abstract DataSource

Represents a data source that can be used to retrieve, manipulate and store data outside the Olympe application environment. This class provides several methods for performing CRUD (create, read, update, delete) operations on data, as well as file upload and download functionality.

To create a new data source, add a Data Connector in your project in DRAW and download the boilerplate. Then implement or extend the required methods: init, destroy, healthCheck, executeQuery and applyTransaction For file capabilities, you must also implement: uploadFileContent, downloadFileContent and deleteFileContent

The CORE library already provide some default connectors such as PostgreSQL and MSSQL. Their implementation is open source and available in CORE on Github.

Extends

• CloudObject

Constructors

Constructor

new DataSource(): DataSource;

Returns

DataSource

Inherited from

CloudObject.constructor

Properties

containsRel

static containsRel: Relation<CloudObject, CloudObject>;

Relation between a container (a CloudObject) that has children (other CloudObjects)

For example, from a folder to the contained elements or from a function to the elements needed for that function to run.

Inherited from

CloudObject.containsRel

---

extendedByRel

static extendedByRel: Relation<CloudObject, CloudObject>;

Inverse relation of extendRel

Inherited from

CloudObject.extendedByRel

---

extendRel

static extendRel: Relation<CloudObject, CloudObject>;

Model CloudObjects can inherit relations and properties from another CloudObject model to mimic their behaviour.

Relation from a model to the CloudObject model it extends. A --extendRel-> B A inherits B's properties and relations.

Inherited from

CloudObject.extendRel

---

instancesRel

static instancesRel: Relation<CloudObject, CloudObject>;

Inverse relation of modelRel between a model and its instances Equivalent to modelRel.getInverse()

Inherited from

CloudObject.instancesRel

---

modelRel

static modelRel: Relation<CloudObject, CloudObject>;

Relation between a CloudObjectand its model instance --modelRel-> model

Inherited from

CloudObject.modelRel

---

nameProp

static nameProp: Property<string>;

Name property for all CloudObjects

Inherited from

CloudObject.nameProp

---

propertyRel

static propertyRel: Relation<CloudObject, PropertyModel>;

Relation between a model and the properties it defines.

Inherited from

CloudObject.propertyRel

Methods

asInstance()

static asInstance<T>(this): T;

Get this CloudObject class as a CloudObject instance.

Type Parameters

Type Parameter
T

Parameters

Parameter	Type
this	Class<T>

Returns

T

the current data type class as a CloudObject instance.

Inherited from

CloudObject.asInstance

---

createWith()

static createWith<T>(
   this, 
   properties, 
   model?, 
   source?): T;

Create an instance of the specified data type (or model) in the local datacloud (not persisted) with the specified property values.

If the model is not specified, it uses this DataType.

Type Parameters

Type Parameter
T

Parameters

Parameter	Type	Description
this	Class<T>	-
properties	Map<InstanceOrTag, any>	mappings of (propertyTag -> propertyValue)
model?	InstanceOrTag	tag of the model of the CloudObject you want to create.
source?	string

Returns

T

newly created CloudObject

Inherited from

CloudObject.createWith

---

exists()

static exists(tag): boolean;

Checks whether a CloudObject exists or not.

Parameters

Parameter	Type	Description
tag	InstanceOrTag	tag of the CloudObject

Returns

boolean

true if tag is valid and references a CloudObject.

Static

Inherited from

CloudObject.exists

---

get()

static get<T>(tag): T;

Get the CloudObject whose tag is specified.

This only works if the CloudObject is already present in the local datacloud cache. (NB: you can use a Query to retrieve a distant CloudObject)

Type Parameters

Type Parameter
T extends CloudObject

Parameters

Parameter	Type	Description
tag	InstanceOrTag	tag of the CloudObject

Returns

T

CloudObject specified by the tag

Static

Inherited from

CloudObject.get

---

getProperties()

static getProperties(): Property<any>[];

The attributes of a CloudObject are called properties. Properties can be of different types, e.g. Property<string>, Property<number>, Property<Date>.

If a Person CloudObject has an age property, all the instances of Person can access the age property using the same tag, the tag of the age property. This method returns all properties defined by the Data Type associated to this class.

Returns

Property<any>[]

All properties defined for a data type

Inherited from

CloudObject.getProperties

---

getRelations()

static getRelations<O, D>(this): (
  | Relation<O, D>
  | Relation<D, O>)[];

Return all the relations whose origin OR destination is the CloudObject associated to this class.

Type Parameters

Type Parameter
O extends CloudObject
D extends CloudObject

Parameters

Parameter	Type
this	Class<O>

Returns

( | Relation<O, D> | Relation<D, O>)[]

All relations defined on the current data type. It can be the destination or the origin of the relations.

Inherited from

CloudObject.getRelations

---

instancesOf()

static instancesOf<T>(model): Query<T, never>;

Return a query starting from all instances of this Data Type.

Type Parameters

Type Parameter
T extends CloudObject

Parameters

Parameter	Type	Description
model	| InstanceOrTag | Class<T>	data type to get instances of

Returns

Query<T, never>

A query starting from the instances of the specified model.

Inherited from

CloudObject.instancesOf

---

applyTransaction()

protected applyTransaction(transaction, options?): Promise<void>;

Applies the provided Operation array to the data source as one transaction

Parameters

Parameter	Type	Description
transaction	Operation[]	The Operation array to apply.
options?	{ batch: boolean; }	the options
options.batch?	boolean	if true, it means that the transaction has been executed using the () function.

Returns

Promise<void>

A Promise that resolves when the transaction is completed. Rejects when the transaction fails.

---

deleteFileContent()

protected deleteFileContent(fileTag, dataType): Promise<void>;

Deletes file content from the data source.

Parameters

Parameter	Type	Description
fileTag	string	The tag of the file.
dataType	string	The file data type

Returns

Promise<void>

A Promise that resolves when the file content is successfully deleted. Rejects otherwise.

---

destroy()

protected destroy(): Promise<void>;

Disconnects the data source.

Returns

Promise<void>

A Promise that resolves when the data source is destroyed.

---

downloadFileContent()

protected downloadFileContent(fileTag, dataType): Promise<Uint8Array | Readable>;

Downloads one file's content from the data source.

Parameters

Parameter	Type	Description
fileTag	string	The tag of the file.
dataType	string	The file data type

Returns

Promise<Uint8Array | Readable>

A Promise that resolves with the binary data of the file as an Uint8Array or a node Readable Stream. Rejects otherwise.

---

equals()

equals(object): boolean;

Compare this CloudObject and the given one and return whether they are identical or not.

Parameters

Parameter	Type	Description
object	any	the object to compare

Returns

boolean

true if the specified object is the same CloudObject

Inherited from

CloudObject.equals

---

executeQuery()

protected executeQuery(query): Promise<DataResult>;

Executes the provided Query once and returns a DataResult.

Parameters

Parameter	Type	Description
query	Query<CloudObject, any>	The Query object to execute.

Returns

Promise<DataResult>

A Promise that resolves with the DataResult object.

---

follow()

follow<D>(relation): Query<D, never>;

Start a query from this instance and follow the relation given as argument. The query starts from this single instance, and follows a relation to an arbitrary number of destination instances. See Query.follow(relation)

The following are equivalent:

myCloudObject.follow(relation);
myCloudObject.query().follow(relation);

Type Parameters

Type Parameter
D extends CloudObject

Parameters

Parameter	Type	Description
relation	Relation<DataSource, D>	the relation to follow from the starting instance (this)

Returns

Query<D, never>

query starting from this and following the relation relation as first step of the query

Inherited from

CloudObject.follow

---

followSingle()

followSingle<D>(relation): QuerySingle<D>;

Start a querySingle from this instance that follows 0..1 relations

The query starts from this instance, and follow the relation to a single destination instance. It is equivalent to QuerySingle.from(this).follow(relation).

Type Parameters

Type Parameter
D extends CloudObject

Parameters

Parameter	Type	Description
relation	Relation<DataSource, D>	to follow from this starting instance

Returns

QuerySingle<D>

a query following 0-1 relations

Inherited from

CloudObject.followSingle

---

get()

get<T>(property): T;

Get the current value of the specified property for this CloudObject instance

Type Parameters

Type Parameter
T

Parameters

Parameter	Type	Description
property	| InstanceOrTag | Property<T>	property or property's tag

Returns

T

property value

Inherited from

CloudObject.get

---

getConfig()

getConfig(key): any;

Retrieves the configuration value associated with the provided key in the data source oConfig.

Parameters

Parameter	Type	Description
key	string	Key to retrieve the configuration value for.

Returns

any

The configuration value associated with the provided key.

---

getId()

getId(): string;

Returns the tag of the data source.

Returns

string

tag of the data source.

---

getModel()

getModel(): CloudObject;

Every CloudObject has a model which defines relations and properties its instances may have.

Returns

CloudObject

the model of this CloudObject instance as a CloudObject instance

Inherited from

CloudObject.getModel

---

getModelTag()

getModelTag(): string;

Every CloudObject has a model which defines relations and properties its instances may have.

Returns

string

the tag of the model of this CloudObject instance

Inherited from

CloudObject.getModelTag

---

getSource()

getSource(): string;

Return the source id that owns this cloud object.

Returns

string

Inherited from

CloudObject.getSource

---

getTag()

getTag(): string;

Every CloudObject has a unique tag.

Returns

string

tag of the CloudObject

Inherited from

CloudObject.getTag

---

healthCheck()

protected healthCheck(): Promise<void>;

Performs a health check on the data source, checking if the connection is alive.

Returns

Promise<void>

A Promise that resolves when the health check is completed successfully, rejects otherwise.

---

init()

protected init(context): Promise<void>;

Initializes the data source connection with custom parameters provided in oConfig. It can also perform a health check to ensure the connection is active. Subscribes to the DataSource.observeDataTypes observable to handle changes to the data types in the data source.

Parameters

Parameter	Type	Description
context	BrickContext	a context with the same livecycle as the Data Source

Returns

Promise<void>

A promise that resolves with void when initialization is complete. Reject if initialization did not complete.

---

isPersisted()

isPersisted(): boolean;

Return the persistence state of this instance.

CloudObjects can either be volatile, and only live in the local cache. In this case, the CloudObject instance is not persisted. If a CloudObjectis persisted, it is stored in an external data store. This means that the instance can be accessible through other Olympe VMs in the same environment.

Returns

boolean

a boolean indicating if this object is persisted in a non-volatile way.

Inherited from

CloudObject.isPersisted

---

name()

name(): string;

Every CloudObject can define a value for its nameProperty. This method returns the current value of that property for this instance.

Returns

string

the value of the name property of this

Inherited from

CloudObject.name

---

observe()

observe<T>(
   context, 
   property, 
waitForValue?): Observable<T>;

Get an observable to the current value of the specified property for this CloudObject instance.

The observable gets the new value each time the property gets updated in the datacloud. The observable gets completed automatically once the specified context is cleared. If waitForValue is set to FALSE (TRUE by default), the first value received by the observable is null if there is no value at call time.

Type Parameters

Type Parameter
T

Parameters

Parameter	Type	Description
context	Context	context to which the Observable is attached
property	| InstanceOrTag | Property<T>	property or property's tag to observe
waitForValue?	boolean	whether the observable wait for a first value to get a value. (Default = true)

Returns

Observable<T>

Observable of property values

Inherited from

CloudObject.observe

---

observeProperties()

observeProperties<T>(context): Observable<[Property<T>, T]>;

Get an observable to pair [property, value] for this CloudObject instance.

The observable gets the new value each time any property gets updated in the datacloud. The observable gets completed automatically once the specified context is cleared.

Type Parameters

Type Parameter
T

Parameters

Parameter	Type	Description
context	Context	Context to which the Observable will be attached

Returns

Observable<[Property<T>, T]>

Observable of property values

Inherited from

CloudObject.observeProperties

---

query()

query(): Query<DataSource, never>;

Create and return a query starting from this instance

Returns

Query<DataSource, never>

a query starting at this CloudObject instance

Inherited from

CloudObject.query

---

toJSON()

toJSON(): Object;

Create a Javascript object from this CloudObject current state, including its tag and property values. It provides the same result as toObject called with nameAsKey = true and inheritedProperties = false.

Returns

Object

Inherited from

CloudObject.toJSON

---

toObject()

toObject(namesAsKey?, inheritedProperties?): Object;

Create a Javascript object from this CloudObject current state.

Parameters

Parameter	Type	Description
namesAsKey?	boolean	If true, use the property name instead of the property tag as keys of the generated object.
inheritedProperties?	boolean	If false, do not including inherited property. By default, it includes them.

Returns

Object

Inherited from

CloudObject.toObject

---

uploadFileContent()

protected uploadFileContent(
   fileTag, 
   dataType, 
binary): Promise<void>;

Uploads one file's content to the data source.

Parameters

Parameter	Type	Description
fileTag	string	The tag of the file.
dataType	string	The file data type
binary	Uint8Array	The binary data of the file.

Returns

Promise<void>

A Promise that resolves when the file content is uploaded. Rejects otherwise.