How to do 4 requirement?

Question about the task

Monitoring thread state

Java Multithreading, Level 5, Lesson 5

Resolved

Idk how to do that

Create a LoggingStateThread thread class, which will display all of the states (State) of the thread passed to the constructor.
The LoggingStateThread thread must terminate itself after the thread passed to the constructor has stopped.
The main() method is not tested.

Requirements:

Create a LoggingStateThread class in a separate file. It must inherit the Thread class.
The LoggingStateThread class must have a field for the thread it will monitor. This field must be initialized through the constructor.
Override the LoggingStateThread class's run() method.
After it starts running, the LoggingStateThread class should display changes to the passed thread's state.
After the monitored thread stops, the LoggingStateThread thread must also stop running.

package com.codegym.task.task25.task2506; /* Monitoring thread state */ public class Solution { public static void main(String[] args) throws InterruptedException { Thread target = new Thread(); LoggingStateThread loggingStateThread = new LoggingStateThread(target); loggingStateThread.start(); // NEW Thread.sleep(100); target.start(); // RUNNABLE Thread.sleep(100); // TERMINATED } }

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Ian De Bie Full Stack Developer

12 September 2022, 02:07

public class LoggingStateThread extends Thread {

    private Thread thread;
    private State state;

    public LoggingStateThread(Thread thread) {
        this.thread = thread;
    }

    @Override
    public void run() {

        super.run();
        while (state != State.TERMINATED) {
            if (state != thread.getState()) {
                state = thread.getState();
                System.out.println(state);
            }
        }

    }

}

Wei Cui

Level 39 , Newark, United States

25 March 2020, 20:56

public void run() {
       //record initial state;
       State state = target.getState();
       System.out.println(state);
       //start new
       super.run();

       //if state stop, this also stop
       while(!state.equals(State.TERMINATED)) {
           State currentState = target.getState();
           if(!state.equals(currentState)) {
               System.out.println(currentState);
               //chang state to the newest state and waiting next change
               state = currentState;
           }
       }


   }

Guadalupe Gagnon

Level 37 , Tampa, United States

24 May 2019, 14:11

useful

I read the requirements as saying to display the Thread's state only when that state has changed (and after the LoggingThreadState thread has started). Try removing line 16 of the LoggingStateThread because this displays the current state when the LTS is started and not a thread state change.

Azja

Level 32 , Krakow, Poland

25 May 2019, 07:35

I forgot to changing lastState variable if it was not equals to current state so i have all time "new" in lastState

Johannes

Level 27 , Centurion, Pretoria, South-Africa

18 May 2020, 10:19

hi why would this display work ? I thought run() is only executed ONCE when you start a thread ? So it will always just display once for the current thread, and it will probably just display that it's waiting or actually started. Either of the two ?

Guadalupe Gagnon

Level 37 , Tampa, United States

18 May 2020, 13:23

run() is only executed once, however you can put the body of the code in a loop to run as long as a termination condition is not triggered, such as the thread moving to TERMINATED state.

Johannes

Level 27 , Centurion, Pretoria, South-Africa

18 May 2020, 14:09

Oh I see now: currentState = target.getState() is refreshed in the while loop.... thanks Guada