Package 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)

Field Summary

Fields

Modifier and Type	Field	Description
static final String	CONTENT_NEGOTIATION_KEY
static final String	CONTEXT_PATH_KEY	Property key to load the URL of the dspace-rdf module.
static final String	CONVERTER_DSOTYPES_KEY	Key of the Property to load the types of DSpaceObjects that should get converted.
static final String	SPARQL_ENDPOINT_KEY	Property key to load the public address of the SPARQL endpoint.
static final String	STORAGE_GRAPHSTORE_ENDPOINT_KEY	Property key to load the address of the SPARQL 1.1 GRAPH STORE HTTP PROTOCOL endpoint.
static final String	STORAGE_GRAPHSTORE_LOGIN_KEY	Property key to load the username if authentication for the graph store endpoint is required.
static final String	STORAGE_GRAPHSTORE_PASSWORD_KEY	Property key to load the password if authentication for the graph store endpoint is required.
static final String	STORAGE_SPARQL_ENDPOINT_KEY	Property key to load the address of the SPARQL endpoint to use within DSpace.
static final String	STORAGE_SPARQL_LOGIN_KEY	Property key to load the username if authentication for the internal SPARQL endpoint is required.
static final String	STORAGE_SPARQL_PASSWORD_KEY	Property key to load the password if authentication for the internal SPARQL endpoint is required.

Method Summary

Modifier and Type	Method	Description
static org.apache.jena.rdf.model.Model	convert(Context context, DSpaceObject dso)	Converts the the provided DSpaceObject into RDF and returns the model.
static org.apache.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(String uri)	Deletes the data identified by the URI from the triple store.
static void	delete(Context ctx, int type, UUID id, String handle, List<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 String	generateIdentifier(Context context, int type, UUID id, String handle, List<String> identifier)	Generates a URI identifying the provided DSpaceObject.
static String	generateIdentifier(Context context, DSpaceObject dso)	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 org.apache.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

Field Details

CONTENT_NEGOTIATION_KEY

public static final String CONTENT_NEGOTIATION_KEY

See Also:

• Constant Field Values

CONVERTER_DSOTYPES_KEY

public static final String CONVERTER_DSOTYPES_KEY

Key of the Property to load the types of DSpaceObjects that should get converted.

See Also:

• Constant Field Values

STORAGE_GRAPHSTORE_PASSWORD_KEY

public static final String STORAGE_GRAPHSTORE_PASSWORD_KEY

Property key to load the password if authentication for the graph store endpoint is required.

See Also:

• Constant Field Values

CONTEXT_PATH_KEY

public static final String CONTEXT_PATH_KEY

Property key to load the URL of the dspace-rdf module. This is necessary to create links from the UI to RDF representation of DSpaceObjects.

See Also:

• Constant Field Values

SPARQL_ENDPOINT_KEY

public static final String SPARQL_ENDPOINT_KEY

Property key to load the public address of the SPARQL endpoint.

See Also:

• Constant Field Values

STORAGE_SPARQL_LOGIN_KEY

public static final String STORAGE_SPARQL_LOGIN_KEY

Property key to load the username if authentication for the internal SPARQL endpoint is required.

See Also:

• Constant Field Values

STORAGE_SPARQL_PASSWORD_KEY

public static final String STORAGE_SPARQL_PASSWORD_KEY

Property key to load the password if authentication for the internal SPARQL endpoint is required.

See Also:

• Constant Field Values

STORAGE_GRAPHSTORE_ENDPOINT_KEY

public static final String STORAGE_GRAPHSTORE_ENDPOINT_KEY

Property key to load the address of the SPARQL 1.1 GRAPH STORE HTTP PROTOCOL endpoint.

See Also:

• Constant Field Values

STORAGE_SPARQL_ENDPOINT_KEY

public static final String STORAGE_SPARQL_ENDPOINT_KEY

Property key to load the address of the SPARQL endpoint to use within DSpace. If the property is empty or does not exist, the public SPARQL endpoint will be used.

See Also:

• Constant Field Values

STORAGE_GRAPHSTORE_LOGIN_KEY

public static final String STORAGE_GRAPHSTORE_LOGIN_KEY

Property key to load the username if authentication for the graph store endpoint is required.

See Also:

• Constant Field Values

Method Details

loadModel

public static org.apache.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 configured 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 - An exception that provides information on a database access error or other errors.

generateIdentifier

public static String generateIdentifier(Context context,
 int type,
 UUID id,
 String handle,
 List<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 (e.g. Constants.ITEM.

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

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

identifier - identifiers of the object.

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 - An exception that provides information on a database access error or other errors.

convert

public static org.apache.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:

org.dspace.rdf.RDFMissingIdentifierException - If no identifier could be generated.

SQLException - if database error

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 org.apache.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:

org.dspace.rdf.RDFMissingIdentifierException - If no identifier could be generated.

SQLException - if database error

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 - if database error

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 - if database error

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,
 UUID id,
 String handle,
 List<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 - The relevant DSpace Context.

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

id - Id of the DspaceObject.

handle - Handle of the DSpaceObject.

identifiers - list of identifiers

Throws:

SQLException - if database error

org.dspace.rdf.RDFMissingIdentifierException - In case that no Identifier could be generated.