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Java > Open Source Codes > org > apache > tapestry > enhance > InjectComponentWorker


1 // Copyright 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.enhance;
16
17 import java.util.Iterator JavaDoc;
18
19 import org.apache.hivemind.ErrorLog;
20 import org.apache.hivemind.service.ClassFabUtils;
21 import org.apache.hivemind.util.Defense;
22 import org.apache.tapestry.IComponent;
23 import org.apache.tapestry.spec.IComponentSpecification;
24 import org.apache.tapestry.spec.IContainedComponent;
25
26 /**
27  * Injects components for which the property attribute of the <component> element was
28  * specified. This makes it easier to reference a particular component from Java code.
29  *
30  * @author Howard M. Lewis Ship
31  * @since 4.0
32  */
33 public class InjectComponentWorker implements EnhancementWorker
34 {
35     private ErrorLog _errorLog;
36
37     public void performEnhancement(EnhancementOperation op, IComponentSpecification spec)
38     {
39         Iterator JavaDoc i = spec.getComponentIds().iterator();
40
41         while (i.hasNext())
42         {
43             String JavaDoc id = (String JavaDoc) i.next();
44
45             IContainedComponent cc = spec.getComponent(id);
46
47             String JavaDoc propertyName = cc.getPropertyName();
48
49             if (propertyName != null)
50             {
51                 try
52                 {
53                     injectComponent(op, id, propertyName);
54                 }
55                 catch (Exception JavaDoc ex)
56                 {
57                     _errorLog.error(EnhanceMessages.errorAddingProperty(propertyName, op
58                             .getBaseClass(), ex), cc.getLocation(), ex);
59                 }
60             }
61         }
62     }
63
64     public void injectComponent(EnhancementOperation op, String JavaDoc componentId, String JavaDoc propertyName)
65     {
66         Defense.notNull(op, "op");
67         Defense.notNull(componentId, "componentId");
68         Defense.notNull(propertyName, "propertyName");
69
70         Class JavaDoc propertyType = EnhanceUtils.extractPropertyType(op, propertyName, null);
71
72         op.claimProperty(propertyName);
73
74         String JavaDoc fieldName = "_$" + propertyName;
75
76         op.addField(fieldName, propertyType);
77
78         EnhanceUtils.createSimpleAccessor(op, fieldName, propertyName, propertyType);
79
80         // I.e. _$fred = (IComponent) getComponent("fred");
81
82         String JavaDoc code = fieldName + " = (" + ClassFabUtils.getJavaClassName(propertyType)
83                 + ") getComponent(\"" + componentId + "\");";
84
85         op.extendMethodImplementation(IComponent.class, EnhanceUtils.FINISH_LOAD_SIGNATURE, code);
86     }
87
88     public void setErrorLog(ErrorLog errorLog)
89     {
90         _errorLog = errorLog;
91     }
92 }
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