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1   /*
2    * Redistribution and use of this software and associated documentation ("Software"), with or
3    * without modification, are permitted provided that the following conditions are met:
4    *
5    * 1. Redistributions of source code must retain copyright statements and notices. Redistributions
6    * must also contain a copy of this document.
7    *
8    * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
9    * conditions and the following disclaimer in the documentation and/or other materials provided with
10   * the distribution.
11   *
12   * 3. The name "Exolab" must not be used to endorse or promote products derived from this Software
13   * without prior written permission of Intalio, Inc. For written permission, please contact
14   * info@exolab.org.
15   *
16   * 4. Products derived from this Software may not be called "Exolab" nor may "Exolab" appear in
17   * their names without prior written permission of Intalio, Inc. Exolab is a registered trademark of
18   * Intalio, Inc.
19   *
20   * 5. Due credit should be given to the Exolab Project (http://www.exolab.org/).
21   *
22   * THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR
23   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
24   * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTALIO, INC. OR ITS
25   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
28   * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
29   * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30   *
31   * Copyright 2004 (C) Intalio, Inc. All Rights Reserved.
32   *
33   * $Id$
34   */
35  package org.exolab.castor.xml.handlers;
36  
37  import java.lang.reflect.Method;
38  import java.lang.reflect.Modifier;
39  
40  import org.exolab.castor.mapping.FieldDescriptor;
41  import org.exolab.castor.mapping.FieldHandler;
42  import org.exolab.castor.mapping.GeneralizedFieldHandler;
43  import org.exolab.castor.mapping.MappingException;
44  
45  /**
46   * An implementation of GeneralizedFieldHandler for classes that have a built-in valueOf(String)
47   * factory method, such as type-safe enumeration classes, java.sql.Timestamp, etc.
48   *
49   * @author <a href="kvisco@intalio.com">Keith Visco</a>
50   * @version $Revision$ $Date: 2006-04-14 04:14:43 -0600 (Fri, 14 Apr 2006) $
51   * @see FieldDescriptor
52   * @see FieldHandler
53   */
54  public class ValueOfFieldHandler extends GeneralizedFieldHandler {
55  
56    /** The Class[] holding the argument types of the factory method. */
57    private static final Class[] ARGS = new Class[] {String.class};
58    /** The Factory Method name. */
59    private static final String METHOD_NAME = "valueOf";
60  
61    /** The class type for this FieldHandler. */
62    private final Class _type;
63    /** The <code>valueOf</code> method reference. */
64    private final Method _valueOf;
65  
66    /**
67     * Creates a new ValueOfFieldHandler.
68     *
69     * @param type the class type to create the FieldHandler for
70     * @throws MappingException if the valueOf method cannot be found
71     */
72    public ValueOfFieldHandler(final Class type) throws MappingException {
73      super();
74      if (type == null) {
75        throw new IllegalArgumentException("The argument 'type' must not be null.");
76      }
77  
78      _type = type;
79  
80      Method method = null;
81      try {
82        method = type.getMethod(METHOD_NAME, ARGS);
83      } catch (java.lang.NoSuchMethodException nsme) {
84        throw new MappingException(nsme);
85      }
86      if (!Modifier.isStatic(method.getModifiers())) {
87        String err = "No static method '" + METHOD_NAME + "' found in class: " + type.getName();
88        throw new MappingException(err);
89      }
90  
91      _valueOf = method;
92    } // -- ValueOfFieldHandler
93  
94    /**
95     * This method is used to convert the value when the getValue method is called. The getValue
96     * method will obtain the actual field value from given 'parent' object. This convert method is
97     * then invoked with the field's value. The value returned from this method will be the actual
98     * value returned by getValue method.
99     *
100    * @param value the object value to convert after performing a get operation
101    * @return the converted value.
102    */
103   public Object convertUponGet(final Object value) {
104     // -- no conversion necessary for marshaling
105     return value;
106   } // -- convertUponGet
107 
108   /**
109    * This method is used to convert the value when the setValue method is called. The setValue
110    * method will call this method to obtain the converted value. The converted value will then be
111    * used as the value to set for the field.
112    *
113    * @param value the object value to convert before performing a set operation
114    * @return the converted value.
115    */
116   public Object convertUponSet(final Object value) {
117     Object[] args = new Object[1];
118 
119     if (value != null) {
120       args[0] = value.toString();
121     }
122 
123     Object result = null;
124 
125     try {
126       result = _valueOf.invoke(null, args);
127     } catch (java.lang.IllegalAccessException iae) {
128       throw new IllegalStateException(iae.getMessage());
129     } catch (java.lang.reflect.InvocationTargetException ite) {
130       throw new IllegalStateException(ite.getMessage());
131     }
132 
133     return result;
134   } // -- convertUponSet;
135 
136   /**
137    * Returns the class type for the field that this GeneralizedFieldHandler converts to and from.
138    * This should be the type that is used in the object model.
139    *
140    * @return the class type of of the field
141    */
142   public Class getFieldType() {
143     return _type;
144   } // -- getFieldType
145 
146   /**
147    * Creates a new instance of the object described by this field.
148    *
149    * @param parent The object for which the field is created
150    * @return A new instance of the field's value
151    * @throws IllegalStateException This field is a simple type and cannot be instantiated
152    */
153   public Object newInstance(final Object parent) throws IllegalStateException {
154     return null;
155   }
156 
157 } // -- ValueOfFieldHandler