Nonlinear Container TreeSet

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 TreeSet from '@ohos.util.TreeSet';

System Capabilities

SystemCapability.Utils.Lang

TreeSet

Attributes

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

constructor

constructor(comparator?:(firstValue: T, secondValue: T) => boolean)

A constructor used to create a TreeSet instance.

Parameters

Name Type Mandatory Description
comparator function No Custom comparator.

Example

let treeSet = new TreeSet();

isEmpty

isEmpty(): boolean

Checks whether this container is empty (contains no entry).

Return value

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

Example

const treeSet = new TreeSet();
let result = treeSet.isEmpty();

has

has(value: T): boolean

Checks whether this container has the specified value.

Parameters

Name Type Mandatory Description
value T Yes Value to query.

Return value

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

Example

let treeSet = new TreeSet();
treeSet.has(123);
treeSet.add(123);
let result1 = treeSet.has(123);

getFirstValue

getFirstValue(): T

Obtains the value of the first entry in this container.

Return value

Type Description
T Value obtained.

Example

let treeSet = new TreeSet();
treeSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
treeSet.add("sdfs");
let result = treeSet.getFirstValue();

getLastValue

getLastValue(): T

Obtains the value of the last entry in this container.

Return value

Type Description
T Value obtained.

Example

let treeSet = new TreeSet();
treeSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
treeSet.add("sdfs");
let result = treeSet.getLastValue();

add

add(value: T): boolean

Adds an entry to this container.

Parameters

Name Type Mandatory Description
value T Yes Entry to add.

Return value

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

Example

let treeSet = new TreeSet();
let result = treeSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");

remove

remove(value: T): boolean

Removes the entry with the specified key from this container.

Parameters

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

Return value

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

Example

let treeSet = new TreeSet();
treeSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
treeSet.add("sdfs");
let result = treeSet.remove("sdfs");

getLowerValue

getLowerValue(key: T): T

Obtains the value that is placed in front of the input key in this container.

Parameters

Name Type Mandatory Description
key T Yes Input key.

Return value

Type Description
T Value obtained.

Example

let treeSet = new TreeSet();
treeSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
treeSet.add("sdfs");
treeSet.add("zdfgsd");
let result = treeSet.getLowerValue("sdfs");

getHigherValue

getHigherValue(key: T): T

Obtains the value that is placed next to the input key in this container.

Parameters

Name Type Mandatory Description
key T Yes Input key.

Return value

Type Description
T Value obtained.

Example

let treeSet = new TreeSet();
treeSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
treeSet.add("sdfs");
treeSet.add("zdfgsd");
let result = treeSet.getHigherValue("sdfs");

popFirst

popFirst(): T

Removes the first entry in this container.

Return value

Type Description
T Entry removed.

Return value

let treeSet = new TreeSet();
treeSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
treeSet.add("sdfs");
let result = treeSet.popFirst();

popLast

popLast(): T

Removes the last entry in this container.

Return value

Type Description
T Entry removed.

Return value

let treeSet = new TreeSet();
treeSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
treeSet.add("sdfs");
let result = treeSet.popLast();

clear

clear(): void

Clears this container and sets its length to 0.

Example

let treeSet = new TreeSet();
treeSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
treeSet.add("sdfs");
treeSet.clear();

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 treeSet = new TreeSet();
treeSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
treeSet.add("sdfs");
let iter = treeSet.values();
let temp = iter.next().value;
while(temp != undefined) {
  console.log("value:" + temp);
  temp = iter.next().value;
}

forEach

forEach(callbackfn: (value?: T, key?: T, set?: TreeSet<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 TreeSet<T> No Instance that invokes the forEach method.

Example

let treeSet = new TreeSet();
treeSet.add("sdfs");
treeSet.add("dfsghsf");
treeSet.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 treeSet = new TreeSet();
treeSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
treeSet.add("sdfs");
let iter = treeSet.entries();
let temp = iter.next().value;
while(temp != undefined) {
  console.log("key:" + temp[0]);
  console.log("value:" + temp[1]);
  temp = iter.next().value;
}

[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 treeSet = new TreeSet();
treeSet.add("Ahfbrgrbgnutfodgorrogorgrogofdfdf");
treeSet.add("sdfs");
  
// Method 1:
for (let item of treeSet) { 
  console.log("value:" + item);
}

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