Java实现生产者消费者模式

package com.ubs.joe.demo;

public class ProductThread implements Runnable{
??? private Count count;
??? public ProductThread(Count count){
?? ??? ?this.count = count;
??? }
??? public void run(){
?? ??? ?while(true){
?? ??? ??? ?try {
?? ??? ??? ??? ?Thread.sleep(1000);
?? ??? ??? ?} catch (InterruptedException e) {
?? ??? ??? ??? ?e.printStackTrace();
?? ??? ??? ?}
?? ??? ??? ?count.incrementCount();
?? ??? ?}
??? }
?? ?
??? public static void main(String [] args){
?? ??? ?Count count = new Count();
?? ??? ?ProductThread d = new ProductThread(count);
?? ??? ?CustomerThread r = new CustomerThread(count);
?? ??? ?Thread t1 = new Thread(d);
?? ??? ?Thread t2 = new Thread(r);
?? ??? ?Thread t3 = new Thread(d);
?? ??? ?Thread t4 = new Thread(r);
?? ??? ?t1.start();
?? ??? ?t2.start();
?? ??? ?t3.start();
?? ??? ?t4.start();
??? }
}

class CustomerThread implements Runnable{
?? ?private Count count;
?? ?public CustomerThread(Count count){
?? ??? ?this.count = count;
??? }
?? ?public void run(){
?? ??? ?while(true){
?? ??? ??? ??? ?try {
?? ??? ??? ??? ??? ?Thread.sleep(1000);
?? ??? ??? ??? ?} catch (InterruptedException e) {
?? ??? ??? ??? ??? ?e.printStackTrace();
?? ??? ??? ??? ?}
?? ??? ??? ??? ?count.decrementCount();?? ?

?? ??? ?}
?? ?}
}

class Count{
?? ?int count = 0;
?? ?int flag = 0;
?? ?public synchronized void incrementCount(){
?? ??? ?while(flag!=0){
?? ??? ??? ?try {
?? ??? ??? ??? ?wait();
?? ??? ??? ?} catch (InterruptedException e) {
?? ??? ??? ??? ?e.printStackTrace();
?? ??? ??? ?}
?? ??? ?}
?? ??? ?count++;
?? ??? ?System.out.println(count);
?? ??? ?if(count==20){
?? ??? ??? ?flag = 1;
?? ??? ??? ?notifyAll();
?? ??? ?}
??? }
?? ?
?? ?public synchronized void decrementCount(){
?? ??? ?while(flag==0){
?? ??? ??? ?try {
?? ??? ??? ??? ?wait();
?? ??? ??? ?} catch (InterruptedException e) {
?? ??? ??? ??? ?e.printStackTrace();
?? ??? ??? ?}
?? ??? ?}
?? ??? ?count--;
?? ??? ?System.out.println(count);
?? ??? ?if(count==0){
?? ??? ??? ?flag = 0;
?? ??? ??? ?notifyAll();
?? ??? ?}
?? ?}
}