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Java > Open Source Codes > com > jsptags > navigation > pager > PagerTagSupport


1 /*
2  * Pager Tag Library
3  *
4  * Copyright (C) 2002 James Klicman <james@jsptags.com>
5  *
6  * This library is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19  */

20
21 package com.jsptags.navigation.pager;
22
23 import javax.servlet.jsp.*;
24 import javax.servlet.jsp.tagext.*;
25
26 public abstract class PagerTagSupport extends TagSupport {
27
28     protected PagerTag pagerTag = null;
29
30     protected final void restoreAttribute(String JavaDoc name, Object JavaDoc oldValue) {
31         if (oldValue != null)
32             pageContext.setAttribute(name, oldValue);
33         else
34             pageContext.removeAttribute(name);
35     }
36
37     private final PagerTag findRequestPagerTag(String JavaDoc pagerId) {
38         Object JavaDoc obj = pageContext.getRequest().getAttribute(pagerId);
39         if (obj instanceof PagerTag)
40             return (PagerTag) obj;
41         return null;
42     }
43
44     public int doStartTag() throws JspException {
45         if (id != null) {
46             pagerTag = findRequestPagerTag(id);
47             if (pagerTag == null)
48                 throw new JspTagException("pager tag with id of \"" + id +
49                                             "\" not found.");
50         } else {
51             pagerTag = (PagerTag) findAncestorWithClass(this, PagerTag.class);
52             if (pagerTag == null) {
53                 pagerTag = findRequestPagerTag(PagerTag.DEFAULT_ID);
54                 if (pagerTag == null)
55                     throw new JspTagException("not nested within a pager tag" +
56                                 " and no pager tag found at request scope.");
57             }
58         }
59
60         return EVAL_BODY_INCLUDE;
61     }
62
63     public int doEndTag() throws JspException {
64         pagerTag = null;
65         return EVAL_PAGE;
66     }
67
68     public void release() {
69         pagerTag = null;
70         super.release();
71     }
72 }
73
74 /* vim:set ts=4 sw=4: */
75
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