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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.lang.reflect.InvocationTargetException;
  32. import java.lang.reflect.Method;
  33. import java.util.HashMap;
  34. import java.util.Map;
  35. import java.util.Set;
  36.  
  37. /*
  38.  * CommandHandler
  39.  * Allows you to register and invoke methods based on keywords/commands
  40.  * Method registed with keyword "unknown" will be invoked if there's no
  41.  * matching keyword
  42.  *
  43.  * @author Manuel Mausz (0728348)
  44.  */
  45. public class CommandHandler
  46. {
  47.   class Exception
  48.     extends java.lang.RuntimeException
  49.   {
  50.     public Exception()
  51.     {
  52.       super();
  53.     }
  54.  
  55.     public Exception(String message)
  56.     {
  57.       super(message);
  58.     }
  59.   }
  60.  
  61.   /*==========================================================================*/
  62.  
  63.   private HashMap<String, Object[]> commands;
  64.  
  65.   /*--------------------------------------------------------------------------*/
  66.  
  67.   public CommandHandler()
  68.   {
  69.     commands = new HashMap<String, Object[]>();
  70.   }
  71.  
  72.   /*--------------------------------------------------------------------------*/
  73.  
  74.   public Set<Map.Entry<String, Object[]>> entrySet()
  75.   {
  76.     return commands.entrySet();
  77.   }
  78.  
  79.   /*--------------------------------------------------------------------------*/
  80.  
  81.   public void register(String cmd, Object obj, String method)
  82.     throws NoSuchMethodException
  83.   {
  84.     Class[] params = { String.class, String[].class };
  85.     Method meth = obj.getClass().getMethod(method, params);
  86.     Object[] tmp = { obj, meth };
  87.     commands.put(cmd, tmp);
  88.   }
  89.  
  90.   /*--------------------------------------------------------------------------*/
  91.  
  92.   public void call(String cmd, String[] args)
  93.     throws Exception
  94.   {
  95.     try
  96.     {
  97.       Object[] meth = commands.get(cmd);
  98.       if (meth == null)
  99.         meth = commands.get("unknown");
  100.       if (meth == null)
  101.       {
  102.         unknown(cmd, args);
  103.         return;
  104.       }
  105.  
  106.       Object[] params = { cmd, args };
  107.       ((Method) meth[1]).invoke(meth[0], (Object[]) params);
  108.     }
  109.     catch (IllegalAccessException e)
  110.     {
  111.       throw new Exception(e.getMessage());
  112.     }
  113.     catch (InvocationTargetException e)
  114.     {
  115.       throw new Exception(e.getCause().getMessage());
  116.     }
  117.     catch (IllegalArgumentException e)
  118.     {
  119.       throw new Exception(e.getMessage());
  120.     }
  121.   }
  122.  
  123.   /*--------------------------------------------------------------------------*/
  124.  
  125.   public void unknown(String cmd, String[] args)
  126.   {
  127.     System.out.println("Error: Unknown command: " + cmd);
  128.     return;
  129.   }
  130. }
  131.