001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020package org.apache.mina.example.tennis; 021 022/** 023 * A tennis ball which has TTL value and state whose value is one of 'PING' and 024 * 'PONG'. 025 * 026 * @author <a href="http://mina.apache.org">Apache MINA Project</a> 027 */ 028public class TennisBall { 029 private final boolean ping; 030 031 private final int ttl; 032 033 /** 034 * Creates a new ball with the specified TTL (Time To Live) value. 035 * 036 * @param ttl The time to live 037 */ 038 public TennisBall(int ttl) { 039 this(ttl, true); 040 } 041 042 /** 043 * Creates a new ball with the specified TTL value and PING/PONG state. 044 */ 045 private TennisBall(int ttl, boolean ping) { 046 this.ttl = ttl; 047 this.ping = ping; 048 } 049 050 /** 051 * @return the TTL value of this ball. 052 */ 053 public int getTTL() { 054 return ttl; 055 } 056 057 /** 058 * @return the ball after {@link TennisPlayer}'s stroke. 059 * The returned ball has decreased TTL value and switched PING/PONG state. 060 */ 061 public TennisBall stroke() { 062 return new TennisBall(ttl - 1, !ping); 063 } 064 065 /** 066 * @return string representation of this message (<code>[PING|PONG] 067 * (TTL)</code>). 068 */ 069 @Override 070 public String toString() { 071 if (ping) { 072 return "PING (" + ttl + ")"; 073 } else { 074 return "PONG (" + ttl + ")"; 075 } 076 } 077}