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1   /*
2    * $Id: Set.java 497654 2007-01-19 00:21:57Z rgielen $
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  package org.apache.struts2.components;
22  
23  import java.io.Writer;
24  
25  import org.apache.struts2.views.annotations.StrutsTag;
26  import org.apache.struts2.views.annotations.StrutsTagAttribute;
27  
28  import com.opensymphony.xwork2.util.ValueStack;
29  
30  /***
31   * <!-- START SNIPPET: javadoc -->
32   * <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
33   * complex expression and then simply reference that variable each time rather than the complex expression. This is
34   * useful in both cases: when the complex expression takes time (performance improvement) or is hard to read (code
35   * readability improvement).</P>
36   *
37   * The scopes available are as follows :-
38   * <ul>
39   *   <li>application - the value will be set in application scope according to servlet spec. using the name as its key</li>
40   *   <li>session - the value will be set in session scope according to servlet spec. using the name as key </li>
41   *   <li>request - the value will be set in request scope according to servlet spec. using the name as key </li>
42   *   <li>page - the value will be set in request scope according to servlet sepc. using the name as key</li>
43   *   <li>action - the value will be set in the request scope and Struts' action context using the name as key</li>
44   * </ul>
45   *
46   * NOTE:<p/>
47   * If no scope is specified, it will default to action scope.
48   *
49   * <!-- END SNIPPET: javadoc -->
50   *
51   * <p/> <b>Parameters</b>
52   *
53   * <!-- START SNIPPET: params -->
54   *
55   * <ul>
56   *
57   * <li>name* (String): The name of the new variable that is assigned the value of <i>value</i></li>
58   *
59   * <li>value (Object): The value that is assigned to the variable named <i>name</i></li>
60   *
61   * <li>scope (String): The scope in which to assign the variable. Can be <b>application</b>, <b>session</b>,
62   * <b>request</b>, <b>page</b>, or <b>action</b>. By default it is <b>action</b>.</li>
63   *
64   * </ul>
65   *
66   * <!-- END SNIPPET: params -->
67   *
68   * <p/> <b>Examples</b>
69   *
70   * <pre>
71   * <!-- START SNIPPET: example -->
72   * &lt;s:set name="personName" value="person.name"/&gt;
73   * Hello, &lt;s:property value="#personName"/&gt;. How are you?
74   * <!-- END SNIPPET: example -->
75   * </pre>
76   *
77   */
78  @StrutsTag(name="set", tldBodyContent="empty", tldTagClass="org.apache.struts2.views.jsp.SetTag", description="Assigns a value to a variable in a specified scope")
79  public class Set extends Component {
80      protected String name;
81      protected String scope;
82      protected String value;
83  
84      public Set(ValueStack stack) {
85          super(stack);
86      }
87  
88      public boolean end(Writer writer, String body) {
89          ValueStack stack = getStack();
90  
91          if (value == null) {
92              value = "top";
93          }
94  
95          Object o = findValue(value);
96  
97          String name;
98          if (altSyntax()) {
99              name = findString(this.name, "name", "Name is required");
100         } else {
101             name = this.name;
102 
103             if (this.name == null) {
104                 throw fieldError("name", "Name is required", null);
105             }
106         }
107 
108         if ("application".equalsIgnoreCase(scope)) {
109             stack.setValue("#application['" + name + "']", o);
110         } else if ("session".equalsIgnoreCase(scope)) {
111             stack.setValue("#session['" + name + "']", o);
112         } else if ("request".equalsIgnoreCase(scope)) {
113             stack.setValue("#request['" + name + "']", o);
114         } else if ("page".equalsIgnoreCase(scope)) {
115             stack.setValue("#attr['" + name + "']", o, false);
116         } else {
117             stack.getContext().put(name, o);
118             stack.setValue("#attr['" + name + "']", o, false);
119         }
120 
121         return super.end(writer, body);
122     }
123 
124     @StrutsTagAttribute(description=" The name of the new variable that is assigned the value of <i>value</i>", required=true)
125     public void setName(String name) {
126         this.name = name;
127     }
128 
129     @StrutsTagAttribute(description="The scope in which to assign the variable. Can be <b>application</b>" +
130                 ", <b>session</b>, <b>request</b>, <b>page</b>, or <b>action</b>.", defaultValue="action")
131     public void setScope(String scope) {
132         this.scope = scope;
133     }
134 
135     @StrutsTagAttribute(description="The value that is assigned to the variable named <i>name</i>")
136     public void setValue(String value) {
137         this.value = value;
138     }
139 }