01: package org.apache.torque.util;
02:
03: /*
04: * Licensed to the Apache Software Foundation (ASF) under one
05: * or more contributor license agreements. See the NOTICE file
06: * distributed with this work for additional information
07: * regarding copyright ownership. The ASF licenses this file
08: * to you under the Apache License, Version 2.0 (the
09: * "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: * Serial version
33: */
34: private static final long serialVersionUID = 4467847559423445120L;
35:
36: /**
37: * Constructs an empty UniqueList.
38: */
39: public UniqueList() {
40: }
41:
42: /**
43: * Copy-constructor. Creates a shallow copy of an UniqueList.
44: * @param list the uniqueList to copy
45: */
46: public UniqueList(UniqueList list) {
47: this .addAll(list);
48: }
49:
50: /**
51: * Adds an Object to the list.
52: *
53: * @param o the Object to add
54: * @return true if the Object is added
55: */
56: public boolean add(Object o) {
57: if (o != null && !contains(o)) {
58: return super .add(o);
59: }
60: return false;
61: }
62: }
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