多线程 Balking设计模式

多线程 Balking设计模式 balking犹豫的意思，举个例子，当平时在饭店吃饭时，喊一声服务员，其中一个服务员看到了，向你走来时，这时，一个更近的服务员过来为你服务了，或者当平时编辑word文档时，word有自动保存功能，还有你自己按保存按钮，当word自动保存时，你也按吧保存按钮，自动保存就会放弃这次操作。

import java.io.FileWriter;
import java.io.Writer;

public class BalkingData {
    private boolean change = false;
    private String content;
    private final String fileName;

    public BalkingData(String content, String fileName) {
        this.change = true;
        this.content = content;
        this.fileName = fileName;
    }

    public void change(String content) {
        synchronized (this) {
            this.content = content;
            this.change = true;
        }
    }

    public void save() throws Exception {
        synchronized (this) {
            if (!change) {
                return;
            }
            doSave();
            change = false;
        }
    }

    private void doSave() throws Exception {
        System.out.println(Thread.currentThread().getName() + " calls do save,content=" + content);
        Thread.sleep(1000);
        try (Writer writer = new FileWriter(fileName, true)) {
            writer.write(content);
            writer.write("\n");
            writer.flush();
        }
    }
}

package com.thread.ch12;

import java.util.Random;

public class CustomerThread extends Thread {
    private final BalkingData balkingData;
    private Random random = new Random(System.currentTimeMillis());

    public CustomerThread(BalkingData balkingData) {
        super("Customer");
        this.balkingData = balkingData;
    }

    @Override
    public void run() {
        try {
            balkingData.save();
            for (int i = 0; i < 20; i++) {
                balkingData.change("NO." + i);
                Thread.sleep(1000);
                balkingData.save();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

package com.thread.ch12;

import java.util.Random;

public class WaterThread extends Thread {
    private final BalkingData balkingData;
    private Random random = new Random(System.currentTimeMillis());

    public WaterThread(BalkingData balkingData) {
        super("Water");
        this.balkingData = balkingData;
    }

    @Override
    public void run() {
        try {
            for (int i = 0; i < 200; i++) {
                balkingData.save();
                Thread.sleep(1000);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

package com.thread.ch12;

public class BalkingClient {
    public static void main(String[] args) {
        BalkingData balkingData = new BalkingData("dsds","F:\\n.txt");
        CustomerThread customerThread = new CustomerThread(balkingData);
        WaterThread waterThread = new WaterThread(balkingData);
        customerThread.start();
        waterThread.start();
    }
}

运行结果

Customer calls do save,content=dsds
Customer calls do save,content=NO.0
Customer calls do save,content=NO.1
Water calls do save,content=NO.2
Water calls do save,content=NO.3
Customer calls do save,content=NO.4
Water calls do save,content=NO.5
Water calls do save,content=NO.6
Customer calls do save,content=NO.7
Water calls do save,content=NO.8
Water calls do save,content=NO.9
Customer calls do save,content=NO.10
Water calls do save,content=NO.11
Customer calls do save,content=NO.12
Water calls do save,content=NO.13
Customer calls do save,content=NO.14
Water calls do save,content=NO.15
Customer calls do save,content=NO.16
Water calls do save,content=NO.17
Customer calls do save,content=NO.18
Customer calls do save,content=NO.19

Process finished with exit code -1

来源：oschina

链接：https://my.oschina.net/lvzi98/blog/3170824

标签

多线程

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