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Java > Open Source Codes > org > apache > tapestry > coerce > TypeConverterWrapper


1 // Copyright 2004, 2005 The Apache Software Foundation
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 package org.apache.tapestry.coerce;
16
17 import java.util.Iterator JavaDoc;
18 import java.util.List JavaDoc;
19
20 import org.apache.hivemind.lib.util.StrategyRegistry;
21 import org.apache.hivemind.lib.util.StrategyRegistryImpl;
22
23 /**
24  * A service implementation that works around an
25  * {@link org.apache.hivemind.lib.util.StrategyRegistry}. The registry is contructed from a
26  * configuration that follows the <code>tapestry.coerce.Converters</code> schema (a List of
27  * {@link org.apache.tapestry.coerce.TypeConverterContribution}plus an additional converter for
28  * nulls.
29  *
30  * @author Howard M. Lewis Ship
31  * @since 4.0
32  */
33 public class TypeConverterWrapper implements TypeConverter
34 {
35     private StrategyRegistry _registry = new StrategyRegistryImpl();
36
37     private List JavaDoc _contributions;
38
39     private TypeConverter _nullConverter;
40
41     public void initializeService()
42     {
43         Iterator JavaDoc i = _contributions.iterator();
44
45         while (i.hasNext())
46         {
47             TypeConverterContribution c = (TypeConverterContribution) i.next();
48
49             _registry.register(c.getSubjectClass(), c.getConverter());
50         }
51     }
52
53     public Object JavaDoc convertValue(Object JavaDoc value)
54     {
55         if (value == null)
56         {
57             if (_nullConverter == null)
58                 return null;
59
60             return _nullConverter.convertValue(null);
61         }
62
63         TypeConverter delegate = (TypeConverter) _registry.getStrategy(value.getClass());
64
65         return delegate.convertValue(value);
66     }
67
68     /**
69      * Sets the List of {@link org.apache.tapestry.coerce.TypeConverterContribution}s.
70      */
71
72     public void setContributions(List JavaDoc contributions)
73     {
74         _contributions = contributions;
75     }
76
77     /**
78      * Sets the converter used to convert null.
79      */
80
81     public void setNullConverter(TypeConverter nullConverter)
82     {
83         _nullConverter = nullConverter;
84     }
85 }
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