Scheduling of threads

Strategy

Preemptive ： High priority thread preemption CPU

Scheduling method

• Form a first in first out queue for threads with the same priority （ First come, first serve ）, Using time slice strategy .
• For high priority , Preemptive strategy using priority scheduling

The priority level of the thread

Three constants :

• MAX_PRIORITY:10
• MIN_PRIORITY:1
• NORM_PRIORITY:5 Default priority

Function method

• getPriority()： Returns the thread priority
• setPriority(int newPriority)： Change the priority of a thread

explain

Inherits the priority of the parent thread when the thread is created
Low priority is only a low probability of obtaining scheduling , It doesn't have to be called after a high priority thread .

Code ： Create three windows to sell tickets total 100 Zhang

class MyWindow extends Thread{
    
    // ticket 
    private static int ticket = 100;
    @Override
    public void run() {
    
        while (true){
    
            if(ticket>0){
    
                System.out.println(getName()+": Selling tickets , The ticket number is ："+ticket);
                ticket--;
            }else break;
        }
    }
}
public class WindowTest {
    
    public static void main(String[] args) {
    
        MyWindow t1 = new MyWindow();
        MyWindow t2 = new MyWindow();
        MyWindow t3 = new MyWindow();
        t1.setName(" window 1");
        t2.setName(" window 2");
        t3.setName(" window 3");

        t1.start();
        t2.start();
        t3.start();
    }
}

There are thread safety issues