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Java > Open Source Codes > com > Yasna > forum > tags > RotateTag


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 javax.servlet.*;
111 import javax.servlet.jsp.*;
112 import javax.servlet.jsp.tagext.*;
113 import javax.servlet.http.*;
114 import com.Yasna.forum.tags.*;
115
116 /**
117  * JSP Tag <b>rotate</b>, used to rotate output within a loop.
118  * <p>
119  * Requires that attribute <b>id</b> be set to the name of a
120  * script variable so that the <b>rotate</b> tag can save state
121  * information about its rotations which it can reuse for the
122  * next loop.
123  * <p>
124  * This tag is designed to be nested within some other looping
125  * tag set.
126  * <p>
127  * <b>rotate_selection</b> tags are nested within the <b>rotate</b>
128  * tag to specify what items to select from for each rotation
129  * within some loop tag set.
130  * <p>
131  * JSP Tag Lib Descriptor
132  * <p><pre>
133  * &lt;name&gt;rotate&lt;/name&gt;
134  * &lt;tagclass&gt;com.Yasna.forum.tags.RotateTag&lt;/tagclass&gt;
135  * &lt;teiclass&gt;com.Yasna.forum.tags.RotateTEI&lt;/teiclass&gt;
136  * &lt;bodycontent&gt;JSP&lt;/bodycontent&gt;
137  * &lt;info&gt;Rotates ouput within a loop.&lt;/info&gt;
138  * &lt;attribute&gt;
139  * &lt;name&gt;id&lt;/name&gt;
140  * &lt;required&gt;true&lt;/required&gt;
141  * &lt;rtexprvalue&gt;false&lt;/rtexprvalue&gt;
142  * &lt;/attribute&gt;
143  * </pre>
144  *
145  * @see RotateSelectionTag
146  *
147  * @author Glenn Nielsen
148  */
149 public class RotateTag extends TagSupport
150 {
151   // Previously saved RotateTag
152 private RotateTag rt = null;
153   // Variables to keep track of rotation selection
154 private int index = 0;
155   private int size = 0;
156   private int total = 0;
157   private boolean total_set = false;
158
159   /**
160    * Method called at start of rotate Tag
161    *
162    * @return EVAL_BODY_INCLUDE
163    */
164   public final int doStartTag() throws JspException
165   {
166     Boolean JavaDoc res;
167
168     // Try to get rotate state information from previous rotation.
169 rt = (RotateTag)pageContext.getAttribute(id,
170         PageContext.PAGE_SCOPE);
171     if( rt == null ) {
172       // First time rotation encountered in a loop, save state information.
173 rt = this;
174       pageContext.setAttribute(id,this,PageContext.PAGE_SCOPE);
175     } else {
176       // Retrieve state information from original RotateTag
177 index = rt.getIndex();
178       total = rt.getTotal();
179     }
180     return EVAL_BODY_INCLUDE;
181   }
182
183   /**
184    * Used when rotate tag is closed to increment to next
185    * rotate_selection.
186    *
187    * @return EVAL_PAGE
188    */
189   public final int doEndTag() throws JspException
190   {
191     index++;
192     if( index >= total )
193       index = 0;
194     total_set = true;
195     rt.setIndex(index);
196     return EVAL_PAGE;
197   }
198
199   /**
200    * Used by a nested rotate_selection tag to determine if
201    * it is its turn to display its body.
202    *
203    * @return true if rotate_selection body should be displayed, false if it isn't its turn
204    */
205   public final boolean myTurn()
206   {
207     if( !rt.equals(this) )return rt.myTurn();
208     size++;
209     if( !total_set ) {
210       total++;
211       if( total == 1 )
212         return true;
213     } else {
214       if( index == ((size-1)%total) )
215         return true;
216     }
217     return false;
218   }
219
220   // Remaining methods are invoked on the original RotateTag
221 // which was saved as a script variable
222
223   /**
224    * Used by current rotate tag to get rotation state information
225    * from a previous iteration of enclosing loop.
226    *
227    * @return total number of rotate_selection tags found
228    */
229   public final int getTotal()
230   {
231     return total;
232   }
233
234   /**
235    * Used by current rotate tag to get rotation state information
236    * from a previous iteration of enclosing loop.
237    *
238    * @return current index of item to rotate from rotate selections
239    */
240   public final int getIndex()
241   {
242     return index;
243   }
244
245   /**
246    * Used to set the next index to use for rotating selections in
247    * the RotateTag script variable.
248    */
249   public final void setIndex(int v)
250   {
251     index = v;
252   }
253 }
254
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