聊聊leaky bucket算法的实现

public class LeakyBucket {

    private final long capacity;
    private final long leaksIntervalInMillis;

    private double used;
    private long lastLeakTimestamp;

    public LeakyBucket(long capacity, long leaksIntervalInMillis) {
        this.capacity = capacity;
        this.leaksIntervalInMillis = leaksIntervalInMillis;

        this.used = 0;
        this.lastLeakTimestamp = System.currentTimeMillis();
    }

    synchronized public boolean tryConsume(int drop) {
        leak();

        if (used + drop > capacity) {
           return false;
        }

        used = used + drop;
        return true;
    }

    private void leak() {
        long currentTimeMillis = System.currentTimeMillis();
        if (currentTimeMillis > lastLeakTimestamp) {
            long millisSinceLastLeak = currentTimeMillis - lastLeakTimestamp;
            long leaks = millisSinceLastLeak / leaksIntervalInMillis;
            if(leaks > 0){
                if(used <= leaks){
                    used = 0;
                }else{
                    used -= (int)leaks;
                }
                this.lastLeakTimestamp = currentTimeMillis;
            }
        }
    }
}