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Java > Open Source Codes > org > apache > torque > util > UniqueList


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 JavaDoc;
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 JavaDoc
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 JavaDoc o)
60     {
61         if (o != null && !contains(o))
62         {
63             return super.add(o);
64         }
65         return false;
66     }
67 }
68
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