1 package org.apache.torque.util;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import java.util.ArrayList;
23
24 /***
25 * List with unique entries. UniqueList does not allow null nor duplicates.
26 *
27 * @author <a href="mailto:mpoeschl@marmot.at">Martin Poeschl</a>
28 * @version $Id: UniqueList.java 473821 2006-11-11 22:37:25Z tv $
29 */
30 public class UniqueList extends ArrayList
31 {
32 /***
33 * Serial version
34 */
35 private static final long serialVersionUID = 4467847559423445120L;
36
37 /***
38 * Constructs an empty UniqueList.
39 */
40 public UniqueList()
41 {
42 }
43
44 /***
45 * Copy-constructor. Creates a shallow copy of an UniqueList.
46 * @param list the uniqueList to copy
47 */
48 public UniqueList(UniqueList list)
49 {
50 this.addAll(list);
51 }
52
53 /***
54 * Adds an Object to the list.
55 *
56 * @param o the Object to add
57 * @return true if the Object is added
58 */
59 public boolean add(Object o)
60 {
61 if (o != null && !contains(o))
62 {
63 return super.add(o);
64 }
65 return false;
66 }
67 }