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Java > Open Source Codes > org > apache > tapestry > annotations > MessageAnnotationWorker


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.annotations;
16
17 import java.lang.reflect.Method JavaDoc;
18 import java.lang.reflect.Modifier JavaDoc;
19
20 import org.apache.hivemind.ApplicationRuntimeException;
21 import org.apache.hivemind.Location;
22 import org.apache.hivemind.service.BodyBuilder;
23 import org.apache.hivemind.service.MethodSignature;
24 import org.apache.tapestry.Tapestry;
25 import org.apache.tapestry.enhance.EnhancementOperation;
26 import org.apache.tapestry.spec.IComponentSpecification;
27
28 /**
29  * Builds a method that accesses component messages.
30  *
31  * @author Howard Lewis Ship
32  * @since 4.0
33  */
34 public class MessageAnnotationWorker implements MethodAnnotationEnhancementWorker
35 {
36
37     public void performEnhancement(EnhancementOperation op, IComponentSpecification spec,
38             Method JavaDoc method, Location location)
39     {
40         if (!method.getReturnType().equals(String JavaDoc.class))
41             throw new ApplicationRuntimeException(AnnotationMessages.returnStringOnly(method
42                     .getReturnType()));
43
44         Message message = method.getAnnotation(Message.class);
45
46         String JavaDoc keyName = message.value();
47
48         if (keyName.equals(""))
49             keyName = convertMethodNameToKeyName(method.getName());
50
51         BodyBuilder builder = new BodyBuilder();
52
53         builder.begin();
54
55         Class JavaDoc[] parameterTypes = method.getParameterTypes();
56         int paramCount = Tapestry.size(parameterTypes);
57
58         if (paramCount > 0)
59         {
60             builder.addln("java.lang.Object[] params = new java.lang.Object[{0}];", paramCount);
61             for (int i = 0; i < paramCount; i++)
62             {
63                 builder.add("params[{0}] = ", i);
64
65                 if (parameterTypes[i].isPrimitive())
66                     builder.add("($w) ");
67
68                 // Parameter $0 is this, so $1 is the first real parameter.
69
70                 builder.addln("${0};", i + 1);
71             }
72         }
73
74         builder.add("return getMessages().");
75
76         if (paramCount == 0)
77             builder.addln("getMessage(\"{0}\");", keyName);
78         else
79             builder.addln("format(\"{0}\", params);", keyName);
80
81         builder.end();
82
83         op.addMethod(Modifier.PUBLIC, new MethodSignature(method), builder.toString());
84
85         if (isGetter(method))
86             op.claimProperty(AnnotationUtils.getPropertyName(method));
87     }
88
89     boolean isGetter(Method JavaDoc method)
90     {
91         // We already know the return type is String
92
93         return method.getName().startsWith("get") && method.getParameterTypes().length == 0;
94     }
95
96     String JavaDoc convertMethodNameToKeyName(String JavaDoc methodName)
97     {
98         StringBuffer JavaDoc buffer = new StringBuffer JavaDoc();
99
100         int cursorx = methodName.startsWith("get") ? 3 : 0;
101         int length = methodName.length();
102         boolean atStart = true;
103
104         while (cursorx < length)
105         {
106             char ch = methodName.charAt(cursorx);
107
108             if (Character.isUpperCase(ch))
109             {
110                 if (!atStart)
111                     buffer.append('-');
112                 buffer.append(Character.toLowerCase(ch));
113             }
114             else
115                 buffer.append(ch);
116
117             atStart = false;
118
119             cursorx++;
120         }
121
122         return buffer.toString();
123     }
124 }
125
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