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Java > Open Source Codes > org > apache > taglibs > application > EqualsInitParameterTag


1 /*
2  * Copyright 1999,2004 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 package org.apache.taglibs.application;
18
19 import java.util.*;
20 import javax.servlet.*;
21 import javax.servlet.http.*;
22 import javax.servlet.jsp.*;
23 import javax.servlet.jsp.tagext.*;
24
25 /**
26  * JSP Tag <b>equalsInitParameter</b>, used to determine if an init parameter
27  * equals the value of the "match" tag attribute.
28  * <p>
29  * Includes the body of the tag if the init parameter equals the value of the
30  * "match" tag attribute.
31  * <p>
32  * You can set the optional tag attribute <b>value</b> to <i>true</i> or
33  * <i>false</i>. The body of the tag is included if equalsInitParameter matches
34  * the value.
35  * <p>
36  * You can set the optional tag attribute <b>ignoreCase</b> to <i>true</i> or
37  * <i>false</i>. If ignoreCase is set to true, then the comparison between the
38  * init parameter and the "match" tag attribute will <i>not</i> be
39  * case-sensitive.
40  * <p>
41  * JSP Tag Lib Descriptor
42  * <p><pre>
43  * &lt;name>equalsInitParameter&lt;/name>;
44  * &lt;tagclass>org.apache.taglibs.application.EqualsInitParamaeterTag&lt;/tagclass>
45  * &lt;bodycontent>JSP&lt;/bodycontent>
46  * &lt;info>Includes the body of the tag if the init parameter equals the
47  * value of the "match" tag attribute.&lt;/info>
48  * &lt;attribute>
49  * &lt;name>name&lt;/name>
50  * &lt;required>true&lt;/required>
51  * &lt;rtexprvalue>false&lt;/rtexprvalue>
52  * &lt;/attribute>
53  * &lt;attribute>
54  * &lt;name>value&lt;/name>
55  * &lt;required>false&lt;/required>
56  * &lt;rtexprvalue>false&lt;/rtexprvalue>
57  * &lt;/attribute>
58  * &lt;attribute>
59  * &lt;name>match&lt;/name>
60  * &lt;required>true&lt;/required>
61  * &lt;rtexprvalue>true&lt;/rtexprvalue>
62  * &lt;/attribute>
63  * &lt;attribute>
64  * &lt;name>ignoreCase&lt;/name>
65  * &lt;required>false&lt;/required>
66  * &lt;rtexprvalue>false&lt;/rtexprvalue>
67  * &lt;/attribute>
68  * </pre>
69  *
70  * @author Morgan Delagrange
71  */
72
73 public class EqualsInitParameterTag extends TagSupport
74 {
75     private String JavaDoc name = null;
76     private String JavaDoc match = null;
77     //default behaviour is don't ignore case and execute body when tag contents
78 //equal value set by setMatch
79 private boolean ignoreCase = false;
80     private boolean value = true;
81
82     /**
83      * Includes the body of the tag if the init parameter equals the value set in the
84      * 'match' attribute.
85      *
86      * @return SKIP_BODY if equalsInitParameter doesn't match value, EVAL_BODY_include if equalsInitParameter matches value
87      */
88     public final int doStartTag() throws JspException
89     {
90         //result is whether or not tag contents equal the match attribute
91 boolean result = false;
92         String JavaDoc initParam = pageContext.getServletContext().getInitParameter(name);
93       
94         if (initParam == null) {
95             result = false;
96         } else {
97             if (ignoreCase) {
98                 result = initParam.equalsIgnoreCase(match);
99             } else {
100                 result = initParam.equals(match);
101             }
102         }
103       
104         if( value == result )
105             return EVAL_BODY_INCLUDE;
106  
107         return SKIP_BODY;
108     }
109
110     /**
111      * Set the required tag attribute <b>name</b>.
112      *
113      * @param String name of init parameter
114      */
115     public final void setName(String JavaDoc str)
116     {
117     name = str;
118     }
119
120     /**
121      * Set the String that will be compared to the init
122      * parameter.
123      *
124      * @param String value to match against the init parameter
125      */
126     public final void setMatch(String JavaDoc str) {
127         match = str;
128     }
129     
130     /**
131      * If ignoreCase is set to true, then the comparison
132      * between the "match" attribute and the
133      * init parameter will <i>not</i> be case sensitive
134      *
135      * @param boolean true = ignore case<BR>false = case sensitive<BR>
136      * default value = false
137      */
138     public final void setIgnoreCase(boolean value)
139     {
140         ignoreCase = value;
141     }
142     
143     /**
144      * Set the optional tag attribute <b>value</b> to true or false.
145      *
146      * @param boolean true or false
147      */
148     public final void setValue(boolean value)
149     {
150     this.value = value;
151     }
152
153 }
154
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