looper.java

Java游戏高级编程！！很不错的！！！Java游戏高级编程！！很不错的

     package com.croftsoft.core.util.loop;

     import com.croftsoft.core.lang.NullArgumentException;
     import com.croftsoft.core.lang.ex.ExceptionHandler;
     import com.croftsoft.core.lang.lifecycle.Lifecycle;

     /*********************************************************************
     * Periodically runs a task in a loop using a separate thread.
     *
     * @author
     *   <a href="http://www.croftsoft.com/">David Wallace Croft</a>
     * @version
     *   2003-05-22
     * @since
     *   2000-04-27
     *********************************************************************/

     public final class  Looper
       implements Lifecycle
     //////////////////////////////////////////////////////////////////////
     //////////////////////////////////////////////////////////////////////
     {

     private final Loopable          loopable;

     private final ExceptionHandler  exceptionHandler;

     private final String            threadName;

     private final int               threadPriority;

     private final boolean           useDaemonThread;

     //

     private LoopGovernor  loopGovernor;

     private Thread        thread;

     private boolean       stopRequested;

     //////////////////////////////////////////////////////////////////////
     //////////////////////////////////////////////////////////////////////

     /*********************************************************************
     * Main constructor.
     *
     * <p>
     * Call the start() method after construction to begin looping.
     * </p>
     *
     * @param  loopable
     *
     *   The loop() method of this object will be called periodically.
     *   Looping will stop if this method returns false.
     *
     * @param  exceptionHandler
     *
     *   Handles all Exceptions generated by runnable.run().
     *   The handleException() Object argument passed will be the loopable.
     *   If null, the default behavior of printing any Exception to the
     *   standard error output and stopping looping will be used.
     *********************************************************************/
     public  Looper (
       Loopable          loopable,
       LoopGovernor      loopGovernor,
       ExceptionHandler  exceptionHandler,
       String            threadName,
       int               threadPriority,
       boolean           useDaemonThread )
     //////////////////////////////////////////////////////////////////////
     {
       NullArgumentException.check ( this.loopable = loopable );

       setLoopGovernor ( loopGovernor );

       this.exceptionHandler = exceptionHandler;

       this.threadName       = threadName;

       this.threadPriority   = threadPriority;

       this.useDaemonThread  = useDaemonThread;
     }

     public  Looper ( Loopable  loopable )
     //////////////////////////////////////////////////////////////////////
     {
       this (
         loopable,
         new FixedDelayLoopGovernor ( 0L, 0 ),
         ( ExceptionHandler ) null,
         ( String ) null,
         Thread.MIN_PRIORITY,
         true );
     }

     //////////////////////////////////////////////////////////////////////
     //////////////////////////////////////////////////////////////////////

     public void  setLoopGovernor ( LoopGovernor  loopGovernor )
     //////////////////////////////////////////////////////////////////////
     {
       NullArgumentException.check ( this.loopGovernor = loopGovernor );
     }

     //////////////////////////////////////////////////////////////////////
     //////////////////////////////////////////////////////////////////////

     public void  init ( )
     //////////////////////////////////////////////////////////////////////
     {
     }

     public synchronized void  start ( )
     //////////////////////////////////////////////////////////////////////
     {
       stopRequested = false;

       if ( thread == null )
       {
         Runnable  runnable =
           new Runnable ( )
           {
             public void  run ( )
             {
               loop ( );
             }
           };

         if ( threadName == null )
         {
           thread = new Thread ( runnable );
         }
         else
         {
           thread = new Thread ( runnable, threadName );
         }

         thread.setPriority ( threadPriority );

         thread.setDaemon ( useDaemonThread );

         thread.start ( );
       }
       else
       {
         notify ( );
       }
     }

     public synchronized void  stop ( )
     //////////////////////////////////////////////////////////////////////
     {
       stopRequested = true;

       thread.interrupt ( );
     }

     public synchronized void  destroy ( )
     //////////////////////////////////////////////////////////////////////
     {
       thread = null;

       stopRequested = false;

       notify ( );
     }

     //////////////////////////////////////////////////////////////////////
     //////////////////////////////////////////////////////////////////////

     private void  loop ( )
     //////////////////////////////////////////////////////////////////////
     {
       while ( thread != null )
       {
         try
         {
           if ( loopable.loop ( ) )
           {
             loopGovernor.govern ( );
           }
           else
           {
             stopRequested = true;
           }
         }
         catch ( InterruptedException  ex )
         {
         }
         catch ( Exception  ex )
         {
           if ( ( exceptionHandler == null )
             || !exceptionHandler.handleException ( ex, loopable ) )
           {
             stopRequested = true;

             ex.printStackTrace ( );
           }
         }

         if ( stopRequested )
         {
           synchronized ( this )
           {
             while ( stopRequested )
             {
               try
               {
                 wait ( );
               }
               catch ( InterruptedException  ex )
               {
               }
             }
           }
         }
       }
     }

     //////////////////////////////////////////////////////////////////////
     //////////////////////////////////////////////////////////////////////
     }