ai.grakn.concept

Interface Relation

All Superinterfaces:

Comparable<Concept>, Concept, Instance

public interface Relation
extends Instance

Encapsulates relationships between Instance

A relation which is an instance of a RelationType defines how instances may relate to one another. It represents how different entities relate to one another. Relations are used to model n-ary relationships between instances.

Author:

fppt

Method Summary

Modifier and Type	Method and Description
Relation	addRolePlayer(RoleType roleType, Instance instance) Expands this Relation to include a new role player which is playing a specific role.
Map<RoleType,Set<Instance>>	allRolePlayers() Retrieve a list of all Instances involved in the Relation, and the Role Types they play.
Relation	resource(Resource resource) Creates a relation from this instance to the provided resource.
Collection<Instance>	rolePlayers(RoleType... roleTypes) Retrieves a list of every Instance involved in the Relation, filtered by RoleType played.
RelationType	type() Retrieve the associated Relation Type for this Relation.

Methods inherited from interface ai.grakn.concept.Instance

plays, relations, resources

Methods inherited from interface ai.grakn.concept.Concept

asEntity, asEntityType, asInstance, asRelation, asRelationType, asResource, asResourceType, asRoleType, asRule, asRuleType, asType, delete, getId, isEntity, isEntityType, isInstance, isRelation, isRelationType, isResource, isResourceType, isRoleType, isRule, isRuleType, isType

Methods inherited from interface java.lang.Comparable

compareTo

Method Detail

resource

Relation resource(Resource resource)

Creates a relation from this instance to the provided resource.

Specified by:

resource in interface Instance

Parameters:

resource - The resource to which a relationship is created

Returns:

The instance itself

type

RelationType type()

Retrieve the associated Relation Type for this Relation.

Specified by:

type in interface Instance

Returns:

The associated Relation Type for this Relation.

See Also:

RelationType

allRolePlayers

Map<RoleType,Set<Instance>> allRolePlayers()

Retrieve a list of all Instances involved in the Relation, and the Role Types they play.

Returns:

A list of all the role types and the instances playing them in this relation.

See Also:

RoleType

rolePlayers

Collection<Instance> rolePlayers(RoleType... roleTypes)

Retrieves a list of every Instance involved in the Relation, filtered by RoleType played.

Parameters:

roleTypes - used to filter the returned instances only to ones that play any of the role types. If blank, returns all role players.

Returns:

a list of every Instance involved in the Relation.

addRolePlayer

Relation addRolePlayer(RoleType roleType,
                       Instance instance)

Expands this Relation to include a new role player which is playing a specific role.

Parameters:

roleType - The Role Type of the new role player.

instance - The new role player.

Returns:

The Relation itself.

Throws:

ConceptNotUniqueException - if the concept is only allowed to play this role once.