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📜  Java.util.ArrayDeque类

📅  最后修改于: 2020-11-14 06:09:12             🧑  作者: Mango

介绍

java.util.ArrayDeque类提供可调整大小的数组并实现Deque接口。以下是关于数组双端队列的要点-

  • 阵列双端队列没有容量限制，因此可以根据需要增长以支持使用。

  • 它们不是线程安全的。在没有外部同步的情况下。

  • 它们不支持多个线程的并发访问。

  • 数组双端队列中禁止使用空元素。

  • 它们比Stack和LinkedList快。

此类及其迭代器实现Collection和Iterator接口的所有可选方法。

类声明

以下是java.util.ArrayDeque类的声明-

public class ArrayDeque
   extends AbstractCollection
   implements Deque, Cloneable, Serializable

在这里表示一个Element，可以是任何类。例如，如果要构建整数数组列表，则将其初始化为-

ArrayList list = new ArrayList();

类的构造函数

Sr.No. Constructor & Description
1

ArrayDeque()

This constructor is used to create an empty array deque with an initial capacity sufficient to hold 16 elements.
2

ArrayDeque(Collection c)

This constructor is used to create a deque containing the elements of the specified collection.
3

ArrayDeque(int numElements)

This constructor is used to create an empty array deque with an initial capacity sufficient to hold the specified number of elements.

类方法

Sr.No. Method & Description
1 boolean add(E e)

This method inserts the specified element at the end of this deque.
2 void addFirst(E e)

This method inserts the specified element at the front of this deque.
3 void addLast(E e)

This method inserts the specified element at the end of this deque.
4 void clear()

This method removes all of the elements from this deque.
5 ArrayDeque clone()

This method returns a copy of this deque.
6 boolean contains(Object o)

This method returns true if this deque contains the specified element.
7 Iterator descendingIterator()

This method returns an iterator over the elements in this deque in reverse sequential order.
8 E element()

This method retrieves, but does not remove, the head of the queue represented by this deque.
9 E getFirst()

This method retrieves, but does not remove, the first element of this deque.
10 E getLast()

This method retrieves, but does not remove, the last element of this deque.
11 boolean isEmpty()

This method returns true if this deque contains no elements.
12 Iterator iterator()

This method returns an iterator over the elements in this deque.
13 boolean offer(E e)

This method inserts the specified element at the end of this deque.
14 boolean offerFirst(E e)

This method inserts the specified element at the front of this deque.
15 boolean offerLast(E e)

This method inserts the specified element at the end of this deque.
16 E peek()

This method retrieves, but does not remove, the head of the queue represented by this deque, or returns null if this deque is empty.
17 E peekFirst()

This method retrieves, but does not remove, the first element of this deque, or returns null if this deque is empty.
18 E peekLast()

This method retrieves, but does not remove, the last element of this deque, or returns null if this deque is empty.
19 E poll()

This method retrieves and removes the head of the queue represented by this deque, or returns null if this deque is empty.
20 E pollFirst()

This method retrieves and removes the first element of this deque, or returns null if this deque is empty.
21 E pollLast()

This method retrieves and removes the last element of this deque, or returns null if this deque is empty.
22 E pop()

This method pops an element from the stack represented by this deque.
23 void push(E e)

This method pushes an element onto the stack represented by this deque.
24 E remove()

This method retrieves and removes the head of the queue represented by this deque.
25 boolean remove(Object o)

This method removes a single instance of the specified element from this deque.
26 E removeFirst()

This method retrieves and removes the first element of this deque.
27 boolean removeFirstOccurrence(Object o)

This method removes the first occurrence of the specified element in this deque.
28 E removeLast()

This method retrieves and removes the last element of this deque.
29 boolean removeLastOccurrence(Object o)

This method removes the last occurrence of the specified element in this deque.
30 int size()

This method returns the number of elements in this deque.
31 object[] toArray()

This method returns an array containing all of the elements in this deque in proper sequence.