1 /**
2 * Copyright 2005-2013 The Kuali Foundation
3 *
4 * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
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 package org.kuali.rice.kns.util;
17
18 /**
19 * This class provides utilities to support the rendering of tables in Kuali without using display tag.
20 *
21 * Normally, displaytag handles the rendering of Kuali tables on various screens, but
22 * there are situations where displaytag is inadequate for the task (e.g. multiple value lookups).
23 * In particular, display tag does not handle POSTing of forms when switching between pages and sorting.
24 *
25 */
26 public final class TableRenderUtil {
27
28 private TableRenderUtil() {
29 throw new UnsupportedOperationException("do not call");
30 }
31
32 /**
33 * Returns the minimum number of pages needed to display a result set of the given page
34 *
35 * @param resultSize number of results
36 * @param maxRowsPerPage maximum number of rows
37 *
38 * @return
39 */
40 public static int computeTotalNumberOfPages(int resultSize, int maxRowsPerPage) {
41 int numPages = resultSize / maxRowsPerPage;
42 if (resultSize % maxRowsPerPage != 0) {
43 // partial page
44 numPages++;
45 }
46 return numPages;
47 }
48
49 /**
50 * This method computes the list index of the first row of the given page
51 *
52 * @param pageNumber first page is index 0
53 * @param resultSize the size of the list being rendered
54 * @param maxRowsPerPage max number of rows on a page
55 * @return the index in the result list of the first row of the given page
56 */
57 public static int computeStartIndexForPage(int pageNumber, int resultSize, int maxRowsPerPage) {
58 if (pageNumber < 0 && pageNumber >= computeTotalNumberOfPages(resultSize, maxRowsPerPage)) {
59 return -1;
60 }
61 return pageNumber * maxRowsPerPage;
62 }
63
64 /**
65 * This method computes the index of the last row of the given page
66 *
67 * @param pageNumber first page is index 0
68 * @param resultSize the size of the list being rendered
69 * @param maxRowsPerPage max number of rows on a page
70 * @return the index in the result list of the last row of the given page
71 */
72 public static int computeLastIndexForPage(int pageNumber, int resultSize, int maxRowsPerPage) {
73 int startIndex = computeStartIndexForPage(pageNumber, resultSize, maxRowsPerPage);
74 if (startIndex == -1) {
75 return -1;
76 }
77 if (startIndex + maxRowsPerPage - 1 < resultSize) {
78 return startIndex + maxRowsPerPage - 1;
79 }
80 // partial page
81 return resultSize - 1;
82 }
83 }