CollectionUtils.java revision 674060f01e9090cd21b3c5656cc3204912ad17a6 
1/*
2 * Copyright 2003,2004 The Apache Software Foundation
3 *
4 *  Licensed under the Apache 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.apache.org/licenses/LICENSE-2.0
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 */
16package org.mockito.cglib.core;
17
18import java.util.*;
19import java.lang.reflect.Array;
20
21/**
22 * @author Chris Nokleberg
23 * @version $Id: CollectionUtils.java,v 1.7 2004/06/24 21:15:21 herbyderby Exp $
24 */
25public class CollectionUtils {
26    private CollectionUtils() { }
27
28    public static Map bucket(Collection c, Transformer t) {
29        Map buckets = new HashMap();
30        for (Iterator it = c.iterator(); it.hasNext();) {
31            Object value = (Object)it.next();
32            Object key = t.transform(value);
33            List bucket = (List)buckets.get(key);
34            if (bucket == null) {
35                buckets.put(key, bucket = new LinkedList());
36            }
37            bucket.add(value);
38        }
39        return buckets;
40    }
41
42    public static void reverse(Map source, Map target) {
43        for (Iterator it = source.keySet().iterator(); it.hasNext();) {
44            Object key = it.next();
45            target.put(source.get(key), key);
46        }
47    }
48
49    public static Collection filter(Collection c, Predicate p) {
50        Iterator it = c.iterator();
51        while (it.hasNext()) {
52            if (!p.evaluate(it.next())) {
53                it.remove();
54            }
55        }
56        return c;
57    }
58
59    public static List transform(Collection c, Transformer t) {
60        List result = new ArrayList(c.size());
61        for (Iterator it = c.iterator(); it.hasNext();) {
62            result.add(t.transform(it.next()));
63        }
64        return result;
65    }
66
67    public static Map getIndexMap(List list) {
68        Map indexes = new HashMap();
69        int index = 0;
70        for (Iterator it = list.iterator(); it.hasNext();) {
71            indexes.put(it.next(), new Integer(index++));
72        }
73        return indexes;
74    }
75}
76
77