/* Copyright (C) 2002-2004 MySQL AB This program is free software; you can redistribute it and/or modify it under the terms of version 2 of the GNU General Public License as published by the Free Software Foundation.  There are special exceptions to the terms and conditions of the GPL  as it is applied to this software. View the full text of the  exception exception in file EXCEPTIONS-CONNECTOR-J in the directory of this  software distribution. 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 */package com.mysql.jdbc;import java.sql.DriverManager;import java.util.Hashtable;import java.util.StringTokenizer;/** * The Debug class allows debug messages on a per-class basis. * * <p> * The user issues a trace() call, listing the classes they wish to debug. * </p> * * @author Mark Matthews */public class Debug {    private static final Hashtable CLASSES = new Hashtable();    private static final Object MUTEX = new Object();    private static boolean watchAll = false;    /**     * Trace a method call.     *     * <p>     * If the user has registered in interest in the Class of Source, then  the     * Source class can trace method calls through this method.     * </p>     *     * @param source the Object issuing the methodCall() method     * @param method the name of the Method     * @param args a list of arguments     */    public static void methodCall(Object source, String method, Object[] args) {        synchronized (MUTEX) {            if (watchAll || CLASSES.contains(source.getClass().getName())) {                // Print the message                StringBuffer mesg = new StringBuffer("\nTRACE: ");                mesg.append(source.toString());                mesg.append(".");                mesg.append(method);                mesg.append("( ");                // Print the argument list                for (int i = 0; i < (args.length - 1); i++) {                    if (args[i] == null) {                        mesg.append("null");                    } else {                        if (args[i] instanceof String) {                            mesg.append("\"");                        }                        mesg.append(args[i].toString());                        if (args[i] instanceof String) {                            mesg.append("\"");                        }                    }                    mesg.append(", ");                }                if (args.length > 0) {                    if (args[args.length - 1] instanceof String) {                        mesg.append("\"");                    }                    mesg.append(args[args.length - 1]);                    if (args[args.length - 1] instanceof String) {                        mesg.append("\"");                    }                }                mesg.append(" )\n");                if (DriverManager.getLogWriter() == null) {                    System.out.println(mesg.toString());                } else {                    DriverManager.println(mesg.toString());                }            }        }    }    /**     * Log a message.     *     * <p>     * If the user has registered in interest in the Class of Source, then  the     * Source class can trace return calls through this method.     * </p>     *     * @param source the Object issuing the msg() method     * @param message the name of the method     */    public static void msg(Object source, String message) {        synchronized (MUTEX) {            if (watchAll || CLASSES.contains(source.getClass().getName())) {                // Print the message                StringBuffer mesg = new StringBuffer("\nTRACE: ");                mesg.append(source.toString());                mesg.append(": ");                mesg.append(message);                mesg.append("\n");                if (DriverManager.getLogWriter() == null) {                    System.out.println(mesg.toString());                } else {                    DriverManager.println(mesg.toString());                }            }        }    }    /**     * Trace a method call.     *     * <p>     * If the user has registered in interest in the Class of Source, then  the     * Source class can trace return calls through this method.     * </p>     *     * @param source the Object issuing the returnValue() method     * @param method the name of the method     * @param value the return value     */    public static void returnValue(Object source, String method, Object value) {        synchronized (MUTEX) {            if (watchAll || CLASSES.contains(source.getClass().getName())) {                // Print the message                StringBuffer mesg = new StringBuffer("\nTRACE: ");                mesg.append(source.toString());                mesg.append(".");                mesg.append(method);                mesg.append(": Returning -> ");                if (value == null) {                    mesg.append("null");                } else {                    mesg.append(value.toString());                }                mesg.append("\n");                                if (DriverManager.getLogWriter() == null) {                    System.out.println(mesg.toString());                } else {                    DriverManager.println(mesg.toString());                }            }        }    }    /**     * Set the classes to trace.     *     * @param classList the list of classes to trace, separated by colons or     *        the keyword &quot;ALL&quot; to trace all classes that use the     *        Debug class.     */    public static void trace(String classList) {        StringTokenizer tokenizer = new StringTokenizer(classList, ":");        synchronized (MUTEX) {            watchAll = false;            if (classList.equals("ALL")) {                watchAll = true;            } else {                while (tokenizer.hasMoreTokens()) {                    String className = tokenizer.nextToken().trim();                    if (!CLASSES.contains(className)) {                        CLASSES.put(className, className);                    }                }            }        }    }}