org.semanticdesktop.aperture.rdf.util
Class ModelUtil

java.lang.Object
  org.semanticdesktop.aperture.rdf.util.ModelUtil

public class ModelUtil
extends Object

This class contains utility methods that facilitate the generation of various values from an RDF2Go model. The interface is deliberately similar to that of a ValueFactory, but this class can be used in situations when the code has to work directly with a model, without it being wrapped in an RDFContainer.

Constructor Summary

ModelUtil()

Method Summary

static Object	convertNode(Node node, Class<?> clazz) Converts a node to an instance of the given class.
static BlankNode	createBlankNode(Model model)
static Literal	createLiteral(Model model, boolean value)
static Literal	createLiteral(Model model, byte value)
static Literal	createLiteral(Model model, double value)
static Literal	createLiteral(Model model, float value)
static Literal	createLiteral(Model model, int value)
static Literal	createLiteral(Model model, long value)
static Literal	createLiteral(Model model, short value)
static Literal	createLiteral(Model model, String label)
static Literal	createLiteral(Model model, String label, URI datatype)
static Statement	createStatement(Model model, Resource subject, URI predicate, Node object)
static URI	createURI(Model model, String uri)
static URI	createURI(Model model, String namespaceUri, String localName)
static Resource	generateRandomResource(Model model) This method creates resources that are used by the framework wherever a blank node is needed.
static URI	generateRandomURI(Model model) This method creates URIs that are used by the framework wherever a random URI is needed.
static List<Node>	getAllPropertyValues(Model model, Resource subject, URI predicate) Returns all values of a given property for the given resource.
static Collection<Resource>	getAllSubjectsWithProperty(Model model, URI predicate, Node object) Returns all resources that have a given property with the given value.
static List<Statement>	getCBD(Resource node, Model model, boolean backwards) Returns the Concise Bounded Description of a RDF Resource in a given Model.
static String	getFileName(URI uri) Returns the file name from the uri.
static String	getLocalName(URI vx) The RDF2Go interface doesn't support getting a local name from the URI.
static Node	getPropertyValue(Model model, Resource subject, URI predicate)
static Resource	getSingleSubjectWithProperty(Model model, URI predicate, Node object) Returns a resource that has a given property with the given value.
static boolean	hasStatement(Model model, Resource subject, URI predicate, Node object)
static void	readFileFromResource(Model model, String path, Syntax syntax) Reads rdf from the resource at the given resource path to the given model
static void	removeAllPropertyValues(Model model, Resource subject, URI predicate) Removes all values of the given property for the given resource.

Methods inherited from class java.lang.Object

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

Constructor Detail

ModelUtil

public ModelUtil()

Method Detail

createLiteral

public static Literal createLiteral(Model model,
                                    String label)
                             throws ModelException

Throws:

ModelException

createLiteral

public static Literal createLiteral(Model model,
                                    String label,
                                    URI datatype)
                             throws ModelException

Throws:

ModelException

createLiteral

public static Literal createLiteral(Model model,
                                    boolean value)
                             throws ModelException

Throws:

ModelException

createLiteral

public static Literal createLiteral(Model model,
                                    long value)
                             throws ModelException

Throws:

ModelException

createLiteral

public static Literal createLiteral(Model model,
                                    int value)
                             throws ModelException

Throws:

ModelException

createLiteral

public static Literal createLiteral(Model model,
                                    short value)
                             throws ModelException

Throws:

ModelException

createLiteral

public static Literal createLiteral(Model model,
                                    byte value)
                             throws ModelException

Throws:

ModelException

createLiteral

public static Literal createLiteral(Model model,
                                    double value)
                             throws ModelException

Throws:

ModelException

createLiteral

public static Literal createLiteral(Model model,
                                    float value)
                             throws ModelException

Throws:

ModelException

createStatement

public static Statement createStatement(Model model,
                                        Resource subject,
                                        URI predicate,
                                        Node object)

createURI

public static URI createURI(Model model,
                            String uri)
                     throws ModelException

Throws:

ModelException

createURI

public static URI createURI(Model model,
                            String namespaceUri,
                            String localName)
                     throws ModelException

Throws:

ModelException

createBlankNode

public static BlankNode createBlankNode(Model model)

getCBD

public static List<Statement> getCBD(Resource node,
                                     Model model,
                                     boolean backwards)
                              throws ModelException

Returns the Concise Bounded Description of a RDF Resource in a given Model.

Parameters:

node - The starting node.

model - The model holding the RDF Graph.

backwards - Indicates whether to traverse nodes backwards (null,null,RESOURCE).

Returns:

A List of Statements.

Throws:

ModelException - Whenever access to the Model throws a ModelException.

See Also:

W3C CBD Spec

hasStatement

public static boolean hasStatement(Model model,
                                   Resource subject,
                                   URI predicate,
                                   Node object)
                            throws ModelException

Throws:

ModelException

getSingleSubjectWithProperty

public static Resource getSingleSubjectWithProperty(Model model,
                                                    URI predicate,
                                                    Node object)

Returns a resource that has a given property with the given value. This method assumes that the inverse of this property is obligatory and functional. That is exactly one such subject must exist. In other cases (no subject or more than one subject) an exception is thrown.

Parameters:

model -

predicate -

object -

Returns:

a resource that has a given property and a give value

Throws:

NullPointerException - if any of the arguments are null

ModelException - if there are no, or more than one resources with the given property and the given value

getAllSubjectsWithProperty

public static Collection<Resource> getAllSubjectsWithProperty(Model model,
                                                              URI predicate,
                                                              Node object)

Returns all resources that have a given property with the given value.

Parameters:

model -

predicate -

object -

Returns:

all resources that have a given property with the given value

getPropertyValue

public static Node getPropertyValue(Model model,
                                    Resource subject,
                                    URI predicate)

Parameters:

model - The model to work with.

subject - The subject.

predicate - The property we would like to find.

Returns:

the value of a given property applied to the given subject. If there is more than value, one of the values is returned, if there is none, null is returned.

getAllPropertyValues

public static List<Node> getAllPropertyValues(Model model,
                                              Resource subject,
                                              URI predicate)

Returns all values of a given property for the given resource.

Parameters:

model - The model in which to look for values.

subject - The resource.

predicate - The property.

Returns:

A list of values for of the given property for the given resource.

removeAllPropertyValues

public static void removeAllPropertyValues(Model model,
                                           Resource subject,
                                           URI predicate)

Removes all values of the given property for the given resource.

Parameters:

model - the model in which to look for values

subject - the resource

predicate - the property

convertNode

public static Object convertNode(Node node,
                                 Class<?> clazz)

Converts a node to an instance of the given class.

Parameters:

node - the node

clazz - class to which the node should be converted, currently only primitive types are supported and following RDF2Go classes: URI, Node and Literal

Returns:

the converted object or null if the conversion doesn't work

generateRandomResource

public static Resource generateRandomResource(Model model)

This method creates resources that are used by the framework wherever a blank node is needed. This method currently creates uris of the form urn:uuid: with a random UUID at the end. In the future some way to configure the behaviour of this method may be implemented. For instance blank nodes may be used.

Parameters:

model - a model for which the random resource should be generated

Returns:

a random resource.

generateRandomURI

public static URI generateRandomURI(Model model)

This method creates URIs that are used by the framework wherever a random URI is needed. This method currently creates uris of the form urn:uuid: with a random UUID at the end, hence they are globally unique. In the future some way to configure the behaviour of this method may be implemented, generating different algorithms or URI prefixes.

Parameters:

model - a model for which the random URI should be generated

Returns:

a random URI.

readFileFromResource

public static void readFileFromResource(Model model,
                                        String path,
                                        Syntax syntax)
                                 throws FileNotFoundException,
                                        IOException,
                                        ModelException

Reads rdf from the resource at the given resource path to the given model

Parameters:

model - the model where the RDF data should be stored

path - the resource path

syntax - the syntax

Throws:

FileNotFoundException - if the resource has not been foud

IOException - if an I/O error occurs in the process

ModelException - ...

getFileName

public static String getFileName(URI uri)

Returns the file name from the uri. More specifically the substring before the first hash, but after the last slash.

Parameters:

uri -

Returns:

the last path element

getLocalName

public static String getLocalName(URI vx)

The RDF2Go interface doesn't support getting a local name from the URI. I 'borrowed' this snippet from the Sesame LiteralImpl.