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  1. /*
  2.  * Copyright (c) 2010, Manuel Mausz. All rights reserved.
  3.  *
  4.  * Redistribution and use in source and binary forms, with or without
  5.  * modification, are permitted provided that the following conditions
  6.  * are met:
  7.  *
  8.  *   - Redistributions of source code must retain the above copyright
  9.  *     notice, this list of conditions and the following disclaimer.
  10.  *
  11.  *   - Redistributions in binary form must reproduce the above copyright
  12.  *     notice, this list of conditions and the following disclaimer in the
  13.  *     documentation and/or other materials provided with the distribution.
  14.  *
  15.  *   - The names of the authors may not be used to endorse or promote products
  16.  *     derived from this software without specific prior written permission.
  17.  *
  18.  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  19.  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  20.  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  21.  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  22.  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  23.  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  24.  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  25.  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  26.  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  27.  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  28.  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29.  */
  30.  
  31. import java.util.HashMap;
  32. import java.lang.reflect.Method;
  33. import java.lang.reflect.InvocationTargetException;
  34.  
  35. /*
  36.  * CommandHandler
  37.  * Allows you to register and invoke methods based on keywords/commands
  38.  * Method registed with keyword "unknown" will be invoked if there's no
  39.  * matching keyword
  40.  *
  41.  * @author Manuel Mausz (0728348)
  42.  */
  43. public class CommandHandler
  44. {
  45.   class Exception
  46.     extends java.lang.RuntimeException
  47.   {
  48.     public Exception()
  49.     {
  50.       super();
  51.     }
  52.  
  53.     public Exception(String message)
  54.     {
  55.       super(message);
  56.     }
  57.   }
  58.  
  59.   /*==========================================================================*/
  60.  
  61.   private HashMap<String, Object[]> commands;
  62.  
  63.   /*--------------------------------------------------------------------------*/
  64.  
  65.   public CommandHandler()
  66.   {
  67.     commands = new HashMap<String, Object[]>();
  68.   }
  69.  
  70.   /*--------------------------------------------------------------------------*/
  71.  
  72.   public void register(String cmd, Object obj, String method)
  73.     throws NoSuchMethodException
  74.   {
  75.     Class[] params = { String.class, String[].class };
  76.     Method meth = obj.getClass().getMethod(method, params);
  77.     Object[] tmp = { obj, meth };
  78.     commands.put(cmd, tmp);
  79.   }
  80.  
  81.   /*--------------------------------------------------------------------------*/
  82.  
  83.   public void call(String cmd, String[] args)
  84.     throws Exception
  85.   {
  86.     try
  87.     {
  88.       Object[] meth = commands.get(cmd);
  89.       if (meth == null)
  90.         meth = commands.get("unknown");
  91.       if (meth == null)
  92.       {
  93.         unknown(cmd, args);
  94.         return;
  95.       }
  96.  
  97.       Object[] params = { cmd, args };
  98.       ((Method) meth[1]).invoke(meth[0], (Object[]) params);
  99.     }
  100.     catch (IllegalAccessException e)
  101.     {
  102.       throw new Exception(e.getMessage());
  103.     }
  104.     catch (InvocationTargetException e)
  105.     {
  106.       throw new Exception(e.getCause().getMessage());
  107.     }
  108.     catch (IllegalArgumentException e)
  109.     {
  110.       throw new Exception(e.getMessage());
  111.     }
  112.   }
  113.  
  114.   /*--------------------------------------------------------------------------*/
  115.  
  116.   public void unknown(String cmd, String[] args)
  117.   {
  118.     System.out.println("Error: Unknown command: " + cmd);
  119.     return;
  120.   }
  121. }
  122.