01: /*
02: * Copyright 2003-2004 The Apache Software Foundation
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
10: * Unless required by applicable law or agreed to in writing, software
11: * distributed under the License is distributed on an "AS IS" BASIS,
12: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13: * See the License for the specific language governing permissions and
14: * limitations under the License.
15: */
16: package org.apache.commons.collections.bag;
17:
18: import java.util.Comparator;
19:
20: import org.apache.commons.collections.SortedBag;
21:
22: /**
23: * Decorates another <code>SortedBag</code> to provide additional behaviour.
24: * <p>
25: * Methods are forwarded directly to the decorated bag.
26: *
27: * @since Commons Collections 3.0
28: * @version $Revision: 155406 $ $Date: 2005-02-26 12:55:26 +0000 (Sat, 26 Feb 2005) $
29: *
30: * @author Stephen Colebourne
31: */
32: public abstract class AbstractSortedBagDecorator extends
33: AbstractBagDecorator implements SortedBag {
34:
35: /**
36: * Constructor only used in deserialization, do not use otherwise.
37: * @since Commons Collections 3.1
38: */
39: protected AbstractSortedBagDecorator() {
40: super ();
41: }
42:
43: /**
44: * Constructor that wraps (not copies).
45: *
46: * @param bag the bag to decorate, must not be null
47: * @throws IllegalArgumentException if list is null
48: */
49: protected AbstractSortedBagDecorator(SortedBag bag) {
50: super (bag);
51: }
52:
53: /**
54: * Gets the bag being decorated.
55: *
56: * @return the decorated bag
57: */
58: protected SortedBag getSortedBag() {
59: return (SortedBag) getCollection();
60: }
61:
62: //-----------------------------------------------------------------------
63: public Object first() {
64: return getSortedBag().first();
65: }
66:
67: public Object last() {
68: return getSortedBag().last();
69: }
70:
71: public Comparator comparator() {
72: return getSortedBag().comparator();
73: }
74:
75: }
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