ELMatchTag


1   /*
2    * $Id: ELMatchTag.java 54933 2004-10-16 17:04:52Z germuska $ 
3    *
4    * Copyright 1999-2004 The Apache Software Foundation.
5    * 
6    * Licensed under the Apache License, Version 2.0 (the "License");
7    * you may not use this file except in compliance with the License.
8    * You may obtain a copy of the License at
9    * 
10   *      http://www.apache.org/licenses/LICENSE-2.0
11   * 
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  
19  package org.apache.strutsel.taglib.logic;
20  
21  import org.apache.struts.taglib.logic.MatchTag;
22  import javax.servlet.jsp.JspException  ;
23  import org.apache.strutsel.taglib.utils.EvalHelper;
24  
25  /**
26   * Evalute the nested body content of this tag if the specified value
27   * is a substring of the specified variable.
28   *<p>
29   * This class is a subclass of the class
30   * <code>org.apache.struts.taglib.logic.MatchTag</code> which provides most of
31   * the described functionality.  This subclass allows all attribute values to
32   * be specified as expressions utilizing the JavaServer Pages Standard Library
33   * expression language.
34   *
35   * @version $Rev: 54933 $
36   */
37  public class ELMatchTag extends MatchTag {
38  
39      /**
40       * Instance variable mapped to "cookie" tag attribute.
41       * (Mapping set in associated BeanInfo class.)
42       */
43      private String   cookieExpr;
44      /**
45       * Instance variable mapped to "header" tag attribute.
46       * (Mapping set in associated BeanInfo class.)
47       */
48      private String   headerExpr;
49      /**
50       * Instance variable mapped to "location" tag attribute.
51       * (Mapping set in associated BeanInfo class.)
52       */
53      private String   locationExpr;
54      /**
55       * Instance variable mapped to "name" tag attribute.
56       * (Mapping set in associated BeanInfo class.)
57       */
58      private String   nameExpr;
59      /**
60       * Instance variable mapped to "parameter" tag attribute.
61       * (Mapping set in associated BeanInfo class.)
62       */
63      private String   parameterExpr;
64      /**
65       * Instance variable mapped to "property" tag attribute.
66       * (Mapping set in associated BeanInfo class.)
67       */
68      private String   propertyExpr;
69      /**
70       * Instance variable mapped to "scope" tag attribute.
71       * (Mapping set in associated BeanInfo class.)
72       */
73      private String   scopeExpr;
74      /**
75       * Instance variable mapped to "value" tag attribute.
76       * (Mapping set in associated BeanInfo class.)
77       */
78      private String   valueExpr;
79  
80      /**
81       * Getter method for "cookie" tag attribute.
82       * (Mapping set in associated BeanInfo class.)
83       */
84      public String   getCookieExpr() { return (cookieExpr); }
85      /**
86       * Getter method for "header" tag attribute.
87       * (Mapping set in associated BeanInfo class.)
88       */
89      public String   getHeaderExpr() { return (headerExpr); }
90      /**
91       * Getter method for "location" tag attribute.
92       * (Mapping set in associated BeanInfo class.)
93       */
94      public String   getLocationExpr() { return (locationExpr); }
95      /**
96       * Getter method for "name" tag attribute.
97       * (Mapping set in associated BeanInfo class.)
98       */
99      public String   getNameExpr() { return (nameExpr); }
100     /**
101      * Getter method for "parameter" tag attribute.
102      * (Mapping set in associated BeanInfo class.)
103      */
104     public String   getParameterExpr() { return (parameterExpr); }
105     /**
106      * Getter method for "property" tag attribute.
107      * (Mapping set in associated BeanInfo class.)
108      */
109     public String   getPropertyExpr() { return (propertyExpr); }
110     /**
111      * Getter method for "scope" tag attribute.
112      * (Mapping set in associated BeanInfo class.)
113      */
114     public String   getScopeExpr() { return (scopeExpr); }
115     /**
116      * Getter method for "value" tag attribute.
117      * (Mapping set in associated BeanInfo class.)
118      */
119     public String   getValueExpr() { return (valueExpr); }
120 
121     /**
122      * Setter method for "cookie" tag attribute.
123      * (Mapping set in associated BeanInfo class.)
124      */
125     public void setCookieExpr(String   cookieExpr) { this.cookieExpr = cookieExpr; }
126     /**
127      * Setter method for "header" tag attribute.
128      * (Mapping set in associated BeanInfo class.)
129      */
130     public void setHeaderExpr(String   headerExpr) { this.headerExpr = headerExpr; }
131     /**
132      * Setter method for "location" tag attribute.
133      * (Mapping set in associated BeanInfo class.)
134      */
135     public void setLocationExpr(String   locationExpr) { this.locationExpr = locationExpr; }
136     /**
137      * Setter method for "name" tag attribute.
138      * (Mapping set in associated BeanInfo class.)
139      */
140     public void setNameExpr(String   nameExpr) { this.nameExpr = nameExpr; }
141     /**
142      * Setter method for "parameter" tag attribute.
143      * (Mapping set in associated BeanInfo class.)
144      */
145     public void setParameterExpr(String   parameterExpr) { this.parameterExpr = parameterExpr; }
146     /**
147      * Setter method for "property" tag attribute.
148      * (Mapping set in associated BeanInfo class.)
149      */
150     public void setPropertyExpr(String   propertyExpr) { this.propertyExpr = propertyExpr; }
151     /**
152      * Setter method for "scope" tag attribute.
153      * (Mapping set in associated BeanInfo class.)
154      */
155     public void setScopeExpr(String   scopeExpr) { this.scopeExpr = scopeExpr; }
156     /**
157      * Setter method for "value" tag attribute.
158      * (Mapping set in associated BeanInfo class.)
159      */
160     public void setValueExpr(String   valueExpr) { this.valueExpr = valueExpr; }
161 
162     /**
163      * String value of expression to be evaluated.
164      */
165     private String     expr;
166 
167     /**
168      * Returns the string value of the expression.  This value will be
169      * evaluated by the JSTL EL engine.
170      */
171     public  String     getExpr() {
172         return (expr);
173     }
174     
175     /**
176      * Sets the string value of the expression.  This expression will be
177      * evaluated by the JSTL EL engine.
178      */
179     public  void  setExpr(String   expr) {
180         this.expr = expr;
181     }
182 
183     /**
184      * Evaluated value of expression.
185      */
186     private String     exprValue;
187 
188     /**
189      * Returns the evaluated expression.
190      */
191     public  String     getExprValue() {
192         return (exprValue);
193     }
194 
195     /**
196      * Sets the evaluated expression.
197      */
198     public  void  setExprValue(String   exprValue) {
199         this.exprValue  = exprValue;
200     }
201     
202     /**
203      * Releases state of custom tag so this instance can be reused.
204      */
205     public void release()
206     {
207         super.release();
208         setCookieExpr(null);
209         setHeaderExpr(null);
210         setLocationExpr(null);
211         setNameExpr(null);
212         setParameterExpr(null);
213         setPropertyExpr(null);
214         setScopeExpr(null);
215         setValueExpr(null);
216         setExpr(null);
217         setExprValue(null);
218     }
219     
220     /**
221      * Process the start tag.
222      *
223      * @exception JspException if a JSP exception has occurred
224      */
225     public int doStartTag() throws JspException   {
226         evaluateExpressions();
227         return (super.doStartTag());
228     }
229 
230     /**
231      * Evaluates the condition that is being tested by this particular tag,
232      * and returns <code>true</code> if the nested body content of this tag
233      * should be evaluated, or <code>false</code> if it should be skipped.
234      *
235      * @param desired Desired value for a true result
236      * @exception JspException if a JSP exception occurs
237      */
238     protected boolean condition(boolean desired) throws JspException   {
239         boolean   result   = false;
240         if (getExprValue() != null) {
241             result   =
242                 ELMatchSupport.condition(desired, getExprValue(), value,
243                                          location, messages, pageContext);
244         }
245         else {
246             result   = super.condition(desired);
247         }
248         return (result);
249     }
250     
251     /**
252      * Processes all attribute values which use the JSTL expression evaluation
253      * engine to determine their values.
254      *
255      * @exception JspException if a JSP exception has occurred
256      */
257     private void evaluateExpressions() throws JspException   {
258         String    string  = null;
259 
260         if ((string = EvalHelper.evalString("cookie", getCookieExpr(),
261                                             this, pageContext)) != null)
262             setCookie(string);
263 
264         if ((string = EvalHelper.evalString("expr", getExpr(),
265                                             this, pageContext)) != null)
266             setExprValue(string);
267 
268         if ((string = EvalHelper.evalString("header", getHeaderExpr(),
269                                             this, pageContext)) != null)
270             setHeader(string);
271 
272         if ((string = EvalHelper.evalString("location", getLocationExpr(),
273                                             this, pageContext)) != null)
274             setLocation(string);
275 
276         if ((string = EvalHelper.evalString("name", getNameExpr(),
277                                             this, pageContext)) != null)
278             setName(string);
279 
280         if ((string = EvalHelper.evalString("parameter", getParameterExpr(),
281                                             this, pageContext)) != null)
282             setParameter(string);
283 
284         if ((string = EvalHelper.evalString("property", getPropertyExpr(),
285                                             this, pageContext)) != null)
286             setProperty(string);
287 
288         if ((string = EvalHelper.evalString("scope", getScopeExpr(),
289                                             this, pageContext)) != null)
290             setScope(string);
291 
292         if ((string = EvalHelper.evalString("value", getValueExpr(),
293                                             this, pageContext)) != null)
294             setValue(string);
295     }
296 }
297
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