/**
 * A Java interface for the Queue ADT.
 * 
 * @param <T> The type of data that the queue stores.
 * 
 * @author Jadrian Miles
 */
public interface Queue<T> {
    /** Adds the given item to the back of the queue. */
    public void enqueue(T item);
  
    /** Removes an item from the front of the queue and returns it.
     * @throws EmptyQueueException if the queue is empty.
     */
    public T dequeue();
  
    /** Returns the item at the front of the queue, without removing it.
     * @throws EmptyQueueException if the queue is empty.
     */
    public T peek();
  
    /** Returns true if the queue is empty. */
    public boolean isEmpty();
  
    /** Removes all items from the queue. */
    public void clear();
    
    /** An exception to indicate that the queue is empty on dequeue or peek. */
    public static class EmptyQueueException extends RuntimeException { }
}