1 /*
2 * $Source$
3 * $Revision$
4 *
5 * Copyright (C) 2003 Tim Pizey
6 *
7 * Part of Melati (http://melati.org), a framework for the rapid
8 * development of clean, maintainable web applications.
9 *
10 * Melati is free software; Permission is granted to copy, distribute
11 * and/or modify this software under the terms either:
12 *
13 * a) the GNU General Public License as published by the Free Software
14 * Foundation; either version 2 of the License, or (at your option)
15 * any later version,
16 *
17 * or
18 *
19 * b) any version of the Melati Software License, as published
20 * at http://melati.org
21 *
22 * You should have received a copy of the GNU General Public License and
23 * the Melati Software License along with this program;
24 * if not, write to the Free Software Foundation, Inc.,
25 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the
26 * GNU General Public License and visit http://melati.org to obtain the
27 * Melati Software License.
28 *
29 * Feel free to contact the Developers of Melati (http://melati.org),
30 * if you would like to work out a different arrangement than the options
31 * outlined here. It is our intention to allow Melati to be used by as
32 * wide an audience as possible.
33 *
34 * This program is distributed in the hope that it will be useful,
35 * but WITHOUT ANY WARRANTY; without even the implied warranty of
36 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
37 * GNU General Public License for more details.
38 *
39 * Contact details for copyright holder:
40 *
41 * Tim Pizey <timp At paneris.org>
42 */
43
44 package org.melati.util;
45
46 import java.util.Vector;
47 import java.util.Enumeration;
48
49
50 /**
51 * All the code common to {@link CountedDumbPagedEnumeration}
52 * and {@link DumbPagedEnumeration}.
53 */
54 public abstract class PagedEnumerationBase<T> implements PagedEnumeration<T> {
55
56 int pageStart, pageSize;
57 Vector<T> page;
58 int totalCount;
59 Enumeration<T> us;
60 int currentPosition;
61
62
63 //
64 // -------------
65 // Enumeration
66 // -------------
67 //
68
69 /**
70 * {@inheritDoc}
71 * @see java.util.Enumeration#hasMoreElements()
72 */
73 public boolean hasMoreElements() {
74 return us.hasMoreElements();
75 }
76
77 /**
78 * {@inheritDoc}
79 * @see java.util.Enumeration#nextElement()
80 */
81 public T nextElement() {
82 currentPosition++;
83 return us.nextElement();
84 }
85
86 //
87 // -----------------
88 // PagedEnumeration
89 // -----------------
90 //
91 @Override
92 public int getPageStart() {
93 return pageStart;
94 }
95
96 @Override
97 public int getPageEnd() {
98 return pageStart + page.size() - 1;
99 }
100
101 @Override
102 public int getTotalCount() {
103 return totalCount;
104 }
105
106 @Override
107 public Integer getPrevPageStart() {
108 int it = pageStart - pageSize;
109 return it < 0 ? null : new Integer(it);
110 }
111
112 @Override
113 public int getCurrentPosition() {
114 return currentPosition;
115 }
116
117 @Override
118 public int getNextPosition() {
119 return hasMoreElements() ? currentPosition + 1 : 0;
120 }
121
122 @Override
123 public boolean nextElementOnThisPage() {
124 return hasMoreElements() && getPageEnd() >= getNextPosition();
125 }
126
127 @Override
128 public int getPageSize() {
129 return page.size();
130 }
131
132
133
134 /**
135 * @return All Pages
136 */
137 public Vector<Page> getPages() {
138 Vector<Page> ret = new Vector<Page>(totalCount / pageSize);
139 int i = 1;
140 while(((i - 1) * pageSize) < totalCount) {
141 ret.addElement(new Page(i, ((i - 1) * pageSize) + 1));
142 i++;
143 }
144 return ret;
145 }
146
147 }