LinkedList实现 - Queue方法

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Queue 方法  

1. 
   
2.     /**
   
3.      * Retrieves, but does not remove, the head (first element) of this list.
   
4.      *
   
5.      * @return the head of this list, or {@code null} if this list is empty
   
6.      * @since 1.5
   
7.      */
   
8.     public E peek() {
   
9.         final Node<E> f = first;
   
10.         return (f == null) ? null : f.item;
    
11.     }
    
12. 
    
13.     /**
    
14.      * Retrieves, but does not remove, the head (first element) of this list.
    
15.      *
    
16.      * @return the head of this list
    
17.      * @throws NoSuchElementException if this list is empty
    
18.      * @since 1.5
    
19.      */
    
20.     public E element() {
    
21.         return getFirst();
    
22.     }
    
23. 
    
24.     /**
    
25.      * Retrieves and removes the head (first element) of this list.
    
26.      *
    
27.      * @return the head of this list, or {@code null} if this list is empty
    
28.      * @since 1.5
    
29.      */
    
30.     public E poll() {
    
31.         final Node<E> f = first;
    
32.         return (f == null) ? null : unlinkFirst(f);
    
33.     }
    
34. 
    
35.     /**
    
36.      * Retrieves and removes the head (first element) of this list.
    
37.      *
    
38.      * @return the head of this list
    
39.      * @throws NoSuchElementException if this list is empty
    
40.      * @since 1.5
    
41.      */
    
42.     public E remove() {
    
43.         return removeFirst();
    
44.     }
    
45. 
    
46.     /**
    
47.      * Adds the specified element as the tail (last element) of this list.
    
48.      *
    
49.      * @param e the element to add
    
50.      * @return {@code true} (as specified by {@link Queue#offer})
    
51.      * @since 1.5
    
52.      */
    
53.     public boolean offer(E e) {
    
54.         return add(e);
    
55.     }
    

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原文链接：https://pdai.tech/md/java/collection/java-collection-LinkedList.html