实验19:中介者模式
本次实验属于模仿型实验,通过本次实验学生将掌握以下内容:
1、理解中介者模式的动机,掌握该模式的结构;
2、能够利用中介者模式解决实际问题。
在“虚拟聊天室”实例中增加一个新的具体聊天室类和一个新的具体会员类,要求如下:
1. 新的具体聊天室中发送的图片大小不得超过20M。
2. 新的具体聊天室中发送的文字长度不得超过100个字符。
3. 新的具体会员类可以发送图片信息和文本信息。
4. 新的具体会员类在发送文本信息时,可以在信息后加上时间。
修改客户端测试类,注意原有系统类代码和客户端代码的修改。
/**
* 抽象聊天室
*/
public abstract class AbstractChatroom
{
public abstract void register(Member member);
public abstract void sendText(String from,String to,String message);
public abstract void sendImage(String from,String to,String image);
}
import java.util.Hashtable;
public class ChatGroup extends AbstractChatroom
{
private Hashtable members = new Hashtable();
@Override
public void register(Member member)
{
if (!members.contains(member))
{
members.put(member.getName(), member);
member.setChatroom(this);
}
}
@Override
public void sendText(String from, String to, String message)
{
Member member = (Member) members.get(to);
String newMessage = message;
//模拟不雅字符过滤
newMessage = message.replaceAll("日", "*");
member.receiveText(from, newMessage);
}
@Override
public void sendImage(String from, String to, String image)
{
Member member = (Member) members.get(to);
//模拟图片大小判断
if (image.length() > 5)
{
System.out.println("图片太大,发送失败!");
} else
{
member.receiveImage(from, image);
}
}
}
import java.util.Hashtable;
/**
* 新的具体聊天室
* @author mendianyu
*/
public class AdvancedChatGroup extends AbstractChatroom
{
private Hashtable members = new Hashtable();
@Override
public void register(Member member)
{
if (!members.contains(member))
{
members.put(member.getName(), member);
member.setChatroom(this);
}
}
@Override
public void sendText(String from, String to, String message)
{
Member member = (Member) members.get(to);
//消息的文字长度不得超过100
if (message.length() > 100)
{
System.out.println("消息太长了,发送失败!");
} else
{
member.receiveText(from, message);
}
}
@Override
public void sendImage(String from, String to, String image)
{
Member member = (Member) members.get(to);
//图片大小不得超过20M
if (image.length() > 20)
{
System.out.println("图片太大了,发送失败!");
} else
{
member.receiveImage(from, image);
}
}
}
/**
* 抽象用户类
*/
public abstract class Member
{
protected AbstractChatroom chatroom;
protected String name;
public Member(String name)
{
this.name = name;
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public AbstractChatroom getChatroom()
{
return chatroom;
}
public void setChatroom(AbstractChatroom chatroom)
{
this.chatroom = chatroom;
}
public abstract void sendText(String to, String message);
public abstract void sendImage(String to, String image);
public void receiveText(String from, String message)
{
System.out.println(from + "发送文本给" + this.name + ",内容为:" + message);
}
public void receiveImage(String from, String image)
{
System.out.println(from + "发送图片给" + this.name + ",内容为:" + image);
}
}
/**
* 普通用户类
*/
public class CommonMember extends Member
{
public CommonMember(String name)
{
super(name);
}
@Override
public void sendText(String to, String message)
{
System.out.println("普通会员发送信息:");
//发送文本
chatroom.sendText(name, to, message);
}
@Override
public void sendImage(String to, String image)
{
System.out.println("普通会员不能发送图片!");
}
}
/**
* 钻石会员类
*/
public class DiamondMember extends Member
{
public DiamondMember(String name)
{
super(name);
}
@Override
public void sendText(String to, String message)
{
System.out.println("钻石会员发送信息:");
//发送文本
chatroom.sendText(name, to, message);
}
@Override
public void sendImage(String to, String image)
{
System.out.println("钻石会员发送图片:");
//发送图片
chatroom.sendImage(name, to, image);
}
}
import java.text.SimpleDateFormat;
import java.util.Date;
/**
* 铂金会员
*
* @author mendianyu
*/
public class AdvancedMember extends Member
{
public AdvancedMember(String name)
{
super(name);
}
@Override
public void sendText(String to, String message)
{
System.out.println("铂金会员发送文本:");
//在消息后面加上时间
SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
String timestamp = dateFormat.format(new Date());
message += " [" + timestamp + "]";
chatroom.sendText(name, to, message);
}
@Override
public void sendImage(String to, String image)
{
System.out.println("铂金会员发送图片");
chatroom.sendImage(name, to, image);
}
}
public class Client
{
public static void main(String[] args)
{
//实例化一个新的聊天室
AbstractChatroom advancedChatroom = new AdvancedChatGroup();
Member member1, member2, member3, member4, member5;
member1 = new CommonMember("张三");
member2 = new DiamondMember("李四");
//实例化新的会员
member3 = new AdvancedMember("王五");
//加入聊天室
advancedChatroom.register(member1);
advancedChatroom.register(member2);
advancedChatroom.register(member3);
member1.sendText("李四", "干嘛呢你俩?");
member1.sendText("王五", "干嘛呢你俩?");
member2.sendText("张三", "我在写作业");
//模拟图片超过20M
member2.sendImage("张三", "11111111111111111111111111111");
member3.sendText("张三", "我在打游戏");
member3.sendImage("张三", "五连绝世");
member1.sendText("王五", "别打游戏了,快出来玩");
//文字长度超过100,发送失败
member3.sendText("张三","1. 新的具体聊天室中发送的图片大小不得超过20M。\n" +
"2. 新的具体聊天室中发送的文字长度不得超过100个字符。\n" +
"3. 新的具体会员类可以发送图片信息和文本信息。\n" +
"4. 新的具体会员类在发送文本信息时,可以在信息后加上时间。\n" +
"修改客户端测试类,注意原有系统类代码和客户端代码的修改。");
}
}