Token Bucket Filter - S1

import java.util.HashSet;
import java.util.Set;

class Demonstrator {
  public static void main(String[] args) throws Exception {
    TokenBucketFiller tokenBucketFiller = new TokenBucketFiller(5);
    Set<Thread> threads = new HashSet<Thread>();

    Thread.sleep(10000);

    for (int i = 0; i < 20; i++) {
      Thread thread =
          new Thread(
              new Runnable() {
                @Override
                public void run() {
                  try {
                    tokenBucketFiller.consumeToken();
                  } catch (InterruptedException ie) {

                  }
                }
              });
      thread.setName("Thread " + i);
      threads.add(thread);
    }

    for (Thread thread : threads) {
      thread.start();
    }

    for (Thread thread : threads) {
      thread.join();
    }
  }
}

class TokenBucketFiller {
  private int maxCapacity;
  private int consumableTokens = 0;
  private long lastConsumedTime = System.currentTimeMillis();

  public TokenBucketFiller(int maxCapacity) {
    this.maxCapacity = maxCapacity;
  }

  public synchronized void consumeToken() throws InterruptedException {
    consumableTokens += (System.currentTimeMillis() - lastConsumedTime) / 1000;
    if (consumableTokens > maxCapacity) {
      consumableTokens = maxCapacity;
    }

    if (consumableTokens == 0) {
      Thread.sleep(1000);
    } else {
      consumableTokens--;
    }

    lastConsumedTime = System.currentTimeMillis();

    System.out.println(
        "Granting "
            + Thread.currentThread().getName()
            + " a token at time "
            + System.currentTimeMillis());
  }
}