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1   /*
2    * $Id: Set.java 651946 2008-04-27 13:41:38Z apetrelli $
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *  http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  package org.apache.struts2.components;
23  
24  import java.io.Writer;
25  
26  import org.apache.struts2.views.annotations.StrutsTag;
27  import org.apache.struts2.views.annotations.StrutsTagAttribute;
28  
29  import com.opensymphony.xwork2.util.ValueStack;
30  
31  /***
32   * <!-- START SNIPPET: javadoc -->
33   * <p>The set tag assigns a value to a variable in a specified scope. It is useful when you wish to assign a variable to a
34   * complex expression and then simply reference that variable each time rather than the complex expression. This is
35   * useful in both cases: when the complex expression takes time (performance improvement) or is hard to read (code
36   * readability improvement).</p>
37   * <p>If the tag is used with body content, the evaluation of the value parameter is omitted. Instead, the String to
38   * which the body eveluates is set as value for the scoped variable.</p>
39   *
40   * The scopes available are as follows :-
41   * <ul>
42   *   <li>application - the value will be set in application scope according to servlet spec. using the name as its key</li>
43   *   <li>session - the value will be set in session scope according to servlet spec. using the name as key </li>
44   *   <li>request - the value will be set in request scope according to servlet spec. using the name as key </li>
45   *   <li>page - the value will be set in page scope according to servlet sepc. using the name as key</li>
46   *   <li>action - the value will be set in the request scope and Struts' action context using the name as key</li>
47   * </ul>
48   *
49   * NOTE:<p/>
50   * If no scope is specified, it will default to action scope.
51   *
52   * <!-- END SNIPPET: javadoc -->
53   *
54   * <p/> <b>Parameters</b>
55   *
56   * <!-- START SNIPPET: params -->
57   *
58   * <ul>
59   *
60   * <li>name* (String): The name of the new variable that is assigned the value of <i>value</i></li>
61   *
62   * <li>value (Object): The value that is assigned to the variable named <i>name</i></li>
63   *
64   * <li>scope (String): The scope in which to assign the variable. Can be <b>application</b>, <b>session</b>,
65   * <b>request</b>, <b>page</b>, or <b>action</b>. By default it is <b>action</b>.</li>
66   *
67   * </ul>
68   *
69   * <!-- END SNIPPET: params -->
70   *
71   * <p/> <b>Examples</b>
72   *
73   * <pre>
74   * <!-- START SNIPPET: example -->
75   * &lt;s:set name="personName" value="person.name"/&gt;
76   * Hello, &lt;s:property value="#personName"/&gt;. How are you?
77   * <!-- END SNIPPET: example -->
78   * </pre>
79   *
80   */
81  @StrutsTag(name="set", tldBodyContent="JSP", tldTagClass="org.apache.struts2.views.jsp.SetTag", description="Assigns a value to a variable in a specified scope")
82  public class Set extends ContextBean {
83      protected String scope;
84      protected String value;
85  
86      public Set(ValueStack stack) {
87          super(stack);
88      }
89  
90      public boolean end(Writer writer, String body) {
91          ValueStack stack = getStack();
92  
93          Object o;
94          if (value == null) {
95              if (body != null && !body.equals("")) {
96                  o = body;
97              } else {
98                  o = findValue("top");
99              }
100         } else {
101             o = findValue(value);
102         }
103 
104         body="";
105 
106         if ("application".equalsIgnoreCase(scope)) {
107             stack.setValue("#application['" + getVar() + "']", o);
108         } else if ("session".equalsIgnoreCase(scope)) {
109             stack.setValue("#session['" + getVar() + "']", o);
110         } else if ("request".equalsIgnoreCase(scope)) {
111             stack.setValue("#request['" + getVar() + "']", o);
112         } else if ("page".equalsIgnoreCase(scope)) {
113             stack.setValue("#attr['" + getVar() + "']", o, false);
114         } else {
115             stack.getContext().put(getVar(), o);
116             stack.setValue("#attr['" + getVar() + "']", o, false);
117         }
118 
119         return super.end(writer, body);
120     }
121 
122     /*
123      * TODO: set required=true when 'id' is dropped after 2.1
124      */
125     @StrutsTagAttribute(description="Name used to reference the value pushed into the Value Stack")
126     public void setVar(String var) {
127        super.setVar(var);
128     }
129 
130     @StrutsTagAttribute(description="Deprecated. Use 'var' instead")
131     public void setName(String name) {
132         setVar(name);
133     }
134 
135     @StrutsTagAttribute(description="The scope in which to assign the variable. Can be <b>application</b>" +
136                 ", <b>session</b>, <b>request</b>, <b>page</b>, or <b>action</b>.", defaultValue="action")
137     public void setScope(String scope) {
138         this.scope = scope;
139     }
140 
141     @StrutsTagAttribute(description="The value that is assigned to the variable named <i>name</i>")
142     public void setValue(String value) {
143         this.value = value;
144     }
145 
146     @Override
147     public boolean usesBody() {
148         return true;
149     }
150 }