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  1.  
  2. import java.util.ArrayDeque;
  3. import java.util.Iterator;
  4. import java.lang.reflect.Method;
  5.  
  6. class HelloWorld
  7. {
  8.     public static void main(String[] args) throws Exception
  9.     {
  10.         Delegate d = new Delegate();
  11.         d.add(null, HelloWorld.class, "foo");
  12.         d.add(null, HelloWorld.class, "bar");
  13.         d.invoke();
  14.     }
  15.  
  16.     public static void foo()
  17.     {
  18.         System.out.println("foo");
  19.     }
  20.  
  21.     public static void bar()
  22.     {
  23.         System.out.println("bar");
  24.     }
  25.  
  26. 	static class Delegate
  27. 	{
  28. 	    ArrayDeque<Pair> methods = new ArrayDeque<Pair>();
  29. 	    Class<?>[] parameterTypes; 
  30.  
  31. 	    public Delegate(Class<?>... parameterTypes)
  32. 	    {
  33. 	        this.parameterTypes = parameterTypes;
  34. 	    }
  35.  
  36. 	    public void add(Object o, Class c, String n) throws Exception
  37. 	    {
  38. 	        Method m = c.getDeclaredMethod(n, parameterTypes);
  39. 	        methods.add(new Pair(o, m));
  40. 	    }
  41.  
  42. 	    public void remove(Object o, Class c, String n) throws Exception
  43. 	    {
  44. 	        Method m = c.getDeclaredMethod(n, parameterTypes);
  45. 	        methods.remove(new Pair(o, m));
  46. 	    }
  47.  
  48. 	    public Object invoke(Object... args) throws Exception
  49. 	    {
  50. 	        Object r = null;
  51. 	        for (Iterator<Pair> i = methods.iterator(); i.hasNext(); )
  52. 	        {
  53. 	            Pair p = i.next();
  54. 	            if (args.length == 0)
  55. 	            {
  56. 	                r = p.m.invoke(p.c);
  57. 	            }
  58. 	            else 
  59. 	            {
  60. 	                r = p.m.invoke(p.c, args);
  61. 	            }
  62. 	        }
  63. 	        return r;
  64. 	    }
  65.  
  66. 	    class Pair
  67. 	    {
  68. 	        public final Object c;
  69. 	        public final Method m;
  70. 	        Pair(Object c, Method m)
  71. 	        {
  72. 	            this.c = c;
  73. 	            this.m = m;
  74. 	        }
  75. 	        public int hashCode()
  76. 	        {
  77. 	            int h = 0;
  78. 	            if (c != null) h ^= c.hashCode();
  79. 	            if (m != null) h ^= m.hashCode();
  80. 	            return h;
  81. 	        }
  82. 	        public boolean equals(Object obj)
  83. 	        {
  84. 	            if (obj == null) return false; if (this == obj) return true;
  85. 	            if (!(obj instanceof Pair)) return false;
  86. 	            Pair p = (Pair)obj;
  87. 	            return (this.c == p.c) && this.m.equals(p.m);
  88. 	        }
  89. 	    }
  90. 	}
  91. }
Success #stdin #stdout 0.07s 380224KB
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foo
bar
https://ideone.com/6fwJNp
language:
Java (HotSpot 12)
created:
10 years ago
visibility:
public

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