org.lenskit.data.entities

Class EntityDerivation

java.lang.Object

org.lenskit.data.entities.EntityDerivation

public class EntityDerivation
extends java.lang.Object

Describe a derivation of one entity from another. This is used to extract bare entities from references in other entity types, e.g. user IDs in ratings, so that you don’t have to have explicit data source for every type of entity in the system.

Method Summary

Modifier and Type	Method and Description
static EntityDerivation	create(EntityType t, EntityType src, TypedName<java.lang.Long> attr) Create a new entity derivation.
static EntityDerivation	fromJSON(com.fasterxml.jackson.databind.JsonNode node) Parse an entity derivation from a JSON node.
TypedName<java.lang.Long>	getAttribute() Get the source attribute for the derivation.
EntityType	getSourceType() Get the source types for the derivation.
EntityType	getType() Get the entity type to be derived.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

create

public static EntityDerivation create(EntityType t,
                                      EntityType src,
                                      TypedName<java.lang.Long> attr)

Create a new entity derivation.

Parameters:

t - The derived entity type.

src - The source type.

attr - The attribute to derive from.

Returns:

An entity derivation.

getType

public EntityType getType()

Get the entity type to be derived.

Returns:

The entity type to derive.

getSourceType

public EntityType getSourceType()

Get the source types for the derivation.

Returns:

The source types for the derivation.

getAttribute

public TypedName<java.lang.Long> getAttribute()

Get the source attribute for the derivation.

Returns:

The attribute whose value contains IDs of the derived entity.

fromJSON

public static EntityDerivation fromJSON(com.fasterxml.jackson.databind.JsonNode node)

Parse an entity derivation from a JSON node.

Parameters:

node - The JSON node.

Returns:

The entity derivation.