ELOptionsCollectionTag


1   /*
2    * $Id: ELOptionsCollectionTag.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.html;
20  
21  import org.apache.struts.taglib.html.OptionsCollectionTag;
22  import javax.servlet.jsp.JspException  ;
23  import org.apache.strutsel.taglib.utils.EvalHelper;
24  
25  /**
26   * Tag for creating multiple &lt;select&gt; options from a collection. The
27   * collection may be part of the enclosing form, or may be independent of
28   * the form. Each element of the collection must expose a 'label' and a
29   * 'value', the property names of which are configurable by attributes of
30   * this tag.
31   * <p>
32   * The collection may be an array of objects, a Collection, an Enumeration,
33   * an Iterator, or a Map.
34   * <p>
35   * <b>NOTE</b> - This tag requires a Java2 (JDK 1.2 or later) platform.
36   *<p>
37   * This class is a subclass of the class
38   * <code>org.apache.struts.taglib.html.OptionsCollectionTag</code> which
39   * provides most of the described functionality.  This subclass allows all
40   * attribute values to be specified as expressions utilizing the JavaServer
41   * Pages Standard Library expression language.
42   *
43   * @version $Rev: 54933 $
44   */
45  public class ELOptionsCollectionTag extends OptionsCollectionTag {
46  
47      /**
48       * Instance variable mapped to "filter" tag attribute.
49       * (Mapping set in associated BeanInfo class.)
50       */
51      private String   filterExpr;
52      /**
53       * Instance variable mapped to "label" tag attribute.
54       * (Mapping set in associated BeanInfo class.)
55       */
56      private String   labelExpr;
57      /**
58       * Instance variable mapped to "name" tag attribute.
59       * (Mapping set in associated BeanInfo class.)
60       */
61      private String   nameExpr;
62      /**
63       * Instance variable mapped to "property" tag attribute.
64       * (Mapping set in associated BeanInfo class.)
65       */
66      private String   propertyExpr;
67      /**
68       * Instance variable mapped to "style" tag attribute.
69       * (Mapping set in associated BeanInfo class.)
70       */
71      private String   styleExpr;
72      /**
73       * Instance variable mapped to "styleClass" tag attribute.
74       * (Mapping set in associated BeanInfo class.)
75       */
76      private String   styleClassExpr;
77      /**
78       * Instance variable mapped to "value" tag attribute.
79       * (Mapping set in associated BeanInfo class.)
80       */
81      private String   valueExpr;
82  
83      /**
84       * Getter method for "filter" tag attribute.
85       * (Mapping set in associated BeanInfo class.)
86       */
87      public String   getFilterExpr() { return (filterExpr); }
88      /**
89       * Getter method for "label" tag attribute.
90       * (Mapping set in associated BeanInfo class.)
91       */
92      public String   getLabelExpr() { return (labelExpr); }
93      /**
94       * Getter method for "name" tag attribute.
95       * (Mapping set in associated BeanInfo class.)
96       */
97      public String   getNameExpr() { return (nameExpr); }
98      /**
99       * Getter method for "property" tag attribute.
100      * (Mapping set in associated BeanInfo class.)
101      */
102     public String   getPropertyExpr() { return (propertyExpr); }
103     /**
104      * Getter method for "style" tag attribute.
105      * (Mapping set in associated BeanInfo class.)
106      */
107     public String   getStyleExpr() { return (styleExpr); }
108     /**
109      * Getter method for "styleClass" tag attribute.
110      * (Mapping set in associated BeanInfo class.)
111      */
112     public String   getStyleClassExpr() { return (styleClassExpr); }
113     /**
114      * Getter method for "value" tag attribute.
115      * (Mapping set in associated BeanInfo class.)
116      */
117     public String   getValueExpr() { return (valueExpr); }
118 
119     /**
120      * Setter method for "filter" tag attribute.
121      * (Mapping set in associated BeanInfo class.)
122      */
123     public void setFilterExpr(String   filterExpr) { this.filterExpr = filterExpr; }
124     /**
125      * Setter method for "label" tag attribute.
126      * (Mapping set in associated BeanInfo class.)
127      */
128     public void setLabelExpr(String   labelExpr) { this.labelExpr = labelExpr; }
129     /**
130      * Setter method for "name" tag attribute.
131      * (Mapping set in associated BeanInfo class.)
132      */
133     public void setNameExpr(String   nameExpr) { this.nameExpr = nameExpr; }
134     /**
135      * Setter method for "property" tag attribute.
136      * (Mapping set in associated BeanInfo class.)
137      */
138     public void setPropertyExpr(String   propertyExpr) { this.propertyExpr = propertyExpr; }
139     /**
140      * Setter method for "style" tag attribute.
141      * (Mapping set in associated BeanInfo class.)
142      */
143     public void setStyleExpr(String   styleExpr) { this.styleExpr = styleExpr; }
144     /**
145      * Setter method for "styleClass" tag attribute.
146      * (Mapping set in associated BeanInfo class.)
147      */
148     public void setStyleClassExpr(String   styleClassExpr) { this.styleClassExpr = styleClassExpr; }
149     /**
150      * Setter method for "value" tag attribute.
151      * (Mapping set in associated BeanInfo class.)
152      */
153     public void setValueExpr(String   valueExpr) { this.valueExpr = valueExpr; }
154 
155     /**
156      * Resets attribute values for tag reuse.
157      */
158     public void release()
159     {
160         super.release();
161         setFilterExpr(null);
162         setLabelExpr(null);
163         setNameExpr(null);
164         setPropertyExpr(null);
165         setStyleExpr(null);
166         setStyleClassExpr(null);
167         setValueExpr(null);
168     }
169 
170     /**
171      * Process the start tag.
172      *
173      * @exception JspException if a JSP exception has occurred
174      */
175     public int doStartTag() throws JspException   {
176         evaluateExpressions();
177         return (super.doStartTag());
178     }
179     
180     /**
181      * Processes all attribute values which use the JSTL expression evaluation
182      * engine to determine their values.
183      *
184      * @exception JspException if a JSP exception has occurred
185      */
186     private void evaluateExpressions() throws JspException   {
187         String    string  = null;
188         Boolean   bool    = null;
189 
190         if ((bool = EvalHelper.evalBoolean("filter", getFilterExpr(),
191                                            this, pageContext)) != null)
192             setFilter(bool.booleanValue());
193 
194         if ((string = EvalHelper.evalString("label", getLabelExpr(),
195                                             this, pageContext)) != null)
196             setLabel(string);
197 
198         if ((string = EvalHelper.evalString("name", getNameExpr(),
199                                             this, pageContext)) != null)
200             setName(string);
201 
202         if ((string = EvalHelper.evalString("property", getPropertyExpr(),
203                                             this, pageContext)) != null)
204             setProperty(string);
205 
206         if ((string = EvalHelper.evalString("style", getStyleExpr(),
207                                             this, pageContext)) != null)
208             setStyle(string);
209 
210         if ((string = EvalHelper.evalString("styleClass", getStyleClassExpr(),
211                                             this, pageContext)) != null)
212             setStyleClass(string);
213 
214         // Note that in contrast to other elements which have "style" and
215         // "styleClass" attributes, this tag does not have a "styleId"
216         // attribute.  This is because this produces the "id" attribute, which
217         // has to be unique document-wide, but this tag can generate more than
218         // one "option" element.  Thus, the base tag, "OptionsCollectionTag"
219         // does not support this attribute.
220 
221         if ((string = EvalHelper.evalString("value", getValueExpr(),
222                                             this, pageContext)) != null)
223             setValue(string);
224     }
225 }
226
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