org.eclipse.rdf4j.sail.inferencer.fc

Class SchemaCachingRDFSInferencer

java.lang.Object

org.eclipse.rdf4j.sail.helpers.SailWrapper

org.eclipse.rdf4j.sail.helpers.NotifyingSailWrapper

org.eclipse.rdf4j.sail.inferencer.fc.SchemaCachingRDFSInferencer

All Implemented Interfaces:

FederatedServiceResolverClient, NotifyingSail, Sail, StackableSail

public class SchemaCachingRDFSInferencer
extends NotifyingSailWrapper

The SchemaCachingRDFSInferencer is an RDFS reasoner that caches all schema (TBox) statements and calculates an inference map to quickly determine inferred statements. The reasoner can also be instantiated with a predefined schema for improved performance.

This reasoner is not a rule based reasoner and will be up to 80x faster than the ForwardChainingRDFSInferencer, as well as being more complete.

The sail puts no limitations on isolation level for read transactions, however all write/delete/update transactions are serializable with exclusive locks. This limits write/delete/update transactions to one transaction at a time.

Author:

Håvard Mikkelsen Ottestad

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	useInferredToCreateSchema

Constructor Summary

Constructors

Constructor and Description
SchemaCachingRDFSInferencer() Instantiate a new SchemaCachingRDFSInferencer
SchemaCachingRDFSInferencer(NotifyingSail data) Instantiate a SchemaCachingRDFSInferencer.
SchemaCachingRDFSInferencer(NotifyingSail data, boolean useAllRdfsRules) Instantiate a SchemaCachingRDFSInferencer.
SchemaCachingRDFSInferencer(NotifyingSail data, Repository schema) Instantiate a SchemaCachingRDFSInferencer with a predefined schema.
SchemaCachingRDFSInferencer(NotifyingSail data, Repository schema, boolean useAllRdfsRules) Instantiate a SchemaCachingRDFSInferencer with a predefined schema.

Method Summary

Modifier and Type	Method and Description
static SchemaCachingRDFSInferencer	fastInstantiateFrom(SchemaCachingRDFSInferencer sailToInstantiateFrom, NotifyingSail store) Instantiate a new SchemaCachingRDFSInferencer from an existing one.
static SchemaCachingRDFSInferencer	fastInstantiateFrom(SchemaCachingRDFSInferencer sailToInstantiateFrom, NotifyingSail store, boolean useAllRdfsRules) Instantiate a new SchemaCachingRDFSInferencer from an existing one.
SchemaCachingRDFSInferencerConnection	getConnection() Opens a connection on the Sail which can be used to query and update data.
IsolationLevel	getDefaultIsolationLevel() Retrieves the default IsolationLevel level on which transactions in this Sail operate.
List<IsolationLevel>	getSupportedIsolationLevels() Retrieve the IsolationLevels supported by this SAIL, ordered by increasing complexity.
ValueFactory	getValueFactory() Gets a ValueFactory object that can be used to create IRI-, blank node-, literal- and statement objects.
void	initialize() Initializes the Sail.
boolean	isAddInferredStatementsToDefaultContext() Inferred statements can either be added to the default context or to the context that the original inserted statement has.
void	setAddInferredStatementsToDefaultContext(boolean addInferredStatementsToDefaultContext) Inferred statements can either be added to the default context or to the context that the original inserted statement has.

Methods inherited from class org.eclipse.rdf4j.sail.helpers.NotifyingSailWrapper

addSailChangedListener, getBaseSail, removeSailChangedListener, setBaseSail

Methods inherited from class org.eclipse.rdf4j.sail.helpers.SailWrapper

getDataDir, isWritable, setDataDir, setFederatedServiceResolver, shutDown, verifyBaseSailSet

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eclipse.rdf4j.sail.Sail

getDataDir, init, isWritable, setDataDir, shutDown

Field Detail

useInferredToCreateSchema

protected volatile boolean useInferredToCreateSchema

Constructor Detail

SchemaCachingRDFSInferencer

public SchemaCachingRDFSInferencer()

Instantiate a new SchemaCachingRDFSInferencer

SchemaCachingRDFSInferencer

public SchemaCachingRDFSInferencer(NotifyingSail data)

Instantiate a SchemaCachingRDFSInferencer.

Parameters:

data - Base sail for storing data.

SchemaCachingRDFSInferencer

public SchemaCachingRDFSInferencer(NotifyingSail data,
                                   Repository schema)

Instantiate a SchemaCachingRDFSInferencer with a predefined schema. The schema will be used for inference, all other schema statements added will be ignored and no schema statements can be removed. Using a predefined schema significantly improves performance.

Parameters:

data - Base sail for storing data.

schema - Repository containing the schema.

SchemaCachingRDFSInferencer

public SchemaCachingRDFSInferencer(NotifyingSail data,
                                   boolean useAllRdfsRules)

Instantiate a SchemaCachingRDFSInferencer.

Parameters:

data - Base sail for storing data.

useAllRdfsRules - Usel all RDFS rules. If set to false rule rdf4a and rdfs4b will be ignore

SchemaCachingRDFSInferencer

public SchemaCachingRDFSInferencer(NotifyingSail data,
                                   Repository schema,
                                   boolean useAllRdfsRules)

Instantiate a SchemaCachingRDFSInferencer with a predefined schema. The schema will be used for inference, all other schema statements added will be ignored and no schema statements can be removed. Using a predefined schema significantly improves performance.

Parameters:

data - Base sail for storing data.

schema - Repository containing the schema.

useAllRdfsRules - Usel all RDFS rules. If set to false rule rdf4a and rdfs4b will be ignore

Method Detail

initialize

public void initialize()
                throws SailException

Description copied from interface: Sail

Initializes the Sail. Care should be taken that required initialization parameters have been set before this method is called. Please consult the specific Sail implementation for information about the relevant parameters.

Specified by:

initialize in interface Sail

Overrides:

initialize in class SailWrapper

Throws:

SailException - If the Sail could not be initialized.

getConnection

public SchemaCachingRDFSInferencerConnection getConnection()
                                                    throws SailException

Description copied from interface: Sail

Opens a connection on the Sail which can be used to query and update data. Depending on how the implementation handles concurrent access, a call to this method might block when there is another open connection on this Sail.

Specified by:

getConnection in interface NotifyingSail

Specified by:

getConnection in interface Sail

Overrides:

getConnection in class NotifyingSailWrapper

Throws:

SailException - If no transaction could be started, for example because the Sail is not writable.

getValueFactory

public ValueFactory getValueFactory()

Description copied from interface: Sail

Gets a ValueFactory object that can be used to create IRI-, blank node-, literal- and statement objects.

Specified by:

getValueFactory in interface Sail

Overrides:

getValueFactory in class SailWrapper

Returns:

a ValueFactory object for this Sail object.

fastInstantiateFrom

public static SchemaCachingRDFSInferencer fastInstantiateFrom(SchemaCachingRDFSInferencer sailToInstantiateFrom,
                                                              NotifyingSail store)

Instantiate a new SchemaCachingRDFSInferencer from an existing one. Fast instantiation extracts the schema lookup tables generated by the existing sail and uses them to populate the lookup tables of a new reasoner. Schema triples can not be queried in the SchemaCachingRDFSInferencer returned by this method.

Parameters:

sailToInstantiateFrom - The SchemaCachingRDFSInferencer to extract the lookup tables from.

store - Base sail for storing data.

Returns:

inferencer

fastInstantiateFrom

public static SchemaCachingRDFSInferencer fastInstantiateFrom(SchemaCachingRDFSInferencer sailToInstantiateFrom,
                                                              NotifyingSail store,
                                                              boolean useAllRdfsRules)

Instantiate a new SchemaCachingRDFSInferencer from an existing one. Fast instantiation extracts the schema lookup tables generated by the existing sail and uses them to populate the lookup tables of a new reasoner. Schema triples can not be queried in the SchemaCachingRDFSInferencer returned by this method.

Parameters:

sailToInstantiateFrom - The SchemaCachingRDFSInferencer to extract the lookup tables from.

store - Base sail for storing data.

useAllRdfsRules - Use all RDFS rules. If set to false rule rdf4a and rdfs4b will be ignore

Returns:

inferencer

getDefaultIsolationLevel

public IsolationLevel getDefaultIsolationLevel()

Description copied from interface: Sail

Retrieves the default IsolationLevel level on which transactions in this Sail operate.

Specified by:

getDefaultIsolationLevel in interface Sail

Overrides:

getDefaultIsolationLevel in class SailWrapper

Returns:

the IsolationLevel that will be used with SailConnection.begin(), for SAIL connections returned by Sail.getConnection().

getSupportedIsolationLevels

public List<IsolationLevel> getSupportedIsolationLevels()

Description copied from interface: Sail

Retrieve the IsolationLevels supported by this SAIL, ordered by increasing complexity.

Specified by:

getSupportedIsolationLevels in interface Sail

Overrides:

getSupportedIsolationLevels in class SailWrapper

Returns:

a non-empty List of supported Isolation Levels, in order of increasing complexity. Every SAIL supports at least one IsolationLevel.

isAddInferredStatementsToDefaultContext

public boolean isAddInferredStatementsToDefaultContext()

Inferred statements can either be added to the default context or to the context that the original inserted statement has.

setAddInferredStatementsToDefaultContext

public void setAddInferredStatementsToDefaultContext(boolean addInferredStatementsToDefaultContext)

Inferred statements can either be added to the default context or to the context that the original inserted statement has. setAddInferredStatementsToDefaultContext(true) will add all inferred statements to the default context.

Which context a tbox statement is added to is undefined.

Before 3.0 default value for addInferredStatementsToDefaultContext was true. From 3.0 the default value is false.

Parameters:

addInferredStatementsToDefaultContext -