인터페이스 Queue Queue 서브 인터페이스: Deque

     FIFO

  Linkedlist  Queue  ，       

E            poll（）：             ，        ，  null

E            peek（）：      ，   ，      ，   null
            PS:          null，          null

 ：  /*      ，  10  */
    Queue queue = new LinkedList();
    queue.offer(new Person("A",16));
    queue.offer(new Person("B",46));
    for(int i = 0;i<8;i++){
        queue.offer(new Person(" "+(char)(i+67),i+10));
    }
    System.out.println(queue);//[(A,16), (B,46), ( C,10), ( D,11), ( E,12), ( F,13), ( G,14), ( H,15), ( I,16), ( J,17)]

    /*   ，       */
    Person p1 = queue.poll();// （    ）
    System.out.println(p1);//(A,16)
    System.out.println(queue);//[(B,46), ( C,10), ( D,11), ( E,12), ( F,13), ( G,14), ( H,15), ( I,16), ( J,17)]

    /*      */
    Person p2 = queue.peek();//      
    System.out.println(p2);//(B,46)
    System.out.println(queue);//[(B,46), ( C,10), ( D,11), ( E,12), ( F,13), ( G,14), ( H,15), ( I,16), ( J,17)]

       ，     

boolean     offerFirst(E e)://         E               

boolean     offerLast(E e):

E           pollFirst();//   

E           pollLast();

E       peekFirst();//    

E       peekLast();

 ：  Deque deque = new LinkedList();
    /*    */
    deque.offerFirst(new Person(" A",12));
    deque.offerFirst(new Person(" B",14));
    System.out.println(deque);
    /*    */
    deque.offerLast(new Person(" C",20));
    deque.offerLast(new Person(" D",25));
    System.out.println(deque);

    /*    */
    Person p1 = deque.pollLast();
    System.out.println(p1);
    System.out.println(deque);

    /*    */
    Person p2 = deque.pollFirst();
    System.out.println(p2);
    System.out.println(deque);
    Person p3 = deque.poll();
    System.out.println(p3);
    System.out.println(deque);