SeqQueue.java

package sjjg;

public final class SeqQueue<T> implements Queue<T> {
	
	private Object[] element;
	private int front,rear;

	public SeqQueue(int length) {
		if(length<64)
			length = 64;
		this.element = new Object[length];
		this.front = this.rear =0;
	}

	public SeqQueue(){
		this(64);
	}
	
	@Override
	public boolean isEmpty() {
		// TODO 自动生成的方法存根
		return this.front == this.rear;
	}

	@Override
	public boolean add(T x) {
		// TODO 自动生成的方法存根
		if(x==null)
			return false;
		if(this.front == (this.rear+1)%this.element.length){
			Object[] temp = this.element;
			this.element = new Object[temp.length*2];
			int j=0;
			for(int i =this.front;i!=this.rear;i=(i+1)%temp.length)
				this.element[j++] = temp[i];
			this.front = 0;
			this.rear = j;											
			}
		this.element[this.rear] = x;
		this.rear = (this.rear+1)%this.element.length;
		return true;
		}

	@Override
	public T peek() {
		// TODO 自动生成的方法存根
		return this.isEmpty()?null:(T)this.element[this.front];
	}

	@Override
	public T poll() {
		// TODO 自动生成的方法存根
		if(this.isEmpty())
			return null;
		T temp = (T)this.element[this.front];
		this.front = (this.front+1)%this.element.length;
		return temp;
	}

}