1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.myfaces.shared_orchestra.util;
20
21 import java.util.HashMap;
22 import java.util.Map;
23 import java.util.Set;
24 import java.util.Iterator;
25
26
27 /**
28 * @author Anton Koinov (latest modification by $Author: grantsmith $)
29 * @version $Revision: 472630 $ $Date: 2006-11-08 15:40:03 -0500 (Wed, 08 Nov 2006) $
30 */
31 public class HashMapUtils
32 {
33 //~ Constructors -------------------------------------------------------------------------------
34
35 protected HashMapUtils()
36 {
37 // block public access
38 }
39
40 //~ Methods ------------------------------------------------------------------------------------
41
42 /**
43 * Calculates initial capacity needed to hold <code>size</code> elements in
44 * a HashMap or Hashtable without forcing an expensive increase in internal
45 * capacity. Capacity is based on the default load factor of .75.
46 * <p>
47 * Usage: <code>Map map = new HashMap(HashMapUtils.calcCapacity(10));<code>
48 * </p>
49 * @param size the number of items that will be put into a HashMap
50 * @return initial capacity needed
51 */
52 public static final int calcCapacity(int size)
53 {
54 return ((size * 4) + 3) / 3;
55 }
56
57 /**
58 * Creates a new <code>HashMap</code> that has all of the elements
59 * of <code>map1</code> and <code>map2</code> (on key collision, the latter
60 * override the former).
61 *
62 * @param map1 the fist hashmap to merge
63 * @param map2 the second hashmap to merge
64 * @return new hashmap
65 */
66 public static HashMap merge(Map map1, Map map2)
67 {
68 HashMap retval = new HashMap(calcCapacity(map1.size() + map2.size()));
69
70 retval.putAll(map1);
71 retval.putAll(map2);
72
73 return retval;
74 }
75
76 /**
77 * spit out each name/value pair
78 */
79 public static String mapToString(Map map){
80 Set entries = map.entrySet();
81 Iterator iter = entries.iterator();
82 StringBuffer buff = new StringBuffer();
83 while (iter.hasNext())
84 {
85 Map.Entry entry = (Map.Entry) iter.next();
86 buff.append("[" + entry.getKey() + "," + entry.getValue() + "]\n");
87 }
88 return buff.toString();
89 }
90
91 }