run()方法和其他类方法之间的通信(java线程)

问题描述

我有任务要做，我很少受困.我必须提供4个服务(A，B，C，D).每个服务都应该有自己的线程.它们应按顺序启动并运行.如果服务A启动则可以启动服务B，如果服务B启动如果服务C启动则可以启动服务D.我设法创建服务及其线程，但是我不知道如何在start()和priority()方法之间创建通信在PriorityService类中.我想检查service(thread)A是否仍在运行，是否要从列表移至第二个服务，依此类推.那可能吗?您还有其他想法如何编写服务依赖项吗?任何建议都是有用的. Tnx.

i have task to do and i'm little stuck. I have to make 4 services (A,B,C,D). Every service should have his own thread. They should start in sequence and run. If service A starts then can start service B, if service B starts if service C starts then can start service D. I manage to create service and their threads but i dont know how should i create communication between start() and priority() method in PriorityService class. I wan to check if service(thread) A is alive and if it is I want to move to second service from list and so on. Is that possible? Do you have any other ideas how to write service dependency?Any advice is useful. Tnx.

这是我的代码:

import java.util.*;

class CreateThread extends Thread{
    private String thread_name;
    public int numb;
    public CreateThread(String thread_name, int i){
        this.thread_name=thread_name;
        System.out.println("Thread " + thread_name + " has started.");
        i=numb;
    }
    public void run(){
        try{
            Thread t = Thread.currentThread();
            System.out.println(thread_name + " status = " + t.getState());
            System.out.println(thread_name + " status = " + t.isAlive());
            t.join();
        }catch(Exception e){
            System.out.println(e);
        }

    }
}

class PriorityService extends ArrayList<Service> {
    public void priority()
    {
         int i=0;
         while(i<size()){
                System.out.println("evo me"+ get(i).service_name);
                    if(get(i).service_name=="Service A")
                        get(i).StartService(get(i).service_name, get(i).thread_name, i);
                    i++;
            }
    }
 }

public class Service {
    public String service_name;
    public String thread_name;

    public Service(String service_name, String thread_name){
        this.service_name=service_name;
        this.thread_name=thread_name;
    }

    public void StartService(String service_name, String thread_name, int i) {
        System.out.println("Service " + service_name + " has started.");
        Thread t=new Thread(new CreateThread(thread_name, i));
        t.start();
    }

    public void StopService() {}
    public static void main (String[] args){
        PriorityService p_s=new PriorityService();
        Service service_A = new Service("Service A", "Thread A");
        Service service_B = new Service("Service B", "Thread B");
        Service service_C = new Service("Service C", "Thread C");
        Service service_D = new Service("Service D", "Thread D");
        p_s.add(service_A);
        p_s.add(service_B);
        p_s.add(service_C);
        p_s.add(service_D);
        p_s.priority();

        for(Service s: p_s)
            System.out.println(s.service_name);

    }
}

推荐答案

您应该为此使用闩锁.

您可以为每对线程使用2个闩锁，这应该可以完成您的工作.因此，线程A和线程B会存在一个闩锁，这意味着直到它们两个都启动并运行后它们才能继续进行.对于C和D同样如此.

You can use 2 Latches for one for each pair of threads and that should do your job. So one Latch will be there for Threads A and B, which implies till bothof them are up and running they can't proceed. Similarly for C and D.

此链接的示例显示了闩锁，看看吧.

This link has an example showing use of Latch, just take a look.

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