@ohos.data.distributedDataObject (Distributed Data Object)

The distributedDataObject module provides basic data object management, including creating, querying, deleting, modifying, and subscribing to data objects, and distributed data object collaboration for the same application among multiple devices. Although this module does not parse user data, you are advised not to transfer sensitive personal data or privacy data due to low-level security of storage path.

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 { distributedDataObject } from '@kit.ArkData';

distributedDataObject.create⁹⁺

create(context: Context, source: object): DataObject

Creates a distributed data object.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Return value

Error codes

For details about the error codes, see Universal Error Codes.

Example

FA model:

// Import the module.
import { featureAbility } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';
// Obtain the context.
let context = featureAbility.getContext();
class SourceObject {
    name: string
    age: number
    isVis: boolean

    constructor(name: string, age: number, isVis: boolean) {
        this.name = name;
        this.age = age;
        this.isVis = isVis;
    }
}

let source: SourceObject = new SourceObject("jack", 18, false);
let g_object: distributedDataObject.DataObject = distributedDataObject.create(context, source);

Stage model:

// Import the module.
import { UIAbility } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';
import { window } from '@kit.ArkUI';

let g_object: distributedDataObject.DataObject|null = null;
class SourceObject {
    name: string
    age: number
    isVis: boolean

    constructor(name: string, age: number, isVis: boolean) {
        this.name = name;
        this.age = age;
        this.isVis = isVis;
    }
}

class EntryAbility extends UIAbility {
    onWindowStageCreate(windowStage: window.WindowStage) {
        let source: SourceObject = new SourceObject("jack", 18, false);
        g_object = distributedDataObject.create(this.context, source);
    }
}

distributedDataObject.genSessionId

genSessionId(): string

Creates a random session ID.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Return value

Example

let sessionId: string = distributedDataObject.genSessionId();

SaveSuccessResponse⁹⁺

Represents the information returned by the callback of save.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

RevokeSaveSuccessResponse⁹⁺

Represents the information returned by the callback of revokeSave.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

BindInfo¹¹⁺

Represents the information about the joint asset in the RDB store to bind. Currently, only the RDB stores are supported.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

DataObject

Provides APIs for managing a distributed data object. Before using any API of this class, use create() to create a DataObject object.

setSessionId⁹⁺

setSessionId(sessionId: string, callback: AsyncCallback<void>): void

Sets a session ID. This API uses an asynchronous callback to return the result. For the devices in the collaboration state in a trusted network, data of the distributed objects with the same session ID can be automatically synced across devices.

Required permissions: ohos.permission.DISTRIBUTED_DATASYNC

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Error codes

For details about the error codes, see Universal Error Codes and Distributed Data Object Error Codes.

Example

// Add g_object to the distributed network.
g_object.setSessionId(distributedDataObject.genSessionId(), ()=>{
    console.info("join session");
});
// g_object exits the distributed network.
g_object.setSessionId("", ()=>{
    console.info("leave all session");
});

setSessionId⁹⁺

setSessionId(callback: AsyncCallback<void>): void

Exits all sessions. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Error codes

For details about the error codes, see Universal Error Codes and Distributed Data Object Error Codes.

Example

// Add g_object to the distributed network.
g_object.setSessionId(distributedDataObject.genSessionId(), ()=>{
    console.info("join session");
});
// Exit the distributed network.
g_object.setSessionId(() => {
    console.info("leave all session.");
});

setSessionId⁹⁺

setSessionId(sessionId?: string): Promise<void>

Sets a session ID. This API uses a promise to return the result. For the devices in the collaboration state in a trusted network, data of the distributed objects with the same session ID can be automatically synced across devices.

Required permissions: ohos.permission.DISTRIBUTED_DATASYNC

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Return value

Error codes

For details about the error codes, see Universal Error Codes and Distributed Data Object Error Codes.

Example

// Add g_object to the distributed network.
g_object.setSessionId(distributedDataObject.genSessionId()).then (()=>{
    console.info("join session.");
    }).catch((error: BusinessError)=>{
        console.error("error:" + error.code + error.message);
});
// Exit the distributed network.
g_object.setSessionId().then (()=>{
    console.info("leave all session.");
    }).catch((error: BusinessError)=>{
        console.error("error:" + error.code + error.message);
});

on(‘change’)⁹⁺

on(type: ‘change’, callback: (sessionId: string, fields: Array<string>) => void): void

Subscribes to data changes of this distributed data object.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Error codes

For details about the error codes, see Universal Error Codes.

Example

g_object.on("change", (sessionId: string, fields: Array<string>) => {
    console.info("change" + sessionId);
    if (g_object != null && fields != null && fields != undefined) {
        for (let index: number = 0; index < fields.length; index++) {
            console.info("changed !" + fields[index] + " " + g_object[fields[index]]);
        }
    }
});

off(‘change’)⁹⁺

off(type: ‘change’, callback?: (sessionId: string, fields: Array<string>) => void): void

Unsubscribes from the data changes of this distributed data object.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Error codes

For details about the error codes, see Universal Error Codes.

Example

// Unregister the specified data change callback.
g_object.off("change", (sessionId: string, fields: Array<string>) => {
    console.info("change" + sessionId);
    if (g_object != null && fields != null && fields != undefined) {
        for (let index: number = 0; index < fields.length; index++) {
            console.info("changed !" + fields[index] + " " + g_object[fields[index]]);
        }
    }
});
// Unregister all data change callbacks.
g_object.off("change");

on(‘status’)⁹⁺

on(type: ‘status’, callback: (sessionId: string, networkId: string, status: ‘online’ |‘offline’ ) => void): void

Subscribes to status changes of this distributed data object.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Error codes

For details about the error codes, see Universal Error Codes.

Example

g_object.on("status", (sessionId: string, networkId: string, status: 'online'|'offline') => {
    console.info("status changed " + sessionId + " " + status + " " + networkId);
});

off(‘status’)⁹⁺

off(type: ‘status’, callback?:(sessionId: string, networkId: string, status: ‘online’ |‘offline’) => void): void

Unsubscribes from the status change of this distributed data object.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Error codes

For details about the error codes, see Universal Error Codes.

Example

// Unregister the specified status change callback.
g_object.off("status", (sessionId: string, networkId: string, status: 'online'|'offline') => {
    console.info("status changed " + sessionId + " " + status + " " + networkId);
});
// Unregister all status change callbacks.
g_object.off("status");

save⁹⁺

save(deviceId: string, callback: AsyncCallback<SaveSuccessResponse>): void

Saves a distributed data object. This API uses an asynchronous callback to return the result.

If the application is active, the saved data will not be released. When the application exits and restarts, the data saved on the device will be restored.

The saved data will be released in the following cases:

• The data is stored for more than 24 hours.
• The application has been uninstalled.
• Data is successfully restored.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Error codes

For details about the error codes, see Universal Error Codes.

Example

g_object.setSessionId("123456");
g_object.save("local", (err: BusinessError, result:distributedDataObject.SaveSuccessResponse) => {
    if (err) {
        console.info("save failed, error code = " + err.code);
        console.info("save failed, error message: " + err.message);
        return;
    }
    console.info("save callback");
    console.info("save sessionId: " + result.sessionId);
    console.info("save version: " + result.version);
    console.info("save deviceId:  " + result.deviceId);
});

save⁹⁺

save(deviceId: string): Promise<SaveSuccessResponse>

Saves a distributed data object. This API uses a promise to return the result.

If the application is active, the saved data will not be released. When the application exits and restarts, the data saved on the device will be restored.

The saved data will be released in the following cases:

• The data is stored for more than 24 hours.
• The application has been uninstalled.
• Data is successfully restored.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Return value

Error codes

For details about the error codes, see Universal Error Codes.

Example

g_object.setSessionId("123456");
g_object.save("local").then((callbackInfo: distributedDataObject.SaveSuccessResponse) => {
    console.info("save callback");
    console.info("save sessionId " + callbackInfo.sessionId);
    console.info("save version " + callbackInfo.version);
    console.info("save deviceId " + callbackInfo.deviceId);
}).catch((err: BusinessError) => {
    console.info("save failed, error code = " + err.code);
    console.info("save failed, error message: " + err.message);
});

revokeSave⁹⁺

revokeSave(callback: AsyncCallback<RevokeSaveSuccessResponse>): void

Revokes the data of this distributed data object saved. This API uses an asynchronous callback to return the result.

If the object is saved on the local device, the data saved on all trusted devices will be deleted. If the object is stored on another device, the data on the local device will be deleted.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Error codes

For details about the error codes, see Universal Error Codes.

Example

g_object.setSessionId("123456");
// Save data for persistence. 
g_object.save("local", (err: BusinessError, result: distributedDataObject.SaveSuccessResponse) => {
    if (err) {
        console.info("save failed, error code = " + err.code);
        console.info("save failed, error message: " + err.message);
        return;
    }
    console.info("save callback");
    console.info("save sessionId: " + result.sessionId);
    console.info("save version: " + result.version);
    console.info("save deviceId:  " + result.deviceId);
});
// Delete the persistence data.
g_object.revokeSave((err: BusinessError, result: distributedDataObject.RevokeSaveSuccessResponse) => {
    if (err) {
      console.info("revokeSave failed, error code = " + err.code);
      console.info("revokeSave failed, error message: " + err.message);
      return;
    }
    console.info("revokeSave callback");
    console.info("revokeSave sessionId " + result.sessionId);
});

revokeSave⁹⁺

revokeSave(): Promise<RevokeSaveSuccessResponse>

Revokes the data of this distributed data object saved. This API uses a promise to return the result.

If the object is saved on the local device, the data saved on all trusted devices will be deleted. If the object is stored on another device, the data on the local device will be deleted.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Return value

Error codes

For details about the error codes, see Universal Error Codes.

Example

g_object.setSessionId("123456");
// Save data for persistence. 
g_object.save("local").then((result: distributedDataObject.SaveSuccessResponse) => {
    console.info("save callback");
    console.info("save sessionId " + result.sessionId);
    console.info("save version " + result.version);
    console.info("save deviceId " + result.deviceId);
}).catch((err: BusinessError) => {
    console.info("save failed, error code = " + err.code);
    console.info("save failed, error message: " + err.message);
});
// Delete the persistence data.
g_object.revokeSave().then((result: distributedDataObject.RevokeSaveSuccessResponse) => {
    console.info("revokeSave callback");
    console.info("sessionId" + result.sessionId);
}).catch((err: BusinessError)=> {
    console.info("revokeSave failed, error code = " + err.code);
    console.info("revokeSave failed, error message = " + err.message);
});

bindAssetStore¹¹⁺

bindAssetStore(assetKey: string, bindInfo: BindInfo, callback: AsyncCallback<void>): void

Binds joint assets. Currently, only the binding between an asset in a distributed data object and an asset in an RDB store is supported. This API uses an asynchronous callback to return the result.

When an asset in a distributed object and an asset in an RDB store point to the same entity asset file, that is, the URIs of the two assets are the same, a conflict occurs. Such assets are called joint assets. To resolve the conflict, bind the joint assets. The binding is automatically released when the application exits the session.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Error codes

For details about the error codes, see Universal Error Codes.

Example

import { UIAbility } from '@kit.AbilityKit';
import { window } from '@kit.ArkUI';
import { commonType } from '@kit.ArkData';
import { BusinessError } from '@kit.BasicServicesKit';

class Note {
  title: string|undefined
  text: string|undefined
  attachment: commonType.Asset|undefined

  constructor(title: string|undefined, text: string|undefined, attachment: commonType.Asset|undefined) {
    this.title = title;
    this.text = text;
    this.attachment = attachment;
  }
}

class EntryAbility extends UIAbility {
  onWindowStageCreate(windowStage: window.WindowStage) {
    let attachment: commonType.Asset = {
      name: 'test_img.jpg',
      uri: 'file://com.example.myapplication/data/storage/el2/distributedfiles/dir/test_img.jpg',
      path: '/dir/test_img.jpg',
      createTime: '2024-01-02 10:00:00',
      modifyTime: '2024-01-02 10:00:00',
      size: '5',
      status: commonType.AssetStatus.ASSET_NORMAL
    }
    let note: Note = new Note('test', 'test', attachment);
    let g_object: distributedDataObject.DataObject = distributedDataObject.create(this.context, note);
    g_object.setSessionId('123456');

    const bindInfo: distributedDataObject.BindInfo = {
      storeName: 'notepad',
      tableName: 'note_t',
      primaryKey: {
        'uuid': '00000000-0000-0000-0000-000000000000'
      },
      field: 'attachment',
      assetName: attachment.name as string
    }

    g_object.bindAssetStore('attachment', bindInfo, (err: BusinessError) => {
      if (err) {
        console.error('bindAssetStore failed.');
      }
      console.info('bindAssetStore success.');
    });
  }
}

bindAssetStore¹¹⁺

bindAssetStore(assetKey: string, bindInfo: BindInfo): Promise<void>

Binds joint assets. Currently, only the binding between an asset in a distributed data object and an asset in an RDB store is supported. This API uses a promise to return the result.

When an asset in a distributed object and an asset in an RDB store point to the same entity asset file, that is, the URIs of the two assets are the same, a conflict occurs. Such assets are called joint assets. To resolve the conflict, bind the joint assets. The binding is automatically released when the application exits the session.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Return value

Error codes

For details about the error codes, see Universal Error Codes.

Example

import { UIAbility } from '@kit.AbilityKit';
import { window } from '@kit.ArkUI';
import { commonType } from '@kit.ArkData';
import { BusinessError } from '@kit.BasicServicesKit';

class Note {
  title: string|undefined
  text: string|undefined
  attachment: commonType.Asset|undefined

  constructor(title: string|undefined, text: string|undefined, attachment: commonType.Asset|undefined) {
    this.title = title;
    this.text = text;
    this.attachment = attachment;
  }
}

class EntryAbility extends UIAbility {
  onWindowStageCreate(windowStage: window.WindowStage) {
    let attachment: commonType.Asset = {
      name: 'test_img.jpg',
      uri: 'file://com.example.myapplication/data/storage/el2/distributedfiles/dir/test_img.jpg',
      path: '/dir/test_img.jpg',
      createTime: '2024-01-02 10:00:00',
      modifyTime: '2024-01-02 10:00:00',
      size: '5',
      status: commonType.AssetStatus.ASSET_NORMAL
    }
    let note: Note = new Note('test', 'test', attachment);
    let g_object: distributedDataObject.DataObject = distributedDataObject.create(this.context, note);
    g_object.setSessionId('123456');

    const bindInfo: distributedDataObject.BindInfo = {
      storeName: 'notepad',
      tableName: 'note_t',
      primaryKey: {
        'uuid': '00000000-0000-0000-0000-000000000000'
      },
      field: 'attachment',
      assetName: attachment.name as string
    }

    g_object.bindAssetStore("attachment", bindInfo).then(() => {
      console.info('bindAssetStore success.');
    }).catch((err: BusinessError) => {
      console.error("bindAssetStore failed, error code = " + err.code);
    });
  }
}

distributedDataObject.createDistributedObject^(deprecated)

createDistributedObject(source: object): DistributedObject

Creates a distributed data object.

NOTE

This API is supported since API version 8 and deprecated since API version 9. You are advised to use distributedDataObject.create.

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Return value

Example

class SourceObject {
    name: string
    age: number
    isVis: boolean

    constructor(name: string, age: number, isVis: boolean) {
        this.name = name
        this.age = age
        this.isVis = isVis
    }
}

let source: SourceObject = new SourceObject("jack", 18, false);
let g_object: distributedDataObject.DistributedObject = distributedDataObject.createDistributedObject(source);

DistributedObject^(deprecated)

Provides APIs for managing a distributed data object. Before using any API of this class, use createDistributedObject() to create a DistributedObject object.

setSessionId^(deprecated)

setSessionId(sessionId?: string): boolean

Sets a session ID. For the devices in the collaboration state in a trusted network, data of the distributed objects with the same session ID can be automatically synced across devices.

NOTE

This API is supported since API version 8 and deprecated since API version 9. You are advised to use setSessionId.

Required permissions: ohos.permission.DISTRIBUTED_DATASYNC

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Return value

Example

class SourceObject {
    name: string
    age: number
    isVis: boolean

    constructor(name: string, age: number, isVis: boolean) {
        this.name = name
        this.age = age
        this.isVis = isVis
    }
}

let source: SourceObject = new SourceObject("jack", 18, false);
let g_object: distributedDataObject.DistributedObject = distributedDataObject.createDistributedObject(source);
// Add g_object to the distributed network.
g_object.setSessionId(distributedDataObject.genSessionId());
// Remove g_object from the distributed network.
g_object.setSessionId("");

on(‘change’)^(deprecated)

on(type: ‘change’, callback: (sessionId: string, fields: Array<string>) => void): void

Subscribes to data changes of this distributed data object.

NOTE

This API is supported since API version 8 and deprecated since API version 9. You are advised to use on(‘change’).

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Example

class SourceObject {
    name: string
    age: number
    isVis: boolean

    constructor(name: string, age: number, isVis: boolean) {
        this.name = name
        this.age = age
        this.isVis = isVis
    }
}

let source: SourceObject = new SourceObject("jack", 18, false);
let g_object: distributedDataObject.DistributedObject = distributedDataObject.createDistributedObject(source);
g_object.on("change", (sessionId: string, fields: Array<string>) => {
    console.info("change" + sessionId);
    if (fields != null && fields != undefined) {
        for (let index: number = 0; index < fields.length; index++) {
            console.info("changed !" + fields[index] + " " + g_object[fields[index]]);
        }
    }
});

off(‘change’)^(deprecated)

off(type: ‘change’, callback?: (sessionId: string, fields: Array<string>) => void): void

Unsubscribes from the data changes of this distributed data object.

NOTE

This API is supported since API version 8 and deprecated since API version 9. You are advised to use off(‘change’).

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Example

class SourceObject {
    name: string
    age: number
    isVis: boolean

    constructor(name: string, age: number, isVis: boolean) {
        this.name = name
        this.age = age
        this.isVis = isVis
    }
}

let source: SourceObject = new SourceObject("jack", 18, false);
let g_object: distributedDataObject.DistributedObject = distributedDataObject.createDistributedObject(source);
// Unregister the specified data change callback.
g_object.off("change", (sessionId: string, fields: Array<string>) => {
    console.info("change" + sessionId);
    if (fields != null && fields != undefined) {
        for (let index: number = 0; index < fields.length; index++) {
            console.info("changed !" + fields[index] + " " + g_object[fields[index]]);
        }
    }
});
// Unregister all data change callbacks.
g_object.off("change");

on(‘status’)^(deprecated)

on(type: ‘status’, callback: (sessionId: string, networkId: string, status: ‘online’|‘offline’ ) => void): void

Subscribes to status changes of this distributed data object.

NOTE

This API is supported since API version 8 and deprecated since API version 9. You are advised to use on(‘status’).

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Example

class SourceObject {
    name: string
    age: number
    isVis: boolean

    constructor(name: string, age: number, isVis: boolean) {
        this.name = name
        this.age = age
        this.isVis = isVis
    }
}

let source: SourceObject = new SourceObject("jack", 18, false);
let g_object: distributedDataObject.DistributedObject = distributedDataObject.createDistributedObject(source);

g_object.on("status", (sessionId: string, networkId: string, status: 'online'|'offline') => {
    console.info("status changed " + sessionId + " " + status + " " + networkId);
});

off(‘status’)^(deprecated)

off(type: ‘status’, callback?: (sessionId: string, networkId: string, status: ‘online’|‘offline’ ) => void): void

Unsubscribes from the status change of this distributed data object.

NOTE

This API is supported since API version 8 and deprecated since API version 9. You are advised to use off(‘status’).

System capability: SystemCapability.DistributedDataManager.DataObject.DistributedObject

Parameters

Example

class SourceObject {
    name: string
    age: number
    isVis: boolean

    constructor(name: string, age: number, isVis: boolean) {
        this.name = name
        this.age = age
        this.isVis = isVis
    }
}

let source: SourceObject = new SourceObject("jack", 18, false);
let g_object: distributedDataObject.DistributedObject = distributedDataObject.createDistributedObject(source);
// Unregister the specified status change callback.
g_object.off("status", (sessionId: string, networkId: string, status: 'online'|'offline') => {
    console.info("status changed " + sessionId + " " + status + " " + networkId);
});
// Unregister all status change callbacks.
g_object.off("status");

你可能感兴趣的鸿蒙文章

harmony 鸿蒙ArkData (ArkData Management)

harmony 鸿蒙Data

harmony 鸿蒙OH_Cursor

harmony 鸿蒙OH_Predicates

harmony 鸿蒙OH_Rdb_Config

harmony 鸿蒙OH_Rdb_Store

harmony 鸿蒙OH_VBucket

harmony 鸿蒙OH_VObject

harmony 鸿蒙Preferences

harmony 鸿蒙_r_d_b