Interview questions about producers and consumers (important)

1、 Deadlock

1.1 summary

1.2 Code implementation

 

 

2、 Thread communication

2.1   

 

 2.2  Usage mode

 

 

 

 

 2.3  Producer consumer

 

package day_02;

import java.util.Random;

/**

 * Similar to printing odd and even numbers , Use wait and notifyAll

 *

 * 1 A business class SynStack  There's a variable , Used to save the number of produced elements

 * 2 There is one in the business class char Array , Elements used to hold production ( If only produce a-z These letters )

 * 3 There need to be two methods in the business class , One is production push , A consumer pop

 *            push Method It is mainly used to add data to the array

 *                     Number to +1 , Also determine whether it is full , When it's full, hang up and wait

 *            pop Method It is mainly used to fetch the data in the array

 *                     Number to -1 , But also to determine whether the consumption is over , When it's over, hang up and wait

 * 4 Two threads , One is responsible for the production of , One is responsible for consumption

 *

 * @author Dawn Education - Handsome and juicy, your brother Ze

 * @Date 2022 year 1 month 25 Japan In the morning 11:14:56

 */

public class Thread_03_ProduceConsumer {

         public static void main(String[] args) {

                  SynStack ss = new SynStack();

                  Thread p = new Thread(new Producer(ss));

                  Thread c = new Thread(new Consumer(ss));

                  p.start();

                  c.start();

         }

}

class Producer implements Runnable{

         SynStack ss ;

        

         public Producer(SynStack ss) {

                  super();

                  this.ss = ss;

         }

         @Override

         public void run() {

                  Random random = new Random();

                  while (true) {

                          char ch = (char) (random.nextInt(26)+97);

                          ss.push(ch);

                  }

         }

}

class Consumer implements Runnable{

         SynStack ss ;

        

         public Consumer(SynStack ss) {

                  super();

                  this.ss = ss;

         }

         @Override

         public void run() {

                  while (true) {

                          try {

                                   Thread.sleep(500);

                          } catch (InterruptedException e) {

                                   e.printStackTrace();

                          }

                          ss.pop();

                  }

         }

}

class SynStack{

         // Container for saving data

         char[] data = new char[6];

         // Number of production

         int count = 0;

         // production

         public synchronized void push(char ch) {

                  // Judge whether it is full

                  if (count == data.length) {

                          try {

                                   this.wait();

                          } catch (InterruptedException e) {

                                   e.printStackTrace();

                          }

                  }

                  // That means it's not full , Started to produce

                  // Awaken consumers to prepare for consumption

                  this.notifyAll();

                  data[count ] = ch;

                  count++;

                  System.out.println(" Produced "+ch+" , The remaining "+count+" Elements ");

         }

         public synchronized char pop(){

                  // Determine whether it is null

                  if (count == 0) {

                          try {

                                   // There's no need to wake up the producers here , Because the producer is full in wait, It's all empty , It means that the producer must not wait

                                   this.wait();

                          } catch (InterruptedException e) {

                                   e.printStackTrace();

                          }

                  }

                   // This is not empty , Start spending

                  count--;

                  char ch = data[count];

                  // Wake up producers

                  this.notifyAll();

                  System.out.println(" The consumption "+ch+" , The remaining "+count+" Elements ");

        

                  return ch;

         }

}

3.  The singleton pattern