SplitTag


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.regexp;
18  
19  import java.util.ArrayList  ;
20  import java.util.Iterator  ;
21  import org.apache.oro.text.*;
22  import org.apache.oro.text.perl.*;
23  import org.apache.oro.text.regex.*;
24  import javax.servlet.*;
25  import javax.servlet.http.*;
26  import javax.servlet.jsp.*;
27  import javax.servlet.jsp.tagext.*;
28  
29  /**
30   * JSP Tag <b>split</b>, used to implement a perl style
31   * split on the text.
32   * <p>
33   * The body of the tag iterates through each string generated
34   * from the split. The normal &lt;jsp:getProperty/&gt; can be
35   * used to get the value of each string split out using the
36   * id of the <b>split</b> tag script variable.
37   * <p>
38   * The attribute <b>text</b> must be set to the id of a
39   * <b>text</b> tag.
40   * <p>
41   * By default, the split is done on whitespace.  Set the
42   * optional attribute <b>regexp</b> to the id of a <b>regexp</b>
43   * tag script variable id to perform the split using a custom
44   * regular expression.
45   * <p>
46   * You can set the optional tag attribute <b>limit</b> to the
47   * number of items you want to limit the split to.
48   * <p>
49   * JSP Tag Lib Descriptor
50   * <p><pre>
51   * &lt;name&gt;split&lt;/name&gt;
52   * &lt;tagclass&gt;org.apache.taglibs.regexp.SplitTag&lt;/tagclass&gt;
53   * &lt;bodycontent&gt;JSP&lt;/bodycontent&gt;
54   * &lt;info&gt;Implements a perl style split on the text.&lt;/info&gt;
55   *   &lt;attribute&gt;
56   *     &lt;name&gt;id&lt;/name&gt;
57   *     &lt;required&gt;true&lt;/required&gt;
58   *     &lt;rtexprvalue&gt;false&lt;/rtexprvalue&gt;
59   *   &lt;/attribute&gt;
60   *   &lt;attribute&gt;
61   *     &lt;name&gt;text&lt;/name&gt;
62   *     &lt;required&gt;true&lt;/required&gt;
63   *     &lt;rtexprvalue&gt;false&lt;/rtexprvalue&gt;
64   *   &lt;/attribute&gt;
65   *   &lt;attribute&gt;
66   *     &lt;name&gt;regexp&lt;/name&gt;
67   *     &lt;required&gt;false&lt;/required&gt;
68   *     &lt;rtexprvalue&gt;false&lt;/rtexprvalue&gt;
69   *   &lt;/attribute&gt;
70   *   &lt;attribute&gt;
71   *     &lt;name&gt;limit&lt;/name&gt;
72   *     &lt;required&gt;false&lt;/required&gt;
73   *     &lt;rtexprvalue&gt;false&lt;/rtexprvalue&gt;
74   *   &lt;/attribute&gt;
75   * </pre>
76   *
77   * @see RegexpTag
78   * @see TextTag
79   * @see RegexpData
80   * @see TextData
81   *
82   * @author Glenn Nielsen
83   */
84  
85  public class SplitTag extends BodyTagSupport
86  {
87      private String   regexpid = null;
88      private String   textid = null;
89      private int limit = -1;
90      private Iterator   values = null;
91      private String   value = null;
92  
93      /**
94       * Setup to split the text based on supplied attributes
95       *
96       * @return EVAL_BODY_TAG if there is a string from the split, BODY_SKIP if no strings resulted from the split
97       */
98      public final int doStartTag() throws JspException
99      {
100     TextData td = (TextData)pageContext.getAttribute(textid,PageContext.PAGE_SCOPE);
101     if( td == null )
102         throw new JspException(
103         "regexp tag split could not find text tag with id: " +
104         textid);
105 
106     Perl5Util perl = new Perl5Util(RegexpData.getPatternCache());
107     String   spliton = "/\\s+/m";
108     if( regexpid != null ) {
109             RegexpData rd = (RegexpData)pageContext.getAttribute(regexpid,PageContext.PAGE_SCOPE);
110             if( rd == null )
111                 throw new JspException(
112                     "regexp tag split could not find regexp tag with id: " +
113                     regexpid);
114         spliton = rd.getRegexp();
115     }
116     ArrayList   split = new ArrayList  ();
117     if( limit > -1 ) {
118         perl.split(split,spliton,td.getText(),limit);
119     } else {
120         perl.split(split,spliton,td.getText());
121     }
122         values = split.iterator();
123     if( !values.hasNext() ) {
124         return SKIP_BODY;
125     }
126 
127     value = (String  )values.next();
128     pageContext.setAttribute(id,this,PageContext.PAGE_SCOPE);
129 
130     return EVAL_BODY_TAG;
131     }
132 
133     /** 
134      * Method called at end of each iteration of the split tag
135      *
136      * @return EVAL_BODY_TAG if there is another string split, or BODY_SKIP if there are no more strings
137      */
138     public final int doAfterBody() throws JspException
139     {
140     if( !values.hasNext() ) {
141         return SKIP_BODY;
142     }
143     value = (String  )values.next();
144     return EVAL_BODY_TAG;
145     }
146 
147     /**
148      * Method called at end of split Tag
149      *
150      * @return EVAL_PAGE
151      */
152     public final int doEndTag() throws JspException
153     {
154         if( id != null && id.length() > 0 )
155             pageContext.removeAttribute(id,PageContext.PAGE_SCOPE);
156     try {
157         if(bodyContent != null)
158         bodyContent.writeOut(bodyContent.getEnclosingWriter());
159     } catch(java.io.IOException   e) {
160         throw new JspException("IO Error: " + e.getMessage());
161     }
162     return EVAL_PAGE;
163     }
164 
165     /*
166      * Set the optional attribute <b>regexp</b>
167      *
168      * @param String name of regexp script variable
169      */
170     public final void setRegexp(String   str)
171     {   
172     regexpid = str;
173     }
174 
175     /*
176      * Set the required attribute <b>text</b>
177      *
178      * @param String name of text script variable
179      */
180     public final void setText(String   str)
181     {               
182         textid = str;
183     }
184 
185     /*
186      * Set the optional attribute <b>limit</b> to the
187      * number of strings to split out of text.
188      *
189      * @param int number of strings to limit split to
190      */
191     public final void setLimit(int limit)
192     {
193     this.limit = limit;
194     }
195 
196     /**
197      * String split out from text can be obtained by the JSP page
198      * using &lt;jsp:getProperty name=<i>"id"</i> property="split"/&gt;
199      *
200      * @return String - string that was split out from text
201      */
202     public final String   getSplit()
203     {
204     return value;
205     }
206 
207 }
208
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