2023/10/23 每日总结

今天完成了设计模式实验19

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。

 

[实验任务一]：虚拟聊天室

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。

源代码

 

package org.test19;

public interface ChatMediator {
    void sendMessage(Message message, Member member);
}


package org.test19;

public class Client {
    public static void main(String[] args) {
        ChatMediator chatMediator = new ConcreteChatMediator();

        Member member1 = new ConcreteMember("Alice", chatMediator);
        Member member2 = new ConcreteMember("Bob", chatMediator);

        member1.sendMessage(new TextMessage("Hello, how are you?"));
        member2.sendMessage(new ImageMessage(15 * 1024 * 1024));  // This should work
        member1.sendMessage(new TextMessage("I'm good, thanks! How about you?"));
        member2.sendMessage(new ImageMessage(25 * 1024 * 1024));

    }
}




package org.test19;

public class ConcreteChatMediator implements ChatMediator{
    @Override
    public void sendMessage(Message message, Member member) {
        // 处理消息的发送逻辑
        member.receiveMessage(message);
    }
}




package org.test19;

public class ConcreteMember implements Member{
    private String name;
    private ChatMediator chatMediator;

    ConcreteMember(String name, ChatMediator chatMediator) {
        this.name = name;
        this.chatMediator = chatMediator;
    }

    @Override
    public void sendMessage(Message message) {
        if (message != null) {
            // 在这里进行图片大小和文本长度的判断
            if (message instanceof TextMessage) {
                if (((TextMessage) message).getContent().length() > 100) {
                    System.out.println("Text message too long. Limit is 100 characters. Message not sent.");
                    return;
                }
            } else if (message instanceof ImageMessage) {
                if (((ImageMessage) message).getSizeInMegaBytes() > 20) {
                    System.out.println("Image size too large. Message not sent.");
                    return;
                }
            }

            chatMediator.sendMessage(message, this);
        } else {
            System.out.println("Message not sent.");
        }
    }

    @Override
    public void receiveMessage(Message message) {
        if (message != null) {
            System.out.println(name + " received: " + message.getContent());
        } else {
            System.out.println(name + " did not receive the message.");
        }
    }
}




package org.test19;

public class ImageMessage extends Message{
    private int sizeInBytes;

    ImageMessage(int sizeInBytes) {
        this.sizeInBytes = sizeInBytes;
    }

    int getSizeInMegaBytes() {
        return sizeInBytes / (1024 * 1024);
    }

    @Override
    public String getContent() {
        return "Image Size: " + sizeInBytes + " bytes";
    }
}




package org.test19;

public interface Member {
    void sendMessage(Message message);
    void receiveMessage(Message message);
}





package org.test19;

public abstract class Message {
    public abstract  String getContent();
}





package org.test19;

public class TextMessage extends Message{

    private String content;

    TextMessage(String content) {
        this.content = content;
    }

    @Override
    public String getContent() {
        return content;
    }
}