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1   /*
2    * $Id: MatchTag.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.logic;
22  
23  import org.apache.struts.taglib.TagUtils;
24  
25  import javax.servlet.http.Cookie;
26  import javax.servlet.http.HttpServletRequest;
27  import javax.servlet.jsp.JspException;
28  
29  /**
30   * Evalute the nested body content of this tag if the specified value is a
31   * substring of the specified variable.
32   *
33   * @version $Rev: 471754 $ $Date: 2004-10-16 12:38:42 -0400 (Sat, 16 Oct 2004)
34   *          $
35   */
36  public class MatchTag extends ConditionalTagBase {
37      // ------------------------------------------------------------- Properties
38  
39      /**
40       * The location where the match must exist (<code>start</code> or
41       * <code>end</code>), or <code>null</code> for anywhere.
42       */
43      protected String location = null;
44  
45      /**
46       * The value to which the variable specified by other attributes of this
47       * tag will be matched.
48       */
49      protected String value = null;
50  
51      public String getLocation() {
52          return (this.location);
53      }
54  
55      public void setLocation(String location) {
56          this.location = location;
57      }
58  
59      public String getValue() {
60          return (this.value);
61      }
62  
63      public void setValue(String value) {
64          this.value = value;
65      }
66  
67      // --------------------------------------------------------- Public Methods
68  
69      /**
70       * Release all allocated resources.
71       */
72      public void release() {
73          super.release();
74          location = null;
75          value = null;
76      }
77  
78      // ------------------------------------------------------ Protected Methods
79  
80      /**
81       * Evaluate the condition that is being tested by this particular tag, and
82       * return <code>true</code> if the nested body content of this tag should
83       * be evaluated, or <code>false</code> if it should be skipped. This
84       * method must be implemented by concrete subclasses.
85       *
86       * @throws JspException if a JSP exception occurs
87       */
88      protected boolean condition()
89          throws JspException {
90          return (condition(true));
91      }
92  
93      /**
94       * Evaluate the condition that is being tested by this particular tag, and
95       * return <code>true</code> if the nested body content of this tag should
96       * be evaluated, or <code>false</code> if it should be skipped. This
97       * method must be implemented by concrete subclasses.
98       *
99       * @param desired Desired value for a true result
100      * @throws JspException if a JSP exception occurs
101      */
102     protected boolean condition(boolean desired)
103         throws JspException {
104         // Acquire the specified variable
105         String variable = null;
106 
107         if (cookie != null) {
108             Cookie[] cookies =
109                 ((HttpServletRequest) pageContext.getRequest()).getCookies();
110 
111             if (cookies == null) {
112                 cookies = new Cookie[0];
113             }
114 
115             for (int i = 0; i < cookies.length; i++) {
116                 if (cookie.equals(cookies[i].getName())) {
117                     variable = cookies[i].getValue();
118 
119                     break;
120                 }
121             }
122         } else if (header != null) {
123             variable =
124                 ((HttpServletRequest) pageContext.getRequest()).getHeader(header);
125         } else if (name != null) {
126             Object value =
127                 TagUtils.getInstance().lookup(pageContext, name, property, scope);
128 
129             if (value != null) {
130                 variable = value.toString();
131             }
132         } else if (parameter != null) {
133             variable = pageContext.getRequest().getParameter(parameter);
134         } else {
135             JspException e =
136                 new JspException(messages.getMessage("logic.selector"));
137 
138             TagUtils.getInstance().saveException(pageContext, e);
139             throw e;
140         }
141 
142         if (variable == null) {
143             JspException e =
144                 new JspException(messages.getMessage("logic.variable", value));
145 
146             TagUtils.getInstance().saveException(pageContext, e);
147             throw e;
148         }
149 
150         // Perform the comparison requested by the location attribute
151         boolean matched = false;
152 
153         if (location == null) {
154             matched = (variable.indexOf(value) >= 0);
155         } else if (location.equals("start")) {
156             matched = variable.startsWith(value);
157         } else if (location.equals("end")) {
158             matched = variable.endsWith(value);
159         } else {
160             JspException e =
161                 new JspException(messages.getMessage("logic.location", location));
162 
163             TagUtils.getInstance().saveException(pageContext, e);
164             throw e;
165         }
166 
167         // Return the final result
168         return (matched == desired);
169     }
170 }