org.apache.marmotta.kiwi.model.rdf

Class KiWiResource

java.lang.Object

org.apache.marmotta.kiwi.model.rdf.KiWiNode

org.apache.marmotta.kiwi.model.rdf.KiWiResource

All Implemented Interfaces:

Serializable, org.openrdf.model.Resource, org.openrdf.model.Value

Direct Known Subclasses:

KiWiAnonResource, KiWiUriResource

public abstract class KiWiResource
extends KiWiNode
implements org.openrdf.model.Resource

KiWiResources correspond to RDF resources. A KiWi resource is either an anonymous resource or a URIResource. A KiWiResource represents an RDF resource. However, there is no 1:1 correspondance, as there may be several KiWiResources in different KnowledgeSpaces that represent the same RDF resource.

Each KiWiResource has a 1:1 correspondance to a content item. Each KiWiResource is also directly related with a Sesame 2 resource in the knowledge base backend. The kiwi.sesame package contains appropriate adaptors for transforming Sesame 2 resources into KiWiResources.

Each KiWiResoure furthermore participates in exactly one knowledge space, where the RDF resource may have different identifiers for the users. This knowledge space defines the getTripleStore().of the node. For this reason, a Sesame 2 Value may correspond to several KiWiNodes in different knowledge spaces.

TODO: we could further simplify the data model by treating TextContent and MediaContent as literals that are in a certain relation with the resource ("kiwi:hasTextContent", "kiwi:hasMediaContent") and introducing the following new literal types: KiWiTextContentLiteral KiWiMediaContentLiteral KiWiStringContentLiteral The class hierarchy should be changed so that from KiWiNode -> KiWiLiteral and from KiWiNode -> KiWiResource there is joined subclass, and from there on single table currently existing functionality should be moved to ContentItemService

Author:

Sebastian Schaffert

See Also:

Serialized Form

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	KiWiResource()
protected	KiWiResource(Date created)

Method Summary

Methods

Modifier and Type	Method and Description
abstract boolean	isAnonymousResource() Return true if the resource is an anonymous resource / blank node
boolean	isLiteral() Return true if the node is a literal.
abstract boolean	isUriResource() Return true in case the node is a uri resource (avoids instanceof test)

Methods inherited from class org.apache.marmotta.kiwi.model.rdf.KiWiNode

getCreated, getId, setCreated, setId

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.openrdf.model.Value

stringValue

Constructor Detail

KiWiResource

protected KiWiResource()

KiWiResource

protected KiWiResource(Date created)

Method Detail

isLiteral

public boolean isLiteral()

Return true if the node is a literal. Since all resources are not literals, returns false.

Specified by:

isLiteral in class KiWiNode

Returns:

false (the node is always a resource)

isAnonymousResource

public abstract boolean isAnonymousResource()

Return true if the resource is an anonymous resource / blank node

Specified by:

isAnonymousResource in class KiWiNode

Returns:

isUriResource

public abstract boolean isUriResource()

Description copied from class: KiWiNode

Return true in case the node is a uri resource (avoids instanceof test)

Specified by:

isUriResource in class KiWiNode

Returns:

true if the node is a URI, false otherwise