org.lenskit.data.entities

Class EntityCollection

java.lang.Object

java.util.AbstractCollection<Entity>

org.lenskit.data.entities.EntityCollection

All Implemented Interfaces:

Serializable, Iterable<Entity>, Collection<Entity>, Describable

public class EntityCollection
extends AbstractCollection<Entity>
implements Serializable, Describable

A collection of entities of a single type. This collection augments the Collection interface with logic for different kinds of (possibly optimized) entity searches.

See Also:

Serialized Form

Method Summary

Modifier and Type	Method and Description
void	describeTo(DescriptionWriter writer) Write this class’s description to a sink.
<T> List<Entity>	find(Attribute<T> attr) Find entities with an attribute.
List<Entity>	find(String name, Object value) Find entities by attribute.
<T> List<Entity>	find(TypedName<T> name, T value) Find entities by attribute.
EntityType	getType() Get the type of entity stored in this collection.
LongSet	idSet()
Iterator<Entity>	iterator()
Entity	lookup(long id) Look up an entity by ID.
static EntityCollectionBuilder	newBuilder(EntityType type) Create a new entity collection builder.
int	size()

Methods inherited from class java.util.AbstractCollection

add, addAll, clear, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

equals, hashCode, parallelStream, removeIf, spliterator, stream

Methods inherited from interface java.lang.Iterable

forEach

Method Detail

newBuilder

public static EntityCollectionBuilder newBuilder(EntityType type)

Create a new entity collection builder.

Returns:

The builder.

getType

public EntityType getType()

Get the type of entity stored in this collection.

Returns:

The entity type this collection stores.

idSet

public LongSet idSet()

lookup

@Nullable
public Entity lookup(long id)

Look up an entity by ID.

Parameters:

id - The entity ID.

Returns:

The entity, or null if no such entity exists.

find

@Nonnull
public <T> List<Entity> find(TypedName<T> name,
                                       T value)

Find entities by attribute.

Parameters:

name - The attribute name.

value - The attribute value.

Returns:

A list of entities for which attribute name has value value.

find

@Nonnull
public <T> List<Entity> find(Attribute<T> attr)

Find entities with an attribute.

Parameters:

attr - The attribute to look for.

T - The attribute type.

Returns:

A list of entities with the specified attribute.

find

@Nonnull
public List<Entity> find(String name,
                                   Object value)

Find entities by attribute.

Parameters:

name - The attribute name.

value - The attribute value.

Returns:

A list of entities for which attribute name has value value.

iterator

@Nonnull
public Iterator<Entity> iterator()

Specified by:

iterator in interface Iterable<Entity>

Specified by:

iterator in interface Collection<Entity>

Specified by:

iterator in class AbstractCollection<Entity>

size

public int size()

Specified by:

size in interface Collection<Entity>

Specified by:

size in class AbstractCollection<Entity>

describeTo

public void describeTo(DescriptionWriter writer)

Description copied from interface: Describable

Write this class’s description to a sink. Anything relevant to this object’s identity should be digested; the idea is that, barring hash collisions, two objects with the same digest are equivalent. Used for things like deterministically generating cache file names.

Specified by:

describeTo in interface Describable

Parameters:

writer - The description writer to use.