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我想用java信号量来解决哲学家用餐问题,但我被卡住了。最高ID的筷子应该可用,但它似乎总是被采取,我不知道为什么。谁能告诉我我犯了什么错误?在java中使用信号量使用哲学家
叉类:
class Fork {
public static Semaphore fork = new Semaphore(1);
public int id;
Fork(int id) {
this.id = id;
}
public int getId() {
return id;
}
public boolean take() {
return fork.tryAcquire();
}
public void putDown() {
fork.release();
}}
哲学家类:
class Philosopher extends Thread {
private Fork fork_low;
private Fork fork_high;
private String name;
Philosopher(Fork fork_low, Fork fork_high, String name) {
this.fork_low = fork_low;
this.fork_high = fork_high;
this.name = name;
}
public void run() {
try {
sleep(1000);
} catch (InterruptedException ex) {
}
while (true) {
eat();
}
}
private void eat(){
if(fork_low.take()){
if(fork_high.take()){
try {
sleep(2000); // eating;
} catch (InterruptedException ex) { }
fork_high.putDown();
fork_low.putDown();
}
else{
fork_low.putDown();
}
}
}}
主营:
public static void main(String[] args) {
String[] names = {"Plato", "Aristotle", "Cicero", "Confucius", "Eratosthenes"};
Fork[] fork = new Fork[5];
Philosopher[] philosopher = new Philosopher[5];
for (int i = 0; i < fork.length; i++) {
fork[i] = new Fork(i);
}
for (int i = 0; i < philosopher.length; i++) {
if (i != philosopher.length - 1) {
philosopher[i] = new Philosopher(fork[i], fork[i+1], names[i]);
philosopher[i].start();
} else {
philosopher[i] = new Philosopher(fork[0], fork[i], names[i]);
philosopher[i].start();
}
}
}
是的,很好,谢谢。 –