package horstmann.ch09_queue1;
import java.util.ArrayList;
/**
    A first-in, first-out bounded collection of objects.
 */
public class BoundedQueue<E>
{
	/**
       Constructs an empty queue.
       @param capacity the maximum capacity of the queue
	 */
	public BoundedQueue(int capacity)
	{
		elements = new ArrayList<E>(capacity);
		head = 0;
		tail = 0;
		size = 0;
	}

	/**
       Removes the object at the head.
       @return the object that has been removed from the queue
       <p><b>Precondition:</b> !isEmpty()</p>
	 */
	public E remove()
	{
		if (debug) System.out.print("removeFirst");
		E r = elements.get(head);
		if (debug) System.out.print(".");
		head++;
		if (debug) System.out.print(".");
		size--;
		if (head == elements.size())
		{
			if (debug) System.out.print(".");
			head = 0;
		}
		if (debug)
			System.out.println("head=" + head + ",tail=" + tail
					+ ",size=" + size);
		return r;
	}

	/**
       Appends an object at the tail.
       @param newValue the object to be appended
       <p><b>Precondition:</b> !isFull();</p>
	 */
	public void add(E newValue)
	{
		if (debug) System.out.print("add");
		elements.set(tail,newValue);
		if (debug) System.out.print(".");
		tail++;
		if (debug) System.out.print(".");
		size++;
		if (tail == elements.size())
		{
			if (debug) System.out.print(".");
			tail = 0;
		}
		if (debug)
			System.out.println("head=" + head + ",tail=" + tail
					+ ",size=" + size);
	}

	public boolean isFull()
	{
		return size == elements.size();
	}

	public boolean isEmpty()
	{
		return size == 0;
	}

	public void setDebug(boolean newValue)
	{
		debug = newValue;
	}

	private ArrayList<E> elements;
	private int head;
	private int tail;
	private int size;
	private boolean debug;
}