new PersistentDataService()
TODO: Document
!!!!!THIS IS A WORK IN PROGRESS generalizing OfflineService, so code started from that
and is evolving from there.
Extends
Members
_persistingObjectDescriptorNames
returns the set of all ObjectDescriptors names that should persist.
_storage
returns a Promise that resolves to the object used by the service to
store data. This is meant to be an abstraction of the "Database"
addMappingForType
Adds a mapping to the service for the specified
type.
- Inherited From:
- Source:
authorization :Object
holds authorization object after a successfull authorization
Type:
- Object
- Inherited From:
- Source:
authorizationPanel :string
Module ID of the panel component used to gather necessary authorization information
Type:
- string
- Inherited From:
- Source:
authorizationPolicy :AuthorizationPolicyType
Returns the AuthorizationPolicyType used by this DataService.
Type:
- AuthorizationPolicyType
- Inherited From:
- Source:
authorizationServices :Array.<string>
Returns the list of moduleIds of DataServices a service accepts to provide
authorization on its behalf. If an array has multiple
authorizationServices, the final choice will be up to the App user
regarding which one to use. This array is expected to return moduleIds,
not objects, allowing the AuthorizationManager to manage unicity
Type:
- Array.<string>
- Inherited From:
- Source:
changedDataObjects :Set.<Object>
A set of the data objects managed by this service or any other descendent
of this service's root service that have
been changed since that root service's data was last saved, or since the
root service was created if that service's data hasn't been saved yet
Since root services are responsible for tracking data objects, subclasses
whose instances will not be root services should override this property
to return their root service's value for it.
Type:
- Set.<Object>
- Inherited From:
- Source:
changesPropertyName
name of the schema property that stores the changes made to the object in this operation
childServices :Set.<DataService>
The child services of this service.
This value is modified by calls to
addChildService() and
removeChildService() and must not
be modified directly.
Type:
- Set.<DataService>
- Inherited From:
- Source:
contextPropertyName
name of the schema property that stores unstructured/custom data for a service
to stash what it may need for further use.
createdDataObjects :Set.<Object>
A set of the data objects created by this service or any other descendent
of this service's root service since
that root service's data was last saved, or since the root service was
created if that service's data hasn't been saved yet.
Since root services are responsible for tracking data objects, subclasses
whose instances will not be root services should override this property
to return their root service's value for it.
Type:
- Set.<Object>
- Inherited From:
- Source:
databaseByModel
Returns the WeakMap keeping track of the storage objects
used for objectDescriptors
databaseForModel
Benoit: 8/8/2017. We are going to use a single database for an App model-group.
If a persistent service is used for a single model, no pbm, to workaround possible
name conflicts in ObjectDescriptors coming from different packages, we'll use the
full moduleId of these ObjectDescriptors to name object stores / tables avoid name conflicts.
Even if different databases end up being used, this choice will work as well.
This API allows for one subclass to decide to use differrent databases for storing different
ObjectDescriptors, or a subclass can decide to use only one.
Returns a Promise for the persistence storage used to store objects
described by the objectDescriptor passed as an argument.
may need to introduce an _method used internally to minimize
use of super()
dataIDPropertyName
name of the schema property that stores the primary key of the object the operation impacts
dataMaxAge :Number
The maximum amount of time a DataService's data will be considered fresh.
ObjectDescriptor's maxAge should take precedence over this and a DataStream's dataMaxAge should
take precedence over a DataService's dataMaxAge global default value.
Type:
- Number
- Inherited From:
- Source:
emptyArrayPromise
- Inherited From:
- Source:
- To Do:
-
- Document.
eventLoopPromise :external:Promise
A possibly shared promise resolved in the next cycle of the event loop
or soon thereafter, at which point the current event handling will be
complete. This is useful for services that need to buffer up actions so
they're committed only once in a given event loop.
Type:
- external:Promise
- Inherited From:
- Source:
initWithModel
- Inherited From:
- Deprecated:
- Yes
- Source:
isOffline :boolean
Returns a value derived from and continuously updated with the value of
navigator.onLine.
Root services are responsible for tracking offline status, and subclasses
not designed to be root services should override this property to get
its value from their root service.
Type:
- boolean
- Inherited From:
- Source:
isRootService :Boolean
Convenience method to assess if a dataService is the rootService
Type:
- Boolean
- Inherited From:
- Source:
lastFetchedPropertyName
name of the schema property that stores the last time the operation's object
(dataID) was last fetched.
lastModifiedPropertyName
name of the schema property that stores the last time the operation's
object was last modified.
mappings :Array.<DataMapping>
The data mappings used by this service to convert objects to raw
data and vice-versa.
Type:
- Array.<DataMapping>
- Inherited From:
- Source:
mappingWithType
Return the mapping to use for the specified type.
- Inherited From:
- Source:
model
The model that this service supports. If the model is
defined the service supports all the object descriptors contained within the model.
- Inherited From:
- Source:
nullFunction :function
A function that does nothing but returns null, useful for terminating
a promise chain that needs to return null, as in the following code:
var self = this;
return this.fetchSomethingAsynchronously().then(function (data) {
return self.doSomethingAsynchronously(data.part);
}).then(this.nullFunction);
Type:
- function
- Inherited From:
- Source:
nullPromise :external:Promise
A shared promise resolved with a value of
`null`, useful for returning from methods like
fetchObjectProperty()
when the requested data is already there.
Type:
- external:Promise
- Inherited From:
- Source:
objectDescriptorForObject
Returns an object descriptor for the provided object. If this service
does not have an object descriptor for this object it will ask its
parent for one.
- Inherited From:
- Source:
offlineService :OfflineService
Type:
- OfflineService
- Inherited From:
- Deprecated:
- Yes
- Source:
- To Do:
-
- Remove any dependency and delete.
operationPropertyName
name of the schema property that stores the type of operation:
This will be create or update or delete
operationTableName
table/property/index name that tracks the date the record was last updated
(nullable) parentService :DataService
A read-only reference to the parent of this service.
This value is modified by calls to
addChildService() and
removeChildService() and cannot
be modified directly.
Data services that have no parents are called
root services.
Type:
- Inherited From:
- Source:
persistentPropertyDescriptors
returns the list of all property descriptors that should persist for the
objectDescriptor passed as an argument. By default, return all propertyDescriptors.
This can be customized and configured when a PersistentDataService is instanciated.
persistsObjectDescriptor
returns true or false depending on wether PersistentDataService has been instructed
to persist the objectDescriptor passed as an argument.
providesAuthorization :boolean
Indicates whether a service can provide user-level authorization to its
data. Defaults to false. Concrete services need to override this as
needed.
Type:
- boolean
- Inherited From:
- Source:
provideStorageForObjectDescriptor
Returns a Promise for the persistence storage used to store objects
described by the objectDescriptor passed as an argument.
may need to introduce an _method used internally to minimize
use of super()
rootService :DataService
Convenience read-only reference to the root of the service tree
containing this service. Most applications have only one root service,
the application's main service.
Type:
- Inherited From:
- Source:
storageByObjectDescriptor
Returns the WeakMap keeping track of the storage objects
used for objectDescriptors
storageForObjectDescriptor
Returns a Promise for the persistence storage used to store objects
described by the objectDescriptor passed as an argument.
Benoit: 8/8/2017: Ideally we want to create these storage lazily, on-demand.
may need to introduce an _method used internally to minimize
use of super()
storageForQuery
This is the opportunity for a PersistentDataService to lazily create the storage needed
to execute this query, or to optimize it if it turns out indexes don't exist for optimally execute a passed query. This could also be lazily and on frequency of request being used, as well as time spent executing it without. Traversing the query's criteria's syntactic tree and looking up
property descriptors' valueDescriptors to navigate the set of persistentStorage needed
and make sure they exit before attempting to fetch from it.
typePropertyName
name of the schema property that stores the name of the type/object store
of the object the operation impacts
types :Array.<DataObjectDescriptor>
The types of data handled by this service. If this `undefined`, `null`,
or an empty array this service is assumed to handled all types of data.
The default implementation of this property returns the union of all
types handled by child services of this service. Subclasses without child
services should override this to directly return an array of the specific
types they handle.
Applications typically have one raw data service
service for each set of related data types and one
main service which is the parent of all
those other services and delegates work to them based on the type of data
to which the work applies. It is possible for child data services to have
children of their own and delegate some or all of their work to them.
A service's types must not be changed after it is added as a child of
another service.
Type:
- Array.<DataObjectDescriptor>
- Inherited From:
- Source:
Methods
_fetchRawData(stream)
Fetch the raw data of this service.
This method should not be called directly from anyone other than this
service's fetchData().
Subclasses that don't override
fetchData() should override this method
to:
1. Fetch the raw records needed to generate the requested data object.
2. Add those records to the specified stream with calls to
addRawData().
3. Indicate that the fetching is done with a call to
rawDataDone().
This method must be asynchronous and return as soon as possible even if
it takes a while to obtain the raw data. The raw data can be provided to
the service at any point after this method is called, even after it
returns, with calls to addRawData()
and rawDataDone().
The default implementation of this method simply calls
rawDataDone() immediately.
Parameters:
Name | Type | Description |
---|---|---|
stream |
DataStream | The stream to which the data objects corresponding to the raw data should be added. This stream must contain a reference to the selector defining what raw data to fetch. |
- Inherited From:
- Source:
_mapObjectToRawData()
- Inherited From:
- Source:
- To Do:
-
- Document.
- Make this method overridable by type name with methods like `mapHazardToRawData()` and `mapProductToRawData()`.
_mapRawDataToObject(record, object, context)
Convert raw data to data objects of an appropriate type.
Subclasses should override this method to map properties of the raw data
to data objects, as in the following:
mapRawDataToObject: {
value: function (object, record) {
object.firstName = record.GIVEN_NAME;
object.lastName = record.FAMILY_NAME;
}
}
Alternatively, subclasses can define a
mapping to do this mapping.
The default implementation of this method uses the service's mapping if
the service has one, and otherwise calls the deprecated
mapFromRawData(), whose default
implementation does nothing.
Parameters:
Name | Type | Description |
---|---|---|
record |
Object | An object whose properties' values hold the raw data. |
object |
Object | An object whose properties must be set or modified to represent the raw data. |
context |
? | The value that was passed in to the addRawData() call that invoked this method. |
- Inherited From:
- Source:
- To Do:
-
- Make this method overridable by type name with methods like `mapRawDataToHazard()` and `mapRawDataToProduct()`.
_persistFetchedDataStream(stream, rawDataArray, context)
Called every time addRawData() is
called while online to optionally cache that data for offline use.
The default implementation does nothing. This is appropriate for
subclasses that do not support offline operation or which operate the
same way when offline as when online.
Other subclasses may override this method to cache data fetched when
online so fetchOfflineData can
use that data when offline.
Parameters:
Name | Type | Description |
---|---|---|
stream |
DataStream | The stream to which the fetched data is being added. |
rawDataArray |
Array | An array of objects whose properties' values hold the raw data. |
context |
? | The context value passed to the addRawData() call that is invoking this method. |
_propertyDescriptorForObjectAndName()
Fetch the value of a data object's property, possibly asynchronously.
The default implementation of this method just return a fulfilled promise
for `null`. Subclasses should override this method to perform any fetch
or other operation required to get the requested data. The subclass
implementations should only use calls to their
root service's
fetchData() to fetch data.
- Inherited From:
- Source:
addChildService(service, typesopt)
Adds a raw data service as a child of this data service and set it to
handle data of the types defined by its types
property.
Child services must have their types property
value or their model set before they are passed in to
this method, and that value cannot change after that. The model property takes
priority of the types property. If the model is defined the service will handle
all the object descriptors associated to the model.
Parameters:
Name | Type | Attributes | Description |
---|---|---|---|
service |
RawDataService | ||
types |
Array |
<optional> |
Types to use instead of the child's types. |
- Inherited From:
- Source:
addRawData(stream, records, context)
To be called by fetchData() or
fetchRawData() when raw data records
are received. This method should never be called outside of those
methods.
This method creates and registers the data objects that
will represent the raw records with repeated calls to
getDataObject(), maps
the raw data to those objects with repeated calls to
mapRawDataToObject(),
and then adds those objects to the specified stream.
Subclasses should not override this method and instead override their
getDataObject() method, their
mapRawDataToObject() method,
their mapping's
mapRawDataToObject() method,
or several of these.
Parameters:
Name | Type | Description |
---|---|---|
stream |
DataStream | - The stream to which the data objects created from the raw data should be added. |
records |
Array | An array of objects whose properties' values hold the raw data. This array will be modified by this method. |
context |
? | An arbitrary value that will be passed to getDataObject() and mapRawDataToObject() if it is provided. |
- Inherited From:
- Source:
authorize()
- Inherited From:
- Source:
Returns:
Promise
cancelDataStream(dataStreamopt, reasonopt)
To be called to indicates that the consumer has lost interest in the passed DataStream.
This will allow the RawDataService feeding the stream to take appropriate measures.
Parameters:
Name | Type | Attributes | Description |
---|---|---|---|
dataStream |
DataStream |
<optional> |
The DataStream to cancel |
reason |
Object |
<optional> |
An object indicating the reason to cancel. |
- Inherited From:
- Source:
cancelRawDataStream(dataStreamopt, reasonopt)
Called through MainService when consumer has indicated that he has lost interest in the passed DataStream.
This will allow the RawDataService feeding the stream to take appropriate measures.
Parameters:
Name | Type | Attributes | Description |
---|---|---|---|
dataStream |
DataStream |
<optional> |
The DataStream to cancel |
reason |
Object |
<optional> |
An object indicating the reason to cancel. |
- Inherited From:
- Source:
createData(objects, type) → {external:Promise}
Save new data passed in objects of type
Parameters:
Name | Type | Description |
---|---|---|
objects |
Object | objects whose data should be created. |
type |
String | type of objects, likely to mean a "table" in storage |
Returns:
- A promise fulfilled when all of the data in
the changed object has been saved.
- Type
- external:Promise
createDataObject(type) → {Object}
Create a new data object of the specified type.
Since root services are responsible for tracking and creating data
objects, subclasses whose instances will not be root services should
override this method to call their root service's implementation of it.
Parameters:
Name | Type | Description |
---|---|---|
type |
DataObjectDescriptor | The type of object to create. |
- Inherited From:
- Source:
Returns:
- The created object.
- Type
- Object
dataIdentifierForObject(object) → {DataIdentifier}
Returns a unique object for a DataIdentifier
fetchObjectProperty() instead
of this method. That method will be called by this method when needed.
Parameters:
Name | Type | Description |
---|---|---|
object |
object | The object whose property values are being requested. |
- Inherited From:
- Source:
Returns:
- An object's DataIdentifier
- Type
- DataIdentifier
decacheObjectProperties()
Since root services are responsible for triggering data objects fetches,
subclasses whose instances will not be root services should override this
method to call their root service's implementation of it.
- Inherited From:
- Source:
- To Do:
-
- Rename and document API and implementation.
deleteData(objects, type) → {external:Promise}
Delete data passed in array.
Parameters:
Name | Type | Description |
---|---|---|
objects |
Object | objects whose data should be saved. |
type |
String | type of objects, likely to mean a "table" in storage |
Returns:
- A promise fulfilled when all of the data in
the changed object has been saved.
- Type
- external:Promise
deleteDataObject(object) → {external:Promise}
Subclasses should override this method to delete a data object when that
object's raw data wouldn't be useful to perform the deletion.
The default implementation maps the data object to raw data and calls
deleteRawData() with the data
object passed in as the `context` argument of that method.
Parameters:
Name | Type | Description |
---|---|---|
object |
Object | The object to delete. |
- Inherited From:
- Source:
Returns:
- A promise fulfilled when the object has
been deleted. The promise's fulfillment value is not significant and will
usually be `null`.
- Type
- external:Promise
deleteOfflineOperations(operations) → {Promise}
Delete operations recorded while offline.
Services overriding the (plural)
performOfflineOperations()
method must invoke this method after each operation they perform is
successfully performed.
This method will be called automatically for services that perform
operations by implementing a
performOfflineOperation()
or `performFooOfflineOperation()` methods (where `foo` is an operation
data type).
Subclasses that provide offline operations support must override this
method to delete the specified offline operations from their records.
Parameters:
Name | Type | Description |
---|---|---|
operations |
Array.<Object> |
- Overrides:
- Source:
Returns:
- A promise fulfilled with a null value when the
operations have been deleted.
- Type
- Promise
deleteRawData(record, context) → {external:Promise}
Subclasses should override this method to delete a data object when that
object's raw data would be useful to perform the deletion.
Parameters:
Name | Type | Description |
---|---|---|
record |
Object | An object whose properties hold the raw data of the object to delete. |
context |
? | An arbitrary value sent by deleteDataObject(). By default this is the object to delete. |
- Inherited From:
- Source:
Returns:
- A promise fulfilled when the object's data
has been deleted. The promise's fulfillment value is not significant and
will usually be `null`.
- Type
- external:Promise
fetchData(queryOrType, optionalCriterianullable, optionalStreamnullable) → (nullable) {DataStream}
Fetch data from the service using its child services.
This method accept types as alternatives to
queries, and its {DataStream} argument is
optional, but when it calls its child services it will provide them with
a query, it provide them with a
[stream]{DataStream}, creating one if necessary, and the stream will
include a reference to the query. Also, if a child service's
implementation of this method return `undefined` or `null`, this method
will return the stream passed in to the call to that child.
The requested data may be fetched asynchronously, in which case the data
stream will be returned immediately but the stream's data will be added
to the stream at a later time.
Parameters:
Name | Type | Attributes | Description |
---|---|---|---|
queryOrType |
DataQuery | DataObjectDescriptor | ObjectDescriptor | function | String | If this argument's value is a query it will define what type of data should be returned and what criteria that data should satisfy. If the value is a type it will only define what type of data should be returned, and the criteria that data should satisfy can be defined using the `criteria` argument. A type is defined as either a DataObjectDesc- riptor, an Object Descriptor, a Construct- or the string module id. The method will convert the passed in type to a Data- ObjectDescriptor (deprecated) or an ObjectDescriptor. This is true whether passing in a DataQuery or a type. | |
optionalCriteria |
Object |
<nullable> |
If the first argument's value is a type this argument can optionally be provided to defines the criteria which the returned data should satisfy. If the first argument's value is a query this argument should be omitted and will be ignored if it is provided. |
optionalStream |
DataStream |
<nullable> |
The stream to which the provided data should be added. If no stream is provided a stream will be created and returned by this method. |
- Overrides:
- Source:
Returns:
- The stream to which the fetched data objects
were or will be added, whether this stream was provided to or created by
this method.
- Type
- DataStream
fetchObjectProperty(object, name) → {external:Promise}
Fetch the value of a data object's property, possibly asynchronously.
The default implementation of this method delegates the fetching to a
child services, or does nothing but return a fulfilled promise for `null`
if no child service can be found to handle the specified object.
Raw data service subclasses should override
this method to perform any fetch or other operation required to get the
requested data. The subclass implementations of this method should use
only fetchData() calls to fetch data.
This method should never be called directly:
getObjectProperties() or
updateObjectProperties()
should be called instead as those methods handles some required caching,
fetch aggregation, and data trigger. Those methods
will call this method if and when that is necessary.
Like the promise returned by
getObjectProperties(), the
promise returned by this method should not pass the requested value to
its callback: That value must instead be set on the object passed in to
this method.
Parameters:
Name | Type | Description |
---|---|---|
object |
object | The object whose property value is being requested. |
name |
string | The name of the single property whose value is being requested. |
- Inherited From:
- Source:
Returns:
- A promise fulfilled when the requested
value has been received and set on the specified property of the passed
in object.
- Type
- external:Promise
getDataObject(type, data, context) → {Object}
Find an existing data object corresponding to the specified raw data, or
if no such object exists, create one.
Since root services are responsible for tracking and creating data
objects, subclasses whose instances will not be root services should
override this method to call their root service's implementation of it.
Parameters:
Name | Type | Description |
---|---|---|
type |
DataObjectDescriptor | The type of object to find or create. |
data |
Object | An object whose property values hold the object's raw data. That data will be used to determine the object's unique identifier. |
context |
? | A value, usually passed in to a raw data service's addRawData() method, that can help in getting or creating the object. |
- Inherited From:
- Source:
Returns:
- The existing object with the unique identifier
specified in the raw data, or if no such object exists a newly created
object of the specified type.
- Type
- Object
getObjectProperties(object, propertyNames) → {external:Promise}
Request possibly asynchronous values of a data object's properties. These
values will only be fetched if necessary and only the first time they are
requested.
To force an update of a value that was previously obtained or set, use
updateObjectProperties()
instead of this method.
Since root services are responsible for determining when to fetch or
update data objects values, subclasses whose instances will not be root
services should override this method to call their root service's
implementation of it.
Subclasses should define how property values are obtained by overriding
fetchObjectProperty() instead
of this method. That method will be called by this method when needed.
Although this method returns a promise, the requested data will not be
passed in to the promise's callback. Instead that callback will received
a `null` value and the requested values will be set on the specified
properties of the object passed in. Those values can be accessed there
when the returned promise is fulfilled, as in the following code:
myService.getObjectProperties(myObject, "x", "y").then(function () {
someFunction(myObject.x, myObject.y);
}
Parameters:
Name | Type | Description |
---|---|---|
object |
object | The object whose property values are being requested. |
propertyNames |
Array.<string> | The names of each of the properties whose values are being requested. These can be provided as an array of strings or as a list of string arguments following the object argument. |
- Inherited From:
- Source:
Returns:
- A promise fulfilled when all of the
requested data has been received and set on the specified properties of
the passed in object.
- Type
- external:Promise
logOut()
- Inherited From:
- Source:
Returns:
Promise
mapFromRawData()
- Inherited From:
- Deprecated:
- Yes
- Source:
- To Do:
-
- Document deprecation in favor of mapRawDataToObject()
mapObjectToRawData(object, record, context)
Public method invoked by the framework during the conversion from
an object to a raw data.
Designed to be overriden by concrete RawDataServices to allow fine-graine control
when needed, beyond transformations offered by an ObjectDescriptorDataMapping or
an ExpressionDataMapping
Parameters:
Name | Type | Description |
---|---|---|
object |
Object | An object whose properties must be set or modified to represent the raw data. |
record |
Object | An object whose properties' values hold the raw data. |
context |
? | The value that was passed in to the addRawData() call that invoked this method. |
- Inherited From:
- Source:
mappingForObject(record, object, context)
Convert raw data to data objects of an appropriate type.
Parameters:
Name | Type | Description |
---|---|---|
record |
Object | An object whose properties' values hold the raw data. |
object |
Object | An object whose properties must be set or modified to represent the raw data. |
context |
? | The value that was passed in to the addRawData() call that invoked this method. |
- Inherited From:
- Source:
- To Do:
-
- Make this method overridable by type name with methods like `mapRawDataToHazard()` and `mapRawDataToProduct()`.
mapRawDataToObject(record, object, context)
Convert raw data to data objects of an appropriate type.
Subclasses should override this method to map properties of the raw data
to data objects:
Parameters:
Name | Type | Description |
---|---|---|
record |
Object | An object whose properties' values hold the raw data. |
object |
Object | An object whose properties must be set or modified to represent the raw data. |
context |
? | The value that was passed in to the addRawData() call that invoked this method. |
- Inherited From:
- Source:
mapSelectorToRawDataQuery(selector) → {DataQuery}
Convert a selector for data objects to a selector for raw data.
The selector returned by this method will be the selector used by methods
that deal with raw data, like
fetchRawData(),
addRawData(),
rawDataDone(), and
writeOfflineData(). Any
[stream]stream available to these methods will have their
selector references temporarly replaced by references to the mapped
selector returned by this method.
The default implementation of this method returns the passed in selector.
Parameters:
Name | Type | Description |
---|---|---|
selector |
DataQuery | A selector defining data objects to select. |
- Inherited From:
- Source:
Returns:
- A selector defining raw data to select.
- Type
- DataQuery
mapToRawData()
- Inherited From:
- Deprecated:
- Yes
- Source:
- To Do:
-
- Document deprecation in favor of mapObjectToRawData()
objectForDataIdentifier(object) → {DataIdentifier}
Returns a unique object for a DataIdentifier
fetchObjectProperty() instead
of this method. That method will be called by this method when needed.
Parameters:
Name | Type | Description |
---|---|---|
object |
object | object |
- Inherited From:
- Source:
Returns:
- object's DataIdentifier
- Type
- DataIdentifier
performOfflineOperation(operation) → {Promise}
Called from
performOfflineOperations()
to perform a particular operation when no more specific
`performFooOfflineOperation()` method is available for that operation,
where `Foo` is the operation's data type.
The default implementation does nothing.
Subclass overriding this method do not need to
delete the passed in
operation after it has successfully been performed: The method calling
this method will take care of that.
Parameters:
Name | Type | Description |
---|---|---|
operation |
DataOperation |
- Inherited From:
- Source:
Returns:
- A promise fulfilled with a null value when the
operation has been performed, or rejected if a problem occured that
should prevent following operations from being performed.
- Type
- Promise
performOfflineOperations() → {Promise}
Perform operations recorded while offline. This will be invoked when the
service comes online after being offline.
The default implementation delegates performance of each operation to
the child service responsible for that operation, as determined by
readOfflineOperations(). It
will batch operations if several consecutive operations belong to the
same child service.
For each operation not handled by a child service, the default
implementation calls a method named `performFooOfflineOperation()`, if
such a method exists in this service where `foo` is the operation's
data type. If no such method exists,
readOfflineOperation() is
called instead.
Subclasses that provide offline support should implement these
`performFooOfflineOperation()` methods or override the
`readOfflineOperation()` method to perform each operation, or they can
override this `performOfflineOperations()` method instead.
Subclass overriding this method are responsible for
deleting operations after
they have been performed. Subclasses implementing
`performFooOfflineOperation()` methods or overriding the
`readOfflineOperation()` method are not.
Parameters:
Type | Description |
---|---|
Array.<DataOperation> | operations |
- Inherited From:
- Source:
Returns:
- A promise fulfilled with a null value when the
operations have been performed, or rejected if a problem occured that
should prevent following operations from being performed.
- Type
- Promise
rawDataDone(stream, context)
To be called once for each fetchData()
or fetchRawData() call received to
indicate that all the raw data meant for the specified stream has been
added to that stream.
Subclasses should not override this method.
Parameters:
Name | Type | Description |
---|---|---|
stream |
DataStream | The stream to which the data objects corresponding to the raw data have been added. |
context |
? | An arbitrary value that will be passed to writeOfflineData() if it is provided. |
- Overrides:
- Source:
rawDataServiceDidAddOneRawData(dataService, dataStream, rawData, object) → {void}
Delegate method allowing the persistent service to do the ground work
as objects are created, avoiding to loop again later
Parameters:
Name | Type | Description |
---|---|---|
dataService |
DataService | |
dataStream |
DataStream | |
rawData |
Object | |
object |
Object |
Returns:
- Type
- void
readOfflineOperations()
Reads all the offline operations recorded on behalf of this service.
The default implementation aggregates this service children's offline
operations, keeping track of which child service is responsible for each
operation.
Subclasses that provide offline support should override this method to
return the operations that have been performed while offline.
- Overrides:
- Source:
recordDataIdentifierForObject(object, dataIdentifier)
Records an object's DataIdentifier
Parameters:
Name | Type | Description |
---|---|---|
object |
object | an Object. |
dataIdentifier |
DataIdentifier | The object whose property values are |
- Inherited From:
- Source:
recordObjectForDataIdentifier(dataIdentifier, object)
Records an object's DataIdentifier
Parameters:
Name | Type | Description |
---|---|---|
dataIdentifier |
DataIdentifier | DataIdentifier |
object |
object | object represented by dataIdentifier |
- Inherited From:
- Source:
registerChildService(child) → {Promise}
Alternative to addChildService().
While addChildService is synchronous, registerChildService is asynchronous
and may take a child whose types property is
a promise instead of an array.
This is useful for example if the child service does not know its types
immediately, e.g. if it must fetch them from a .mjson descriptors file.
If the child's types is an array, it is guaranteed to behave exactly
like addChildService.
Parameters:
Name | Type | Description |
---|---|---|
child |
DataService | service to add to this service. |
|
Promise | ObjectDescriptor | Array.<ObjectDescriptor> |
- Inherited From:
- Source:
Returns:
- Type
- Promise
removeChildService(service, typesopt)
Remove a raw data service as a child of this service and clear its parent
if that service is a child of this service.
The performance of this method is O(m) + O(n), where m is the number of
children of this service handling the same type as the child service to
remove and n is the number of types handled by all children of this
service.
Parameters:
Name | Type | Attributes | Description |
---|---|---|---|
service |
RawDataService | ||
types |
Array |
<optional> |
Types to use instead of the child's types. |
- Inherited From:
- Source:
removeDataIdentifierForObject(object)
Remove an object's DataIdentifier
Parameters:
Name | Type | Description |
---|---|---|
object |
object | an object |
- Inherited From:
- Source:
removeObjectForDataIdentifier(object)
Remove an object's DataIdentifier
Parameters:
Name | Type | Description |
---|---|---|
object |
object | an object |
- Inherited From:
- Source:
saveDataObject(object) → {external:Promise}
Save changes made to a data object.
Parameters:
Name | Type | Description |
---|---|---|
object |
Object | The object whose data should be saved. |
- Inherited From:
- Source:
Returns:
- A promise fulfilled when all of the data in
the changed object has been saved.
- Type
- external:Promise
saveRawData(record, context) → {external:Promise}
Subclasses should override this method to save a data object when that
object's raw data would be useful to perform the save.
Parameters:
Name | Type | Description |
---|---|---|
record |
Object | An object whose properties hold the raw data of the object to save. |
context |
? | An arbitrary value sent by saveDataObject(). By default this is the object to save. |
- Inherited From:
- Source:
Returns:
- A promise fulfilled when the object's data
has been saved. The promise's fulfillment value is not significant and
will usually be `null`.
- Type
- external:Promise
spliceWithArray(array, insert, index, length)
Splice an array into another array.
Parameters:
Name | Type | Description |
---|---|---|
array |
Array | The array to modify. |
insert |
Array | The items to splice into that array. |
index |
number | The index at which to splice those items, by default `0`. |
length |
number | The number of items of the original array to replace with items from the spliced array, by default `array.length`. |
- Inherited From:
- Source:
unregisterChildService() → {Promise}
Alternative to removeChildService().
While removeChildService is synchronous, unregisterChildService is asynchronous
and may take a child whose types property is
a promise instead of an array.
This is useful for example if the child service does not know its types
immediately, e.g. if it must fetch them from a .mjson descriptors file.
If the child's types is an array, it is guaranteed to behave exactly
like removeChildService.
- Inherited From:
- Source:
Returns:
- Type
- Promise
updateData(objects, type, context) → {external:Promise}
Save updates made to an array of existing data objects.
Parameters:
Name | Type | Description |
---|---|---|
objects |
Array | objects whose data should be updated. |
type |
String | type of objects, likely to mean a "table" in storage |
context |
Object | an object that will be associated with operations |
Returns:
- A promise fulfilled when all of the data in
objects has been saved.
- Type
- external:Promise
updateObjectProperties(object, propertyNames) → {external:Promise}
Request possibly asynchronous values of a data object's properties,
forcing asynchronous values to be re-fetched and updated even if they
had previously been fetched or set.
Except for the forced update, this method behaves exactly like
getObjectProperties().
Since root services are responsible for determining when to fetch or
update data objects values, subclasses whose instances will not be root
services should override this method to call their root service's
implementation of it.
Subclasses should define how property values are obtained by overriding
fetchObjectProperty() instead
of this method. That method will be called by this method when needed.
Parameters:
Name | Type | Description |
---|---|---|
object |
object | The object whose property values are being requested. |
propertyNames |
Array.<string> | The names of each of the properties whose values are being requested. These can be provided as an array of strings or as a list of string arguments following the object argument. |
- Inherited From:
- Source:
Returns:
- A promise fulfilled when all of the
requested data has been received and set on the specified properties of
the passed in object.
- Type
- external:Promise
writeOfflineData(records, selectornullable, context) → {external:Promise}
Called with all the data passed to
addRawData() to allow storing of that
data for offline use.
The default implementation does nothing. This is appropriate for
subclasses that do not support offline operation or which operate the
same way when offline as when online.
Other subclasses may override this method to store data fetched when
online so fetchData can use that data
when offline.
Parameters:
Name | Type | Attributes | Description |
---|---|---|---|
records |
Object | An array of objects whose properties' values hold the raw data. | |
selector |
DataQuery |
<nullable> |
- Describes how the raw data was selected. |
context |
? | The value that was passed in to the rawDataDone() call that invoked this method. |
- Inherited From:
- Source:
Returns:
- A promise fulfilled when the raw data has
been saved. The promise's fulfillment value is not significant and will
usually be `null`.
- Type
- external:Promise