ArrayQueueCirc.java

public class ArrayQueueCirc <T> implements QueueInterface <T> {
	private T[] queue;
	private int tailIndex;
	private int headIndex;
	public static final int DEF_SIZE = 50;
	public ArrayQueueCirc()
	{
		init(DEF_SIZE);
	}
	public ArrayQueueCirc(int size)
	{
		init(size);
	}
	public void init(int size)
	{
		if(size <= 0)
		{
			return;
		}
		tailIndex = headIndex = 0;
		queue = (T[])(new Object[size]);
	}
	public void enqueue(T aData)
	{
		if(queue[headIndex] != null && headIndex == tailIndex)
		{
			return;
		}
		queue[tailIndex] = aData;
		tailIndex = (tailIndex + 1) % queue.length;
	}
	public T dequeue()
	{
		T ret = queue[headIndex];
		headIndex = (headIndex + 1) % queue.length;
		return ret;
	}
	public T peek()
	{
		return queue[headIndex];
	}
	public void print()
	{
		System.out.println(queue[headIndex]);
		for(int i = (headIndex + 1) % queue.length; i != tailIndex; i = (i + 1) % queue.length)
		{
			System.out.println(queue[i]);
		}
	}

}