() {
	return sequenceNumber;
    }

    /** 
     * Set the sequence number.
     * <p>
     * Sequence numbers are normally assigned in the LogRecord constructor,
     * so it should not normally be necessary to use this method.
     */
    public void setSequenceNumber(long seq) {
	sequenceNumber = seq;
    }

    /**
     * Get the  name of the class that (allegedly) issued the logging request.
     * <p>
     * Note that this sourceClassName is not verified and may be spoofed.
     * This information may either have been provided as part of the
     * logging call, or it may have been inferred automatically by the
     * logging framework.  In the latter case, the information may only
     * be approximate and may in fact describe an earlier call on the
     * stack frame.
     * <p>
     * May be null if no information could be obtained.
     *
     * @return the source class name
     */  
    public String getSourceClassName() {
	if (needToInferCaller) {
	    inferCaller();
	}
	return sourceClassName;
    }

    /**
     * Set the name of the class that (allegedly) issued the logging request.
     *
     * @param sourceClassName the source class name
     */  
    public void setSourceClassName(String sourceClassName) {
	this.sourceClassName = sourceClassName;
	needToInferCaller = false;
    }

    /**
     * Get the  name of the method that (allegedly) issued the logging request.
     * <p>
     * Note that this sourceMethodName is not verified and may be spoofed.
     * This information may either have been provided as part of the
     * logging call, or it may have been inferred automatically by the
     * logging framework.  In the latter case, the information may only
     * be approximate and may in fact describe an earlier call on the
     * stack frame.
     * <p>
     * May be null if no information could be obtained.
     *
     * @return the source method name
     */  
    public String getSourceMethodName() {
	if (needToInferCaller) {
	    inferCaller();
	}
	return sourceMethodName;
    }

    /**
     * Set the name of the method that (allegedly) issued the logging request.
     *
     * @param sourceMethodName the source method name
     */  
    public void setSourceMethodName(String sourceMethodName) {
	this.sourceMethodName = sourceMethodName;
	needToInferCaller = false;
    }

    /**
     * Get the "raw" log message, before localization or formatting.
     * <p>
     * May be null, which is equivalent to the empty string "".
     * <p>
     * This message may be either the final text or a localization key.
     * <p>
     * During formatting, if the source logger has a localization
     * ResourceBundle and if that ResourceBundle has an entry for
     * this message string, then the message string is replaced
     * with the localized value.
     *
     * @return the raw message string
     */
    public String getMessage() {
	return message;
    }

    /**
     * Set the "raw" log message, before localization or formatting.
     *
     * @param message the raw message string
     */
    public void setMessage(String message) {
	this.message = message;
    }

    /**
     * Get the parameters to the log message.
     *
     * @return the log message parameters.  May be null if
     *			there are no parameters.
     */
    public Object[] getParameters() {
	return parameters;
    }

    /**
     * Set the parameters to the log message.
     *
     * @param parameters the log message parameters.
     */
    public void setParameters(Object parameters[]) {
	this.parameters = parameters;
    }

    /**
     * Get an identifier for the thread where the message originated.
     * <p>
     * This is a thread identifier within the Java VM and may or
     * may not map to any operating system ID.
     *
     * @return thread ID
     */
    public int getThreadID() {
	return threadID;
    }

    /**
     * Set an identifier for the thread where the message originated.
     * @param threadID 	the thread ID
     */
    public void setThreadID(int threadID) {
	this.threadID = threadID;
    }

    /**
     * Get event time in milliseconds since 1970.
     *
     * @return event time in millis since 1970
     */
    public long getMillis() {
	return millis;
    }

    /**
     * Set event time.
     *
     * @param millis event time in millis since 1970
     */
    public void setMillis(long millis) {
	this.millis = millis;
    }

    /**
     * Get any throwable associated with the log record.
     * <p>
     * If the event involved an exception, this will be the
     * exception object. Otherwise null.
     *
     * @return a throwable
     */
    public Throwable getThrown() {
	return thrown;
    }

    /**
     * Set a throwable associated with the log event.
     *
     * @param thrown  a throwable
     */
    public void setThrown(Throwable thrown) {
	this.thrown = thrown;
    }

    /**
     * @serialData Default fields, followed by a two byte version number
     * (major byte, followed by minor byte), followed by information on
     * the log record parameter array.  If there is no parameter array, 
     * then -1 is written.  If there is a parameter array (possible of zero
     * length) then the array length is written as an integer, followed
     * by String values for each parameter.  If a parameter is null, then
     * a null String is written.  Otherwise the output of Object.toString()
     * is written.
     */
    private void writeObject(ObjectOutputStream out) throws IOException {
	// We have to call defaultWriteObject first.
	out.defaultWriteObject();

	// Write our version number.
	out.writeByte(1);
	out.writeByte(0);
	if (parameters == null) {
	    out.writeInt(-1);
	    return;
	}
	out.writeInt(parameters.length);
	// Write string values for the parameters.
	for (int i = 0; i < parameters.length; i++) {
	    if (parameters[i] == null) {
	        out.writeObject(null);
	    } else {
	        out.writeObject(parameters[i].toString());
	    }
	}
    }

    private void readObject(ObjectInputStream in) 
   			throws IOException, ClassNotFoundException {
	// We have to call defaultReadObject first.
	in.defaultReadObject();

	// Read version number.
	byte major = in.readByte();
	byte minor = in.readByte();
	if (major != 1) {
	    throw new IOException("LogRecord: bad version: " + major + "." + minor);
	}
	int len = in.readInt();
	if (len == -1) {
	    parameters = null;
	} else {
	    parameters = new Object[len];
	    for (int i = 0; i < parameters.length; i++) {
	        parameters[i] = in.readObject();
	    }
	}
	// If necessary, try to regenerate the resource bundle.
	if (resourceBundleName != null) {
	    try {
	    	resourceBundle = ResourceBundle.getBundle(resourceBundleName);
	    } catch (MissingResourceException ex) {
		// This is not a good place to throw an exception,
		// so we simply leave the resourceBundle null.
		resourceBundle = null;
	    }
	}

	needToInferCaller = false;
    }

    // Private method to infer the caller's class and method names
    private void inferCaller() {
	needToInferCaller = false;
	// Get the stack trace.
	StackTraceElement stack[] = (new Throwable()).getStackTrace();
	// First, search back to a method in the Logger class.
	int ix = 0;
	while (ix < stack.length) {
	    StackTraceElement frame = stack[ix];
	    String cname = frame.getClassName();
	    if (cname.equals("java.util.logging.Logger")) {
		break;
	    }
	    ix++;
	}
	// Now search for the first frame before the "Logger" class.
	while (ix < stack.length) {
	    StackTraceElement frame = stack[ix];
	    String cname = frame.getClassName();
	    if (!cname.equals("java.util.logging.Logger")) {
		// We've found the relevant frame.
	        setSourceClassName(cname);
	        setSourceMethodName(frame.getMethodName());
		return;
	    }
	    ix++;
	}
	// We haven't found a suitable frame, so just punt.  This is
        // OK as we are only commited to making a "best effort" here.
    }
}