org.dspace.rdf

Class RDFUtil

java.lang.Object

org.dspace.rdf.RDFUtil

public class RDFUtil
extends Object

Author:

Pascal-Nicolas Becker (dspace -at- pascal -hyphen- becker -dot- de)

Constructor Summary

Constructors

Constructor and Description
RDFUtil()

Method Summary

Methods

Modifier and Type	Method and Description
static com.hp.hpl.jena.rdf.model.Model	convert(Context context, DSpaceObject dso) Converts the the provided DSpaceObject into RDF and returns the model.
static com.hp.hpl.jena.rdf.model.Model	convertAndStore(Context context, DSpaceObject dso) Converts a DSpaceObject into RDF data and stores them using the configured RDFStorage.
static void	delete(Context ctx, int type, int id, String handle, String[] identifiers) This is a shortcut to generate an RDF identifier for a DSpaceObject and to delete the identified data from the named graph.
static void	delete(String uri) Deletes the data identified by the URI from the triple store.
static String	generateIdentifier(Context context, DSpaceObject dso) Generates a URI identifying the provided DSpaceObject.
static String	generateIdentifier(Context context, int type, int id, String handle, String[] identifier) Generates a URI identifying the provided DSpaceObject.
static void	isPublic(Context context, DSpaceObject dso) Checks whether the provided DSpaceObject is readable within the provided context and if the DSO is an Item whether it is archived, discoverable and not withdrawn.
static boolean	isPublicBoolean(Context context, DSpaceObject dso) Does the same as isPublic(Context, DSpaceObject) but returns a boolean instead of throwing exceptions.
static com.hp.hpl.jena.rdf.model.Model	loadModel(String identifier) Loads converted data of a DSpaceObject identified by the URI provided as identifier.

Methods inherited from class java.lang.Object

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

Constructor Detail

RDFUtil

public RDFUtil()

Method Detail

loadModel

public static com.hp.hpl.jena.rdf.model.Model loadModel(String identifier)

Loads converted data of a DSpaceObject identified by the URI provided as identifier. This method uses the RDFStorage configurated in the DSpace configuration. Close the model (Model.close()) as soon as possible to free system resources.

Parameters:

identifier - A URI representing the object you want to load data about.

Returns:

A model containing the RDF data to the specified identifier or null if no data could be found.

generateIdentifier

public static String generateIdentifier(Context context,
                        DSpaceObject dso)
                                 throws SQLException

Generates a URI identifying the provided DSpaceObject. This method automatically loads and instantiates the URIGenerator configured in DSpace configuration. Please note that URIs can be generated for DSpaceObjects of the type SITE, COMMUNITY, COLLECTION or ITEM only. Currently dspace-rdf doesn't support Bundles or Bitstreams as independent entity.

Parameters:

context - DSpace Context.

dso - DSpace Object you want to get an identifier for.

Returns:

URI to identify the DSO or null if no URI could be generated. This can happen f.e. if you use a URIGenerator that uses persistent identifier like DOIs or Handles but there is no such identifier assigned to the provided DSO.

Throws:

SQLException

generateIdentifier

public static String generateIdentifier(Context context,
                        int type,
                        int id,
                        String handle,
                        String[] identifier)
                                 throws SQLException

Generates a URI identifying the provided DSpaceObject. This method automatically loads and instantiates the URIGenerator configured in DSpace configuration. Please note that URIs can be generated for DSpaceObjects of the type SITE, COMMUNITY, COLLECTION or ITEM only. Currently dspace-rdf doesn't support Bundles or Bitstreams as independent entity.

Parameters:

context - DSpace Context.

type - Type of the DSpaceObject you want to generate a URI for (g.e. Constants.ITEM.

id - ID of the DSpaceObject you want to generate a URI for.

handle - Handle of the DSpaceObject you want to generate a URI for.

Returns:

URI to identify the DSO or null if no URI could be generated. This can happen f.e. if you use a URIGenerator that uses persistent identifier like DOIs or Handles but there is no such identifier assigned to the provided DSO.

Throws:

SQLException

convert

public static com.hp.hpl.jena.rdf.model.Model convert(Context context,
                                      DSpaceObject dso)
                                               throws org.dspace.rdf.RDFMissingIdentifierException,
                                                      SQLException,
                                                      ItemNotArchivedException,
                                                      ItemWithdrawnException,
                                                      ItemNotDiscoverableException,
                                                      AuthorizeException,
                                                      IllegalArgumentException

Converts the the provided DSpaceObject into RDF and returns the model. Please note that dspace-rdf doesn't support Bundles or Bitstreams as independent entity. You can convert DSpaceObjects of type SITE, COMMUNITY, COLLECTION or ITEM.

Parameters:

context - Consider that the converted data will be stored in a triple store, that is outside the range of the DSpace authorization mechanism. Unless you are really sure what you are doing, you should provide the context of an anonymous user here, as the triple store probably provides a public SPARQL endpoint.

dso - DSpaceObject to convert.

Returns:

The converted data or null if the conversion result is empty. Remember to close the model as soon as you don't need it anymore.

Throws:

RDFMissingIdentifierException - If no identifier could be generated.

SQLException

ItemNotArchivedException - If you want to convert an Item that is not archived.

ItemWithdrawnException - If you want to convert an Item that is withdrawn.

ItemNotDiscoverableException - If you want to convert an Item that is not discoverable.

AuthorizeException - If the DSpaceObject does not have READ permissions with the provided context.

IllegalArgumentException - If the DSpaceObject is not of type SITE, COMMUNITY, COLLECTION or ITEM.

convertAndStore

public static com.hp.hpl.jena.rdf.model.Model convertAndStore(Context context,
                                              DSpaceObject dso)
                                                       throws org.dspace.rdf.RDFMissingIdentifierException,
                                                              SQLException,
                                                              ItemNotArchivedException,
                                                              ItemWithdrawnException,
                                                              ItemNotDiscoverableException,
                                                              AuthorizeException,
                                                              IllegalArgumentException

Converts a DSpaceObject into RDF data and stores them using the configured RDFStorage. Please note that dspace-rdf doesn't support Bundles or Bitstreams as independent entity. You can convert DSpaceObjects of type SITE, COMMUNITY, COLLECTION or ITEM.

Parameters:

context - Consider that the converted data will be stored in a triple store, that is outside the range of the DSpace authorization mechanism. Unless you are really sure what you are doing, you should provide the context of an anonymous user here, as the triple store probably provides a public SPARQL endpoint.

dso - DSpaceObject to convert.

Returns:

The converted data or null if the conversion result is empty. Remember to close the model as soon as you don't need it anymore.

Throws:

RDFMissingIdentifierException - If no identifier could be generated.

SQLException

ItemNotArchivedException - If you want to convert an Item that is not archived.

ItemWithdrawnException - If you want to convert an Item that is withdrawn.

ItemNotDiscoverableException - If you want to convert an Item that is not discoverable.

AuthorizeException - If the DSpaceObject does not have READ permissions with the provided context.

IllegalArgumentException - If the DSpaceObject is not of type SITE, COMMUNITY, COLLECTION or ITEM.

isPublic

public static void isPublic(Context context,
            DSpaceObject dso)
                     throws SQLException,
                            ItemNotArchivedException,
                            ItemWithdrawnException,
                            ItemNotDiscoverableException,
                            AuthorizeException

Checks whether the provided DSpaceObject is readable within the provided context and if the DSO is an Item whether it is archived, discoverable and not withdrawn.

Parameters:

context - Consider that the converted data will be stored in a triple store, that is outside the range of the DSpace authorization mechanism. Unless you are really sure what you are doing, you should provide the context of an anonymous user here, as the triple store probably provides a public SPARQL endpoint.

dso - The DSpaceObjet to check.

Throws:

SQLException

ItemNotArchivedException - If dso is an Item and is not archived.

ItemWithdrawnException - If dso is an Item and is withdrawn.

ItemNotDiscoverableException - If dso is an Item and is not discoverable.

AuthorizeException - If context does not grant READ permissions for dso.

isPublicBoolean

public static boolean isPublicBoolean(Context context,
                      DSpaceObject dso)
                               throws SQLException

Does the same as isPublic(Context, DSpaceObject) but returns a boolean instead of throwing exceptions. For those who don't want to deal with catching exceptions.

Parameters:

context - Consider that the converted data will be stored in a triple store, that is outside the range of the DSpace authorization mechanism. Unless you are really sure what you are doing, you should provide the context of an anonymous user here, as the triple store probably provides a public SPARQL endpoint.

dso - The DSpaceObjet to check.

Returns:

true if isPublic(Context, DSpaceObject) doesn't throw an exception, false if it did.

Throws:

SQLException

delete

public static void delete(String uri)

Deletes the data identified by the URI from the triple store.

Parameters:

uri - URI to identify the named graph to delete.

delete

public static void delete(Context ctx,
          int type,
          int id,
          String handle,
          String[] identifiers)
                   throws SQLException,
                          org.dspace.rdf.RDFMissingIdentifierException

This is a shortcut to generate an RDF identifier for a DSpaceObject and to delete the identified data from the named graph.

Parameters:

ctx -

type - DSpaceObject type (g.e. Constants.ITEM).

id - Id of the DspaceObject.

handle - Handle of the DSpaceObject.

Throws:

SQLException

RDFMissingIdentifierException - In case that no Identifier could be generated.