FrameTour-BE/src/main/java/com/ycwl/basic/ratelimiter/SlidingWindowRateLimiter.java

package com.ycwl.basic.ratelimiter;

import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;


public class SlidingWindowRateLimiter {
    private final Semaphore semaphore;
    private final ScheduledExecutorService scheduler = new ScheduledThreadPoolExecutor(1);

    public SlidingWindowRateLimiter(int maxRequestsPerSecond) {
        this.semaphore = new Semaphore(maxRequestsPerSecond);
        // Schedule a task to release all permits every second
        scheduler.scheduleAtFixedRate(() -> semaphore.release(maxRequestsPerSecond - semaphore.availablePermits()), 1, 1, TimeUnit.SECONDS);
    }

    public void allowRequest() throws InterruptedException {
        semaphore.acquire();
    }

    public void shutdown() {
        scheduler.shutdown();
    }
}