package DataStructures;

/**
 * A first-in-first-out (FIFO) queue of objects.
 * @param <E> the type of elements held in this queue
 * @author Peter Williams
 */

public interface Queue<E> {
    /**
     * Indicates the status of the queue.
     * @return <code>true</code> if the queue is empty.
     */
    public boolean isEmpty();

    /**
     * Attaches an item to the queue.
     * @param item the item of type E to be queued.
     */
    public void enqueue(E item);

    /**
     * Detaches an item from the queue.
     * @return the item least recently queued.
     * @exception NoSuchElementException if the queue is empty.
     */
    public E dequeue();
}