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Java > Open Source Codes > org > apache > mina > example > tennis > TennisBall


1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one
3  * or more contributor license agreements. See the NOTICE file
4  * distributed with this work for additional information
5  * regarding copyright ownership. The ASF licenses this file
6  * to you under the Apache License, Version 2.0 (the
7  * "License"); you may not use this file except in compliance
8  * with the License. You may obtain a copy of the License at
9  *
10  * http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing,
13  * software distributed under the License is distributed on an
14  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15  * KIND, either express or implied. See the License for the
16  * specific language governing permissions and limitations
17  * under the License.
18  *
19  */
20 package org.apache.mina.example.tennis;
21
22 /**
23  * A tennis ball which has TTL value and state whose value is one of 'PING' and
24  * 'PONG'.
25  *
26  * @author The Apache Directory Project (mina-dev@directory.apache.org)
27  * @version $Rev: 555855 $, $Date: 2007-07-13 12:19:00 +0900 (금, 13 7월 2007) $
28  */
29 public class TennisBall {
30     private final boolean ping;
31
32     private final int ttl;
33
34     /**
35      * Creates a new ball with the specified TTL (Time To Live) value.
36      */
37     public TennisBall(int ttl) {
38         this(ttl, true);
39     }
40
41     /**
42      * Creates a new ball with the specified TTL value and PING/PONG state.
43      */
44     private TennisBall(int ttl, boolean ping) {
45         this.ttl = ttl;
46         this.ping = ping;
47     }
48
49     /**
50      * Returns the TTL value of this ball.
51      */
52     public int getTTL() {
53         return ttl;
54     }
55
56     /**
57      * Returns the ball after {@link TennisPlayer}'s stroke.
58      * The returned ball has decreased TTL value and switched PING/PONG state.
59      */
60     public TennisBall stroke() {
61         return new TennisBall(ttl - 1, !ping);
62     }
63
64     /**
65      * Returns string representation of this message (<code>[PING|PONG]
66      * (TTL)</code>).
67      */
68     public String JavaDoc toString() {
69         if (ping) {
70             return "PING (" + ttl + ")";
71         } else {
72             return "PONG (" + ttl + ")";
73         }
74     }
75 }
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