org.apache.jena.reasoner

Class BaseInfGraph

java.lang.Object

org.apache.jena.graph.impl.GraphBase

org.apache.jena.reasoner.BaseInfGraph

All Implemented Interfaces:

Graph, GraphWithPerform, InfGraph

Direct Known Subclasses:

BasicForwardRuleInfGraph, LPBackwardRuleInfGraph, TransitiveInfGraph

public abstract class BaseInfGraph
extends GraphBase
implements InfGraph

A base level implementation of the InfGraph interface.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BaseInfGraph.InfCapabilities An InfCapabilities notes that size may not be accurate, and some triples may be irremovable.
static class	BaseInfGraph.InfFindSafeCapabilities An InfCapabilities notes that size may not be accurate, and some triples may be irremovable.
static class	BaseInfGraph.InfTransactionHandler

Field Summary

Fields inherited from class org.apache.jena.graph.impl.GraphBase

TOSTRING_TRIPLE_BASE, TOSTRING_TRIPLE_LIMIT

Fields inherited from interface org.apache.jena.graph.Graph

emptyGraph

Constructor Summary

Constructors

Constructor and Description
BaseInfGraph(Graph data, Reasoner reasoner) Constructor

Method Summary

Modifier and Type	Method and Description
void	clear() Remove all the statements from this graph.
InfGraph	cloneWithPremises(Graph premises) Return a new inference graph which is a clone of the current graph together with an additional set of data premises.
void	close() Free all resources, any further use of this Graph is an error.
ExtendedIterator<Triple>	find(Node subject, Node property, Node object, Graph param) An extension of the Graph.find interface which allows the caller to encode complex expressions in RDF and then refer to those expressions within the query triple.
ExtendedIterator<Triple>	find(TriplePattern pattern) Basic pattern lookup interface.
abstract ExtendedIterator<Triple>	findWithContinuation(TriplePattern pattern, Finder continuation) Extended find interface used in situations where the implementator may or may not be able to answer the complete query.
Capabilities	getCapabilities() Answer the InfCapabilities of this InfGraph.
Graph	getDeductionsGraph() Returns a derivations graph.
Iterator<Derivation>	getDerivation(Triple triple) Return the derivation of the given triple (which is the result of some previous find operation).
Node	getGlobalProperty(Node property) Test a global boolean property of the graph.
PrefixMapping	getPrefixMapping() Inference graphs share the prefix-mapping of their underlying raw graph.
Graph	getRawGraph() Return the raw RDF data Graph being processed (i.e.
Reasoner	getReasoner() Return the Reasoner which is being used to answer queries to this graph.
abstract Graph	getSchemaGraph() Return the schema graph, if any, bound into this inference graph.
TransactionHandler	getTransactionHandler() Answer a transaction handler bound to this graph.
int	getVersion() Return a version stamp for this graph which can be used to fast-fail concurrent modification exceptions.
int	graphBaseSize() Return the number of triples in the just the base graph
boolean	isEmpty() Answer true iff this graph is empty.
boolean	isPrepared() Answer true iff this graph has been through the prepare() step.
void	performAdd(Triple t) Add one triple to the data graph, run any rules triggered by the new data item, recursively adding any generated triples.
void	performDelete(Triple t) Removes the triple t (if possible) from the set belonging to this graph.
void	prepare() Perform any initial processing and caching.
void	rebind() Cause the inference graph to reconsult the underlying graph to take into account changes.
void	rebind(Graph data) Replace the underlying data graph for this inference graph and start any inferences over again.
void	remove(Node s, Node p, Node o) Remove all triples that match by find(s, p, o)
void	reset() Reset any internal caches.
void	setDerivationLogging(boolean logOn) Switch on/off drivation logging
boolean	testGlobalProperty(Node property) A convenience version of getGlobalProperty which can only return a boolean result.
ValidityReport	validate() Test the consistency of the bound data.

Methods inherited from class org.apache.jena.graph.impl.GraphBase

add, contains, contains, delete, dependsOn, find, find, forTestingOnly_graphBaseFind, getEventManager, getStatisticsHandler, isClosed, isIsomorphicWith, notifyAdd, notifyDelete, size, toString, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.jena.graph.Graph

add, contains, contains, delete, dependsOn, find, find, find, getEventManager, getStatisticsHandler, isClosed, isIsomorphicWith, size

Constructor Detail

BaseInfGraph

public BaseInfGraph(Graph data,
                    Reasoner reasoner)

Constructor

Parameters:

data - the raw data file to be augmented with entailments

reasoner - the engine, with associated tbox data, whose find interface can be used to extract all entailments from the data.

Method Detail

getPrefixMapping

public PrefixMapping getPrefixMapping()

Inference graphs share the prefix-mapping of their underlying raw graph.

Specified by:

getPrefixMapping in interface Graph

Overrides:

getPrefixMapping in class GraphBase

See Also:

Graph.getPrefixMapping()

getCapabilities

public Capabilities getCapabilities()

Answer the InfCapabilities of this InfGraph.

Specified by:

getCapabilities in interface Graph

Overrides:

getCapabilities in class GraphBase

remove

public void remove(Node s,
                   Node p,
                   Node o)

Description copied from class: GraphBase

Remove all triples that match by find(s, p, o)

Specified by:

remove in interface Graph

Overrides:

remove in class GraphBase

clear

public void clear()

Description copied from class: GraphBase

Remove all the statements from this graph.

Specified by:

clear in interface Graph

Overrides:

clear in class GraphBase

getTransactionHandler

public TransactionHandler getTransactionHandler()

Description copied from class: GraphBase

Answer a transaction handler bound to this graph. The default is SimpleTransactionHandler, which handles no transactions.

Specified by:

getTransactionHandler in interface Graph

Overrides:

getTransactionHandler in class GraphBase

getRawGraph

public Graph getRawGraph()

Return the raw RDF data Graph being processed (i.e. the argument to the Reasonder.bind call that created this InfGraph).

Specified by:

getRawGraph in interface InfGraph

getReasoner

public Reasoner getReasoner()

Return the Reasoner which is being used to answer queries to this graph.

Specified by:

getReasoner in interface InfGraph

rebind

public void rebind(Graph data)

Replace the underlying data graph for this inference graph and start any inferences over again. This is primarily using in setting up ontology imports processing to allow an imports multiunion graph to be inserted between the inference graph and the raw data, before processing.

Specified by:

rebind in interface InfGraph

Parameters:

data - the new raw data graph

rebind

public void rebind()

Cause the inference graph to reconsult the underlying graph to take into account changes. Normally changes are made through the InfGraph's add and remove calls are will be handled appropriately. However, in some cases changes are made "behind the InfGraph's back" and this forces a full reconsult of the changed data.

Specified by:

rebind in interface InfGraph

reset

public void reset()

Reset any internal caches. Some systems, such as the tabled backchainer, retain information after each query. A reset will wipe this information preventing unbounded memory use at the expense of more expensive future queries. A reset does not cause the raw data to be reconsulted and so is less expensive than a rebind.

Specified by:

reset in interface InfGraph

prepare

public void prepare()

Perform any initial processing and caching. This call is optional. Most engines either have negligable set up work or will perform an implicit "prepare" if necessary. The call is provided for those occasions where substantial preparation work is possible (e.g. running a forward chaining rule system) and where an application might wish greater control over when this prepration is done.

Specified by:

prepare in interface InfGraph

getDeductionsGraph

public Graph getDeductionsGraph()

Returns a derivations graph. The rule reasoners typically create a graph containing those triples added to the base graph due to rule firings. In some applications it can useful to be able to access those deductions directly, without seeing the raw data which triggered them. In particular, this allows the forward rules to be used as if they were rewrite transformation rules.

Specified by:

getDeductionsGraph in interface InfGraph

Returns:

the deductions graph, if relevant for this class of inference engine or null if not.

getGlobalProperty

public Node getGlobalProperty(Node property)

Test a global boolean property of the graph. This might included properties like consistency, OWLSyntacticValidity etc. It remains to be seen what level of generality is needed here. We could replace this by a small number of specific tests for common concepts.

Specified by:

getGlobalProperty in interface InfGraph

Parameters:

property - the URI of the property to be tested

Returns:

a Node giving the value of the global property, this may be a boolean literal, some other literal value (e.g. a size).

testGlobalProperty

public boolean testGlobalProperty(Node property)

A convenience version of getGlobalProperty which can only return a boolean result.

Specified by:

testGlobalProperty in interface InfGraph

validate

public ValidityReport validate()

Test the consistency of the bound data. This normally tests the validity of the bound instance data against the bound schema data.

Specified by:

validate in interface InfGraph

Returns:

a ValidityReport structure

find

public ExtendedIterator<Triple> find(Node subject,
                                     Node property,
                                     Node object,
                                     Graph param)

An extension of the Graph.find interface which allows the caller to encode complex expressions in RDF and then refer to those expressions within the query triple. For example, one might encode a class expression and then ask if there are any instances of this class expression in the InfGraph.

Specified by:

find in interface InfGraph

Parameters:

subject - the subject Node of the query triple, may be a Node in the graph or a node in the parameter micro-graph or null

property - the property to be retrieved or null

object - the object Node of the query triple, may be a Node in the graph or a node in the parameter micro-graph.

param - a small graph encoding an expression which the subject and/or object nodes refer.

findWithContinuation

public abstract ExtendedIterator<Triple> findWithContinuation(TriplePattern pattern,
                                                              Finder continuation)

Extended find interface used in situations where the implementator may or may not be able to answer the complete query. It will attempt to answer the pattern but if its answers are not known to be complete then it will also pass the request on to the nested Finder to append more results.

Parameters:

pattern - a TriplePattern to be matched against the data

continuation - either a Finder or a normal Graph which will be asked for additional match results if the implementor may not have completely satisfied the query.

find

public ExtendedIterator<Triple> find(TriplePattern pattern)

Basic pattern lookup interface. This implementation assumes that the underlying findWithContinuation will have also consulted the raw data.

Parameters:

pattern - a TriplePattern to be matched against the data

Returns:

a ExtendedIterator over all Triples in the data set that match the pattern

setDerivationLogging

public void setDerivationLogging(boolean logOn)

Switch on/off drivation logging

Specified by:

setDerivationLogging in interface InfGraph

getDerivation

public Iterator<Derivation> getDerivation(Triple triple)

Return the derivation of the given triple (which is the result of some previous find operation). Not all reasoneers will support derivations.

Specified by:

getDerivation in interface InfGraph

Returns:

an iterator over Derivation records or null if there is no derivation information available for this triple.

graphBaseSize

public int graphBaseSize()

Return the number of triples in the just the base graph

isEmpty

public boolean isEmpty()

Answer true iff this graph is empty. [Used to be in QueryHandler, but moved in here because it's a more primitive operation.]

Specified by:

isEmpty in interface Graph

Overrides:

isEmpty in class GraphBase

close

public void close()

Free all resources, any further use of this Graph is an error.

Specified by:

close in interface Graph

Overrides:

close in class GraphBase

getVersion

public int getVersion()

Return a version stamp for this graph which can be used to fast-fail concurrent modification exceptions.

performAdd

public void performAdd(Triple t)

Add one triple to the data graph, run any rules triggered by the new data item, recursively adding any generated triples.

Specified by:

performAdd in interface GraphWithPerform

Overrides:

performAdd in class GraphBase

performDelete

public void performDelete(Triple t)

Removes the triple t (if possible) from the set belonging to this graph.

Specified by:

performDelete in interface GraphWithPerform

Overrides:

performDelete in class GraphBase

getSchemaGraph

public abstract Graph getSchemaGraph()

Return the schema graph, if any, bound into this inference graph.

cloneWithPremises

public InfGraph cloneWithPremises(Graph premises)

Return a new inference graph which is a clone of the current graph together with an additional set of data premises. The default implementation loses ALL partial deductions so far. Some subclasses may be able to a more efficient job.

isPrepared

public boolean isPrepared()

Answer true iff this graph has been through the prepare() step. For testing purposes.

Returns:

Whether the graph is prepared