BeanProviderPropertyAccessor


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.bean;
16  
17  import java.util.Map  ;
18  
19  import ognl.ObjectPropertyAccessor;
20  import ognl.OgnlException;
21  
22  import org.apache.tapestry.IBeanProvider;
23  
24  /**
25   *  Adapts a {@link org.apache.tapestry.IBeanProvider} to
26   *  <a HREF="http://www.ognl.org">OGNL</a> by exposing the named
27   *  beans provided by the provider as read-only properties of
28   *  the provider.
29   * 
30   *  <p>This is registered by {@link org.apache.tapestry.AbstractComponent}.
31   *
32   *  @author Howard Lewis Ship
33   *  @since 2.2
34   *
35   **/
36  
37  public class BeanProviderPropertyAccessor extends ObjectPropertyAccessor
38  {
39      /**
40       *  Checks to see if the name matches the name of a bean inside
41       *  the provider and returns that bean if so.
42       *  Otherwise, invokes the super implementation.
43       * 
44       **/
45      
46      public Object   getProperty(Map   context, Object   target, Object   name) throws OgnlException
47      {
48          IBeanProvider provider = (IBeanProvider)target;
49          String   beanName = (String  )name;
50          
51          if (provider.canProvideBean(beanName))
52              return provider.getBean(beanName);
53          
54          return super.getProperty(context, target, name);
55      }
56  
57      /**
58       *  Returns true if the name matches a bean provided by the provider.
59       *  Otherwise invokes the super implementation.
60       * 
61       **/
62      
63      public boolean hasGetProperty(Map   context, Object   target, Object   oname) throws OgnlException
64      {
65          IBeanProvider provider = (IBeanProvider)target;
66          String   beanName = (String  )oname;
67  
68          if (provider.canProvideBean(beanName))
69              return true;
70              
71          return super.hasGetProperty(context, target, oname);
72      }
73  
74  }
75
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