org.trellisldp.api

Interface Resource

All Known Implementing Classes:

FileResource, Resource.SpecialResources, TriplestoreResource

public interface Resource

The central resource abstraction for a Trellis-based linked data server.

See Also:

Linked Data Platform Specification

API Note:

A common implementation pattern for this interface is to initialize the Resource object with metadata such as getModified(), getInteractionModel() and other data fetched by the accessors. The resource content, on the other hand, is often loaded on-demand via the stream() method. This pattern tends to reduce the number of requests to the persistence layer while also limiting the data held in memory for a given Resource object.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Resource.SpecialResources

Method Summary

Modifier and Type	Method and Description
default Dataset	dataset() Retrieve the RDF Quads for a resource.
default Optional<BinaryMetadata>	getBinaryMetadata() Retrieve a BinaryMetadata for this resouce, if it is a LDP-NR.
Optional<IRI>	getContainer() Get the container for this resource.
default Stream<Map.Entry<String,String>>	getExtraLinkRelations() Get any extra implementation-defined link relations for this resource.
IRI	getIdentifier() Get an identifier for this resource.
default Optional<IRI>	getInsertedContentRelation() Retrieve the inserted content relation if this is an LDP Indirect container.
IRI	getInteractionModel() Get the LDP interaction model for this resource.
default Optional<IRI>	getMemberOfRelation() Retrieve the member of relation IRI.
default Optional<IRI>	getMemberRelation() Retrieve the member relation if this is an LDP Direct or Indirect container.
default Optional<IRI>	getMembershipResource() Retrieve the membership resource if this is an LDP Direct or Indirect container.
Instant	getModified() Get the last modified date.
default String	getRevision() Get the revision or state tag of the resource.
default boolean	hasAcl() Test whether this resource has an ACL resource.
Stream<Quad>	stream() Retrieve the RDF Quads for a resource.
default Stream<Quad>	stream(Collection<IRI> graphNames) Retrieve the RDF Quads for a set of named graphs.
default Stream<Quad>	stream(IRI graphName) Retrieve the RDF Quads for a given named graph.

Method Detail

getIdentifier

IRI getIdentifier()

Get an identifier for this resource.

Returns:

the identifier

getInteractionModel

IRI getInteractionModel()

Get the LDP interaction model for this resource.

Returns:

the interaction model

getModified

Instant getModified()

Get the last modified date.

Returns:

the last-modified date

getRevision

default String getRevision()

Get the revision or state tag of the resource.

Returns:

the revision tag of the resource

API Note:

the return value of this method should be unique to the state of the resource. That is, it should be unique across all resources on the server, and whenever a given resource changes, this revision tag should also change. This value will be used as the raw material for generating an ETag in the HTTP layer, and it should not return null.

Implementation Requirements:

the default implementation returns a concatenation of the resource identifier and the modification date.

getContainer

Optional<IRI> getContainer()

Get the container for this resource.

Returns:

the identifier for a container, if one exists.

API Note:

returning an empty Optional should indicate here that the resource is not contained by any parent resource. This may be because it is a root resource and therefore not contained by any other resource. Alternatively, it could mean that a PUT operation was used to create the resource.

getMembershipResource

default Optional<IRI> getMembershipResource()

Retrieve the membership resource if this is an LDP Direct or Indirect container.

Returns:

the membership resource

Implementation Requirements:

Other LDP resource types will always return an empty Optional value

getMemberRelation

default Optional<IRI> getMemberRelation()

Retrieve the member relation if this is an LDP Direct or Indirect container.

Returns:

the ldp:hasMemberRelation IRI

Implementation Requirements:

Other LDP resource types will always return an empty Optional value

getMemberOfRelation

default Optional<IRI> getMemberOfRelation()

Retrieve the member of relation IRI.

Returns:

the ldp:isMemberOfRelation IRI

Implementation Requirements:

Other LDP resource types will always return an empty Optional value

getInsertedContentRelation

default Optional<IRI> getInsertedContentRelation()

Retrieve the inserted content relation if this is an LDP Indirect container.

Returns:

the inserted content relation

Implementation Requirements:

Other LDP resource types will always return an empty Optional value

stream

Stream<Quad> stream()

Retrieve the RDF Quads for a resource.

Returns:

the RDF quads

dataset

default Dataset dataset()

Retrieve the RDF Quads for a resource.

Returns:

the RDF quads

stream

default Stream<Quad> stream(IRI graphName)

Retrieve the RDF Quads for a given named graph.

Parameters:

graphName - the named graph

Returns:

the RDF quads

stream

default Stream<Quad> stream(Collection<IRI> graphNames)

Retrieve the RDF Quads for a set of named graphs.

Parameters:

graphNames - the named graphs

Returns:

the RDF quads

getBinaryMetadata

default Optional<BinaryMetadata> getBinaryMetadata()

Retrieve a BinaryMetadata for this resouce, if it is a LDP-NR.

Returns:

the binary metadata

Implementation Requirements:

Other LDP resource types will always return an empty Optional value

hasAcl

default boolean hasAcl()

Test whether this resource has an ACL resource.

Returns:

true if this resource has and ACL resource; false otherwise

getExtraLinkRelations

default Stream<Map.Entry<String,String>> getExtraLinkRelations()

Get any extra implementation-defined link relations for this resource.

Returns:

a stream of relation types

API Note:

Each entry will be used to create a link header, such that the key refers to the URI and the value is the "rel" portion. For example, an item with key="http://example.com/author001" and value="author" will result in the header Link: <http://example.com/author001>; rel="author".