1 /*
2 * Copyright (c) 2003, Henri Yandell
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or
6 * without modification, are permitted provided that the
7 * following conditions are met:
8 *
9 * + Redistributions of source code must retain the above copyright notice,
10 * this list of conditions and the following disclaimer.
11 *
12 * + Redistributions in binary form must reproduce the above copyright notice,
13 * this list of conditions and the following disclaimer in the documentation
14 * and/or other materials provided with the distribution.
15 *
16 * + Neither the name of Genjava-Core nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
21 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
24 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32 package com.generationjava.collections;
33
34 import java.util.Hashtable;
35 import java.util.Enumeration;
36 import java.util.Vector;
37
38 import org.apache.commons.collections.IteratorUtils;
39
40 /***
41 * Take an enumeration of different types of objects.
42 * Pass them into this object and then get them out by classname.
43 */
44 public class EnumerationGrouper implements Grouper {
45
46 static private Enumeration nullEnum = IteratorUtils.asEnumeration(IteratorUtils.EMPTY_ITERATOR);
47
48 private Hashtable table = new Hashtable();
49
50 public EnumerationGrouper(Enumeration enum) {
51 addEnumeration(enum);
52 }
53
54 /***
55 * Add this enumeration to the grouper.
56 */
57 public void addEnumeration(Enumeration enum) {
58 while(enum.hasMoreElements()) {
59 Object obj = enum.nextElement();
60 String classname = obj.getClass().getName();
61 Object vec = table.get(classname);
62 if(vec == null) {
63 vec = new Vector();
64 table.put(classname, vec);
65 }
66 ((Vector)vec).addElement(obj);
67 }
68 }
69
70 /***
71 * Get an enumeration of all the Classes of type classname.
72 */
73 public Enumeration enumerateGroup(String classname) {
74 Object vec = table.get(classname);
75 if(vec instanceof Vector) {
76 return ((Vector)vec).elements();
77 } else {
78 return nullEnum;
79 }
80 }
81
82 /***
83 * Enumerate over the types this group contains.
84 */
85 public Enumeration enumerateTypes() {
86 return table.keys();
87 }
88
89 }