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1   // 
2   // Copyright (c) 2003,2004 , Caltha - Gajda, Krzewski, Mach, Potempski Sp.J. 
3   // All rights reserved. 
4   // 
5   // Redistribution and use in source and binary forms, with or without modification,  
6   // are permitted provided that the following conditions are met: 
7   //  
8   // * Redistributions of source code must retain the above copyright notice,  
9   //	 this list of conditions and the following disclaimer. 
10  // * Redistributions in binary form must reproduce the above copyright notice,  
11  //	 this list of conditions and the following disclaimer in the documentation  
12  //	 and/or other materials provided with the distribution. 
13  // * Neither the name of the Caltha - Gajda, Krzewski, Mach, Potempski Sp.J.  
14  //	 nor the names of its contributors may be used to endorse or promote products  
15  //	 derived from this software without specific prior written permission. 
16  // 
17  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"  
18  // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED  
19  // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
20  // IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,  
21  // INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,  
22  // BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
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26  // POSSIBILITY OF SUCH DAMAGE. 
27  // 
28  package org.objectledge.pico.customization;
29  
30  import java.lang.reflect.Field;
31  
32  import org.picocontainer.ComponentAdapter;
33  import org.picocontainer.Parameter;
34  import org.picocontainer.PicoContainer;
35  import org.picocontainer.PicoInstantiationException;
36  import org.picocontainer.defaults.ComponentParameter;
37  
38  /***
39   * 
40   *
41   * @author <a href="mailto:rafal@caltha.pl">Rafal Krzewski</a>
42   * @version $Id: CustomizingComponentParameter.java,v 1.1 2005/02/04 02:28:25 rafal Exp $
43   */
44  public class CustomizingComponentParameter
45      extends ComponentParameter 
46  {
47      /*** A CustomizedComponentParameter with null componentKey */
48      public static final Parameter DEFAULT = new CustomizingComponentParameter();
49      
50      // TODO copied from pico 
51      private Object componentKey;
52      
53      /***
54       * Creates new CustomizedComponentParameter instance.
55       */
56      public CustomizingComponentParameter()
57      {
58          super();
59      }
60  
61      /***
62       * Creates new CustomizedComponentParameter instance.
63       * 
64       * @param componentKey the component key.
65       */
66      public CustomizingComponentParameter(Object componentKey)
67      {
68          super(componentKey);
69          this.componentKey = componentKey;
70      }
71      
72      //////////////////////////////////////////////////////////////////////////////////////////////
73      
74      /***
75       * {@inheritDoc}
76       */
77      public Object resolveInstance(PicoContainer container, ComponentAdapter adapter,
78          Class expectedType)
79          throws PicoInstantiationException
80      {
81          ComponentAdapter resolvedAdapter = resolveAdapter(container, adapter, expectedType);
82          if(resolvedAdapter instanceof CustomizedComponentAdapter)
83          {
84              return ((CustomizedComponentAdapter)resolvedAdapter).getComponentInstance(container,
85                  adapter.getComponentKey(), adapter.getComponentImplementation());
86          }
87          return super.resolveInstance(container, adapter, expectedType);
88      }
89  
90      // private ///////////////////////////////////////////////////////////////////////////////////
91      
92      // TODO copied from pico
93      private ComponentAdapter resolveAdapter(PicoContainer container, ComponentAdapter adapter,
94          Class expectedType)
95      {
96  
97          final ComponentAdapter result = getTargetAdapter(container, expectedType);
98          if(result == null)
99          {
100             return null;
101         }
102 
103         // can't depend on ourselves
104         if(adapter != null && adapter.getComponentKey().equals(result.getComponentKey()))
105         {
106             return null;
107         }
108 
109         if(!expectedType.isAssignableFrom(result.getComponentImplementation()))
110         {
111             // check for primitive value
112             if(expectedType.isPrimitive())
113             {
114                 try
115                 {
116                     final Field field = result.getComponentImplementation().getField("TYPE");
117                     final Class type = (Class)field.get(result.getComponentInstance(null));
118                     if(expectedType.isAssignableFrom(type))
119                     {
120                         return result;
121                     }
122                 }
123                 catch(NoSuchFieldException e)
124                 {
125                     // ignored
126                 }
127                 catch(IllegalArgumentException e)
128                 {
129                     // ignored
130                 }
131                 catch(IllegalAccessException e)
132                 {
133                     // ignored
134                 }
135                 catch(ClassCastException e)
136                 {
137                     // ignored
138                 }
139             }
140             return null;
141         }
142         return result;
143     }
144 
145     // TODO copied from pico
146     private ComponentAdapter getTargetAdapter(PicoContainer container, Class expectedType)
147     {
148         if(componentKey != null)
149         {
150             // key tells us where to look so we follow
151             return container.getComponentAdapter(componentKey);
152         }
153         else
154         {
155             return container.getComponentAdapterOfType(expectedType);
156         }
157     }
158 }