问题描述
public class Chat {
int flag=0;
public synchronized void Friend1(String msg) {
if(flag>0) {
try {
wait();
}
catch(InterruptedException e) {
e.printstacktrace();
}
}
System.out.println(msg);
flag=1;
notify();
}
public synchronized void Friend2(String msg) {
if(flag==0) {
try {
wait();
}
catch(InterruptedException e) {
e.printstacktrace();
}
}
System.out.println(msg);
flag=0;
notify();
}
public synchronized void Friend3(String msg) {
if(flag<0) {
try {
wait();
}
catch(InterruptedException e) {
e.printstacktrace();
}
}
System.out.println(msg);
flag=(-1);
notify();
}
}
public class T1 implements Runnable {
Chat m;
String[] s1= {"Hi","How are you all?","Why what happened","Yes,We are in a hectic situation but we have to continue our studies and be strong inside","Fave faith in Allah! Eveything will be ok"};
public T1(Chat m1) {
this.m=m1;
new Thread(this,"Friend1").start();
}
public void run() {
for(int i=0; i<s1.length; i++) {
m.Friend1(s1[i]);
}
}
}
public class T2 implements Runnable{
Chat m;
String[] s2= {"Hy","I am fine","Is there anything wrong?","There is nothing we can do about in this pandemic situation but to study and pray","Everything will be fine soon"};
public T2(Chat m2) {
this.m=m2;
new Thread(this,"Answer").start();
}
public void run() {
for(int i=0; i<s2.length; i++) {
m.Friend2(s2[i]);
}
}
}
public class T3 implements Runnable {
Chat m;
String[] s3= {"Hello","I am not fine","I am very depressed about my online classes","I feel too much preassure","Yeap I will start praying to Allah that everything comes around"};
public T3(Chat m3) {
this.m=m3;
new Thread(this,"Friends3").start();
}
public void run() {
for(int i=0; i<s3.length; i++) {
m.Friend3(s3[i]);
}
}
}
public class Main {
public static void main(String[] args) {
Chat m=new Chat();
new T1(m);
new T2(m);
new T3(m);
}
}
输出为： 嗨
嗨
你们好吗？
我很好
为什么会发生
有什么问题吗？
是的，我们处在忙碌的状况中，但我们必须继续学习并保持坚强的内心
在这种大流行的情况下，除了学习和祈祷外，我们无能为力
相信真主！一切都会好的
很快一切都会好起来
你好
解决方法
以您为例，您知道每个线程都应在上一个之后打印短语：
- 1点后2点
- 3点2分后
- 3后1
因此，您可以创建一个变量，该变量将是应该立即执行操作的线程的存储号：
AtomicInteger currentSpeaker = new AtomicInteger(1);
每个线程可以在打印下一个短语并为下一个线程设置新值之前检查此变量：
public class T1 implements Runnable {
Chat m;
String[] s1 = {"Hi","How are you all?","Why what happened","Yes,We are in a hectic situation but we have to continue our studies and be strong inside","Fave faith in Allah! Eveything will be ok"};
public T1(Chat m1) {
this.m = m1;
new Thread(this,"Friend1").start();
}
public void run() {
for (int i = 0; i < s1.length; i++) {
while (currentSpeaker.get() != 1) delay(100L);
m.Friend1(s1[i]);
currentSpeaker.set(2);
}
}
}
public class T2 implements Runnable {
Chat m;
String[] s2 = {"Hy","I am fine","Is there anything wrong?","There is nothing we can do about in this pandemic situation but to study and pray","Everything will be fine soon"};
public T2(Chat m2) {
this.m = m2;
new Thread(this,"Answer").start();
}
public void run() {
for (int i = 0; i < s2.length; i++) {
while (currentSpeaker.get() != 2) delay(100L);
m.Friend2(s2[i]);
currentSpeaker.set(3);
}
}
}
public class T3 implements Runnable {
Chat m;
String[] s3 = {"Hello","I am not fine","I am very depressed about my online classes","I feel too much preassure","Yeap I will start praying to Allah that everything comes around"};
public T3(Chat m3) {
this.m = m3;
new Thread(this,"Friends3").start();
}
public void run() {
for (int i = 0; i < s3.length; i++) {
while (currentSpeaker.get() != 3) delay(100L);
m.Friend3(s3[i]);
currentSpeaker.set(1);
}
}
}
我创建了方法延迟，以使代码不易阅读：
public static void delay(long t) {
try {
Thread.sleep(t);
} catch (InterruptedException e) {}
}
输出：
嗨
嗨
你好
你们好吗？
我很好
我不好
为什么会发生
有什么问题吗？
我对在线课程感到非常沮丧
是的，我们处在忙碌的状况中，但我们必须继续学习 内心坚强
在这种大流行情况下，我们无能为力 学习祈祷
我太放心了
相信真主！一切都会好的
很快一切都会好起来
是的，我将开始向阿拉祈祷一切都会发生