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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.myfaces.view.facelets.tag.jsf;
20  
21  import java.io.IOException;
22  
23  import javax.el.ValueExpression;
24  import javax.faces.component.UIComponent;
25  import javax.faces.component.ValueHolder;
26  import javax.faces.context.FacesContext;
27  import javax.faces.convert.Converter;
28  import javax.faces.view.ValueHolderAttachedObjectHandler;
29  import javax.faces.view.facelets.ComponentHandler;
30  import javax.faces.view.facelets.ConverterHandler;
31  import javax.faces.view.facelets.FaceletContext;
32  import javax.faces.view.facelets.MetaRuleset;
33  import javax.faces.view.facelets.TagAttribute;
34  import javax.faces.view.facelets.TagException;
35  import javax.faces.view.facelets.TagHandlerDelegate;
36  
37  import org.apache.myfaces.view.facelets.FaceletCompositionContext;
38  import org.apache.myfaces.view.facelets.tag.MetaRulesetImpl;
39  
40  /**
41   * Handles setting a Converter instance on a ValueHolder. Will wire all attributes set to the Converter instance
42   * created/fetched. Uses the "binding" attribute for grabbing instances to apply attributes to. <p/> Will only
43   * set/create Converter is the passed UIComponent's parent is null, signifying that it wasn't restored from an existing
44   * tree.
45   * 
46   * @author Leonardo Uribe (latest modification by $Author: struberg $)
47   * @version $Revision: 1194861 $ $Date: 2011-10-29 05:02:34 -0500 (Sat, 29 Oct 2011) $
48   *
49   * @since 2.0
50   */
51  public class ConverterTagHandlerDelegate extends TagHandlerDelegate implements ValueHolderAttachedObjectHandler
52  {
53      private ConverterHandler _delegate;
54      
55      public ConverterTagHandlerDelegate(ConverterHandler delegate)
56      {
57          _delegate = delegate;
58      }
59  
60      /**
61       * Set Converter instance on parent ValueHolder if it's not being restored.
62       * <ol>
63       * <li>Cast to ValueHolder</li>
64       * <li>If "binding" attribute was specified, fetch/create and re-bind to expression.</li>
65       * <li>Otherwise, call {@link #createConverter(FaceletContext) createConverter}.</li>
66       * <li>Call {@link ObjectHandler#setAttributes(FaceletContext, Object) setAttributes} on Converter instance.</li>
67       * <li>Set the Converter on the ValueHolder</li>
68       * <li>If the ValueHolder has a localValue, convert it and set the value</li>
69       * </ol>
70       * 
71       * @see ValueHolder
72       * @see Converter
73       * @see #createConverter(FaceletContext)
74       * @see javax.faces.view.facelets.FaceletHandler#apply(javax.faces.view.facelets.FaceletContext, javax.faces.component.UIComponent)
75       */
76      @Override
77      public void apply(FaceletContext ctx, UIComponent parent) throws IOException
78      {
79          // only process if it's been created
80          if (!ComponentHandler.isNew(parent))
81          {
82              return;
83          }
84          if (parent instanceof ValueHolder)
85          {
86              applyAttachedObject(ctx.getFacesContext(), parent);
87          }
88          else if (UIComponent.isCompositeComponent(parent))
89          {
90              if (getFor() == null)
91              {
92                  throw new TagException(_delegate.getTag(), "is nested inside a composite component"
93                          + " but does not have a for attribute.");
94              }
95              FaceletCompositionContext mctx = FaceletCompositionContext.getCurrentInstance(ctx);
96              mctx.addAttachedObjectHandler(parent, _delegate);
97          }
98          else
99          {
100             throw new TagException(_delegate.getTag(),
101                     "Parent not composite component or an instance of ValueHolder: " + parent);
102         }      
103     }
104 
105     /**
106      * Create a Converter instance
107      * 
108      * @param ctx
109      *            FaceletContext to use
110      * @return Converter instance, cannot be null
111      */
112     protected Converter createConverter(FaceletContext ctx)
113     {
114         if (_delegate.getConverterId(ctx) == null)
115         {
116             throw new TagException(_delegate.getTag(),
117                                     "Default behavior invoked of requiring a converter-id passed in the "
118                                     + "constructor, must override ConvertHandler(ConverterConfig)");
119         }
120         return ctx.getFacesContext().getApplication().createConverter(_delegate.getConverterId(ctx));
121     }
122 
123     @Override
124     public MetaRuleset createMetaRuleset(Class type)
125     {
126         return new MetaRulesetImpl(_delegate.getTag(), type).ignore("binding");
127     }
128 
129     public void applyAttachedObject(FacesContext context, UIComponent parent)
130     {
131         // Retrieve the current FaceletContext from FacesContext object
132         FaceletContext faceletContext = (FaceletContext) context.getAttributes().get(
133                 FaceletContext.FACELET_CONTEXT_KEY);
134         
135         // cast to a ValueHolder
136         ValueHolder vh = (ValueHolder) parent;
137         ValueExpression ve = null;
138         Converter c = null;
139         if (_delegate.getBinding() != null)
140         {
141             ve = _delegate.getBinding().getValueExpression(faceletContext, Converter.class);
142             c = (Converter) ve.getValue(faceletContext);
143         }
144         if (c == null)
145         {
146             c = this.createConverter(faceletContext);
147             if (ve != null)
148             {
149                 ve.setValue(faceletContext, c);
150             }
151         }
152         if (c == null)
153         {
154             throw new TagException(_delegate.getTag(), "No Converter was created");
155         }
156         _delegate.setAttributes(faceletContext, c);
157         vh.setConverter(c);
158         Object lv = vh.getLocalValue();
159         FacesContext faces = faceletContext.getFacesContext();
160         if (lv instanceof String)
161         {
162             vh.setValue(c.getAsObject(faces, parent, (String) lv));
163         }
164     }
165 
166     public String getFor()
167     {
168         TagAttribute forAttribute = _delegate.getTagAttribute("for");
169         
170         if (forAttribute == null)
171         {
172             return null;
173         }
174         else
175         {
176             return forAttribute.getValue();
177         }
178     }
179 }