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:
19: /* $Id: Stack.java 473861 2006-11-12 03:51:14Z gregor $ */
20:
21: package org.apache.lenya.util;
22:
23: import java.util.Vector;
24:
25: /**
26: * A helper class to implement a stack. Unlike java.util.Stack, this stack
27: * discards old elements once maxsize is reached.
28: * @see java.util.Stack
29: */
30: public class Stack extends Vector {
31: /**
32: *
33: */
34: private static final long serialVersionUID = 1L;
35: int maxsize = 0;
36:
37: /**
38: * Creates a new Stack object.
39: * @param _maxsize The maximum size of the stack
40: */
41: public Stack(int _maxsize) {
42: this .maxsize = _maxsize;
43: }
44:
45: /**
46: * Push an object on the stack
47: * @param object The object
48: */
49: public void push(Object object) {
50: insertElementAt(object, 0);
51:
52: if (size() == (this .maxsize + 1)) {
53: removeElementAt(this.maxsize);
54: }
55: }
56: }
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