BeanPropertyDescriptor


1   /*
2    * Copyright 2001-2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.axis.utils;
17  
18  import org.apache.axis.components.logger.LogFactory;
19  import org.apache.commons.logging.Log;
20  
21  import java.beans.IndexedPropertyDescriptor  ;
22  import java.beans.PropertyDescriptor  ;
23  import java.lang.reflect.Array  ;
24  import java.lang.reflect.Method  ;
25  import java.lang.reflect.InvocationTargetException  ;
26  
27  
28  /**
29   * This class represents a field/property in a value type (a class with either
30   * bean-style getters/setters or public fields).
31   *
32   * It is essentially a thin wrapper around the PropertyDescriptor from the
33   * JavaBean utilities.  We wrap it with this class so that we can create
34   * the subclass FieldPropertyDescriptor and access public fields (who
35   * wouldn't have PropertyDescriptors normally) via the same interface.
36   *
37   * There are also some interesting tricks where indexed properties are
38   * concerned, mostly involving the fact that we manage the arrays here
39   * rather than relying on the value type class to do it itself.
40   *
41   * @author Rich Scheuerle <scheu@us.ibm.com>
42   * @author Glen Daniels (gdaniels@apache.org)
43   **/
44  public class BeanPropertyDescriptor
45  {
46      protected static Log log =
47          LogFactory.getLog(BeanPropertyDescriptor.class.getName());
48  
49      protected PropertyDescriptor   myPD = null;
50  
51      protected static final Object  [] noArgs = new Object  [] {};
52  
53      /**
54       * Constructor (takes a PropertyDescriptor)
55       *
56       * @param pd
57       */
58      public BeanPropertyDescriptor(PropertyDescriptor   pd) {
59          myPD = pd;
60      }
61  
62      /**
63       * Protected constructor for use by our children
64       */
65      protected BeanPropertyDescriptor() {
66      }
67  
68      /**
69       * Get our property name.
70       */
71      public String   getName(){
72          return myPD.getName();
73      }
74  
75      /**
76       * Query if property is readable
77       * @return true if readable
78       */
79      public boolean isReadable() {
80          return (myPD.getReadMethod() != null);
81      }
82  
83      /**
84       * Query if property is writeable
85       * @return true if writeable
86       */
87      public boolean isWriteable() {
88          return (myPD.getWriteMethod() != null);
89      }
90  
91      /**
92       * Query if property is indexed 
93       * 
94       * @return true if indexed methods exist 
95       */
96      public boolean isIndexed() {
97          return (myPD instanceof IndexedPropertyDescriptor  );
98      }
99  
100     /**
101      * Query if property is indexed or if it' an array.
102      *
103      * @return true if indexed methods exist or if it's an array
104      */
105     public boolean isIndexedOrArray() {
106         return (isIndexed() || isArray());
107     }
108 
109     /**
110      * Query if property is an array (excluded byte[]).
111      * @return true if it's an array (excluded byte[])
112      */
113     public boolean isArray() {
114         return ((myPD.getPropertyType() != null) && myPD.getPropertyType()
115                                    .isArray());
116     }
117 
118     /**
119      * Get the property value
120      * @param obj is the object
121      * @return the entire propery value
122      */
123     public Object   get(Object   obj) 
124         throws InvocationTargetException  , IllegalAccessException   {
125         Method   readMethod = myPD.getReadMethod();
126         if (readMethod != null) {
127             return readMethod.invoke(obj, noArgs);
128         } else {
129             throw new IllegalAccessException  (Messages.getMessage("badGetter00"));
130         }
131     }
132 
133     /**
134      * Set the property value
135      * @param obj is the object
136      * @param newValue is the new value
137      */
138     public void set(Object   obj, Object   newValue) 
139         throws InvocationTargetException  , IllegalAccessException   {
140         Method   writeMethod = myPD.getWriteMethod();
141         if (writeMethod != null) {
142             writeMethod.invoke(obj, new Object  [] {newValue});
143         } else {
144             throw new IllegalAccessException  (Messages.getMessage("badSetter00"));
145         }
146     }    
147 
148     /** 
149      * Get an indexed property
150      * @param obj is the object
151      * @param i the index
152      * @return the object at the indicated index
153      */
154     public Object   get(Object   obj, int i) 
155         throws InvocationTargetException  , IllegalAccessException   {
156         if (!isIndexed()) {
157             return Array.get(get(obj), i);
158         } else {
159             IndexedPropertyDescriptor   id = (IndexedPropertyDescriptor  )myPD;
160             return id.getIndexedReadMethod().invoke(obj,
161                                                     new Object  [] {
162                                                         new Integer  (i)});
163         }
164     }
165 
166     /**
167      * Set an indexed property value
168      * @param obj is the object
169      * @param i the index
170      * @param newValue is the new value
171      */
172     public void set(Object   obj, int i, Object   newValue) 
173         throws InvocationTargetException  , IllegalAccessException   {
174         // Set the new value
175         if (isIndexed()) {
176             IndexedPropertyDescriptor   id = (IndexedPropertyDescriptor  )myPD;
177             growArrayToSize(obj, id.getIndexedPropertyType(), i);
178             id.getIndexedWriteMethod().invoke(obj,
179                                               new Object  [] {
180                                                   new Integer  (i), newValue});
181         } else {
182             growArrayToSize(obj, myPD.getPropertyType().getComponentType(), i);
183             Array.set(get(obj), i, newValue);
184         }
185     }
186 
187     /**
188      * Grow the array 
189      * @param obj
190      * @param componentType
191      * @param i
192      * @throws InvocationTargetException
193      * @throws IllegalAccessException
194      */ 
195     protected void growArrayToSize(Object   obj, Class   componentType, int i) throws InvocationTargetException  , IllegalAccessException   {
196         // Get the entire array and make sure it is large enough
197         Object   array = get(obj);
198         if (array == null || Array.getLength(array) <= i) {
199             // Construct a larger array of the same type            
200             Object   newArray = Array.newInstance(componentType, i + 1);
201             // Copy over the old elements
202             if (array != null) {
203                 System.arraycopy(array, 0, newArray, 0, Array.getLength(array));
204             }
205             // Set the object to use the larger array
206             set(obj, newArray);
207         }
208     }
209 
210     /**
211      * Get the type of a property
212      * @return the type of the property
213      */     
214     public Class   getType() {
215         if (isIndexed()) {
216             return ((IndexedPropertyDescriptor  )myPD).getIndexedPropertyType();
217         } else {
218             return myPD.getPropertyType();
219         }
220     }
221 
222     public Class   getActualType() {
223         return myPD.getPropertyType();
224     }
225 }
226
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