log.java

UML设计测试工具

/*
 * USE - UML based specification environment
 * Copyright (C) 1999-2004 Mark Richters, University of Bremen
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* $ProjectHeader: use 2-3-0-release.1 Mon, 12 Sep 2005 20:18:33 +0200 green $ */

package org.tzi.use.util;

import java.io.*;
import java.util.Date;
import java.text.DateFormat;

/** 
 * Class Log provides a set of static methods for writing log messages
 * on output streams.
 *
 * @version     $ProjectVersion: 2-3-0-release.1 $
 * @author      Mark Richters 
 */
public final class Log {

    private static PrintStream fOut = System.out;
    private static PrintStream fErr = System.err;

    private static DateFormat fDateFormat = null;

    private static boolean fVerbose = false;
    private static boolean fPrintTime = false;
    private static boolean fTrace = false;
    private static boolean fPrintStackTraces = true;
    private static boolean fDidOutput = false;

    // utility class
    private Log() {}
    

    /**
     * Sets verbose flag. Determines whether verbose messages are
     * printed.
     */
    public static void setVerbose(boolean onOff) {
        fVerbose = onOff;
    }

    public static boolean isVerbose() {
        return fVerbose;
    }

    /**
     * Sets print time flag. Determines whether messages are prefixed
     * with the current time.  
     */
    public static void setPrintTime(boolean onOff) {
        fPrintTime = onOff;
    }

    public static boolean isPrintingTime() {
        return fPrintTime;
    }

    /**
     * Sets trace flag. Determines whether trace messages are
     * printed.
     */
    public static void setTrace(boolean onOff) {
        fTrace = onOff;
    }

    public static boolean isTracing() {
        return fTrace;
    }

    /**
     * Turns printing of stack traces on/off.
     */
    public static void setPrintStackTrace(boolean onOff) {
        fPrintStackTraces = onOff;
    }

    public static boolean isPrintingStackTraces() {
        return fPrintStackTraces;
    }

    /**
     * Resets flag indicating that output occurred. Flag is set by
     * output methods. After some complex operations clients can ask
     * if some output occurred without bothering about verbosity
     * settings.
     */
    public static void resetOutputFlag() {
        fDidOutput = false;
    }

    public static boolean didOutput() {
        return fDidOutput;
    }

    public static PrintStream out() {
        return fOut;
    }

    /**
     * Output routines.
     */
    public static void println(String s) {
        if (fPrintTime ) {
            if (fDateFormat == null )
                fDateFormat = DateFormat.getTimeInstance(DateFormat.MEDIUM);
            fOut.print(fDateFormat.format(new Date()) + ": ");
        }
        fOut.println(s);
        fDidOutput = true;
    }
    
    public static void print(String s) {
        fOut.print(s);
        fDidOutput = true;
    }
    
    public static void println() {
        fOut.println();
        fDidOutput = true;
    }
    
    /**
     * Print messages only if verbose flag is on.
     */
    public static void verbose(String s) {
        if (fVerbose )
            println(s);
    }

    /**
     * Print messages only if trace flag is on.
     */
    public static void trace(String msg) {
        if (fTrace )
            println("* " + msg);
    }

    public static void trace(Object location, String msg) {
        trace(location, msg, false);
    }

    public static void trace(Object location, String msg, boolean flush) {
        if (fTrace ) {
            String className = location.getClass().getName();
            if (className.startsWith("org.tzi.use") )
                className = className.substring("org.tzi.use".length());
            println("* " + className + ": " + msg);
            if (flush )
                fOut.flush();
        }
    }

    /**
     * Print error messages.
     */
    public static void error(String s) {
        fErr.println("Error: " + s);
        fDidOutput = true;
    }

    public static void error(Object location, String msg) {
        String className = location.getClass().getName();
        fErr.println("error in " + className + ": " + msg);
    }

    public static void error(Exception e) {
        String className = e.getClass().getName();
        fErr.println("exception " + className + ": " + e.getMessage());
        if (fPrintStackTraces )
            e.printStackTrace();
        fDidOutput = true;
    }

    public static void error(String s, Exception e) {
        String className = e.getClass().getName();
        fErr.println("exception " + className + ": " + s + 
                     " reason: " + e.getMessage());
        if (fPrintStackTraces )
            e.printStackTrace();
        fDidOutput = true;
    }

}