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Java > Open Source Codes > org > apache > tapestry > binding > AssetBinding


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.binding;
16
17 import org.apache.hivemind.Location;
18 import org.apache.hivemind.util.Defense;
19 import org.apache.tapestry.BindingException;
20 import org.apache.tapestry.IAsset;
21 import org.apache.tapestry.IComponent;
22 import org.apache.tapestry.coerce.ValueConverter;
23
24 /**
25  * A binding that is connected to an asset provided by a component.
26  *
27  * @author Howard M. Lewis Ship
28  * @since 4.0
29  */
30 public class AssetBinding extends AbstractBinding
31 {
32     private final IComponent _component;
33
34     private final String JavaDoc _assetName;
35
36     public AssetBinding(String JavaDoc description, ValueConverter valueConverter, Location location,
37             IComponent component, String JavaDoc assetName)
38     {
39         super(description, valueConverter, location);
40
41         Defense.notNull(component, "component");
42         Defense.notNull(assetName, "assetName");
43
44         _component = component;
45         _assetName = assetName;
46     }
47
48     public Object JavaDoc getObject()
49     {
50         IAsset result = _component.getAsset(_assetName);
51
52         if (result == null)
53             throw new BindingException(BindingMessages.missingAsset(_component, _assetName),
54                     _component, getLocation(), this, null);
55
56         return result;
57     }
58
59     public Object JavaDoc getComponent()
60     {
61         return _component;
62     }
63 }
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