org.apache.jena.sparql.util

Class DyadicDatasetGraph

java.lang.Object

org.apache.jena.atlas.lib.Pair<T,T>

org.apache.jena.atlas.lib.PairOfSameType<DatasetGraph>

org.apache.jena.sparql.util.DyadicDatasetGraph

All Implemented Interfaces:

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

Direct Known Subclasses:

DifferenceDatasetGraph, IntersectionDatasetGraph, UnionDatasetGraph

public abstract class DyadicDatasetGraph
extends org.apache.jena.atlas.lib.PairOfSameType<DatasetGraph>
implements DatasetGraph

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)
void	add(Node g, Node s, Node p, Node o) Add a quad
void	add(Quad quad) Add a quad
void	addGraph(Node graphName, Graph graph) Add the given graph to the dataset.
void	begin() Start a transaction which is READ mode and which will switch to WRITE if an update is attempted but only if no intermediate transaction has performed an update.
void	begin(ReadWrite readWrite) Start either a READ or WRITE transaction.
void	begin(TxnType type) Start a transaction. READ or WRITE transactions start in that state and do not change for the lifetime of the transaction.
void	clear() Remove everything - remove all named graphs, clear the default graph
void	close() Close the dataset
void	commit() Commit a transaction - finish the transaction and make any changes permanent (if a "write" transaction)
boolean	contains(Quad q) Test whether the dataset contains a quad (including default graph)- may include wildcards, Node.ANY or null
void	delete(Node g, Node s, Node p, Node o) Delete a quad
void	delete(Quad quad) Delete a quad
void	deleteAny(Node g, Node s, Node p, Node o) Delete any quads matching the pattern
void	end() Finish the transaction - if a write transaction and commit() has not been called, then abort
Iterator<Quad>	find() Iterate over all quads in the dataset graph
Iterator<Quad>	find(Node g, Node s, Node p, Node o) Find matching quads in the dataset (including default graph) - may include wildcards, Node.ANY or null
Iterator<Quad>	find(Quad q) Find matching quads in the dataset - may include wildcards, Node.ANY or null
Iterator<Quad>	findNG(Node g, Node s, Node p, Node o) Find matching quads in the dataset in named graphs only - may include wildcards, Node.ANY or null
Context	getContext() Get the context associated with this object - may be null
Lock	getLock() Return a lock for the dataset to help with concurrency control
Graph	getUnionGraph() Return a Graph that is the union of all named graphs in this dataset.
boolean	isEmpty() Test whether the dataset is empty
boolean	isInTransaction() Say whether inside a transaction.
boolean	promote(Transactional.Promote txnType) Attempt to promote a transaction from "read" mode to "write" and the transaction.
void	removeGraph(Node graphName) Remove all data associated with the named graph.
DatasetGraph	setContext(Context c)
void	setDefaultGraph(Graph g) Set the default graph.
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 transactions if it provides Transactional.begin()/ Transactional.commit()/Transactional.end().
ReadWrite	transactionMode() Return the current mode of the transaction - "read" or "write".
TxnType	transactionType() Return the transaction type used in begin(TxnType).

Methods inherited from class org.apache.jena.atlas.lib.PairOfSameType

apply, both, either, forEach

Methods inherited from class org.apache.jena.atlas.lib.Pair

car, cdr, create, equals, getLeft, getRight, hashCode, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

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

contains, containsGraph, getDefaultGraph, getGraph, listGraphNodes

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

promote

Method Detail

commit

public void commit()

Description copied from interface: Transactional

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

Specified by:

commit in interface Transactional

begin

public void begin()

Description copied from interface: Transactional

Start a transaction which is READ mode and which will switch to WRITE if an update is attempted but only if no intermediate transaction has performed an update.

See Transactional.begin(TxnType) for more details an options.

May not be implemented. See Transactional.begin(ReadWrite) is guaranteed to be provided.

Specified by:

begin in interface Transactional

begin

public void begin(TxnType type)

Description copied from interface: Transactional

Start a transaction.
READ or WRITE transactions start in that state and do not change for the lifetime of the transaction.

• WRITE: this guarantees a WRITE will complete if commit() is called. The same as begin(ReadWrite.WRITE).
• READ: the transaction can not promote to WRITE,ensuring read-only access to the data. The same as begin(ReadWrite.READ).
• READ_PROMOTE: the transaction will go from "read" to "write" if an update is attempted and if the dataset has not been changed by another write transaction. See also Transactional.promote().
• READ_COMMITTED_PROMOTE: Use this with care. The promotion will succeed but changes from other transactions become visible.

Read committed: at the point transaction attempts promotion from "read" to "write", the system checks if the dataset has change since the transaction started (called begin). If READ_PROMOTE, the dataset must not have changed; if READ_COMMITTED_PROMOTE any intermediate changes are visible but the application can not assume any data it has read in the transaction is the same as it was at the point the transaction started.

This operation is optional and some implementations may throw a JenaTransactionException exception for some or all TxnType values.

See Transactional.begin(ReadWrite) for a form that is required of implementations.

Specified by:

begin in interface Transactional

promote

public boolean promote(Transactional.Promote txnType)

Description copied from interface: Transactional

Attempt to promote a transaction from "read" mode to "write" and the transaction. This method allows the form of promotion to be specified. The transaction must not have been started with READ, which is read-only.

An argument of READ_PROMOTE treats the promotion as if the transaction was started with READ_PROMOTE (any other writer commiting since the transaction started blocks promotion) and READ_COMMITTED_PROMOTE treats the promotion as if the transaction was started with READ_COMMITTED_PROMOTE (intemediate writer commits become visible).

Returns "true" if the transaction is in write mode after the call. The method always succeeds of the transaction is already "write".

This method returns true if a READ_PROMOTE or READ_COMMITTED_PROMOTE is promoted.

This method returns false if a READ_PROMOTE can't be promoted - the transaction is still valid and in "read" mode.

This method throws an exception if there is an attempt to promote a READ transaction.

Specified by:

promote in interface Transactional

transactionMode

public ReadWrite transactionMode()

Description copied from interface: Transactional

Return the current mode of the transaction - "read" or "write". If the caller is not in a transaction, this method returns null.

Specified by:

transactionMode in interface Transactional

transactionType

public TxnType transactionType()

Description copied from interface: Transactional

Return the transaction type used in begin(TxnType). If the caller is not in a transaction, this method returns null.

Specified by:

transactionType in interface Transactional

begin

public void begin(ReadWrite readWrite)

Description copied from interface: Transactional

Start either a READ or WRITE transaction.

Specified by:

begin in interface Transactional

abort

public void abort()

Description copied from interface: Transactional

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

Specified by:

abort in interface Transactional

end

public void end()

Description copied from interface: Transactional

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

Specified by:

end in interface Transactional

isInTransaction

public boolean isInTransaction()

Description copied from interface: Transactional

Say whether inside a transaction.

Specified by:

isInTransaction in interface Transactional

setDefaultGraph

public void setDefaultGraph(Graph g)

Description copied from interface: DatasetGraph

Set the default graph. Set the active graph if it was null. This replaces the contents default graph, not merge data into it. Do not assume that the same object is returned by DatasetGraph.getDefaultGraph()

Specified by:

setDefaultGraph in interface DatasetGraph

addGraph

public void addGraph(Node graphName,
                     Graph graph)

Description copied from interface: DatasetGraph

Add the given graph to the dataset. Replaces any existing data for the named graph; to add data, get the graph and add triples to it, or add quads to the dataset. Do not assume that the same Java object is returned by DatasetGraph.getGraph(org.apache.jena.graph.Node)

Specified by:

addGraph in interface DatasetGraph

removeGraph

public void removeGraph(Node graphName)

Description copied from interface: DatasetGraph

Remove all data associated with the named graph. This will include prefixes associated with the graph.

Specified by:

removeGraph in interface DatasetGraph

add

public void add(Quad quad)

Description copied from interface: DatasetGraph

Add a quad

Specified by:

add in interface DatasetGraph

delete

public void delete(Quad quad)

Description copied from interface: DatasetGraph

Delete a quad

Specified by:

delete in interface DatasetGraph

add

public void add(Node g,
                Node s,
                Node p,
                Node o)

Description copied from interface: DatasetGraph

Add a quad

Specified by:

add in interface DatasetGraph

delete

public void delete(Node g,
                   Node s,
                   Node p,
                   Node o)

Description copied from interface: DatasetGraph

Delete a quad

Specified by:

delete in interface DatasetGraph

deleteAny

public void deleteAny(Node g,
                      Node s,
                      Node p,
                      Node o)

Description copied from interface: DatasetGraph

Delete any quads matching the pattern

Specified by:

deleteAny in interface DatasetGraph

clear

public void clear()

Description copied from interface: DatasetGraph

Remove everything - remove all named graphs, clear the default graph

Specified by:

clear in interface DatasetGraph

find

public Iterator<Quad> find()

Description copied from interface: DatasetGraph

Iterate over all quads in the dataset graph

Specified by:

find in interface DatasetGraph

find

public Iterator<Quad> find(Quad q)

Description copied from interface: DatasetGraph

Find matching quads in the dataset - may include wildcards, Node.ANY or null

Specified by:

find in interface DatasetGraph

See Also:

Graph.find(Triple)

find

public Iterator<Quad> find(Node g,
                           Node s,
                           Node p,
                           Node o)

Description copied from interface: DatasetGraph

Find matching quads in the dataset (including default graph) - may include wildcards, Node.ANY or null

Specified by:

find in interface DatasetGraph

See Also:

Graph.find(Node,Node,Node)

findNG

public Iterator<Quad> findNG(Node g,
                             Node s,
                             Node p,
                             Node o)

Description copied from interface: DatasetGraph

Find matching quads in the dataset in named graphs only - may include wildcards, Node.ANY or null

Specified by:

findNG in interface DatasetGraph

See Also:

Graph.find(Node,Node,Node)

getUnionGraph

public Graph getUnionGraph()

Description copied from interface: DatasetGraph

Return a Graph that is the union of all named graphs in this dataset. This union graph is read-only (its prefix mapping in the current JVM may be changed but that may not persist).

Specified by:

getUnionGraph in interface DatasetGraph

contains

public boolean contains(Quad q)

Description copied from interface: DatasetGraph

Test whether the dataset contains a quad (including default graph)- may include wildcards, Node.ANY or null

Specified by:

contains in interface DatasetGraph

getLock

public Lock getLock()

Description copied from interface: DatasetGraph

Return a lock for the dataset to help with concurrency control

Specified by:

getLock in interface DatasetGraph

See Also:

Lock

getContext

public Context getContext()

Description copied from interface: DatasetGraph

Get the context associated with this object - may be null

Specified by:

getContext in interface DatasetGraph

setContext

public DatasetGraph setContext(Context c)

close

public void close()

Description copied from interface: DatasetGraph

Close the dataset

Specified by:

close in interface org.apache.jena.atlas.lib.Closeable

Specified by:

close in interface DatasetGraph

supportsTransactions

public boolean supportsTransactions()

Description copied from interface: DatasetGraph

A DatasetGraph supports transactions if it provides Transactional.begin()/ Transactional.commit()/Transactional.end(). The core storage DatasetGraphs provide fully serialized transactions. A DatasetGraph that provides functionality across independent systems can not provide such strong guarantees. For example, it may use MRSW locking and some isolation control. Specifically, it would not necessarily provide Transactional.abort().

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

Specified by:

supportsTransactions in interface DatasetGraph

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.

Specified by:

supportsTransactionAbort in interface DatasetGraph

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

isEmpty

public boolean isEmpty()

Description copied from interface: DatasetGraph

Test whether the dataset is empty

Specified by:

isEmpty in interface DatasetGraph