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 MINA Project (dev@mina.apache.org)
27 * @version $Rev: 576217 $, $Date: 2007-09-17 01:55:27 +0200 (lun, 17 sep 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 @Override
69 public String toString() {
70 if (ping) {
71 return "PING (" + ttl + ")";
72 } else {
73 return "PONG (" + ttl + ")";
74 }
75 }
76 }