1 /* |
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2 * Copyright 2005-2008 Sun Microsystems, Inc. All Rights Reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. Sun designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Sun in the LICENSE file that accompanied this code. |
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10 * |
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11 * This code is distributed in the hope that it will be useful, but WITHOUT |
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 * version 2 for more details (a copy is included in the LICENSE file that |
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15 * accompanied this code). |
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16 * |
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17 * You should have received a copy of the GNU General Public License version |
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18 * 2 along with this work; if not, write to the Free Software Foundation, |
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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20 * |
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21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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22 * CA 95054 USA or visit www.sun.com if you need additional information or |
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23 * have any questions. |
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24 */ |
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25 package sun.swing; |
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26 |
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27 import java.security.*; |
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28 import java.lang.reflect.*; |
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29 |
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30 /** |
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31 * A utility for accessing and invoking methods, via reflection, |
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32 * that would otherwise be unaccessible. |
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33 * |
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34 * @author Shannon Hickey |
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35 */ |
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36 public class AccessibleMethod { |
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37 |
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38 private final Method method; |
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39 |
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40 /** |
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41 * Construct an instance for the given params. |
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42 * |
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43 * @param klass the class to which the method belongs |
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44 * @param methodName the name of the method |
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45 * @param paramTypes the paramater type array |
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46 * @throws NullPointerException if <code>klass</code> |
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47 * or <code>name</code> is <code>null</code> |
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48 * @throws NoSuchMethodException if the method can't be found |
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49 */ |
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50 public AccessibleMethod(Class klass, |
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51 String methodName, |
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52 Class ... paramTypes) throws NoSuchMethodException { |
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53 try { |
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54 method = AccessController.doPrivileged( |
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55 new AccessMethodAction(klass, methodName, paramTypes)); |
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56 } catch (PrivilegedActionException e) { |
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57 throw (NoSuchMethodException)e.getCause(); |
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58 } |
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59 } |
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60 |
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61 /** |
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62 * Invoke the method that this object represents. |
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63 * Has the same behavior and throws the same exceptions as |
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64 * <code>java.lang.reflect.Method.invoke</code> with one |
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65 * exception: This method does not throw |
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66 * <code>IllegalAccessException</code> since the target |
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67 * method has already been made accessible. |
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68 * |
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69 * @param obj the object the underlying method is invoked from |
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70 * @param args the arguments used for the method call |
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71 * @return the result of dispatching the method represented by |
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72 * this object on <code>obj</code> with parameters |
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73 * <code>args</code> |
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74 * @see java.lang.reflect.Method#invoke |
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75 */ |
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76 public Object invoke(Object obj, Object ... args) |
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77 throws IllegalArgumentException, InvocationTargetException { |
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78 |
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79 try { |
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80 return method.invoke(obj, args); |
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81 } catch (IllegalAccessException e) { |
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82 // should never happen since we've made it accessible |
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83 throw new AssertionError("accessible method inaccessible"); |
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84 } |
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85 } |
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86 |
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87 /** |
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88 * Invoke the method that this object represents, with the |
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89 * expectation that the method being called throws no |
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90 * checked exceptions. |
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91 * <p> |
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92 * Simply calls <code>this.invoke(obj, args)</code> |
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93 * but catches any <code>InvocationTargetException</code> |
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94 * and returns the cause wrapped in a runtime exception. |
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95 * |
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96 * @param obj the object the underlying method is invoked from |
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97 * @param args the arguments used for the method call |
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98 * @return the result of dispatching the method represented by |
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99 * this object on <code>obj</code> with parameters |
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100 * <code>args</code> |
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101 * @see #invoke |
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102 */ |
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103 public Object invokeNoChecked(Object obj, Object ... args) { |
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104 try { |
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105 return invoke(obj, args); |
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106 } catch (InvocationTargetException ex) { |
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107 if (ex.getCause() instanceof RuntimeException) { |
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108 throw (RuntimeException)ex.getCause(); |
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109 } else { |
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110 throw new RuntimeException(ex.getCause()); |
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111 } |
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112 } |
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113 } |
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114 |
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115 /** The action used to fetch the method and make it accessible */ |
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116 private static class AccessMethodAction implements PrivilegedExceptionAction<Method> { |
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117 private final Class<?> klass; |
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118 private final String methodName; |
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119 private final Class[] paramTypes; |
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120 |
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121 public AccessMethodAction(Class klass, |
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122 String methodName, |
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123 Class ... paramTypes) { |
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124 |
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125 this.klass = klass; |
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126 this.methodName = methodName; |
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127 this.paramTypes = paramTypes; |
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128 } |
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129 |
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130 public Method run() throws NoSuchMethodException { |
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131 Method method = klass.getDeclaredMethod(methodName, paramTypes); |
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132 method.setAccessible(true); |
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133 return method; |
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134 } |
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135 } |
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136 } |
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