org.apache.jena.query

Interface Dataset

All Superinterfaces:

Transactional

All Known Implementing Classes:

DatasetImpl, DatasetOne

public interface Dataset
extends Transactional

Query is over a Dataset, a collection of named graphs and a background graph (also called the default graph or unnamed graph).

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.jena.sparql.core.Transactional

Transactional.Promote

Method Summary

Modifier and Type	Method and Description
void	abort() Abort a transaction - finish the transaction and undo any changes (if a "write" transaction)
Dataset	addNamedModel(String uri, Model model) Set a named graph.
DatasetGraph	asDatasetGraph() Get the dataset in graph form
void	begin(ReadWrite readWrite) Start either a READ or WRITE transaction
void	close() Close the dataset, potentially releasing any associated resources.
void	commit() Commit a transaction - finish the transaction and make any changes permanent (if a "write" transaction)
boolean	containsNamedModel(String uri) Does the dataset contain a model with the name supplied?
void	end() Finish the transaction - if a write transaction and commit() has not been called, then abort
Context	getContext() Get the context associated with this dataset
Model	getDefaultModel() Get the default graph as a Jena Model
Lock	getLock() Get the lock for this dataset
Model	getNamedModel(String uri) Get a graph by name as a Jena Model
Model	getUnionModel() Get the graph which is the unionof all named graphs as a Jena Model
boolean	isEmpty()
boolean	isInTransaction() Say whether a transaction is active
Iterator<String>	listNames() List the names
Dataset	removeNamedModel(String uri) Remove a named graph.
Dataset	replaceNamedModel(String uri, Model model) Change a named graph for another using the same name
Dataset	setDefaultModel(Model model) Set the default graph.
boolean	supportsTransactionAbort() Declare whether abort() is supported.
boolean	supportsTransactions() Does this dataset support transactions? Supporting transactions means that the dataset implementation provides begin(org.apache.jena.query.ReadWrite), commit(), end() which otherwise may throw UnsupportedOperationException.

Methods inherited from interface org.apache.jena.sparql.core.Transactional

begin, begin, promote, promote, transactionMode, transactionType

Method Detail

getDefaultModel

Model getDefaultModel()

Get the default graph as a Jena Model

getUnionModel

Model getUnionModel()

Get the graph which is the unionof all named graphs as a Jena Model

setDefaultModel

Dataset setDefaultModel(Model model)

Set the default graph. Can be set to null for none.

Parameters:

model - the default graph to set

Returns:

this Dataset for continued usage

getNamedModel

Model getNamedModel(String uri)

Get a graph by name as a Jena Model

containsNamedModel

boolean containsNamedModel(String uri)

Does the dataset contain a model with the name supplied?

addNamedModel

Dataset addNamedModel(String uri,
                      Model model)

Set a named graph.

Parameters:

uri - the name of the graph to set

model - the graph to set

Returns:

this Dataset for continued usage

removeNamedModel

Dataset removeNamedModel(String uri)

Remove a named graph.

Parameters:

uri - the name of the gaph to remove

Returns:

this Dataset for continued usage

replaceNamedModel

Dataset replaceNamedModel(String uri,
                          Model model)

Change a named graph for another using the same name

Parameters:

uri - the name of the graph to replace

model - the graph with which to replace it

Returns:

this Dataset for continued usage

listNames

Iterator<String> listNames()

List the names

getLock

Lock getLock()

Get the lock for this dataset

getContext

Context getContext()

Get the context associated with this dataset

supportsTransactions

boolean supportsTransactions()

Does this dataset support transactions? Supporting transactions means that the dataset implementation provides begin(org.apache.jena.query.ReadWrite), commit(), end() which otherwise may throw UnsupportedOperationException.

See supportsTransactionAbort() for abort(). A Dataset that provides functionality across independent systems can not provide all features strong guarantees. For example, they may use MRSW locking and some isolation control. Specifically, they do not necessarily provide abort().

In addition, check details of a specific implementation.

supportsTransactionAbort

boolean supportsTransactionAbort()

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

begin

void begin(ReadWrite readWrite)

Start either a READ or WRITE transaction

Specified by:

begin in interface Transactional

commit

void commit()

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

Specified by:

commit in interface Transactional

abort

void abort()

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

Specified by:

abort in interface Transactional

isInTransaction

boolean isInTransaction()

Say whether a transaction is active

Specified by:

isInTransaction in interface Transactional

end

void end()

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

Specified by:

end in interface Transactional

asDatasetGraph

DatasetGraph asDatasetGraph()

Get the dataset in graph form

close

void close()

Close the dataset, potentially releasing any associated resources. The dataset can not be used for query after this call.

isEmpty

boolean isEmpty()

Returns:

Whether this Dataset is empty of triples, whether in the default graph or in any named graph.