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ColumnComparator.java | - | 0% | 0% | 0% |
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1 | // Copyright 2004, 2005 The Apache Software Foundation | |
2 | // | |
3 | // Licensed under the Apache License, Version 2.0 (the "License"); | |
4 | // you may not use this file except in compliance with the License. | |
5 | // You may obtain a copy of the License at | |
6 | // | |
7 | // http://www.apache.org/licenses/LICENSE-2.0 | |
8 | // | |
9 | // Unless required by applicable law or agreed to in writing, software | |
10 | // distributed under the License is distributed on an "AS IS" BASIS, | |
11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
12 | // See the License for the specific language governing permissions and | |
13 | // limitations under the License. | |
14 | ||
15 | package org.apache.tapestry.contrib.table.model.simple; | |
16 | ||
17 | import java.util.Comparator; | |
18 | ||
19 | /** | |
20 | * In order to provide more generic behaviour, ITableColumn | |
21 | * has no "column value" concept. The comparator it returns | |
22 | * compares two table rows, rather than values specific to the column. | |
23 | * <p> | |
24 | * SimpleTableColumn introduces the concept of "column value" and | |
25 | * allows one to extract that "column value" from the row using | |
26 | * the getColumnValue() method. In practice comparisons are also typically | |
27 | * done between these values rather than the full row objects. | |
28 | * <p> | |
29 | * This comparator extracts the column values from the rows passed | |
30 | * and uses the provided comparator to compare the values. | |
31 | * It therefore allows a comparator designed for comparing column values to be | |
32 | * quickly wrapped and used as a comparator comparing rows, which is what | |
33 | * ITableColumn is expected to return. | |
34 | * <p> | |
35 | * Example: | |
36 | * <p> | |
37 | * objColumn.setComparator(new ColumnComparator(objColumn, objBeanComparator)); | |
38 | * | |
39 | * @author mindbridge | |
40 | * | |
41 | */ | |
42 | public class ColumnComparator implements Comparator | |
43 | { | |
44 | private SimpleTableColumn m_objColumn; | |
45 | private Comparator m_objComparator; | |
46 | ||
47 | 0 | public ColumnComparator(SimpleTableColumn objColumn, Comparator objComparator) |
48 | { | |
49 | 0 | m_objColumn = objColumn; |
50 | 0 | m_objComparator = objComparator; |
51 | } | |
52 | ||
53 | /** | |
54 | * @see java.util.Comparator#compare(Object, Object) | |
55 | */ | |
56 | 0 | public int compare(Object objRow1, Object objRow2) |
57 | { | |
58 | 0 | Object objValue1 = m_objColumn.getColumnValue(objRow1); |
59 | 0 | Object objValue2 = m_objColumn.getColumnValue(objRow2); |
60 | ||
61 | 0 | return m_objComparator.compare(objValue1, objValue2); |
62 | } | |
63 | ||
64 | } |
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