1 /*
2 * Copyright 2007-2008 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 class TableRenderUtil {
27 /**
28 * Returns the minimum number of pages needed to display a result set of the given page
29 *
30 * @param resultSize number of results
31 * @param maxRowsPerPage maximum number of rows
32 *
33 * @return
34 */
35 public static int computeTotalNumberOfPages(int resultSize, int maxRowsPerPage) {
36 int numPages = resultSize / maxRowsPerPage;
37 if (resultSize % maxRowsPerPage != 0) {
38 // partial page
39 numPages++;
40 }
41 return numPages;
42 }
43
44 /**
45 * This method computes the list index of the first row of the given page
46 *
47 * @param pageNumber first page is index 0
48 * @param resultSize the size of the list being rendered
49 * @param maxRowsPerPage max number of rows on a page
50 * @return the index in the result list of the first row of the given page
51 */
52 public static int computeStartIndexForPage(int pageNumber, int resultSize, int maxRowsPerPage) {
53 if (pageNumber < 0 && pageNumber >= computeTotalNumberOfPages(resultSize, maxRowsPerPage)) {
54 return -1;
55 }
56 return pageNumber * maxRowsPerPage;
57 }
58
59 /**
60 * This method computes the index of the last row of the given page
61 *
62 * @param pageNumber first page is index 0
63 * @param resultSize the size of the list being rendered
64 * @param maxRowsPerPage max number of rows on a page
65 * @return the index in the result list of the last row of the given page
66 */
67 public static int computeLastIndexForPage(int pageNumber, int resultSize, int maxRowsPerPage) {
68 int startIndex = computeStartIndexForPage(pageNumber, resultSize, maxRowsPerPage);
69 if (startIndex == -1) {
70 return -1;
71 }
72 if (startIndex + maxRowsPerPage - 1 < resultSize) {
73 return startIndex + maxRowsPerPage - 1;
74 }
75 // partial page
76 return resultSize - 1;
77 }
78 }