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Java > Open Source Codes > org > apache > jasper > tagplugins > jstl > core > Set


1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one or more
3  * contributor license agreements. See the NOTICE file distributed with
4  * this work for additional information regarding copyright ownership.
5  * The ASF licenses this file to You under the Apache License, Version 2.0
6  * (the "License"); you may not use this file except in compliance with
7  * the License. You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17
18
19 package org.apache.jasper.tagplugins.jstl.core;
20
21 import org.apache.jasper.compiler.tagplugin.TagPlugin;
22 import org.apache.jasper.compiler.tagplugin.TagPluginContext;
23 import org.apache.jasper.tagplugins.jstl.Util;
24
25 public class Set implements TagPlugin {
26     
27     public void doTag(TagPluginContext ctxt) {
28         
29         //the flags to indicate whether the attributes have been specified
30 boolean hasValue = false, hasVar = false, hasScope = false,
31         hasTarget = false;
32         
33         //the scope name
34 String JavaDoc strScope;
35         //the id of the scope
36 int iScope;
37         
38         //initialize the flags
39 hasValue = ctxt.isAttributeSpecified("value");
40         hasVar = ctxt.isAttributeSpecified("var");
41         hasScope = ctxt.isAttributeSpecified("scope");
42         hasTarget = ctxt.isAttributeSpecified("target");
43         
44         //the temp variables name
45 String JavaDoc resultName = ctxt.getTemporaryVariableName();
46         String JavaDoc targetName = ctxt.getTemporaryVariableName();
47         String JavaDoc propertyName = ctxt.getTemporaryVariableName();
48         
49         //initialize the "result" which will be assigned to the var or target.property
50 ctxt.generateJavaSource("Object " + resultName + " = null;");
51         if(hasValue){
52             ctxt.generateJavaSource(resultName + " = ");
53             ctxt.generateAttribute("value");
54             ctxt.generateJavaSource(";");
55         }else{
56             ctxt.dontUseTagPlugin();
57             return;
58         }
59         
60         //initialize the strScope
61 if(hasScope){
62             strScope = ctxt.getConstantAttribute("scope");
63         }else{
64             strScope = "page";
65         }
66         
67         //get the iScope according to the strScope
68 iScope = Util.getScope(strScope);
69         
70         //if the attribute var has been specified then assign the result to the var;
71 if(hasVar){
72             String JavaDoc strVar = ctxt.getConstantAttribute("var");
73             ctxt.generateJavaSource("if(null != " + resultName + "){");
74             ctxt.generateJavaSource(" pageContext.setAttribute(\"" + strVar + "\"," + resultName + "," + iScope + ");");
75             ctxt.generateJavaSource("} else {");
76             if(hasScope){
77                 ctxt.generateJavaSource(" pageContext.removeAttribute(\"" + strVar + "\"," + iScope + ");");
78             }else{
79                 ctxt.generateJavaSource(" pageContext.removeAttribute(\"" + strVar + "\");");
80             }
81             ctxt.generateJavaSource("}");
82             
83             //else assign the result to the target.property
84 }else if(hasTarget){
85             
86             //generate the temp variable name
87 String JavaDoc pdName = ctxt.getTemporaryVariableName();
88             String JavaDoc successFlagName = ctxt.getTemporaryVariableName();
89             String JavaDoc index = ctxt.getTemporaryVariableName();
90             String JavaDoc methodName = ctxt.getTemporaryVariableName();
91             
92             //initialize the property
93 ctxt.generateJavaSource("String " + propertyName + " = null;");
94             ctxt.generateJavaSource("if(");
95             ctxt.generateAttribute("property");
96             ctxt.generateJavaSource(" != null){");
97             ctxt.generateJavaSource(" " + propertyName + " = (");
98             ctxt.generateAttribute("property");
99             ctxt.generateJavaSource(").toString();");
100             ctxt.generateJavaSource("}");
101             
102             //initialize the target
103 ctxt.generateJavaSource("Object " + targetName + " = ");
104             ctxt.generateAttribute("target");
105             ctxt.generateJavaSource(";");
106             
107             //the target is ok
108 ctxt.generateJavaSource("if(" + targetName + " != null){");
109             
110             //if the target is a map, then put the result into the map with the key property
111 ctxt.generateJavaSource(" if(" + targetName + " instanceof java.util.Map){");
112             ctxt.generateJavaSource(" if(null != " + resultName + "){");
113             ctxt.generateJavaSource(" ((java.util.Map) " + targetName + ").put(" + propertyName + "," + resultName + ");");
114             ctxt.generateJavaSource(" }else{");
115             ctxt.generateJavaSource(" ((java.util.Map) " + targetName + ").remove(" + propertyName + ");");
116             ctxt.generateJavaSource(" }");
117             
118             //else assign the result to the target.property
119 ctxt.generateJavaSource(" }else{");
120             ctxt.generateJavaSource(" try{");
121             
122             //get all the property of the target
123 ctxt.generateJavaSource(" java.beans.PropertyDescriptor " + pdName + "[] = java.beans.Introspector.getBeanInfo(" + targetName + ".getClass()).getPropertyDescriptors();");
124             
125             //the success flag is to imply whether the assign is successful
126 ctxt.generateJavaSource(" boolean " + successFlagName + " = false;");
127             
128             //find the right property
129 ctxt.generateJavaSource(" for(int " + index + "=0;" + index + "<" + pdName + ".length;" + index + "++){");
130             ctxt.generateJavaSource(" if(" + pdName + "[" + index + "].getName().equals(" + propertyName + ")){");
131             
132             //get the "set" method;
133 ctxt.generateJavaSource(" java.lang.reflect.Method " + methodName + " = " + pdName + "[" + index + "].getWriteMethod();");
134             ctxt.generateJavaSource(" if(null == " + methodName + "){");
135             ctxt.generateJavaSource(" throw new JspException(\"No setter method in &lt;set&gt; for property \"+" + propertyName + ");");
136             ctxt.generateJavaSource(" }");
137             
138             //invoke the method through the reflection
139 ctxt.generateJavaSource(" if(" + resultName + " != null){");
140             ctxt.generateJavaSource(" " + methodName + ".invoke(" + targetName + ", new Object[]{(" + methodName + ".getParameterTypes()[0]).cast(" + resultName + ")});");
141             ctxt.generateJavaSource(" }else{");
142             ctxt.generateJavaSource(" " + methodName + ".invoke(" + targetName + ", new Object[]{null});");
143             ctxt.generateJavaSource(" }");
144             ctxt.generateJavaSource(" " + successFlagName + " = true;");
145             ctxt.generateJavaSource(" }");
146             ctxt.generateJavaSource(" }");
147             ctxt.generateJavaSource(" if(!" + successFlagName + "){");
148             ctxt.generateJavaSource(" throw new JspException(\"Invalid property in &lt;set&gt;:\"+" + propertyName + ");");
149             ctxt.generateJavaSource(" }");
150             ctxt.generateJavaSource(" }");
151             
152             //catch the el exception and throw it as a JspException
153 ctxt.generateJavaSource(" catch (IllegalAccessException ex) {");
154             ctxt.generateJavaSource(" throw new JspException(ex);");
155             ctxt.generateJavaSource(" } catch (java.beans.IntrospectionException ex) {");
156             ctxt.generateJavaSource(" throw new JspException(ex);");
157             ctxt.generateJavaSource(" } catch (java.lang.reflect.InvocationTargetException ex) {");
158             ctxt.generateJavaSource(" throw new JspException(ex);");
159             ctxt.generateJavaSource(" }");
160             ctxt.generateJavaSource(" }");
161             ctxt.generateJavaSource("}else{");
162             ctxt.generateJavaSource(" throw new JspException();");
163             ctxt.generateJavaSource("}");
164         }
165     }
166     
167 }
168
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