* Copyright (c) 2021-2022 Huawei Device Co., Ltd.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
* Double-Ended Queue (Deque) is a data structure implemented based on a circular queue. It supports insertion and
* deletion of elements at both ends. It follows the principles of First In First Out (FIFO) and Last In First Out (LIFO
* ). Deque can dynamically adjust the capacity based on project requirements. It doubles the capacity each time.
* Queue allows element removal at the front and insertion at the rear. Compared with [Queue]{@link @ohos.util.Queue},
* which only allows element deletion at the front and insertion at the back, Deque permits insertion and deletion at
* both ends.
* Both [ArrayList]{@link @ohos.util.ArrayList} and Deque support insertion and deletion at the ends, but Deque does not
* support insertion in the middle. Deque is more efficient than an ArrayList for inserting and deleting elements at the
* front, whereas an ArrayList excels in element access efficiency.
* **Recommended use case**: Use **Deque** when you need to frequently insert or remove elements at both the ends of a
* container.
* This topic uses the following to identify the use of generics:
*
* - T: Type
*
* > **NOTE**
* >
* > - Container classes, implemented in static languages, have restrictions on storage locations and properties, and do
* > not support custom properties or methods.
*
* @file
* @kit ArkTS
*/
* Double-ended queue (deque) is a sequence container implemented based on the queue data structure that
* follows the principles of First In First Out (FIFO) and Last In First Out (LIFO).
* It allows insertion and removal of elements at both the ends.
*
* @syscap SystemCapability.Utils.Lang
* @crossplatform [since 10]
* @atomicservice [since 12]
* @since 8 dynamic
* @since 23 static
*/
declare class Deque<T> {
* A constructor used to create a **Deque** instance.
*
* @throws { BusinessError } 10200012 - The Deque's constructor cannot be directly invoked.
* @syscap SystemCapability.Utils.Lang
* @crossplatform [since 10]
* @atomicservice [since 12]
* @since 8 dynamic
* @since 23 static
*/
constructor();
* Number of elements in a Deque.
*
* @syscap SystemCapability.Utils.Lang
* @crossplatform [since 10]
* @atomicservice [since 12]
* @since 8 dynamic
*/
length: number;
* Gets the element number of the Deque.
*
* @syscap SystemCapability.Utils.Lang
* @crossplatform
* @atomicservice
* @since 23 static
*/
get length(): int;
* Inserts an element at the front of this Deque.
*
* @param { T } element - Target element.
* @throws { BusinessError } 10200011 - The insertFront method cannot be bound.
* @syscap SystemCapability.Utils.Lang
* @crossplatform [since 10]
* @atomicservice [since 12]
* @since 8 dynamic
* @since 23 static
*/
insertFront(element: T): void;
* Inserts an element at the end of this Deque.
*
* @param { T } element - Target element.
* @throws { BusinessError } 10200011 - The insertEnd method cannot be bound.
* @syscap SystemCapability.Utils.Lang
* @crossplatform [since 10]
* @atomicservice [since 12]
* @since 8 dynamic
* @since 23 static
*/
insertEnd(element: T): void;
* Checks whether this Deque has the specified element.
*
* @param { T } element - Target element.
* @returns { boolean } Operation result. The value **true** is returned if the specified element is contained;
* otherwise, **false** is returned.
* @throws { BusinessError } 10200011 - The has method cannot be bound.
* @syscap SystemCapability.Utils.Lang
* @crossplatform [since 10]
* @atomicservice [since 12]
* @since 8 dynamic
* @since 23 static
*/
has(element: T): boolean;
* Obtains the first element of this Deque.
*
* @returns { T } First element of the T type obtained.
* @throws { BusinessError } 10200011 - The getFirst method cannot be bound.
* @throws { BusinessError } 10200010 - Container is empty. [since 23] [staticonly]
* @syscap SystemCapability.Utils.Lang
* @crossplatform [since 10]
* @atomicservice [since 12]
* @since 8 dynamic
* @since 23 static
*/
getFirst(): T;
* Obtains the last element of this Deque.
*
* @returns { T } Last element of the T type obtained.
* @throws { BusinessError } 10200011 - The getLast method cannot be bound.
* @throws { BusinessError } 10200010 - Container is empty. [since 23] [staticonly]
* @syscap SystemCapability.Utils.Lang
* @crossplatform [since 10]
* @atomicservice [since 12]
* @since 8 dynamic
* @since 23 static
*/
getLast(): T;
* Removes the first element of this Deque.
*
* @returns { T } First element removed.
* @throws { BusinessError } 10200011 - The popFirst method cannot be bound.
* @throws { BusinessError } 10200010 - Container is empty. [since 23] [staticonly]
* @syscap SystemCapability.Utils.Lang
* @crossplatform [since 10]
* @atomicservice [since 12]
* @since 8 dynamic
* @since 23 static
*/
popFirst(): T;
* Removes the last element of this Deque.
*
* @returns { T } Last element removed.
* @throws { BusinessError } 10200011 - The popLast method cannot be bound.
* @throws { BusinessError } 10200010 - Container is empty. [since 23] [staticonly]
* @syscap SystemCapability.Utils.Lang
* @crossplatform [since 10]
* @atomicservice [since 12]
* @since 8 dynamic
* @since 23 static
*/
popLast(): T;
* Uses a callback to traverse each element in the **Deque** instance.
*
* @param { function } callbackFn - Callback invoked to traverse the elements in the Deque.
* @param { Object } [thisArg] - Value of **this** to use when **callbackFn** is invoked. The default value is this
* instance.
* @throws { BusinessError } 10200011 - The forEach method cannot be bound.
* @syscap SystemCapability.Utils.Lang
* @crossplatform [since 10]
* @atomicservice [since 12]
* @since 8 dynamic
*/
forEach(callbackFn: (value: T, index?: number, deque?: Deque<T>) => void, thisArg?: Object): void;
* Iterates over elements in a generic Deque (double-ended queue) and executes a callback function for each element.
*
* @param { DequeForEachCb<T> } callbackFn - A callback function to execute for each element.
* @syscap SystemCapability.Utils.Lang
* @crossplatform
* @atomicservice
* @since 23 static
*/
forEach(callbackFn: DequeForEachCb<T>): void;
* Returns the item at that index.
*
* @param { int } index - The zero-based index of the desired code unit.
* Throws error if index < 0 or index >= deque.length.
* The value should be an integer.
* @returns { T } The element in the deque matching the given index.
* @throws { BusinessError } 10200001 - The value of index is out of range.
* @syscap SystemCapability.Utils.Lang
* @crossplatform
* @atomicservice
* @since 23 static
*/
[index: int]: T;
* returns an iterator.Each item of the iterator is a Javascript Object
*
* @returns { IterableIterator<T> }
* @throws { BusinessError } 10200011 - The Symbol.iterator method cannot be bound.
* @syscap SystemCapability.Utils.Lang
* @crossplatform [since 10]
* @atomicservice [since 12]
* @since 8 dynamic
*/
[Symbol.iterator](): IterableIterator<T>;
* Returns an iterator. Each item of the iterator is a ArkTS Object
*
* @returns { IterableIterator<T> }
* @syscap SystemCapability.Utils.Lang
* @crossplatform
* @atomicservice
* @since 23 static
*/
$_iterator(): IterableIterator<T>;
}
* The type of Deque forEach callback function.
*
* @param { T } value - The current element being processed
* @param { int } index - The index of the current element
* @param { Deque<T> } deque - The Deque instance being traversed
* @returns { void } This callback does not return a value
* @syscap SystemCapability.Utils.Lang
* @atomicservice
* @since 23 static
*/
export type DequeForEachCb<T> = (value: T, index: int, deque: Deque<T>) => void;
export default Deque;
