org.apache.jena.sparql.core

Class DatasetGraphMap

java.lang.Object

org.apache.jena.sparql.core.DatasetGraphBase

org.apache.jena.sparql.core.DatasetGraphBaseFind

org.apache.jena.sparql.core.DatasetGraphTriplesQuads

org.apache.jena.sparql.core.DatasetGraphMap

All Implemented Interfaces:

org.apache.jena.atlas.lib.Closeable, DatasetGraph, Transactional

public class DatasetGraphMap
extends DatasetGraphTriplesQuads

Implementation of a DatasetGraph as an extensible set of graphs. Subclasses need to manage any implicit graph creation.

This implementation provides copy-in, copy-out for DatasetGraphTriplesQuads.addGraph(org.apache.jena.graph.Node, org.apache.jena.graph.Graph).

See DatasetGraphMapLink for a DatasetGraph that holds graphs as provided.

See Also:

DatasetGraphMapLink

Constructor Summary

Constructors

Constructor and Description
DatasetGraphMap() DatasetGraphMap defaulting to storage in memory.
DatasetGraphMap(DatasetGraphFactory.GraphMaker graphMaker) DatasetGraphMap with a specific policy for graph creation.
DatasetGraphMap(Graph defaultGraph, DatasetGraphFactory.GraphMaker graphMaker)

Method Summary

Modifier and Type	Method and Description
void	abort() Abort a transaction - finish the transaction and undo any changes (if a "write" transaction)
void	begin(ReadWrite mode) Start either a READ or WRITE transaction
void	commit() Commit a transaction - finish the transaction and make any changes permanent (if a "write" transaction)
void	end() Finish the transaction - if a write transaction and commit() has not been called, then abort
Graph	getDefaultGraph() Get the default graph as a Jena Graph
Graph	getGraph(Node graphNode) Get the graph named by graphNode : returns null on no graph NB Whether a dataset contains a graph if there are no triples is not defined - see the specifc implementation.
boolean	isInTransaction() Say whether inside a transaction.
Iterator<Node>	listGraphNodes() Iterate over all names of named graphs
long	size() Get the size (number of named graphs) - may be -1 for unknown
boolean	supportsTransactionAbort() Declare whether Transactional.abort() is supported.
boolean	supportsTransactions() A DatasetGraph supports tranactions if it provides Transactional.begin(org.apache.jena.query.ReadWrite)/ Transactional.commit()/Transactional.end().

Methods inherited from class org.apache.jena.sparql.core.DatasetGraphTriplesQuads

add, add, addGraph, delete, delete, removeGraph, setDefaultGraph

Methods inherited from class org.apache.jena.sparql.core.DatasetGraphBaseFind

find, findInUnionGraph, findNG, findQuadsInUnionGraph

Methods inherited from class org.apache.jena.sparql.core.DatasetGraphBase

clear, close, contains, contains, containsGraph, deleteAny, find, find, getContext, getLock, isEmpty, toString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

DatasetGraphMap

public DatasetGraphMap()

DatasetGraphMap defaulting to storage in memory.

DatasetGraphMap

public DatasetGraphMap(DatasetGraphFactory.GraphMaker graphMaker)

DatasetGraphMap with a specific policy for graph creation. This allows control over the storage.

DatasetGraphMap

public DatasetGraphMap(Graph defaultGraph,
                       DatasetGraphFactory.GraphMaker graphMaker)

Method Detail

begin

public void begin(ReadWrite mode)

Description copied from interface: Transactional

Start either a READ or WRITE transaction

commit

public void commit()

Description copied from interface: Transactional

Commit a transaction - finish the transaction and make any changes permanent (if a "write" transaction)

abort

public void abort()

Description copied from interface: Transactional

Abort a transaction - finish the transaction and undo any changes (if a "write" transaction)

isInTransaction

public boolean isInTransaction()

Description copied from interface: Transactional

Say whether inside a transaction.

end

public void end()

Description copied from interface: Transactional

Finish the transaction - if a write transaction and commit() has not been called, then abort

supportsTransactions

public boolean supportsTransactions()

Description copied from interface: DatasetGraph

A DatasetGraph supports tranactions if it provides Transactional.begin(org.apache.jena.query.ReadWrite)/ Transactional.commit()/Transactional.end(). There core storage DatasetGraph that provide fully serialized transactions. DatasetGraph that provide functionality acorss independent systems can not provide such strong guarantees. For example, they may use MRSW locking and some isolation control. Specifically, they do not necessarily provide Transactional.abort().

See DatasetGraph.supportsTransactionAbort() for Transactional.abort(). In addition, check details of a specific implementation.

supportsTransactionAbort

public boolean supportsTransactionAbort()

Description copied from interface: DatasetGraph

Declare whether Transactional.abort() is supported. This goes along with clearing up after exceptions inside application transaction code.

listGraphNodes

public Iterator<Node> listGraphNodes()

Description copied from interface: DatasetGraph

Iterate over all names of named graphs

getDefaultGraph

public Graph getDefaultGraph()

Description copied from interface: DatasetGraph

Get the default graph as a Jena Graph

Specified by:

getDefaultGraph in interface DatasetGraph

Specified by:

getDefaultGraph in class DatasetGraphBase

getGraph

public Graph getGraph(Node graphNode)

Description copied from interface: DatasetGraph

Get the graph named by graphNode : returns null on no graph NB Whether a dataset contains a graph if there are no triples is not defined - see the specifc implementation. Some datasets are "open" - they have all graphs even if no triples,

Specified by:

getGraph in interface DatasetGraph

Specified by:

getGraph in class DatasetGraphBase

size

public long size()

Description copied from interface: DatasetGraph

Get the size (number of named graphs) - may be -1 for unknown

Specified by:

size in interface DatasetGraph

Overrides:

size in class DatasetGraphBase