debug.java

Vyger offers a D & D and Rogue-like environment in a graphical online roleplay game.

/*
 * Light And Shadow. A Persistent Universe based on Robert Jordan's Wheel of Time Books.
 * Copyright (C) 2001-2002 WOTLAS Team
 *
 * 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.
 */
 
package wotlas.utils;

import java.io.PrintStream;

/** A Debug Utility.<br>
 *( a tracer support would be interessant to add )
 * 
 * @author Aldiss
 */

public class Debug {

 /*------------------------------------------------------------------------------------*/

    /** 
     * A debug level used for notification messages,
     * does not represent any serious problem. 
     */
       public static final byte NOTICE = 0;

    /** 
     * A debug level warning of an undesireable occurrence,
     * but the program has recovered and is continuing OK.
     */
       public static final byte WARNING = 1;

    /** 
     * A debug level indicating an important error,
     * the program will probably recover but some things are now wrong.
     */
       public static final byte ERROR = 2;

    /** 
     * A debug level indicating a critical problem,
     * the program will very likely stop working.
     */
       public static final byte CRITICAL = 3;

    /** 
     * A debug level indicating complete failure,
     * the program is about to crash.  
     */
       public static final byte FAILURE = 4;

 /*------------------------------------------------------------------------------------*/

    /**
     * Current level we are working at.
     * Under this level we filter messages.
     */
       private static byte level = NOTICE;

    /**
     * Display exception stack trace ?
     */
       private static boolean displayExceptionStack = true;


    /**
     * the output stream we are going to use
     */
       private static PrintStream out = System.err;

 /*------------------------------------------------------------------------------------*/

    /** To print a debug message.
     *
     * @param code FAILURE, CRITICAL, ...
     * @param src_obj object reporting the error.
     * @param info a short text about the error.
     */
       public synchronized static void signal( byte code, Object src_obj, String info )
       {
          if(code<level)
       	     return;

          String debug_msg = "";

          switch( code ) {
             case FAILURE:
	          debug_msg += "FAILURE"; break;
             case CRITICAL:
                  debug_msg += "CRITICAL"; break;
             case ERROR:
                  debug_msg += "ERROR"; break;
             case WARNING:
                  debug_msg += "WARNING"; break;
             case NOTICE:
                  debug_msg += "NOTICE"; break;
             default:
	          debug_msg += "UNKNOWN"; break;
           }

          if(src_obj!=null)
             debug_msg += " - " + src_obj.getClass().getName() +"\n   "+info;
          else 
             debug_msg += " - " +info;
                
          out.println( debug_msg );
       }

 /*------------------------------------------------------------------------------------*/

    /** To print a debug message with the content of an exception.
     *
     * @param code FAILURE, CRITICAL, ...
     * @param src_obj class reporting the error.
     * @param e exception raised.
     */
       public synchronized static void signal( byte code, Object src_obj, Exception e ) {
          if(e!=null) {
             if(e.getMessage()!=null)
                signal( code, src_obj, e.getMessage() );
             else
                signal( code, src_obj, e.toString() );
          }
          else
             signal( code, src_obj, "<null exception>" );

          if( displayExceptionStack && e!=null )
              out.println( "EXCEPTION STACK: "+getStackTrace(e) );
       }

 /*------------------------------------------------------------------------------------*/

  /** Changes the level of debugging. We don't print errors under the specified level.
   *
   * @param level code ( NOTICE, WARNING, ... ) under which we filter.
   */
     static public void setLevel( byte level ) {
       Debug.level=level;
     }

 /*------------------------------------------------------------------------------------*/

  /** To set/unset the display of exception stack trace.
   *
   * @param display set to true if you want to see exception stack trace.
   */
     static public void displayExceptionStack( boolean display ) {
       Debug.displayExceptionStack=display;
     }

 /*------------------------------------------------------------------------------------*/

  /** To get the stack trace of an exception.
   *
   * @param e exception to inspect
   */

     static public String getStackTrace(Exception e) {
       java.io.StringWriter s = new java.io.StringWriter();    
       e.printStackTrace(new java.io.PrintWriter(s));
       String trace = s.toString();
       
       if(trace==null || trace.length()==0 || trace.equals("null"))
          return e.toString();
       else
          return trace;
     }

 /*------------------------------------------------------------------------------------*/

  /** To exit properly.
   */
     static public void exit() {
       // We close our printStream ( can be a log so we do things properly )
          out.flush();
          System.exit(0);
     }

 /*------------------------------------------------------------------------------------*/

  /** To set the PrintStream for this Debug Utility.
   *  @param out PrintStream to use.
   */
     static public void setPrintStream( PrintStream out ) {
     	 Debug.out = out;
     }

 /*------------------------------------------------------------------------------------*/

  /** To get the PrintStream of this Debug Utility.
   *  @return out PrintStream we use.
   */
     static public PrintStream getPrintStream() {
     	 return out;
     }

 /*------------------------------------------------------------------------------------*/

  /** To flush the printStream.
   *  @param out PrintStream to use.
   */
     static public void flushPrintStream() {
     	 out.flush();
     }

 /*------------------------------------------------------------------------------------*/

}