KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > com > quadcap > util > collections > Queue


1 package com.quadcap.util.collections;
2
3 /* Copyright 1997 - 2003 Quadcap Software. All rights reserved.
4  *
5  * This software is distributed under the Quadcap Free Software License.
6  * This software may be used or modified for any purpose, personal or
7  * commercial. Open Source redistributions are permitted. Commercial
8  * redistribution of larger works derived from, or works which bundle
9  * this software requires a "Commercial Redistribution License"; see
10  * http://www.quadcap.com/purchase.
11  *
12  * Redistributions qualify as "Open Source" under one of the following terms:
13  *
14  * Redistributions are made at no charge beyond the reasonable cost of
15  * materials and delivery.
16  *
17  * Redistributions are accompanied by a copy of the Source Code or by an
18  * irrevocable offer to provide a copy of the Source Code for up to three
19  * years at the cost of materials and delivery. Such redistributions
20  * must allow further use, modification, and redistribution of the Source
21  * Code under substantially the same terms as this license.
22  *
23  * Redistributions of source code must retain the copyright notices as they
24  * appear in each source code file, these license terms, and the
25  * disclaimer/limitation of liability set forth as paragraph 6 below.
26  *
27  * Redistributions in binary form must reproduce this Copyright Notice,
28  * these license terms, and the disclaimer/limitation of liability set
29  * forth as paragraph 6 below, in the documentation and/or other materials
30  * provided with the distribution.
31  *
32  * The Software is provided on an "AS IS" basis. No warranty is
33  * provided that the Software is free of defects, or fit for a
34  * particular purpose.
35  *
36  * Limitation of Liability. Quadcap Software shall not be liable
37  * for any damages suffered by the Licensee or any third party resulting
38  * from use of the Software.
39  */

40
41 /**
42  * This class implements a queue with a capacity.
43  *
44  * @author Stan Bailes
45  */

46 public interface Queue {
47     /**
48      * Specify the maximum capacity of this queue, -1 means unbounded.
49      *
50      * @param capacity the new capacity of the queue, or -1 to specify a
51      * queue of unlimited size.
52      */

53     public void setCapacity(int capacity);
54     
55     /**
56      * Return the number of items in the queue.
57      * @return the queue's size
58      */

59     public int size();
60
61     /**
62      * Add an object to the front of the queue.
63      *
64      * @param obj the object to add
65      */

66     public void addFront(Object JavaDoc obj);
67
68     /**
69      * Add an object to the back of the queue.
70      * @param obj the object to add
71      */

72     public void addBack(Object JavaDoc obj);
73
74     /**
75      * Access the object at the front of the queue. Throw a runtime exception
76      * if the queue is empty.
77      *
78      * @return the item at the head of the queue
79      */

80     public Object JavaDoc head();
81
82     /**
83      * Access the object at the back of the queue. Throw a runtime exception
84      * if the queue is empty.
85      *
86      * @return the item at the tail of the queue
87      */

88     public Object JavaDoc tail();
89
90     /**
91      * Remove and return the item at the front of the queue. Throw a
92      * runtime exception if the queue is empty.
93      *
94      * @return the item at the head of the queue
95      */

96     public Object JavaDoc popFront();
97     
98     /**
99      * Remove and return the item at the back of the queue. Throw a
100      * runtime exception if the queue is empty.
101      *
102      * @return the item at the tail of the queue
103      */

104     public Object JavaDoc popBack();
105     
106 }
107
Popular Tags