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1   /*
2    *  Copyright 2007 Tacos.
3    * 
4    *  Licensed under the Apache License, Version 2.0 (the "License");
5    *  you may not use this file except in compliance with the License.
6    *  You may obtain a copy of the License at
7    * 
8    *       http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   *  Unless required by applicable law or agreed to in writing, software
11   *  distributed under the License is distributed on an "AS IS" BASIS,
12   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   *  See the License for the specific language governing permissions and
14   *  limitations under the License.
15   *  under the License.
16   */
17  package net.sf.tacos.binding;
18  
19  import net.sf.tacos.asset.AbsoluteAsset;
20  import org.apache.hivemind.Location;
21  import org.apache.hivemind.util.Defense;
22  import org.apache.tapestry.BindingException;
23  import org.apache.tapestry.IAsset;
24  import org.apache.tapestry.IComponent;
25  import org.apache.tapestry.binding.AbstractBinding;
26  import org.apache.tapestry.coerce.ValueConverter;
27  import org.apache.tapestry.services.AbsoluteURLBuilder;
28  
29  /**
30   * A binding that is connected to an asset provided by a component.
31   * 
32   * @author Andreas Andreou
33   * @since 4.1
34   */
35  public class AbsoluteAssetBinding extends AbstractBinding
36  {
37      private final IComponent component;
38      private AbsoluteURLBuilder absoluteURLBuilder;
39  
40      public AbsoluteAssetBinding(String description, ValueConverter valueConverter, 
41              AbsoluteURLBuilder absoluteURLBuilder, Location location, IComponent component, String assetName)
42      {
43          super(assetName, valueConverter, location);
44  
45          Defense.notNull(component, "component");
46          Defense.notNull(assetName, "assetName");
47  
48          this.component = component;
49          this.absoluteURLBuilder = absoluteURLBuilder;
50      }
51  
52      public Object getObject()
53      {
54          IAsset asset = component.getAsset(_description);
55  
56          if (asset == null)
57              throw new BindingException("Component " + component.getExtendedId() + 
58                      " does not contain an asset named ''" + _description + "''.",
59                      component, getLocation(), this, null);
60  
61          return new AbsoluteAsset(asset, absoluteURLBuilder);
62      }
63  
64      public Object getComponent()
65      {
66          return component;
67      }
68  }
69