ForEachTag


1   /**
2    * Copyright (C) 2001 Yasna.com. All rights reserved.
3    *
4    * ===================================================================
5    * The Apache Software License, Version 1.1
6    *
7    * Redistribution and use in source and binary forms, with or without
8    * modification, are permitted provided that the following conditions
9    * are met:
10   *
11   * 1. Redistributions of source code must retain the above copyright
12   *    notice, this list of conditions and the following disclaimer.
13   *
14   * 2. Redistributions in binary form must reproduce the above copyright
15   *    notice, this list of conditions and the following disclaimer in
16   *    the documentation and/or other materials provided with the
17   *    distribution.
18   *
19   * 3. The end-user documentation included with the redistribution,
20   *    if any, must include the following acknowledgment:
21   *       "This product includes software developed by
22   *        Yasna.com (http://www.yasna.com)."
23   *    Alternately, this acknowledgment may appear in the software itself,
24   *    if and wherever such third-party acknowledgments normally appear.
25   *
26   * 4. The names "Yazd" and "Yasna.com" must not be used to
27   *    endorse or promote products derived from this software without
28   *    prior written permission. For written permission, please
29   *    contact yazd@yasna.com.
30   *
31   * 5. Products derived from this software may not be called "Yazd",
32   *    nor may "Yazd" appear in their name, without prior written
33   *    permission of Yasna.com.
34   *
35   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
36   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
37   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
38   * DISCLAIMED.  IN NO EVENT SHALL YASNA.COM OR
39   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
41   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
42   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
43   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
44   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
45   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46   * SUCH DAMAGE.
47   * ====================================================================
48   *
49   * This software consists of voluntary contributions made by many
50   * individuals on behalf of Yasna.com. For more information
51   * on Yasna.com, please see <http://www.yasna.com>.
52   */
53  
54  /**
55   * Copyright (C) 2000 CoolServlets.com. All rights reserved.
56   *
57   * ===================================================================
58   * The Apache Software License, Version 1.1
59   *
60   * Redistribution and use in source and binary forms, with or without
61   * modification, are permitted provided that the following conditions
62   * are met:
63   *
64   * 1. Redistributions of source code must retain the above copyright
65   *    notice, this list of conditions and the following disclaimer.
66   *
67   * 2. Redistributions in binary form must reproduce the above copyright
68   *    notice, this list of conditions and the following disclaimer in
69   *    the documentation and/or other materials provided with the
70   *    distribution.
71   *
72   * 3. The end-user documentation included with the redistribution,
73   *    if any, must include the following acknowledgment:
74   *       "This product includes software developed by
75   *        CoolServlets.com (http://www.coolservlets.com)."
76   *    Alternately, this acknowledgment may appear in the software itself,
77   *    if and wherever such third-party acknowledgments normally appear.
78   *
79   * 4. The names "Jive" and "CoolServlets.com" must not be used to
80   *    endorse or promote products derived from this software without
81   *    prior written permission. For written permission, please
82   *    contact webmaster@coolservlets.com.
83   *
84   * 5. Products derived from this software may not be called "Jive",
85   *    nor may "Jive" appear in their name, without prior written
86   *    permission of CoolServlets.com.
87   *
88   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
89   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
90   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
91   * DISCLAIMED.  IN NO EVENT SHALL COOLSERVLETS.COM OR
92   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
93   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
94   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
95   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
96   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
97   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
98   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
99   * SUCH DAMAGE.
100  * ====================================================================
101  *
102  * This software consists of voluntary contributions made by many
103  * individuals on behalf of CoolServlets.com. For more information
104  * on CoolServlets.com, please see <http://www.coolservlets.com>.
105  */
106 
107 package com.Yasna.forum.tags;
108 
109 import java.io.*;
110 import java.util.*;
111 import javax.servlet.*;
112 import javax.servlet.jsp.*;
113 import javax.servlet.jsp.tagext.*;
114 import javax.servlet.http.*;
115 import com.Yasna.forum.*;
116 import com.Yasna.forum.tags.*;
117 
118 /**
119  * JSP Tag <b>foreach</b>, used to implement a simple numbered loop.
120  * <p>
121  * Requires that attribute <b>id</b> be set to the name of a
122  * script variable for later use in JSP to retrieve the value
123  * of the loop counter using &lt;jsp:getProperty/&gt;.
124  * <p>
125  * Requires that attribute <b>begin</b> be set to the number at
126  * which the foreach loop should start.
127  * <p>
128  * Requires that attribute <b>end</b> be set to the number at
129  * which the foreach loop should end.
130  * <p>
131  * Optional attribute <b>step</b> specifies how much the foreach
132  * counter should be incremented for each loop, default is 1.
133  * <p>
134  * During each loop the body of the foreach tag is processed.
135  * <p>
136  * JSP Tag Lib Descriptor
137  * <p><pre>
138  *  &lt;name&gt;foreach&lt;/name&gt;
139  *  &lt;tagclass&gt;com.Yasna.forum.tags.ForEachTag&lt;/tagclass&gt;
140  *  &lt;teiclass&gt;com.Yasna.forum.tags.ForEachTEI&lt;/teiclass&gt;
141  *  &lt;bodycontent&gt;JSP&lt;/bodycontent&gt;
142  *  &lt;info&gt;Implement a loop.&lt;/info&gt;
143  *  &lt;attribute&gt;
144  *    &lt;name&gt;id&lt;/name&gt;
145  *    &lt;required&gt;true&lt;/required&gt;
146  *    &lt;rtexprvalue&gt;false&lt;/rtexprvalue&gt;
147  *  &lt;/attribute&gt;
148  *  &lt;attribute&gt;
149  *    &lt;name&gt;begin&lt;/name&gt;
150  *    &lt;required&gt;true&lt;/required&gt;
151  *    &lt;rtexprvalue&gt;false&lt;/rtexprvalue&gt;
152  *  &lt;/attribute&gt;
153  *  &lt;attribute&gt;
154  *    &lt;name&gt;end&lt;/name&gt;
155  *    &lt;required&gt;true&lt;/required&gt;
156  *    &lt;rtexprvalue&gt;false&lt;/rtexprvalue&gt;
157  *  &lt;/attribute&gt;
158  *  &lt;attribute&gt;
159  *    &lt;name&gt;step&lt;/name&gt;
160  *    &lt;required&gt;false&lt;/required&gt;
161  *    &lt;rtexprvalue&gt;false&lt;/rtexprvalue&gt;
162  *  &lt;/attribute&gt;
163  * </pre>
164  *
165  * @author Glenn Nielsen
166  */
167 public class ForEachTag extends BodyTagSupport
168 {
169   private int begin = 0;
170   private int end = 0;
171   private int index = 0;
172   private int step = 1;
173 
174   /**
175    * Method called at start of foreach Tag
176    *
177    * @return an EVAL_BODY_TAG if foreach should loop, or a SKIP_BODY if foreach is completed.
178    */
179   public final int doStartTag() throws JspException
180   {
181     // Save the script variable for use by JSP getProperty
182     pageContext.setAttribute(id,this,PageContext.PAGE_SCOPE);
183     if( index > end )
184       return SKIP_BODY;
185     return EVAL_BODY_TAG;
186   }
187 
188   /**
189    * Method called at end of a foreach loop
190    *
191    * @return an EVAL_BODY_TAG if foreach should loop again, or a SKIP_BODY if foreach is completed.
192    */
193   public final int doAfterBody() throws JspException
194   {
195     index += step;
196     if( index > end )
197       return SKIP_BODY;
198     return EVAL_BODY_TAG;
199   }
200 
201   /**
202    * Method called at end of foreach Tag
203    * @return EVAL_PAGE
204    */
205   public final int doEndTag() throws JspException
206   {
207     try
208     {
209       if(bodyContent != null)
210         bodyContent.writeOut(bodyContent.getEnclosingWriter());
211     } catch(java.io.IOException   e)
212     {
213       throw new JspException("IO Error: " + e.getMessage());
214     }
215     return EVAL_PAGE;
216   }
217 
218   /**
219    * Set the beginning index of the foreach loop
220    */
221   public final void setBegin(String   beg)
222   {
223     index = begin = Integer.valueOf(beg).intValue();
224   }
225 
226   /**
227    * Set the ending index of the foreach loop
228    */
229   public final void setEnd(String   last)
230   {
231     end = Integer.valueOf(last).intValue();
232   }
233 
234   /**
235    * Set the index step of the foreach loop
236    */
237   public final void setStep(String   last)
238   {
239     step = Integer.valueOf(last).intValue();
240   }
241 
242   /**
243    * foreach loop value property which can be obtained by the JSP page
244    * using &lt;jsp:getProperty name=<i>"id"</i> property="value"/&gt;
245    *
246    * @return String - current value of the foreach counter
247    */
248   public final String   getValue()
249   {
250     return "" + index;
251   }
252 
253   /**
254    * Remove the script variable after foreach tag closed out
255    */
256   public final void release()
257   {
258     if( id != null && id.length() > 0 )
259       pageContext.removeAttribute(id,PageContext.PAGE_SCOPE);
260   }
261 
262 }
263
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