哲学家进餐

/*
 * The solution uses Java Streams to handle the synchronization and actions of the philosophers.
 * The approach ensures that the actions are executed in a synchronized manner to avoid deadlocks.
 */

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.stream.IntStream;

public class DiningPhilosophersStream {
    private final Lock[] forks = IntStream.range(0, 5)
                                          .mapToObj(i -> new ReentrantLock())
                                          .toArray(Lock[]::new);

    public void wantsToEat(int philosopher,
                           Runnable pickLeftFork,
                           Runnable pickRightFork,
                           Runnable eat,
                           Runnable putLeftFork,
                           Runnable putRightFork) throws InterruptedException {
        int leftFork = philosopher;
        int rightFork = (philosopher + 1) % 5;

        // Ensure we always pick up the lower numbered fork first to avoid deadlock
        if (philosopher % 2 == 0) {
            forks[leftFork].lock();
            pickLeftFork.run();
            forks[rightFork].lock();
            pickRightFork.run();
        } else {
            forks[rightFork].lock();
            pickRightFork.run();
            forks[leftFork].lock();
            pickLeftFork.run();
        }

        eat.run();

        putLeftFork.run();
        forks[leftFork].unlock();
        putRightFork.run();
        forks[rightFork].unlock();
    }
}