Bank.java

class Bank {

  private Counter[] counters;
  private static int nextCounterPos = 0;
  private Queue queue;

  public Bank(int numOfCounters, Queue queue) {
    this.counters = new Counter[numOfCounters];
    this.queue = queue;
  }

  public void addCounter(Counter counter) {
    this.counters[nextCounterPos] = counter;
    nextCounterPos++;
  }

  public Counter nextAvailableCounter() {
    Counter availCounter  = null;
    for (int i = 0; i < this.counters.length; i += 1) {
      if (this.counters[i].isAvailable()) {
        availCounter = this.counters[i];
        break;
      }
    }
    return availCounter;
  }

  public boolean joinQueue(QueueItem q) {
    return this.queue.enq(q);
  }

  public boolean joinQueuePossible() {
    return !this.queue.isFull();
  }

  public QueueItem leaveQueue() {
    return (QueueItem) this.queue.deq();
  }

  @Override
  public String toString() {
    return "" + this.queue;
  }
}