01 /*
02 *
03 * Licensed to the Apache Software Foundation (ASF) under one
04 * or more contributor license agreements. See the NOTICE file
05 * distributed with this work for additional information
06 * regarding copyright ownership. The ASF licenses this file
07 * to you under the Apache License, Version 2.0 (the
08 * "License"); you may not use this file except in compliance
09 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 *
20 */
21 package org.apache.qpid.util;
22
23 import java.util.concurrent.ConcurrentLinkedQueue;
24 import java.util.concurrent.atomic.AtomicInteger;
25
26 public class ConcurrentLinkedQueueAtomicSize<E> extends ConcurrentLinkedQueue<E>
27 {
28 AtomicInteger _size = new AtomicInteger(0);
29
30 public int size()
31 {
32 return _size.get();
33 }
34
35 public boolean offer(E o)
36 {
37
38 if (super.offer(o))
39 {
40 _size.incrementAndGet();
41 return true;
42 }
43
44 return false;
45 }
46
47 public E poll()
48 {
49 E e = super.poll();
50
51 if (e != null)
52 {
53 _size.decrementAndGet();
54 }
55
56 return e;
57 }
58
59 @Override
60 public boolean remove(Object o)
61 {
62 if (super.remove(o))
63 {
64 _size.decrementAndGet();
65 return true;
66 }
67
68 return false;
69 }
70 }
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