Olympe SDK

Class: GraphDef

olympe.dc. GraphDef

GraphDef is the class that gives the ability to generate a GraphDef query or subscription. A graph is defined by its base (or root) instance (or tag) and by the relations to follow (recursively or not). By default, relations are followed from where the previous one stopped, but its possible to 'walk back' the tree of relations, up to the root.

Example:

const graphDef = new olympe.dc.GraphDef('Joe')
    .follow(Friend).follow(Friend)
    .backToRoot()
    .follow(Partner)
    .follow(Friend).follow(Friend);

graphDef.execute((error, result) => { ... });

Creates a GraphDef referencing 'Joe', his partner, their friends and their friend's friends, and would look like this:

GraphDefTree

And the resulting sub-graph would look like this:

GraphDef

new GraphDef(baseTag [, operation])

Creates an instance of GraphDef.

Parameters:
Name Type Argument Default Description
baseTag olympe.dc.InstanceTag

The base tag for the graph.
operation olympe.dc.GraphDefOperation <optional>
 olympe.dc.GraphDefOperation.SUBSCRIBE

The graphdef operation

Members

<non-null> followRules :olympe.dc.FollowRules

Type:
  • olympe.dc.FollowRules

Methods

<static> deleteInstance(instance [, callback])

Sends a 'delete' graph request to delete the specified instance from the data-cloud.

Parameters:
Name Type Argument Description
instance olympe.dc.InstanceTag

The instance to delete.
callback olympe.dc.Manager.TransactionCallback <optional>

The function that will be provided with the result.

<static> deleteInstances(instances [, callback])

Sends a 'delete' graph request to delete the specified list of instances from the data-cloud.

Parameters:
Name Type Argument Description
instances Array.<olympe.dc.InstanceTag>

The instances to delete.
callback olympe.dc.Manager.TransactionCallback <optional>

The function to pass the result.

<static> fromJSON(json)

Deserializes a GraphDef from a JSON object or string.

Parameters:
Name Type Description
json string | Object
Returns:
Type
olympe.dc.GraphDef

activateFollowRules(rule)

Activates the follow rules option for the current GraphDef node.

Parameters:
Name Type Description
rule olympe.dc.FollowRules

The 'follow' rule to activate.
Returns:

This GraphDef.

Type
olympe.dc.GraphDef

add(relation [, recursive] [, apply])

Adds a relation to the GraphDef at the same node.

Parameters:
Name Type Argument Default Description
relation olympe.dc.registry.Relation

The relation.
recursive boolean <optional>
 false

true when we want to recurse on this relation
apply boolean <optional>
 true

true to apply the operation.
Returns:

This GraphDef.

Type
olympe.dc.GraphDef

addSkipCoveragePredicate(predicate)

Adds a predicate function to skip the check of coverage of specific relations. Works only for implicit graphdefs.

Parameters:
Name Type Description
predicate olympe.dc.GraphDef.SkipCoveragePredicate
Returns:

This GraphDef.

Type
olympe.dc.GraphDef

back( [times])

Moves back up one or more hops in the graph.

Parameters:
Name Type Argument Default Description
times number <optional>
 1

Number of hops.
Returns:

This GraphDef.

Type
olympe.dc.GraphDef

backToRoot()

Moves back to the top of the graph.

Returns:

This GraphDef.

Type
olympe.dc.GraphDef

buildQuery( [context])

Builds the GraphQuery corresponding to this Graphdef, which will be used to monitor the state of the subscription

Parameters:
Name Type Argument Description
context olympe.df.ExecutionContext <optional>
Returns:

The graph query associated to the current state of this graphdef.

Type
olympe.dc.query.GraphQuery

execute( [callback])

Executes this graphdef request. Effectively passes this graphdef to the query engine for it to subscribe to it or to pull it, depending on the operation. In case of subscription, also schedules unsubscription to it upon detachment of the current context. The optional specified callback will be called with the graphdef query result within the current execution context.

Parameters:
Name Type Argument Description
callback olympe.dc.query.GraphQuery.GraphResultHandler <optional>

The callback function.

follow(relation [, recursive])

Extends the graph by specifying a relation to follow.

Parameters:
Name Type Argument Default Description
relation olympe.dc.registry.Relation

The relation.
recursive boolean <optional>
 false

true when we want to recurse on this relation
Returns:

This GraphDef.

Type
olympe.dc.GraphDef

getBlocks()

Return an iterable object of all the blocks of this graphdef

Throw an error if the graphdef is in fact an implicit one.

Returns:
Type
Iterable.<!olympe.dc.query.GraphQueryBlock>

getCreationReason()

Returns the reason of this graphdef creation, if one has been set.

Returns:
Type
string

getFollowRules()

Return the follow rules activated for this graphdef. The follow rule 'olympe.dc.FollowRules.NONE' indicates an explicit graphdef

Returns:
Type
olympe.dc.FollowRules

getId()

Generate and return the id of a graphdef based on its content.

Returns:

The graphdef id.

Type
string

getOperation()

Gets the operation (SUBSCRIBE, PULL, QUERY) associated with this GraphDef.

Returns:

The operation.

Type
olympe.dc.GraphDefOperation

getRootTag()

Return the tag of the root instance of this graphdef

Returns:
Type
string

getSkipCoveragePredicates()

Returns the list of skip predicates.

Returns:
Type
Array.<!olympe.dc.GraphDef.SkipCoveragePredicate>

isImplicit()

Return true if current graphdef is implicit

Returns:
Type
boolean

setCreationReason(reason)

Set the reason of this graphdef creation. This is used for debug purposes.

Parameters:
Name Type Description
reason string
Returns:

This GraphDef.

Type
olympe.dc.GraphDef

toJSON()

Serializes this GraphDef into a JSON string.

Returns:
Type
string

Type Definitions

SkipCoveragePredicate(root, relation)

Predicate functions used to skip specific verification of coverage.

Parameters:
Name Type Description
root string
relation olympe.dc.query.Relation
Returns:
Type
boolean