01: /*
02: * Copyright 2007 The Kuali Foundation.
03: *
04: * Licensed under the Educational Community License, Version 1.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.opensource.org/licenses/ecl1.php
09: *
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.core.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,
36: int maxRowsPerPage) {
37: int numPages = resultSize / maxRowsPerPage;
38: if (resultSize % maxRowsPerPage != 0) {
39: // partial page
40: numPages++;
41: }
42: return numPages;
43: }
44:
45: /**
46: * This method computes the list index of the first row of the given page
47: *
48: * @param pageNumber first page is index 0
49: * @param resultSize the size of the list being rendered
50: * @param maxRowsPerPage max number of rows on a page
51: * @return the index in the result list of the first row of the given page
52: */
53: public static int computeStartIndexForPage(int pageNumber,
54: int resultSize, int maxRowsPerPage) {
55: if (pageNumber < 0
56: && pageNumber >= computeTotalNumberOfPages(resultSize,
57: maxRowsPerPage)) {
58: return -1;
59: }
60: return pageNumber * maxRowsPerPage;
61: }
62:
63: /**
64: * This method computes the index of the last row of the given page
65: *
66: * @param pageNumber first page is index 0
67: * @param resultSize the size of the list being rendered
68: * @param maxRowsPerPage max number of rows on a page
69: * @return the index in the result list of the last row of the given page
70: */
71: public static int computeLastIndexForPage(int pageNumber,
72: int resultSize, int maxRowsPerPage) {
73: int startIndex = computeStartIndexForPage(pageNumber,
74: resultSize, maxRowsPerPage);
75: if (startIndex == -1) {
76: return -1;
77: }
78: if (startIndex + maxRowsPerPage - 1 < resultSize) {
79: return startIndex + maxRowsPerPage - 1;
80: }
81: // partial page
82: return resultSize - 1;
83: }
84: }
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