de.fuberlin.wiwiss.ng4j.db
Class NamedGraphSetDB

java.lang.Object
  de.fuberlin.wiwiss.ng4j.impl.NamedGraphSetIO
      de.fuberlin.wiwiss.ng4j.db.NamedGraphSetDB

All Implemented Interfaces:

NamedGraphSet

public class NamedGraphSetDB
extends NamedGraphSetIO
implements NamedGraphSet

A NamedGraphSet implementation backed by a relational database.

The real work is done by a QuadDB instance. This class provides a NamedGraphSet view onto the QuadDB.

Author:

Richard Cyganiak (richard@cyganiak.de)

Constructor Summary

NamedGraphSetDB(Connection connection)
Creates a persistent NamedGraphSet from a database connection.

NamedGraphSetDB(Connection connection, String tablePrefix)
Creates a persistent NamedGraphSet from a database connection using a table prefix.

NamedGraphSetDB(QuadDB db)
Creates a new NamedGraphSet.

Method Summary

void	addGraph(NamedGraph graph) Adds a NamedGraph to the set.
void	addQuad(Quad quad) Adds a quad to the NamedGraphSet.
Graph	asJenaGraph(Node defaultGraphForAdding) Returns the union graph of the NamedGraphSet.
NamedGraphModel	asJenaModel(String defaultGraphForAdding) Returns a Jena Model view on the NamedGraphSet, equivalent to the union graph of all graphs in the graph set.
void	clear() Deletes all NamedGraphs from the set.
void	close() Closes the NamedGraphSet and frees up resources held.
boolean	containsGraph(Node graphName) Tells wether the NamedGraphSet contains a NamedGraph.
boolean	containsGraph(String graphNameURI) Tells wether the NamedGraphSet contains a NamedGraph.
boolean	containsQuad(Quad pattern) Tells wether the NamedGraphSet contains a quad or quads matching a pattern.
long	countGraphs() Returns the number of NamedGraphs in the set.
int	countQuads() Counts the Quads in the NamedGraphSet.
NamedGraph	createGraph(Node graphName) Creates a new NamedGraph and adds it to the set.
NamedGraph	createGraph(String graphNameURI) Creates a new NamedGraph and adds it to the set.
static void	delete(Connection connection) Drops the persistent NamedGraphSet from the database.
static void	delete(Connection connection, String tablePrefix) Drops a persistent NamedGraphSet from a database.
Iterator	findQuads(Node graphName, Node subject, Node predicate, Node object) Finds Quads that match a pattern.
Iterator	findQuads(Quad pattern) Finds Quads that match a quad pattern.
NamedGraph	getGraph(Node graphName) Returns the NamedGraph with a specific name from the GraphSet.
NamedGraph	getGraph(String graphNameURI) Returns the NamedGraph with a specific name from the GraphSet.
boolean	isEmpty() Tells wether the set contains any NamedGraphs.
Iterator	listGraphs() Returns an iterator over all NamedGraphs in the set.
void	removeGraph(Node graphName) Removes a NamedGraph from the set.
void	removeGraph(String graphNameURI) Removes the NamedGraph with a specific name.
void	removeQuad(Quad pattern) Deletes Quads from the NamedGraphSet.

Methods inherited from class de.fuberlin.wiwiss.ng4j.impl.NamedGraphSetIO

read, read, read, write, write

Methods inherited from class java.lang.Object

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

Methods inherited from interface de.fuberlin.wiwiss.ng4j.NamedGraphSet

read, read, read, write, write

Constructor Detail

NamedGraphSetDB

public NamedGraphSetDB(QuadDB db)

Creates a new NamedGraphSet. The necessary tables will be created automatically if they don't exist.

Parameters:

db - A QuadDB instance which provides persistence for this NamedGraphSet.

NamedGraphSetDB

public NamedGraphSetDB(Connection connection)

Creates a persistent NamedGraphSet from a database connection. The necessary tables will be created automatically if they don't exist.

Parameters:

connection - A connection to an SQL database

NamedGraphSetDB

public NamedGraphSetDB(Connection connection,
                       String tablePrefix)

Creates a persistent NamedGraphSet from a database connection using a table prefix. The necessary tables will be created if they don't exist. The table prefix allows storing multiple NamedGraphSets in a single database.

Parameters:

connection - A connection to an SQL database

tablePrefix - a prefix for all tables used by the new NamedGraphSet

Method Detail

delete

public static void delete(Connection connection)

Drops the persistent NamedGraphSet from the database.

Parameters:

connection - A connection to an SQL database

delete

public static void delete(Connection connection,
                          String tablePrefix)

Drops a persistent NamedGraphSet from a database. Must be used to delete persistent NamedGraphSets that were created with a table prefix.

Parameters:

connection - A connection to an SQL database

tablePrefix - The prefix of the tables used by the NamedGraphSet

addGraph

public void addGraph(NamedGraph graph)

Description copied from interface: NamedGraphSet

Adds a NamedGraph to the set. Will replace a NamedGraph with the same name that is already in the set.

Specified by:

addGraph in interface NamedGraphSet

Parameters:

graph - The NamedGraph to be added

removeGraph

public void removeGraph(Node graphName)

Description copied from interface: NamedGraphSet

Removes a NamedGraph from the set. Nothing happens if no graph with that name is contained in the set. Node.ANY will remove all graphs from the set.

Specified by:

removeGraph in interface NamedGraphSet

Parameters:

graphName - The name of the NamedGraph to be removed

removeGraph

public void removeGraph(String graphNameURI)

Description copied from interface: NamedGraphSet

Removes the NamedGraph with a specific name. Nothing happens if no graph with that name is contained in the set. Node.ANY will remove all graphs from the set.

Specified by:

removeGraph in interface NamedGraphSet

Parameters:

graphNameURI - The name of the NamedGraph to be removed

containsGraph

public boolean containsGraph(Node graphName)

Description copied from interface: NamedGraphSet

Tells wether the NamedGraphSet contains a NamedGraph.

Specified by:

containsGraph in interface NamedGraphSet

Parameters:

graphName - The name of a NamedGraph

Returns:

True if the set contains a graph with that name, false otherwise.

containsGraph

public boolean containsGraph(String graphNameURI)

Description copied from interface: NamedGraphSet

Tells wether the NamedGraphSet contains a NamedGraph.

Specified by:

containsGraph in interface NamedGraphSet

Parameters:

graphNameURI - The name of a NamedGraph

Returns:

True if the set contains a graph with that name, false otherwise.

getGraph

public NamedGraph getGraph(Node graphName)

Description copied from interface: NamedGraphSet

Returns the NamedGraph with a specific name from the GraphSet. Changes to the graph will be reflected in the set.

Specified by:

getGraph in interface NamedGraphSet

Parameters:

graphName - The name of the NamedGraph to be returned

Returns:

The graph with that name, or null if no graph with that name is contained in the set

getGraph

public NamedGraph getGraph(String graphNameURI)

Description copied from interface: NamedGraphSet

Returns the NamedGraph with a specific name from the GraphSet. Changes to the graph will be reflected in the set.

Specified by:

getGraph in interface NamedGraphSet

Parameters:

graphNameURI - The name of the NamedGraph to be returned

Returns:

The graph with that name, or null if no graph with that name is contained in the set

createGraph

public NamedGraph createGraph(Node graphName)

Description copied from interface: NamedGraphSet

Creates a new NamedGraph and adds it to the set. An existing graph with the same name will be replaced.

Specified by:

createGraph in interface NamedGraphSet

Parameters:

graphName - The name of the NamedGraph to be created; must be an URI node

Returns:

The newly created NamedGraph instance

createGraph

public NamedGraph createGraph(String graphNameURI)

Description copied from interface: NamedGraphSet

Creates a new NamedGraph and adds it to the set. An existing graph with the same name will be replaced.

Specified by:

createGraph in interface NamedGraphSet

Parameters:

graphNameURI - The name of the NamedGraph to be created; must be an URI

Returns:

The newly created NamedGraph instance

listGraphs

public Iterator listGraphs()

Description copied from interface: NamedGraphSet

Returns an iterator over all NamedGraphs in the set.

Specified by:

listGraphs in interface NamedGraphSet

Returns:

An iterator over all NamedGraphs in the set

countGraphs

public long countGraphs()

Description copied from interface: NamedGraphSet

Returns the number of NamedGraphs in the set. Empty graphs are counted.

Specified by:

countGraphs in interface NamedGraphSet

Returns:

The number of NamedGraphs in the set.

isEmpty

public boolean isEmpty()

Description copied from interface: NamedGraphSet

Tells wether the set contains any NamedGraphs.

Specified by:

isEmpty in interface NamedGraphSet

Returns:

True if the set contains any NamedGraphs, false otherwise

clear

public void clear()

Description copied from interface: NamedGraphSet

Deletes all NamedGraphs from the set.

Specified by:

clear in interface NamedGraphSet

addQuad

public void addQuad(Quad quad)

Description copied from interface: NamedGraphSet

Adds a quad to the NamedGraphSet. The argument must not contain any wildcards. If the quad is already present, nothing happens. A new named graph will automatically be created if necessary.

Specified by:

addQuad in interface NamedGraphSet

Parameters:

quad - A quad to be added to the NamedGraphSet

containsQuad

public boolean containsQuad(Quad pattern)

Description copied from interface: NamedGraphSet

Tells wether the NamedGraphSet contains a quad or quads matching a pattern. Quad patterns are Quad instances with Node.ANY in one or more positions.

Specified by:

containsQuad in interface NamedGraphSet

Parameters:

pattern - A quad or quad pattern

Returns:

True if The NamedGraphSet contains matching quads, false otherwise

removeQuad

public void removeQuad(Quad pattern)

Description copied from interface: NamedGraphSet

Deletes Quads from the NamedGraphSet. The argument may contain wildcards (Node.ANY). All matching Quads will be deleted. If no Quads match, nothing happens. This operation will not delete any NamedGraphs from the set. Empty NamedGraphs will be retained.

Specified by:

removeQuad in interface NamedGraphSet

Parameters:

pattern - A quad or quad pattern to be deleted

countQuads

public int countQuads()

Description copied from interface: NamedGraphSet

Counts the Quads in the NamedGraphSet. Identical Triples in different NamedGraphs are counted individually.

Specified by:

countQuads in interface NamedGraphSet

Returns:

The number of Quads in the set

findQuads

public Iterator findQuads(Quad pattern)

Description copied from interface: NamedGraphSet

Finds Quads that match a quad pattern. The argument may contain wildcards (Node.ANY).

Specified by:

findQuads in interface NamedGraphSet

Parameters:

pattern - A quad or quad pattern

Returns:

An iterator over all Quads that match the pattern

findQuads

public Iterator findQuads(Node graphName,
                          Node subject,
                          Node predicate,
                          Node object)

Description copied from interface: NamedGraphSet

Finds Quads that match a pattern. All arguments may be Node.ANY to match everything in that position.

Specified by:

findQuads in interface NamedGraphSet

Parameters:

graphName - The graph to find triples from

subject - The subject to be matched

predicate - The predicate to be matched

object - The object to be matched

Returns:

An iterator over all Quads that match the pattern

asJenaGraph

public Graph asJenaGraph(Node defaultGraphForAdding)

Description copied from interface: NamedGraphSet

Returns the union graph of the NamedGraphSet. The graph is backed by the NamedGraphSet: Subsequent changes to one are reflected in the other.

Add operations to the union graph are all written to the default graph specified as the argument.

Delete operations remove the triple from all NamedGraphs.

Specified by:

asJenaGraph in interface NamedGraphSet

Parameters:

defaultGraphForAdding - The name of the default graph used for adding triples; must be an URI

Returns:

A Graph view on the NamedGraphSet

asJenaModel

public NamedGraphModel asJenaModel(String defaultGraphForAdding)

Description copied from interface: NamedGraphSet

Returns a Jena Model view on the NamedGraphSet, equivalent to the union graph of all graphs in the graph set.

Add operations on the returned model are all written to the default graph.

Read and write operations one the returned model have the behaviour of NamedGraphSet.read(String, String) and NamedGraphSet.write(OutputStream, String, String).

All Statements returned by the NamedGraphModel can be casted to NamedGraphStatement to access information about the graphs they are contained in.

Specified by:

asJenaModel in interface NamedGraphSet

Parameters:

defaultGraphForAdding - The name of the default graph used for adding triples; must be an URI

Returns:

A Model view on the NamedGraphSet

close

public void close()

Description copied from interface: NamedGraphSet

Closes the NamedGraphSet and frees up resources held. Any subsequent calls to methods of the object have undefined results.

Specified by:

close in interface NamedGraphSet