Nonlinear Container LightWeightSet

icon-note.gif NOTE The initial APIs of this module are supported since API version 8. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

import LightWeightSet from '@ohos.util.LightWeightSet';  

System Capabilities

SystemCapability.Utils.Lang

LightWeightSet

Attributes

Name Type Readable Writable Description
length number Yes No Number of entries in a lightweight set (called container later).

constructor

constructor()

A constructor used to create a LightWeightSet instance.

Example

let lightWeightSet = new LightWeightSet();

isEmpty

isEmpty(): boolean

Checks whether this container is empty.

Return value

Type Description
boolean Returns true if the container is empty; returns false otherwise.

Example

const lightWeightSet = new LightWeightSet();
let result = lightWeightSet.isEmpty();

add

add(obj: T): boolean

Adds an entry to this container.

Parameters

Name Type Mandatory Description
obj T Yes Entry to add.

Return value

Type Description
boolean Returns true if the entry is added successfully; returns false otherwise.

Example

let lightWeightSet = new LightWeightSet();
let result = lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");

addAll

addAll(set: LightWeightSet<T>): boolean

Adds all entries in a LightWeightSet instance to this container.

Parameters

Name Type Mandatory Description
set LightWeightSet<T> Yes LightWeightSet instance whose entries are to be added to the current container.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
lightWeightSet.add("sdfs");
let set = new LightWeightSet();
set.add("sfage");
let result = lightWeightSet.addAll(set);

hasAll

hasAll(set: LightWeightSet<T>): boolean

Checks whether this container contains all entries of the specified LightWeightSet instance.

Parameters

Name Type Mandatory Description
set LightWeightSet<T> Yes LightWeightSet instance to be used for comparison.

Return value

Type Description
boolean Returns true if all the entries in the specified LightWeightSet instance are contained; returns false otherwise.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
lightWeightSet.add("sdfs");
let set = new LightWeightSet();
set.add("sdfs");
let result = lightWeightSet.hasAll(set);

has

has(key: T): boolean

Checks whether this container has the specified key.

Parameters

Name Type Mandatory Description
key T Yes Key to query.

Return value

Type Description
boolean Returns true if the specified key is contained; returns false otherwise.

Example

let lightWeightSet = new LightWeightSet();
let result = lightWeightSet.has(123);
lightWeightSet.add(123);
result = lightWeightSet.has(123);

equal

equal(obj: Object): boolean

Checks whether this container contains objects of the same type as the specified obj.

Parameters

Name Type Mandatory Description
obj Object Yes Object to be used for comparison.

Return value

Type Description
boolean Returns true if the container contains objects of the same type as the specified obj; returns false otherwise.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
lightWeightSet.add("sdfs");
let obj = ["Ahfbrgrbgnutfodgorrogorgrogofdfdf", "sdfs"];
let result = lightWeightSet.equal(obj);

increaseCapacityTo

increaseCapacityTo(minimumCapacity: number): void

Increases the capacity of this container.

Parameters

Name Type Mandatory Description
minimumCapacity number Yes Minimum number of entries to accommodate in the container.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.increaseCapacityTo(10);

getIndexOf

getIndexOf(key: T): number

Obtains the position index of the entry with the specified key in this container.

Parameters

Name Type Mandatory Description
key T Yes Key of the entry to query.

Return value

Type Description
number Position index of the entry.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
lightWeightSet.add("sdfs");
let result = lightWeightSet.getIndexOf("sdfs");

remove

remove(key: T): T

Removes an entry of the specified key from this container.

Parameters

Name Type Mandatory Description
key T Yes Key of the entry to remove.

Return value

Type Description
T Value of the entry removed.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
lightWeightSet.add("sdfs");
let result = lightWeightSet.remove("sdfs");

removeAt

removeAt(index: number): boolean

Removes the entry at the specified position from this container.

Parameters

Name Type Mandatory Description
index number Yes Position index of the entry.

Return value

Type Description
boolean Returns true if the entry is removed successfully; returns false otherwise.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
lightWeightSet.add("sdfs");
let result = lightWeightSet.removeAt(1);

getValueAt

getValueAt(index: number): T

Obtains the value of the entry at the specified position in this container.

Parameters

Name Type Mandatory Description
index number Yes Position index of the entry.

Return value

Type Description
T Value obtained.

Parameters

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
lightWeightSet.add("sdfs");
let result = lightWeightSet.getValueAt(1);

clear

clear(): void

Clears this container and sets its length to 0.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
lightWeightSet.add("sdfs");
lightWeightSet.clear();

toString

toString(): String

Obtains a string that contains all entries in this container.

Return value

Type Description
String String obtained.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
lightWeightSet.add("sdfs");
let result = lightWeightSet.toString();

toArray

toArray(): Array<T>

Obtains an array that contains all objects in this container.

Return value

Type Description
Array<T> Array obtained.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
lightWeightSet.add("sdfs");
let result = lightWeightSet.toArray();

values

values(): IterableIterator<T>

Obtains an iterator that contains all the values in this container.

Return value

Type Description
IterableIterator<T> Iterator obtained.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
lightWeightSet.add("sdfs");
let iter = lightWeightSet.values();
let index = 0;
while(index < lightWeightSet.length) {
  console.log(JSON.stringify(iter.next().value));
  index++;
}

forEach

forEach(callbackfn: (value?: T, key?: T, set?: LightWeightSet<T>) => void, thisArg?: Object): void

Uses a callback to traverse the entries in this container and obtain their position indexes.

Parameters

Name Type Mandatory Description
callbackfn function Yes Callback invoked to traverse the entries in the container.
thisArg Object No Value to use when the callback is invoked.

callbackfn

Name Type Mandatory Description
value T No Value of the entry that is currently traversed.
key T No Key of the entry that is currently traversed (same as value).
set LightWeightSet<T> No Instance that invokes the forEach method.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("sdfs");
lightWeightSet.add("dfsghsf");
lightWeightSet.forEach((value, key) => {
  console.log("value:" + value, key);
});

entries

entries(): IterableIterator<[T, T]>

Obtains an iterator that contains all the entries in this container.

Return value

Type Description
IterableIterator<[T, T]> Iterator obtained.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
lightWeightSet.add("sdfs");
let iter = lightWeightSet.entries();
let index = 0;
while(index < lightWeightSet.length) {
  console.log(JSON.stringify(iter.next().value));
  index++;
}

[Symbol.iterator]

[Symbol.iterator](): IterableIterator<T>

Obtains an iterator, each item of which is a JavaScript object.

Return value

Type Description
IterableIterator<T> Iterator obtained.

Example

let lightWeightSet = new LightWeightSet();
lightWeightSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
lightWeightSet.add("sdfs");

// Method 1:
for (let item of lightWeightSet) { 
  console.log("value:" + item);
}

// Method 2:
let iter = lightWeightSet[Symbol.iterator]();
let temp = iter.next().value;
while(temp != undefined) {
  console.log("value:" + temp);
  temp = iter.next().value;
}