中介者模式

/**
 * 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。");
    }
}