Java : ArrayDeque 示例

Java 中的 ArrayDeque (Java SE 23 & JDK 23) 及其示例。
您将找到大多数 ArrayDeque<E> 方法的代码示例。

注解 :

本文可能使用了翻译软件以方便阅读。另请查看英文原文。

简介

Deque 接口的可调整大小数组实现。数组双端队列没有容量限制；它们会根据需要增大以支持使用。 (机器翻译)

Class diagram

final var deque = new ArrayDeque<String>();

deque.addLast("aaa");
deque.addLast("bbb");
deque.addLast("ccc");

System.out.println(deque); // [aaa, bbb, ccc]

System.out.println(deque.removeFirst()); // aaa
System.out.println(deque); // [bbb, ccc]

System.out.println(deque.removeFirst()); // bbb
System.out.println(deque); // [ccc]

System.out.println(deque.removeFirst()); // ccc
System.out.println(deque); // []

final var deque = new ArrayDeque<String>();

deque.addLast("xxx");
deque.addLast("yyy");
deque.addLast("zzz");

System.out.println(deque); // [xxx, yyy, zzz]

System.out.println(deque.removeLast()); // zzz
System.out.println(deque); // [xxx, yyy]

System.out.println(deque.removeLast()); // yyy
System.out.println(deque); // [xxx]

System.out.println(deque.removeLast()); // xxx
System.out.println(deque); // []

Constructors

ArrayDeque ()

构造一个空数组双端队列，其初始容量足以容纳 16 个元素。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []
System.out.println(deque.isEmpty()); // true

deque.addLast("aaa");
deque.addLast("bbb");
deque.addLast("ccc");

System.out.println(deque); // [aaa, bbb, ccc]
System.out.println(deque.size()); // 3

ArrayDeque (int numElements)

构造一个空数组双端队列，其初始容量足以容纳指定数量的元素。 (机器翻译)

final var deque = new ArrayDeque<String>(10000000);
System.out.println(deque); // []

final var startTime = System.nanoTime();

for (int i = 0; i < 1000000; i++) {
    deque.addLast(String.valueOf(i));
}

final var endTime = System.nanoTime();

// 0.022946 sec.
System.out.printf("%f sec.%n", (endTime - startTime) / 1000000000.0);

final var deque = new ArrayDeque<String>(1);
System.out.println(deque); // []

final var startTime = System.nanoTime();

for (int i = 0; i < 1000000; i++) {
    deque.addLast(String.valueOf(i));
}

final var endTime = System.nanoTime();

// 0.029112 sec.
System.out.printf("%f sec.%n", (endTime - startTime) / 1000000000.0);

ArrayDeque (Collection<? extends E> c)

构造一个包含指定集合的元素的双端队列，按照集合迭代器返回的顺序排列。 (机器翻译)

final var c = List.of("a", "b", "c");

final var deque = new ArrayDeque<>(c);
System.out.println(deque); // [a, b, c]
System.out.println(deque.size()); // 3

Methods

boolean add (E e)

将指定元素插入此双端队列的末尾。 (机器翻译)

This method is equivalent to addLast(E e).

boolean addAll (Collection<? extends E> c)

将指定集合中的所有元素添加到此双端队列的末尾，就像对每个元素调用 addLast(E) 一样，按照集合迭代器返回的顺序添加它们。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

System.out.println(deque.addAll(List.of("a1"))); // true
System.out.println(deque); // [a1]

System.out.println(deque.addAll(List.of("b1", "b2"))); // true
System.out.println(deque); // [a1, b1, b2]

System.out.println(deque.addAll(List.of("c1", "c2", "c3"))); // true
System.out.println(deque); // [a1, b1, b2, c1, c2, c3]

void addFirst (E e)

将指定元素插入此双端队列的前面。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

deque.addFirst("aaa");
System.out.println(deque); // [aaa]

deque.addFirst("bbb");
System.out.println(deque); // [bbb, aaa]

deque.addFirst("ccc");
System.out.println(deque); // [ccc, bbb, aaa]

void addLast (E e)

将指定元素插入此双端队列的末尾。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

deque.addLast("aaa");
System.out.println(deque); // [aaa]

deque.addLast("bbb");
System.out.println(deque); // [aaa, bbb]

deque.addLast("ccc");
System.out.println(deque); // [aaa, bbb, ccc]

void clear ()

从此双端队列中删除所有元素。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

deque.addLast("a");
System.out.println(deque); // [a]

deque.addLast("b");
System.out.println(deque); // [a, b]

deque.clear();
System.out.println(deque); // []

ArrayDeque<E> clone ()

返回此双端队列的副本。 (机器翻译)

final var deque = new ArrayDeque<String>();
deque.addLast("a");
deque.addLast("b");
deque.addLast("c");

System.out.println(deque); // [a, b, c]

final var cloned = deque.clone();
System.out.println(cloned); // [a, b, c]
System.out.println(cloned.getClass()); // class java.util.ArrayDeque

boolean contains (Object o)

如果此双端队列包含指定元素，则返回 true。 (机器翻译)

final var deque = new ArrayDeque<>(List.of("aaa", "bbb", "ccc"));
System.out.println(deque); // [aaa, bbb, ccc]

System.out.println(deque.contains("aaa")); // true
System.out.println(deque.contains("bbb")); // true
System.out.println(deque.contains("XXX")); // false

Iterator<E> descendingIterator ()

返回以相反顺序遍历此双端队列中元素的迭代器。 (机器翻译)

final var deque = new ArrayDeque<>(List.of("aaa", "bbb", "ccc"));
System.out.println(deque); // [aaa, bbb, ccc]

final var iterator = deque.descendingIterator();

System.out.println("-- forEachRemaining --");
iterator.forEachRemaining(System.out::println);

// Result
// ↓
//-- forEachRemaining --
//ccc
//bbb
//aaa

E element ()

检索此双端队列所表示的队列的头部，但不移除该队列。 (机器翻译)

This method is equivalent to getFirst().

void forEach (Consumer<? super E> action)

对 Iterable 的每个元素执行给定的操作，直到所有元素都已处理或该操作引发异常。 (机器翻译)

final var deque = new ArrayDeque<>(List.of("aaa", "bbb", "ccc"));
System.out.println(deque); // [aaa, bbb, ccc]

System.out.println("-- forEach --");
deque.forEach(value -> {
    System.out.println("value = " + value);
});

// Result
// ↓
//-- forEach --
//value = aaa
//value = bbb
//value = ccc

E getFirst ()

检索此双端队列的第一个元素，但不删除它。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

deque.addLast("aaa");
deque.addLast("bbb");
deque.addLast("ccc");

System.out.println(deque.getFirst()); // aaa
System.out.println(deque); // [aaa, bbb, ccc]

System.out.println(deque.removeFirst()); // aaa
System.out.println(deque); // [bbb, ccc]

System.out.println(deque.getFirst()); // bbb
System.out.println(deque); // [bbb, ccc]

System.out.println(deque.removeFirst()); // bbb
System.out.println(deque); // [ccc]

System.out.println(deque.getFirst()); // ccc
System.out.println(deque); // [ccc]

System.out.println(deque.removeFirst()); // ccc
System.out.println(deque); // []

try {
    deque.getFirst();
} catch (NoSuchElementException e) {
    System.out.println(e);
}

// Result
// ↓
//java.util.NoSuchElementException

E getLast ()

检索此双端队列的最后一个元素，但不删除它。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

deque.addLast("aaa");
deque.addLast("bbb");
deque.addLast("ccc");

System.out.println(deque.getLast()); // ccc
System.out.println(deque); // [aaa, bbb, ccc]

System.out.println(deque.removeLast()); // ccc
System.out.println(deque); // [aaa, bbb]

System.out.println(deque.getLast()); // bbb
System.out.println(deque); // [aaa, bbb]

System.out.println(deque.removeLast()); // bbb
System.out.println(deque); // [aaa]

System.out.println(deque.getLast()); // aaa
System.out.println(deque); // [aaa]

System.out.println(deque.removeLast()); // aaa
System.out.println(deque); // []

try {
    deque.getLast();
} catch (NoSuchElementException e) {
    System.out.println(e);
}

// Result
// ↓
//java.util.NoSuchElementException

boolean isEmpty ()

如果此双端队列不包含任何元素，则返回 true。 (机器翻译)

final var deque = new ArrayDeque<String>();
deque.addLast("a");
deque.addLast("b");
deque.addLast("c");

System.out.println(deque); // [a, b, c]
System.out.println(deque.isEmpty()); // false

deque.clear();
System.out.println(deque); // []
System.out.println(deque.isEmpty()); // true

Iterator<E> iterator ()

返回此双端队列中元素的迭代器。 (机器翻译)

final var deque = new ArrayDeque<>(List.of("aaa", "bbb", "ccc"));
System.out.println(deque); // [aaa, bbb, ccc]

final var iterator = deque.iterator();

System.out.println("-- forEachRemaining --");
iterator.forEachRemaining(value -> {
    System.out.println("value = " + value);
});

// Result
// ↓
//-- forEachRemaining --
//value = aaa
//value = bbb
//value = ccc

boolean offer (E e)

将指定元素插入此双端队列的末尾。 (机器翻译)

This method is equivalent to offerLast(E e).

boolean offerFirst (E e)

将指定元素插入此双端队列的前面。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

System.out.println(deque.offerFirst("aaa")); // true
System.out.println(deque); // [aaa]

System.out.println(deque.offerFirst("bbb")); // true
System.out.println(deque); // [bbb, aaa]

System.out.println(deque.offerFirst("ccc")); // true
System.out.println(deque); // [ccc, bbb, aaa]

boolean offerLast (E e)

将指定元素插入此双端队列的末尾。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

System.out.println(deque.offerLast("aaa")); // true
System.out.println(deque); // [aaa]

System.out.println(deque.offerLast("bbb")); // true
System.out.println(deque); // [aaa, bbb]

System.out.println(deque.offerLast("ccc")); // true
System.out.println(deque); // [aaa, bbb, ccc]

E peek ()

检索此双端队列所表示的队列的头部，但不移除该队列；如果此双端队列为空，则返回 null。 (机器翻译)

This method is equivalent to peekFirst().

E peekFirst ()

检索此双端队列的第一个元素，但不删除该元素；如果此双端队列为空，则返回 null。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

deque.addLast("aaa");
deque.addLast("bbb");
deque.addLast("ccc");

System.out.println(deque.peekFirst()); // aaa
System.out.println(deque); // [aaa, bbb, ccc]

System.out.println(deque.pollFirst()); // aaa
System.out.println(deque); // [bbb, ccc]

System.out.println(deque.peekFirst()); // bbb
System.out.println(deque); // [bbb, ccc]

System.out.println(deque.pollFirst()); // bbb
System.out.println(deque); // [ccc]

System.out.println(deque.peekFirst()); // ccc
System.out.println(deque); // [ccc]

System.out.println(deque.pollFirst()); // ccc
System.out.println(deque); // []

System.out.println(deque.peekFirst()); // null
System.out.println(deque); // []

E peekLast ()

检索此双端队列的最后一个元素，但不删除该元素；如果此双端队列为空，则返回 null。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

deque.addLast("aaa");
deque.addLast("bbb");
deque.addLast("ccc");

System.out.println(deque.peekLast()); // ccc
System.out.println(deque); // [aaa, bbb, ccc]

System.out.println(deque.pollLast()); // ccc
System.out.println(deque); // [aaa, bbb]

System.out.println(deque.peekLast()); // bbb
System.out.println(deque); // [aaa, bbb]

System.out.println(deque.pollLast()); // bbb
System.out.println(deque); // [aaa]

System.out.println(deque.peekLast()); // aaa
System.out.println(deque); // [aaa]

System.out.println(deque.pollLast()); // aaa
System.out.println(deque); // []

System.out.println(deque.peekLast()); // null
System.out.println(deque); // []

E poll ()

检索并移除此双端队列所表示的队列的头部（换句话说，此双端队列的第一个元素），如果此双端队列为空，则返回 null。 (机器翻译)

This method is equivalent to pollFirst().

E pollFirst ()

检索并移除此双端队列的第一个元素，如果此双端队列为空，则返回 null。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

deque.addLast("aaa");
deque.addLast("bbb");
deque.addLast("ccc");

System.out.println(deque); // [aaa, bbb, ccc]

System.out.println(deque.pollFirst()); // aaa
System.out.println(deque); // [bbb, ccc]

System.out.println(deque.pollFirst()); // bbb
System.out.println(deque); // [ccc]

System.out.println(deque.pollFirst()); // ccc
System.out.println(deque); // []

System.out.println(deque.pollFirst()); // null
System.out.println(deque); // []

E pollLast ()

检索并移除此双端队列的最后一个元素，如果此双端队列为空，则返回 null。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

deque.addLast("aaa");
deque.addLast("bbb");
deque.addLast("ccc");

System.out.println(deque); // [aaa, bbb, ccc]

System.out.println(deque.pollLast()); // ccc
System.out.println(deque); // [aaa, bbb]

System.out.println(deque.pollLast()); // bbb
System.out.println(deque); // [aaa]

System.out.println(deque.pollLast()); // aaa
System.out.println(deque); // []

System.out.println(deque.pollLast()); // null
System.out.println(deque); // []

E pop ()

从此双端队列所表示的堆栈中弹出一个元素。 (机器翻译)

This method is equivalent to removeFirst().

void push (E e)

将一个元素推送到此双端队列所表示的堆栈上。 (机器翻译)

This method is equivalent to addFirst(E e).

E remove ()

检索并移除此双端队列所表示的队列的头。 (机器翻译)

This method is equivalent to removeFirst().

boolean remove (Object o)

从此双端队列中删除指定元素的单个实例。 (机器翻译)

This method is equivalent to removeFirstOccurrence(Object o).

boolean removeAll (Collection<?> c)

删除此集合中所有包含在指定集合中的元素（可选操作）。 (机器翻译)

final var src = List.of("a", "b", "a", "b", "A", "B");
System.out.println(src); // [a, b, a, b, A, B]

{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.removeAll(List.<String>of())); // false
    System.out.println(deque); // [a, b, a, b, A, B]
}
{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.removeAll(List.of("a"))); // true
    System.out.println(deque); // [b, b, A, B]
}
{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.removeAll(List.of("a", "b"))); // true
    System.out.println(deque); // [A, B]
}
{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.removeAll(List.of("b", "a"))); // true
    System.out.println(deque); // [A, B]
}
{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.removeAll(List.of("A"))); // true
    System.out.println(deque); // [a, b, a, b, B]
}
{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.removeAll(List.of("X", "Y", "Z"))); // false
    System.out.println(deque); // [a, b, a, b, A, B]
}
{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.removeAll(List.of("A", "X", "Y", "Z"))); // true
    System.out.println(deque); // [a, b, a, b, B]
}

E removeFirst ()

检索并删除此双端队列的第一个元素。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

deque.addLast("aaa");
deque.addLast("bbb");
deque.addLast("ccc");

System.out.println(deque); // [aaa, bbb, ccc]

System.out.println(deque.removeFirst()); // aaa
System.out.println(deque); // [bbb, ccc]

System.out.println(deque.removeFirst()); // bbb
System.out.println(deque); // [ccc]

System.out.println(deque.removeFirst()); // ccc
System.out.println(deque); // []

try {
    deque.removeFirst();
} catch (NoSuchElementException e) {
    System.out.println(e);
}

// Result
// ↓
//java.util.NoSuchElementException

boolean removeFirstOccurrence (Object o)

移除此双端队列中第一次出现的指定元素（从头到尾遍历双端队列时）。 (机器翻译)

final var deque = new ArrayDeque<>(List.of("aaa", "BBB", "aaa", "BBB", "ccc"));
System.out.println(deque); // [aaa, BBB, aaa, BBB, ccc]

System.out.println(deque.removeFirstOccurrence("aaa")); // true
System.out.println(deque); // [BBB, aaa, BBB, ccc]

System.out.println(deque.removeFirstOccurrence("BBB")); // true
System.out.println(deque); // [aaa, BBB, ccc]

System.out.println(deque.removeFirstOccurrence("BBB")); // true
System.out.println(deque); // [aaa, ccc]

System.out.println(deque.removeFirstOccurrence("XXX")); // false
System.out.println(deque); // [aaa, ccc]

boolean removeIf (Predicate<? super E> filter)

删除此集合中满足给定谓词的所有元素（可选操作）。 (机器翻译)

final var deque = new ArrayDeque<String>();
deque.addLast("aaa");
deque.addLast("BBB");
deque.addLast("ccc");
deque.addLast("DDD");

System.out.println(deque); // [aaa, BBB, ccc, DDD]

final var ret = deque.removeIf(s -> {
    return s.equals(s.toUpperCase());
});

System.out.println(ret); // true
System.out.println(deque); // [aaa, ccc]

final var deque = new ArrayDeque<String>();
deque.addLast("aaa");
deque.addLast("bbb");

System.out.println(deque); // [aaa, bbb]

final var ret = deque.removeIf(s -> s.equals(s.toUpperCase()));

System.out.println(ret); // false
System.out.println(deque); // [aaa, bbb]

E removeLast ()

检索并删除此双端队列的最后一个元素。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []

deque.addLast("aaa");
deque.addLast("bbb");
deque.addLast("ccc");

System.out.println(deque); // [aaa, bbb, ccc]

System.out.println(deque.removeLast()); // ccc
System.out.println(deque); // [aaa, bbb]

System.out.println(deque.removeLast()); // bbb
System.out.println(deque); // [aaa]

System.out.println(deque.removeLast()); // aaa
System.out.println(deque); // []

try {
    deque.removeLast();
} catch (NoSuchElementException e) {
    System.out.println(e);
}

// Result
// ↓
//java.util.NoSuchElementException

boolean removeLastOccurrence (Object o)

移除此双端队列中最后一次出现的指定元素（从头到尾遍历双端队列时）。 (机器翻译)

final var deque = new ArrayDeque<>(List.of("aaa", "BBB", "aaa", "BBB", "ccc"));
System.out.println(deque); // [aaa, BBB, aaa, BBB, ccc]

System.out.println(deque.removeLastOccurrence("BBB")); // true
System.out.println(deque); // [aaa, BBB, aaa, ccc]

System.out.println(deque.removeLastOccurrence("aaa")); // true
System.out.println(deque); // [aaa, BBB, ccc]

System.out.println(deque.removeLastOccurrence("XXX")); // false
System.out.println(deque); // [aaa, BBB, ccc]

boolean retainAll (Collection<?> c)

仅保留此集合中包含在指定集合中的元素（可选操作）。 (机器翻译)

final var src = List.of("a", "b", "a", "b", "A", "B");
System.out.println(src); // [a, b, a, b, A, B]

{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.retainAll(List.<String>of())); // true
    System.out.println(deque); // []
}
{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.retainAll(List.of("a", "b"))); // true
    System.out.println(deque); // [a, b, a, b]
}
{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.retainAll(List.of("b", "a"))); // true
    System.out.println(deque); // [a, b, a, b]
}
{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.retainAll(List.of("A"))); // true
    System.out.println(deque); // [A]
}
{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.retainAll(List.of("X", "Y", "Z"))); // true
    System.out.println(deque); // []
}
{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.retainAll(List.of("A", "X", "Y", "Z"))); // true
    System.out.println(deque); // [A]
}
{
    final var deque = new ArrayDeque<>(src);
    System.out.println(deque); // [a, b, a, b, A, B]

    System.out.println(deque.retainAll(List.of("a", "b", "A", "B"))); // false
    System.out.println(deque); // [a, b, a, b, A, B]
}

int size ()

返回此双端队列中的元素数量。 (机器翻译)

final var deque = new ArrayDeque<String>();
System.out.println(deque); // []
System.out.println(deque.size()); // 0

deque.addLast("aaa");
System.out.println(deque); // [aaa]
System.out.println(deque.size()); // 1

deque.addLast("bbb");
System.out.println(deque); // [aaa, bbb]
System.out.println(deque.size()); // 2

deque.addLast("ccc");
System.out.println(deque); // [aaa, bbb, ccc]
System.out.println(deque.size()); // 3

Spliterator<E> spliterator ()

针对该双端队列中的元素创建一个后期绑定且快速失败的 Spliterator。 (机器翻译)

final var deque = new ArrayDeque<>(List.of("aaa", "bbb", "ccc"));
System.out.println(deque); // [aaa, bbb, ccc]

final var spliterator = deque.spliterator();

System.out.println("-- forEachRemaining --");
spliterator.forEachRemaining(value -> {
    System.out.println("value = " + value);
});

// Result
// ↓
//-- forEachRemaining --
//value = aaa
//value = bbb
//value = ccc

Object[] toArray ()

返回一个按正确顺序包含此双端队列中所有元素的数组（从第一个元素到最后一个元素）。 (机器翻译)

final var deque = new ArrayDeque<>(List.of("a", "b", "c"));
System.out.println(deque); // [a, b, c]

final Object[] array = deque.toArray();
System.out.println(Arrays.toString(array)); // [a, b, c]

<T> T[] toArray (T[] a)

返回一个按正确顺序包含此双端队列中所有元素的数组（从第一个元素到最后一个元素）；返回数组的运行时类型是指定数组的类型。 (机器翻译)

final var deque = new ArrayDeque<>(List.of("a", "b", "c"));
System.out.println(deque); // [a, b, c]

final String[] array = deque.toArray(new String[0]);
System.out.println(Arrays.toString(array)); // [a, b, c]

final var deque = new ArrayDeque<>(List.of("a", "b", "c"));
System.out.println(deque); // [a, b, c]

{
    final String[] array = new String[3];
    System.out.println(Arrays.toString(array)); // [null, null, null]

    final var ret = deque.toArray(array);
    System.out.println(Arrays.toString(array)); // [a, b, c]
    System.out.println(Arrays.toString(ret)); // [a, b, c]
}
{
    final String[] array = new String[5];
    System.out.println(Arrays.toString(array)); // [null, null, null, null, null]

    final var ret = deque.toArray(array);
    System.out.println(Arrays.toString(array)); // [a, b, c, null, null]
    System.out.println(Arrays.toString(ret)); // [a, b, c, null, null]
}
{
    final String[] array = new String[1];
    System.out.println(Arrays.toString(array)); // [null]

    final var ret = deque.toArray(array);
    System.out.println(Arrays.toString(array)); // [null]
    System.out.println(Arrays.toString(ret)); // [a, b, c]
}

Methods declared in AbstractCollection

containsAll, toString

请参阅下面的链接。

AbstractCollection 示例

Methods declared in Collection

containsAll, equals, hashCode, parallelStream, stream, toArray

请参阅下面的链接。

Collection 示例

Methods declared in Deque

reversed

请参阅下面的链接。

Deque 示例

API 示例

Java : ArrayDeque 示例

简介

Constructors

ArrayDeque ()

ArrayDeque (int numElements)

ArrayDeque (Collection<? extends E> c)

Methods

boolean add (E e)

boolean addAll (Collection<? extends E> c)

void addFirst (E e)

void addLast (E e)

void clear ()

ArrayDeque<E> clone ()

boolean contains (Object o)

Iterator<E> descendingIterator ()

E element ()

void forEach (Consumer<? super E> action)

E getFirst ()

E getLast ()

boolean isEmpty ()

Iterator<E> iterator ()

boolean offer (E e)

boolean offerFirst (E e)

boolean offerLast (E e)

E peek ()

E peekFirst ()

E peekLast ()

E poll ()

E pollFirst ()

E pollLast ()

E pop ()

void push (E e)

E remove ()

boolean remove (Object o)

boolean removeAll (Collection<?> c)

E removeFirst ()

boolean removeFirstOccurrence (Object o)

boolean removeIf (Predicate<? super E> filter)

E removeLast ()

boolean removeLastOccurrence (Object o)

boolean retainAll (Collection<?> c)

int size ()

Spliterator<E> spliterator ()

Object[] toArray ()

<T> T[] toArray (T[] a)

Methods declared in AbstractCollection

containsAll, toString

Methods declared in Collection

containsAll, equals, hashCode, parallelStream, stream, toArray

Methods declared in Deque

reversed

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