com.bigdata.rdf.spo

Class SPO

java.lang.Object

com.bigdata.rdf.spo.SPO

All Implemented Interfaces:

IElement, ISPO, Serializable, org.openrdf.model.Statement

public class SPO
extends Object
implements ISPO, Serializable

Represents a triple, triple+SID, or quad. When used to represent a triple, the statement identifier MAY be set on the triple after the object has been instantiated. When used to represent a quad, the context position SHOULD be treated as immutable and #setStatementIdentifier(IV) will reject arguments if they can not be validated as statement identifiers (based on their bit pattern).

Version:

$Id$

Author:

Bryan Thompson

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
byte	flags Bit flags used to represent statement type, user flag, override, modified enum, and sidable flag.
IV	o The internal value for the object position.
IV	p The internal value for the predicate position.
IV	s The internal value for the subject position.

Constructor Summary

Constructors

Constructor and Description
SPO(BigdataResource s, BigdataURI p, BigdataValue o, StatementEnum type) Construct a triple from BigdataValues and the specified statement type.
SPO(BigdataStatement stmt) Construct a triple/quad from a BigdataStatement.
SPO(IConstant<IV> s, IConstant<IV> p, IConstant<IV> o, StatementEnum type) Variant to create an SPO from constants (used by the unit tests).
SPO(IPredicate<ISPO> predicate) Variant to create an SPO from a predicate - the StatementEnum and statement identifier are not specified.
SPO(IV s, IV p, IV o) Triple constructor for a statement whose type is NOT known.
SPO(IV s, IV p, IV o, IV c) Quads constructor.
SPO(IV s, IV p, IV o, IV c, StatementEnum type) Quads constructor with StatementEnum.
SPO(IV s, IV p, IV o, StatementEnum type) Construct a triple.

Method Summary

Methods

Modifier and Type	Method and Description
IV	c() The term identifier for the SID/context position (slot 3) -or- #NULL.
boolean	equals(ISPO stmt2) True iff the ISPOs are the same object or if the same term identifiers are assigned for the subject, predicate and object positions, and the same StatementEnum are the same.
boolean	equals(Object o)
IV	get(int index) Return the s,p,o, or c value corresponding to the given index.
org.openrdf.model.Resource	getContext()
ModifiedEnum	getModified() Return the state of the transient modified flag.
org.openrdf.model.Value	getObject()
org.openrdf.model.URI	getPredicate()
IV	getStatementIdentifier() The statement identifier (optional).
StatementEnum	getStatementType() Whether the statement is StatementEnum.Explicit, StatementEnum.Inferred or an StatementEnum.Axiom.
org.openrdf.model.Resource	getSubject()
boolean	getUserFlag() Return true IFF the SPO has the user flag bit set.
int	hashCode() Hash code for the (s,p,o) per Sesame's Statement.hashCode().
boolean	hasStatementIdentifier() true IFF AbstractTripleStore#isStatement(IV) returns true for ISPO.c().
boolean	hasStatementType() Return true iff the statement type is known.
boolean	isAxiom() Return true IFF the SPO is marked as StatementEnum.Axiom.
boolean	isExplicit() Return true IFF the SPO is marked as StatementEnum.Explicit.
boolean	isFullyBound() Return true iff all position (s,p,o) are non-#NULL.
boolean	isInferred() Return true IFF the SPO is marked as StatementEnum.Inferred.
boolean	isModified()
boolean	isOverride() When true the statement will be written onto the database with exactly its current ISPO.getStatementType() (default false).
IV	o() The term identifier for the object position (slot 2) -or- #NULL.
IV	p() The term identifier for the predicate position (slot 1) -or- #NULL.
IV	s() The term identifier for the subject position (slot 0) -or- #NULL.
void	setModified(ModifiedEnum modified) Set a transient flag indicating whether or not the persistent state of the statement was modified when it was last written onto the database.
void	setOverride(boolean override) Set the override flag.
void	setStatementType(StatementEnum type) Set the statement type for this statement.
void	setUserFlag(boolean userFlag) Set the user flag bit on this SPO.
String	toString() Return a representation of the statement using the term identifiers (the identifiers are NOT resolved to terms).
String	toString(IRawTripleStore store) Resolves the term identifiers to terms against the store and returns a representation of the statement using IRawTripleStore.toString(IV, IV, IV).
static String	toString(IV iv) Represents the term identifier together with its type (literal, bnode, uri, or statement identifier).

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

s

public final IV s

The internal value for the subject position.

p

public final IV p

The internal value for the predicate position.

o

public final IV o

The internal value for the object position.

flags

public byte flags

Bit flags used to represent statement type, user flag, override, modified enum, and sidable flag. Much more compact representation.

Constructor Detail

SPO

public SPO(IV s,
   IV p,
   IV o)

Triple constructor for a statement whose type is NOT known.

Note: This is primarily used when you want to discover the type of the statement.

See Also:

AbstractTripleStore#bulkCompleteStatements(ISPOIterator)

SPO

public SPO(IV s,
   IV p,
   IV o,
   IV c)

Quads constructor.

Parameters:

s -

p -

o -

c -

SPO

public SPO(IV s,
   IV p,
   IV o,
   StatementEnum type)

Construct a triple.

Note: When the statement is StatementEnum.Inferred you MUST also construct the appropriate Justification.

Parameters:

s -

p -

o -

type - The statement type.

SPO

public SPO(IV s,
   IV p,
   IV o,
   IV c,
   StatementEnum type)

Quads constructor with StatementEnum.

Parameters:

s -

p -

o -

c -

type -

SPO

public SPO(IConstant<IV> s,
   IConstant<IV> p,
   IConstant<IV> o,
   StatementEnum type)

Variant to create an SPO from constants (used by the unit tests).

Parameters:

s -

p -

o -

type -

SPO

public SPO(IPredicate<ISPO> predicate)

Variant to create an SPO from a predicate - the StatementEnum and statement identifier are not specified. This may be used as a convenience to extract the {s, p, o, c} from an IPredicate or from an IAccessPath when the predicate is not known to be an SPOPredicate.

Parameters:

predicate - The predicate.

SPO

public SPO(BigdataResource s,
   BigdataURI p,
   BigdataValue o,
   StatementEnum type)

Construct a triple from BigdataValues and the specified statement type.

Parameters:

s -

p -

o -

type -

SPO

public SPO(BigdataStatement stmt)

Construct a triple/quad from a BigdataStatement. The term identifiers and statement type information available on the BigdataStatement will be used to initialize the SPO.

Parameters:

stmt - The statement.

Method Detail

get

public final IV get(int index)

Description copied from interface: ISPO

Return the s,p,o, or c value corresponding to the given index.

Specified by:

get in interface IElement

Specified by:

get in interface ISPO

Parameters:

index - The legal values are: s=0, p=1, o=2, c=3.

Returns:

The value at the specified index.

s

public final IV s()

Description copied from interface: ISPO

The term identifier for the subject position (slot 0) -or- #NULL.

Specified by:

s in interface ISPO

p

public final IV p()

Description copied from interface: ISPO

The term identifier for the predicate position (slot 1) -or- #NULL.

Specified by:

p in interface ISPO

o

public final IV o()

Description copied from interface: ISPO

The term identifier for the object position (slot 2) -or- #NULL.

Specified by:

o in interface ISPO

c

public final IV c()

Description copied from interface: ISPO

The term identifier for the SID/context position (slot 3) -or- #NULL. The semantics of the returned value depend on the database mode. For triples, it is unused. For triples+SIDs, it is the statement identifier as assigned by the lexicon. For quads, it is the context (aka named graph) and #NULL iff the context was not bound.

Specified by:

c in interface ISPO

See Also:

AbstractTripleStore.Options#STATEMENT_IDENTIFIERS, AbstractTripleStore.Options#QUADS

getStatementIdentifier

public final IV getStatementIdentifier()

Description copied from interface: ISPO

The statement identifier (optional). This has nearly identical semantics to ISPO.c(), but will throw an exception if the 4th position is not bound.

Statement identifiers are a unique per-triple identifier assigned when a statement is first asserted against the database and are are defined iff AbstractTripleStore.Options#STATEMENT_IDENTIFIERS was specified.

Specified by:

getStatementIdentifier in interface ISPO

hasStatementIdentifier

public final boolean hasStatementIdentifier()

Description copied from interface: ISPO

true IFF AbstractTripleStore#isStatement(IV) returns true for ISPO.c().

Specified by:

hasStatementIdentifier in interface ISPO

setOverride

public void setOverride(boolean override)

Description copied from interface: ISPO

Set the override flag.

Specified by:

setOverride in interface ISPO

Parameters:

override - the new value.

isOverride

public boolean isOverride()

Description copied from interface: ISPO

When true the statement will be written onto the database with exactly its current ISPO.getStatementType() (default false).

Note: This feature is used by TruthMaintenance when we need to downgrade an ISPO from "Explicit" to "Inferred". Normally, a statement is automatically upgraded from "Inferred" to "Explicit" so without ISPO.setOverride(boolean) you could not downgrade the StatementEnum in the database without first deleting the statement (which would also delete its justifications).

Specified by:

isOverride in interface ISPO

isExplicit

public final boolean isExplicit()

Return true IFF the SPO is marked as StatementEnum.Explicit.

Specified by:

isExplicit in interface ISPO

isInferred

public final boolean isInferred()

Return true IFF the SPO is marked as StatementEnum.Inferred.

Specified by:

isInferred in interface ISPO

isAxiom

public final boolean isAxiom()

Return true IFF the SPO is marked as StatementEnum.Axiom.

Specified by:

isAxiom in interface ISPO

getUserFlag

public final boolean getUserFlag()

Return true IFF the SPO has the user flag bit set.

Specified by:

getUserFlag in interface ISPO

setUserFlag

public final void setUserFlag(boolean userFlag)

Set the user flag bit on this SPO.

Specified by:

setUserFlag in interface ISPO

hashCode

public int hashCode()

Hash code for the (s,p,o) per Sesame's Statement.hashCode(). It DOES NOT consider the context position.

Specified by:

hashCode in interface org.openrdf.model.Statement

Overrides:

hashCode in class Object

equals

public boolean equals(Object o)

Specified by:

equals in interface org.openrdf.model.Statement

Overrides:

equals in class Object

equals

public boolean equals(ISPO stmt2)

True iff the ISPOs are the same object or if the same term identifiers are assigned for the subject, predicate and object positions, and the same StatementEnum are the same.

Note: This is NOT the same test as BigdataStatementImpl.equals(Object) since the latter is implemented per the Statement interface.

toString

public String toString()

Return a representation of the statement using the term identifiers (the identifiers are NOT resolved to terms).

Overrides:

toString in class Object

See Also:

ITripleStore#toString(IV, IV, IV)

toString

public static String toString(IV iv)

Represents the term identifier together with its type (literal, bnode, uri, or statement identifier).

Parameters:

iv - The term identifier.

Returns:

toString

public String toString(IRawTripleStore store)

Resolves the term identifiers to terms against the store and returns a representation of the statement using IRawTripleStore.toString(IV, IV, IV).

Specified by:

toString in interface ISPO

Parameters:

store - The store (optional). When non-null the store will be used to resolve term identifiers to terms.

Returns:

The externalized representation of the statement.

isFullyBound

public final boolean isFullyBound()

Description copied from interface: ISPO

Return true iff all position (s,p,o) are non-#NULL.

Note: SPOs are sometimes used to represent triple patterns, e.g., in the tail of a Justification. This method will return true if the "triple pattern" is fully bound and false if there are any unbound positions.

Note: BigdataStatements are not fully bound when they are instantiated during parsing until their term identifiers have been resolved against a database's lexicon.

Specified by:

isFullyBound in interface ISPO

getStatementType

public final StatementEnum getStatementType()

Description copied from interface: ISPO

Whether the statement is StatementEnum.Explicit, StatementEnum.Inferred or an StatementEnum.Axiom.

Specified by:

getStatementType in interface ISPO

Returns:

The StatementEnum type -or- null if the statement type has not been specified.

setStatementType

public final void setStatementType(StatementEnum type)

Description copied from interface: ISPO

Set the statement type for this statement.

Specified by:

setStatementType in interface ISPO

Parameters:

type - The statement type.

hasStatementType

public final boolean hasStatementType()

Description copied from interface: ISPO

Return true iff the statement type is known. true iff the statement type is known for this statement.

Specified by:

hasStatementType in interface ISPO

isModified

public boolean isModified()

Specified by:

isModified in interface ISPO

setModified

public void setModified(ModifiedEnum modified)

Description copied from interface: ISPO

Set a transient flag indicating whether or not the persistent state of the statement was modified when it was last written onto the database. Modification can indicate that the statement was inserted, retracted, or had its associated StatementEnum in the database updated.

Specified by:

setModified in interface ISPO

getModified

public ModifiedEnum getModified()

Description copied from interface: ISPO

Return the state of the transient modified flag. This flag indicates whether or not the persistent state of the statement was modified when it was written onto the database. Modification can indicate that the statement was inserted, retracted, or had its associated StatementEnum in the database updated.

Specified by:

getModified in interface ISPO

getContext

public org.openrdf.model.Resource getContext()

Note: This methods rely on the fact that IV implements Value. The returned IV will act like a Value if it is inline or if it has been materialized. If the IV is not-inline and its value has not been materialized from the appropriate index or explicitly set through IVCache.setValue(BigdataValue), then an attempt to access the state of the Value through its Value interface will throw a NotMaterializedException.

Specified by:

getContext in interface org.openrdf.model.Statement

getObject

public org.openrdf.model.Value getObject()

Note: This methods rely on the fact that IV implements Value. The returned IV will act like a Value if it is inline or if it has been materialized. If the IV is not-inline and its value has not been materialized from the appropriate index or explicitly set through IVCache.setValue(BigdataValue), then an attempt to access the state of the Value through its Value interface will throw a NotMaterializedException.

Specified by:

getObject in interface org.openrdf.model.Statement

getPredicate

public org.openrdf.model.URI getPredicate()

Note: This methods rely on the fact that IV implements Value. The returned IV will act like a Value if it is inline or if it has been materialized. If the IV is not-inline and its value has not been materialized from the appropriate index or explicitly set through IVCache.setValue(BigdataValue), then an attempt to access the state of the Value through its Value interface will throw a NotMaterializedException.

Specified by:

getPredicate in interface org.openrdf.model.Statement

getSubject

public org.openrdf.model.Resource getSubject()

Note: This methods rely on the fact that IV implements Value. The returned IV will act like a Value if it is inline or if it has been materialized. If the IV is not-inline and its value has not been materialized from the appropriate index or explicitly set through IVCache.setValue(BigdataValue), then an attempt to access the state of the Value through its Value interface will throw a NotMaterializedException.

Specified by:

getSubject in interface org.openrdf.model.Statement