01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one or more
03: * contributor license agreements. See the NOTICE file distributed with
04: * this work for additional information regarding copyright ownership.
05: * The ASF licenses this file to You under the Apache License, Version 2.0
06: * (the "License"); you may not use this file except in compliance with
07: * the License. You may obtain a copy of the License at
08: *
09: * http://www.apache.org/licenses/LICENSE-2.0
10: *
11: * Unless required by applicable law or agreed to in writing, software
12: * distributed under the License is distributed on an "AS IS" BASIS,
13: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14: * See the License for the specific language governing permissions and
15: * limitations under the License.
16: */
17:
18: package org.apache.jetspeed.util;
19:
20: /**
21: * Simple FIFO implementation of Queue interface extending Vector
22: * as storage backend.
23: *
24: * @author <a href="mailto:raphael@apache.org">Rapha\u00ebl Luta</a>
25: * @version $Id: FIFOQueue.java 516448 2007-03-09 16:25:47Z ate $
26: */
27: public class FIFOQueue extends java.util.Vector implements Queue {
28: /**
29: * Adds a new object into the queue
30: */
31: public synchronized void push(Object obj) {
32: this .add(obj);
33: }
34:
35: /**
36: * Gets the first object in the queue and remove it from the queue
37: */
38: public synchronized Object pop() {
39:
40: if (this .size() == 0) {
41: return null;
42: }
43:
44: return this .remove(0);
45: }
46:
47: /**
48: * Gets the first object in the queue without removing it from the queue
49: */
50: public synchronized Object peek() {
51:
52: if (this .size() == 0) {
53: return null;
54: }
55:
56: return this .get(0);
57: }
58: }
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