abstractDataSource
Hierarchy
- CloudObject
- DataSource
Index
Constructors
Properties
Methods
- applyTransaction
- deleteFileContent
- destroy
- downloadFileContent
- equals
- executeQuery
- follow
- followSingle
- get
- getConfig
- getId
- getModel
- getModelTag
- getSource
- getTag
- healthCheck
- init
- isPersisted
- name
- observe
- observeProperties
- query
- toJSON
- toObject
- uploadFileContent
- asInstance
- createWith
- exists
- get
- getProperties
- getRelations
- instancesOf
Constructors
constructor
Returns DataSource
Properties
staticcontainsRel
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.
staticextendRel
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.
staticextendedByRel
Inverse relation of extendRel
staticinstancesRel
Inverse relation of modelRel between a model and its instances
Equivalent to modelRel.getInverse()
staticmodelRel
Relation between a CloudObjectand its model
instance --modelRel-> model
staticnameProp
Name property for all CloudObjects
staticpropertyRel
Relation between a model and the properties it defines.
Methods
applyTransaction
Applies the provided Operation array to the data source as one transaction
Parameters
transaction: Operation[]
The Operation array to apply.
optionaloptions: TransactionOptions
the options
Returns Promise<void>
A Promise that resolves when the transaction is completed. Rejects when the transaction fails.
deleteFileContent
Deletes file content from the data source.
Parameters
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
Disconnects the data source.
Returns Promise<void>
A Promise that resolves when the data source is destroyed.
downloadFileContent
Downloads one file’s content from the data source.
Parameters
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
Compare this CloudObject and the given one and return whether they are identical or not.
Parameters
object: any
the object to compare
Returns boolean
true if the specified object is the same CloudObject
executeQuery
Executes the provided Query once and returns a DataResult.
Parameters
query: Query<CloudObject, any>
The Query object to execute.
Returns Promise<DataResult>
A Promise that resolves with the DataResult object.
follow
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
- D: CloudObject<D>
Parameters
relation: Relation<DataSource, D>
the relation to follow from the starting instance (
this)
Returns Query<D, never>
query starting from
thisand following the relationrelationas first step of the query
followSingle
Start a
querySinglefrom this instance that follows 0..1 relationsThe 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
- D: CloudObject<D>
Parameters
relation: Relation<DataSource, D>
to follow from this starting instance
Returns QuerySingle<D>
a query following 0-1 relations
get
Get the current value of the specified property for this CloudObject instance
Type parameters
- T
Parameters
property: InstanceOrTag | Property<T>
property or property’s tag
Returns T
property value
getConfig
Retrieves the configuration value associated with the provided key in the data source oConfig.
Parameters
key: string
Key to retrieve the configuration value for.
Returns any
The configuration value associated with the provided key.
getId
Returns the tag of the data source.
Returns string
tag of the data source.
getModel
Every
CloudObjecthas a model which defines relations and properties its instances may have.Returns CloudObject
the model of this
CloudObjectinstance as aCloudObjectinstance
getModelTag
Every
CloudObjecthas a model which defines relations and properties its instances may have.Returns string
the tag of the model of this
CloudObjectinstance
getSource
Return the source id that owns this cloud object.
Returns string
getTag
Every
CloudObjecthas a unique tag.Returns string
tag of the CloudObject
healthCheck
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
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
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
Return the persistence state of this instance.
CloudObjects can either be volatile, and only live in the local cache. In this case, theCloudObjectinstance is not persisted. If aCloudObjectis 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.
name
Every
CloudObjectcan define a value for itsnameProperty. This method returns the current value of that property for this instance.Returns string
the value of the
name propertyofthis
observe
Get an observable to the current value of the specified property for this
CloudObjectinstance.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
waitForValueis 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
- T
Parameters
context: Context
context to which the Observable is attached
property: InstanceOrTag | Property<T>
property or property’s tag to observe
optionalwaitForValue: boolean
whether the observable wait for a first value to get a value. (Default = true)
Returns Observable<T>
Observable of property values
observeProperties
Get an observable to pair [property, value] for this
CloudObjectinstance.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
- T
Parameters
context: Context
Context to which the Observable will be attached
Returns Observable<[Property<T>, T]>
Observable of property values
query
Create and return a query starting from this instance
Returns Query<DataSource, never>
a query starting at this
CloudObjectinstance
toJSON
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
toObject
Create a Javascript object from this CloudObject current state.
Parameters
optionalnamesAsKey: boolean
If true, use the property name instead of the property tag as keys of the generated object.
optionalinheritedProperties: boolean
If false, do not including inherited property. By default, it includes them.
Returns Object
uploadFileContent
Uploads one file’s content to the data source.
Parameters
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.
staticasInstance
Get this
CloudObjectclass as aCloudObjectinstance.Type parameters
- T
Parameters
this: Class<T>
Returns T
the current data type class as a CloudObject instance.
staticcreateWith
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
thisDataType.Type parameters
- T
Parameters
this: Class<T>
properties: Map<InstanceOrTag, any>
mappings of (propertyTag -> propertyValue)
optionalmodel: InstanceOrTag
tag of the model of the
CloudObjectyou want to create.optionalsource: string
Returns T
newly created
CloudObject
staticexists
Checks whether a
CloudObjectexists or not.Parameters
tag: InstanceOrTag
tag of the
CloudObject
Returns boolean
trueiftagis valid and references a CloudObject.
staticget
Get the CloudObject whose tag is specified.
This only works if the
CloudObjectis already present in the local datacloud cache. (NB: you can use a Query to retrieve a distant CloudObject)Type parameters
- T: CloudObject<T>
Parameters
tag: InstanceOrTag
tag of the
CloudObject
Returns T
CloudObjectspecified by the tag
staticgetProperties
The attributes of a CloudObject are called properties. Properties can be of different types, e.g.
Property<string>,Property<number>,Property<Date>.If a
PersonCloudObjecthas anageproperty, all the instances ofPersoncan access theageproperty using the same tag, the tag of theageproperty. This method returns all properties defined by the Data Type associated to this class.Returns Property<any>[]
All properties defined for a data type
staticgetRelations
Return all the relations whose origin OR destination is the CloudObject associated to this class.
Type parameters
- O: CloudObject<O>
- D: CloudObject<D>
Parameters
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.
staticinstancesOf
Return a query starting from all instances of this Data Type.
Type parameters
- T: CloudObject<T>
Parameters
model: InstanceOrTag | Class<T>
data type to get instances of
Returns Query<T, never>
A query starting from the instances of the specified model.
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,executeQueryandapplyTransactionFor file capabilities, you must also implement:uploadFileContent,downloadFileContentanddeleteFileContentThe CORE library already provide some default connectors such as PostgreSQL and MSSQL. Their implementation is open source and available in CORE on Github.