Queue 구현

package review1;

import java.util.ArrayList;

public class QueueImplements<T> {
	private ArrayList<T> queue = new ArrayList<T>();
	
	//데이터 삽입
	public void enqueue(T item){
		queue.add(item);
	}
	
	//데이터 삭제
	public T dequeue(){
		if(queue.isEmpty()){
			return null;
		}
		return queue.remove(0);
	}
	
	public boolean isEmpty(){
		return queue.isEmpty();
	}

	public void printAll(){
		System.out.print("[");
		for(int i=0; i<queue.size();i++){
			if(i == queue.size()-1) 
				System.out.print(queue.get(i));
			else
				System.out.print(queue.get(i)+", ");
		}
		System.out.println("]");
	}
	
	public T peek(){
		return queue.get(0);
	}

	public static void main(String[] args) {
		QueueImplements<Integer> queue = new QueueImplements<Integer>();
		queue.enqueue(1);
		queue.enqueue(5);
		queue.enqueue(4);
		queue.printAll();
		
		System.out.println(queue.dequeue());
		System.out.println(queue.peek());
		queue.printAll();

		
	}

}