2009/05/20 - Apache Shale has been retired.

For more information, please explore the Attic.


1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to you under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.shale.util;
19  
20  import javax.faces.FacesException;
21  import javax.faces.context.FacesContext;
22  import javax.faces.convert.Converter;
23  import javax.faces.convert.ConverterException;
24  
25  /***
26   * <p>Helper class to provide access to by-type JavaServer Faces
27   * <code>Converter</code> capabilities.  This implementation is stateless
28   * and maintains no cached information, so instances may be freely created
29   * and destroyed with no side effects.</p>
30   *
31   * $Id: ConverterHelper.java 464373 2006-10-16 04:21:54Z rahul $
32   *
33   * @since 1.0.1
34   */
35  public class ConverterHelper {
36  
37  
38      // -------------------------------------------------------- Static Variables
39  
40  
41      /***
42       * <p>Messages for this class.</p>
43       */
44      private static Messages messages =
45              new Messages("org.apache.shale.resources.Bundle",
46                           ConverterHelper.class.getClassLoader());
47  
48  
49      // ---------------------------------------------------------- Public Methods
50  
51  
52      /***
53       * <p>Use the registered by-type <code>Converter</code> to convert the
54       * specified String value to a corresponding Object value.</p>
55       *
56       * @param context <code>FacesContext</code> for the current request
57       * @param type Type to which this value should be converted
58       *  (used to select the appropriate by-type converter)
59       * @param value Value to be converted
60       *
61       * @exception ConverterException if a conversion error occurs
62       */
63      public Object asObject(FacesContext context, Class type, String value) {
64  
65          if (String.class == type) {
66              return value;
67          }
68          return converter(context, type).getAsObject(context, context.getViewRoot(), value);
69  
70      }
71  
72  
73      /***
74       * <p>Use the registered by-type <code>Converter</code> to convert the
75       * specified Object value to a corresponding String value.</p>
76       *
77       * @param context <code>FacesContext</code> for the current request
78       * @param type Type from which this value should be converted
79       *  (used to select the appropriate by-type converter)
80       * @param value Value to be converted
81       *
82       * @exception ConverterException if a conversion error occurs
83       */
84      public String asString(FacesContext context, Class type, Object value) {
85  
86          if (value == null) {
87              return null;
88          } else if ((String.class == type) && (value instanceof String)) {
89              return (String) value;
90          }
91          return converter(context, type).getAsString(context, context.getViewRoot(), value);
92  
93      }
94  
95  
96      // --------------------------------------------------------- Private Methods
97  
98  
99      /***
100      * <p>Return an appropriate <code>Converter</code> instance for the
101      * specified type.</p>
102      *
103      * @param context <code>FacesContext</code> for the current request
104      * @param type Type for which to retrieve a <code>Converter</code>
105      *
106      * @exception ConverterException if no <code>Converter</code> has been
107      *  registered for the specified type
108      */
109     private Converter converter(FacesContext context, Class type) {
110 
111         if (type == null) {
112             throw new ConverterException(messages.getMessage("convHelper.missing",
113                                                              context.getViewRoot().getLocale()));
114         }
115 
116         Converter converter = null;
117         try {
118             converter = context.getApplication().createConverter(type);
119         } catch (FacesException e) {
120             throw new ConverterException(e);
121         }
122         if (converter == null) {
123             throw new ConverterException(messages.getMessage("convHelper.noConverter",
124                                                              context.getViewRoot().getLocale(),
125                                                              new Object[] { type.getName() }));
126         }
127         return converter;
128 
129     }
130 
131 
132 }