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1   /*
2    * $Id: StrutsTag.java 471754 2006-11-06 14:55:09Z husted $
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.struts.taglib.bean;
22  
23  import org.apache.struts.config.ModuleConfig;
24  import org.apache.struts.taglib.TagUtils;
25  import org.apache.struts.util.MessageResources;
26  
27  import javax.servlet.jsp.JspException;
28  import javax.servlet.jsp.tagext.TagSupport;
29  
30  /**
31   * Define a scripting variable that exposes the requested Struts internal
32   * configuraton object.
33   *
34   * @version $Rev: 471754 $ $Date: 2004-10-16 12:38:42 -0400 (Sat, 16 Oct 2004)
35   *          $
36   */
37  public class StrutsTag extends TagSupport {
38      /**
39       * The message resources for this package.
40       */
41      protected static MessageResources messages =
42          MessageResources.getMessageResources(
43              "org.apache.struts.taglib.bean.LocalStrings");
44  
45      // ------------------------------------------------------------- Properties
46  
47      /**
48       * The name of the scripting variable that will be exposed as a page scope
49       * attribute.
50       */
51      protected String id = null;
52  
53      /**
54       * The name of the <code>ActionFormBean</code> object to be exposed.
55       */
56      protected String formBean = null;
57  
58      /**
59       * The name of the <code>ActionForward</code> object to be exposed.
60       */
61      protected String forward = null;
62  
63      /**
64       * The name of the <code>ActionMapping</code> object to be exposed.
65       */
66      protected String mapping = null;
67  
68      public String getId() {
69          return (this.id);
70      }
71  
72      public void setId(String id) {
73          this.id = id;
74      }
75  
76      public String getFormBean() {
77          return (this.formBean);
78      }
79  
80      public void setFormBean(String formBean) {
81          this.formBean = formBean;
82      }
83  
84      public String getForward() {
85          return (this.forward);
86      }
87  
88      public void setForward(String forward) {
89          this.forward = forward;
90      }
91  
92      public String getMapping() {
93          return (this.mapping);
94      }
95  
96      public void setMapping(String mapping) {
97          this.mapping = mapping;
98      }
99  
100     // --------------------------------------------------------- Public Methods
101 
102     /**
103      * Retrieve the required configuration object and expose it as a scripting
104      * variable.
105      *
106      * @throws JspException if a JSP exception has occurred
107      */
108     public int doStartTag() throws JspException {
109         // Validate the selector arguments
110         int n = 0;
111 
112         if (formBean != null) {
113             n++;
114         }
115 
116         if (forward != null) {
117             n++;
118         }
119 
120         if (mapping != null) {
121             n++;
122         }
123 
124         if (n != 1) {
125             JspException e =
126                 new JspException(messages.getMessage("struts.selector"));
127 
128             TagUtils.getInstance().saveException(pageContext, e);
129             throw e;
130         }
131 
132         // Retrieve our module configuration information
133         ModuleConfig config =
134             TagUtils.getInstance().getModuleConfig(pageContext);
135 
136         // Retrieve the requested object to be exposed
137         Object object = null;
138         String selector = null;
139 
140         if (formBean != null) {
141             selector = formBean;
142             object = config.findFormBeanConfig(formBean);
143         } else if (forward != null) {
144             selector = forward;
145             object = config.findForwardConfig(forward);
146         } else if (mapping != null) {
147             selector = mapping;
148             object = config.findActionConfig(mapping);
149         }
150 
151         if (object == null) {
152             JspException e =
153                 new JspException(messages.getMessage("struts.missing", selector));
154 
155             TagUtils.getInstance().saveException(pageContext, e);
156             throw e;
157         }
158 
159         // Expose this value as a scripting variable
160         pageContext.setAttribute(id, object);
161 
162         return (SKIP_BODY);
163     }
164 
165     /**
166      * Release all allocated resources.
167      */
168     public void release() {
169         super.release();
170         id = null;
171         formBean = null;
172         forward = null;
173         mapping = null;
174     }
175 }