資料結構——java Queue類

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定義    

隊列是一種特殊的線性表，它只允許在表的前端進行刪除操作，而在表的後端進行插入操作。

LinkedList類實現了Queue介面，因此我們可以把LinkedList當成Queue來用

 

圖例            

 Queue本身是一種先入先出的模型(FIFO)，和我們日常生活中的排隊模型很類似。根據不同的實現，他們主要有數組和鏈表兩種實現形式。如：

 

 

 

 

與隊列相關的類的關係圖如下：

 

常用方法              

序號	方法名	描述
1	boolean add(E e)	將指定的元素插入到隊列中。
2	Object element()	檢索該隊列的頭。
	boolean offer(E e)	將指定元素插入到該隊列中（在該隊列容量之內）。
3	Object peek()	檢索該隊列的頭，如果該隊列為空白返回null。
4	Object poll()	檢索並刪除該隊列的頭，如果該隊列為空白返回null。
5	Object remove()	檢索並刪除該隊列的頭。

 

源碼

 

 1 package java.util; 2  3 public interface Queue<E> extends Collection<E> { 4     /** 5      * Inserts the specified element into this queue if it is possible to do so 6      * immediately without violating capacity restrictions, returning 7      * {@code true} upon success and throwing an {@code IllegalStateException} 8      * if no space is currently available. 9      *10      * @param e the element to add11      * @return {@code true} (as specified by {@link Collection#add})12      * @throws IllegalStateException if the element cannot be added at this13      *         time due to capacity restrictions14      * @throws ClassCastException if the class of the specified element15      *         prevents it from being added to this queue16      * @throws NullPointerException if the specified element is null and17      *         this queue does not permit null elements18      * @throws IllegalArgumentException if some property of this element19      *         prevents it from being added to this queue20      */21     boolean add(E e);22 23     /**24      * Inserts the specified element into this queue if it is possible to do25      * so immediately without violating capacity restrictions.26      * When using a capacity-restricted queue, this method is generally27      * preferable to {@link #add}, which can fail to insert an element only28      * by throwing an exception.29      *30      * @param e the element to add31      * @return {@code true} if the element was added to this queue, else32      *         {@code false}33      * @throws ClassCastException if the class of the specified element34      *         prevents it from being added to this queue35      * @throws NullPointerException if the specified element is null and36      *         this queue does not permit null elements37      * @throws IllegalArgumentException if some property of this element38      *         prevents it from being added to this queue39      */40     boolean offer(E e);41 42     /**43      * Retrieves and removes the head of this queue.  This method differs44      * from {@link #poll poll} only in that it throws an exception if this45      * queue is empty.46      *47      * @return the head of this queue48      * @throws NoSuchElementException if this queue is empty49      */50     E remove();51 52     /**53      * Retrieves and removes the head of this queue,54      * or returns {@code null} if this queue is empty.55      *56      * @return the head of this queue, or {@code null} if this queue is empty57      */58     E poll();59 60     /**61      * Retrieves, but does not remove, the head of this queue.  This method62      * differs from {@link #peek peek} only in that it throws an exception63      * if this queue is empty.64      *65      * @return the head of this queue66      * @throws NoSuchElementException if this queue is empty67      */68     E element();69 70     /**71      * Retrieves, but does not remove, the head of this queue,72      * or returns {@code null} if this queue is empty.73      *74      * @return the head of this queue, or {@code null} if this queue is empty75      */76     E peek();77 }

 

 

參考：http://blog.csdn.net/u010617952/article/details/51726789

資料結構——java Queue類