01: /*******************************************************************************
02: * Licensed to the Apache Software Foundation (ASF) under one
03: * or more contributor license agreements. See the NOTICE file
04: * distributed with this work for additional information
05: * regarding copyright ownership. The ASF licenses this file
06: * to you under the Apache License, Version 2.0 (the
07: * "License"); you may not use this file except in compliance
08: * with the License. You may obtain a copy of the License at
09: *
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: *******************************************************************************/package org.ofbiz.base.util.collections;
19:
20: import java.util.AbstractSet;
21: import java.util.Collection;
22: import java.util.Iterator;
23: import java.util.LinkedList;
24: import java.util.List;
25:
26: /**
27: * OrderedSet - Set interface wrapper around a LinkedList
28: *
29: */
30: public class OrderedSet extends AbstractSet {
31:
32: // This set's back LinkedList
33: private List backedList = new LinkedList();
34:
35: /**
36: * Constructs a set containing the elements of the specified
37: * collection, in the order they are returned by the collection's
38: * iterator.
39: */
40: public OrderedSet() {
41: }
42:
43: /**
44: * Constructs a set containing the elements of the specified
45: * collection, in the order they are returned by the collection's
46: * iterator.
47: *
48: * @param c the collection whose elements are to be placed into this set.
49: */
50: public OrderedSet(Collection c) {
51: Iterator i = c.iterator();
52:
53: while (i.hasNext())
54: add(i.next());
55: }
56:
57: /**
58: * @see java.util.Collection#iterator()
59: */
60: public Iterator iterator() {
61: return backedList.iterator();
62: }
63:
64: /**
65: * @see java.util.Collection#size()
66: */
67: public int size() {
68: return backedList.size();
69: }
70:
71: /**
72: * @see java.util.Collection#add(java.lang.Object)
73: */
74: public boolean add(Object obj) {
75: int index = backedList.indexOf(obj);
76:
77: if (index == -1)
78: return backedList.add(obj);
79: else {
80: backedList.set(index, obj);
81: return false;
82: }
83: }
84: }
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