/**
* Acquires the given number of permits from this {@code RateLimiter}, blocking until the request
* be granted.
*
* @param permits the number of permits to acquire
*/
public void acquire(int permits) {
checkPermits(permits);
long microsToWait;
synchronized (this) {
microsToWait = reserveNextTicket(permits, readSafeMicros());
}
ticker.sleepMicrosUninterruptibly(microsToWait);
}
/**
* Acquires the given number of permits from this {@code RateLimiter} if it can be obtained
* without exceeding the specified {@code timeout}, or returns {@code false} immediately (without
* waiting) if the permits would not have been granted before the timeout expired.
*
* @param permits the number of permits to acquire
* @param timeout the maximum time to wait for the permits
* @param unit the time unit of the timeout argument
* @return {@code true} if the permits were acquired, {@code false} otherwise
*/
public boolean tryAcquire(int permits, long timeout, TimeUnit unit) {
checkPermits(permits);
long timeoutMicros = unit.toMicros(timeout);
long microsToWait;
synchronized (this) {
long nowMicros = readSafeMicros();
if (nextFreeTicketMicros > nowMicros + timeoutMicros) {
return false;
} else {
microsToWait = reserveNextTicket(permits, nowMicros);
}
}
ticker.sleepMicrosUninterruptibly(microsToWait);
return true;
}
private long readSafeMicros() {
return TimeUnit.NANOSECONDS.toMicros(ticker.read() - offsetNanos);
}
private RateLimiter(SleepingTicker ticker) {
this.ticker = ticker;
this.offsetNanos = ticker.read();
}
