MethodHelper


1   /**
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3    * ("Software"), with or without modification, are permitted provided
4    * that the following conditions are met:
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8    *    copy of this document.
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11   *    above copyright notice, this list of conditions and the
12   *    following disclaimer in the documentation and/or other
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16   *    products derived from this Software without prior written
17   *    permission of Exoffice Technologies.  For written permission,
18   *    please contact info@exolab.org.
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20   * 4. Products derived from this Software may not be called "Exolab"
21   *    nor may "Exolab" appear in their names without prior written
22   *    permission of Exoffice Technologies. Exolab is a registered
23   *    trademark of Exoffice Technologies.
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25   * 5. Due credit should be given to the Exolab Project
26   *    (http://www.exolab.org/).
27   *
28   * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
29   * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
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33   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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37   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
39   * OF THE POSSIBILITY OF SUCH DAMAGE.
40   *
41   * Copyright 2003-2005 (C) Exoffice Technologies Inc. All Rights Reserved.
42   *
43   * $Id: MethodHelper.java,v 1.2 2005/04/02 13:47:16 tanderson Exp $
44   */
45  package org.exolab.jms.net.util;
46  
47  import java.lang.reflect.Method  ;
48  import java.util.ArrayList  ;
49  
50  
51  /**
52   * Helper class for performing reflection.
53   *
54   * @author <a HREF="mailto:tma@netspace.net.au">Tim Anderson</a>
55   * @version $Revision: 1.2 $ $Date: 2005/04/02 13:47:16 $
56   */
57  public final class MethodHelper {
58  
59      /**
60       * Prevent construction of helper class.
61       */
62      private MethodHelper() {
63      }
64  
65      /**
66       * Returns all the interface-declared methods of a class.
67       * This includes those implemented by superclasses.
68       *
69       * @param clazz the class
70       * @return a list of the interface-declared methods for <code>clazz</code>
71       */
72      public static Method  [] getAllInterfaceMethods(Class   clazz) {
73          final int size = 10;
74          ArrayList   result = new ArrayList  (size);
75          getInterfaceMethods(getAllInterfaces(clazz), result);
76          return (Method  []) result.toArray(new Method  [0]);
77      }
78  
79      /**
80       * Returns the interface-declared methods of a class.
81       *
82       * @param clazz the class
83       * @return a list of the interface-declared methods for <code>clazz</code>
84       */
85      public static Method  [] getInterfaceMethods(Class   clazz) {
86          final int size = 10;
87          ArrayList   result = new ArrayList  (size);
88          getInterfaceMethods(clazz.getInterfaces(), result);
89          return (Method  []) result.toArray(new Method  [0]);
90      }
91  
92      /**
93       * Calculates a unique identifier for a method. The identifier is unique
94       * within the declaring class.
95       *
96       * @param method the method
97       * @return a unique identifier for <code>method</code>
98       */
99      public static long getMethodID(Method   method) {
100         final int shift = 32;
101         long hash = method.getDeclaringClass().getName().hashCode();
102         hash ^= method.getName().hashCode();
103         hash ^= method.getReturnType().getName().hashCode();
104         Class  [] args = method.getParameterTypes();
105         for (int i = 0; i < args.length; ++i) {
106             hash ^= ((long) args[i].getName().hashCode()) << shift;
107         }
108         return hash;
109     }
110 
111     /**
112      * Determines all of the interface-declared methods from a set of interfaces
113      * and their super-interfaces.
114      *
115      * @param interfaces the interfaces
116      * @param result     the array to contain the result
117      */
118     private static void getInterfaceMethods(Class  [] interfaces,
119                                             ArrayList   result) {
120         for (int i = 0; i < interfaces.length; ++i) {
121             Class   iface = interfaces[i];
122             getInterfaceMethods(iface.getInterfaces(), result);
123             Method  [] methods = iface.getMethods();
124             for (int j = 0; j < methods.length; ++j) {
125                 if (methods[j].getDeclaringClass() == interfaces[i]) {
126                     result.add(methods[j]);
127                 }
128             }
129         }
130     }
131 
132     /**
133      * Returns all of the interfaces implemented by a class.
134      *
135      * @param clazz the class
136      * @return a list of the interfaces implemented by the class.
137      */
138     public static Class  [] getAllInterfaces(Class   clazz) {
139         ArrayList   result = new ArrayList  ();
140         getAllInterfaces(clazz, result);
141         return (Class  []) result.toArray(new Class  [0]);
142     }
143 
144     /**
145      * Returns all of the interfaces inplemented by a class.
146 
147      * @param clazz the class
148      * @param result     the array to contain the result
149      */
150     private static void getAllInterfaces(Class   clazz, ArrayList   result) {
151         Class  [] interfaces = clazz.getInterfaces();
152         for (int i = 0; i < interfaces.length; ++i) {
153             if (!result.contains(interfaces[i])) {
154                 result.add(interfaces[i]);
155             }
156         }
157         Class   superClass = clazz.getSuperclass();
158         if (superClass != null) {
159             getAllInterfaces(superClass, result);
160         }
161     }
162 }
163
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