Package org.eclipse.rdf4j.query.algebra

Class ZeroLengthPath

java.lang.Object

org.eclipse.rdf4j.query.algebra.AbstractQueryModelNode

org.eclipse.rdf4j.query.algebra.ZeroLengthPath

All Implemented Interfaces:

Serializable, Cloneable, GraphPatternGroupable, QueryModelNode, TupleExpr, VariableScopeChange

public class ZeroLengthPath
extends AbstractQueryModelNode
implements TupleExpr

A tuple expression that matches a path of length zero against an RDF graph. They can can be targeted at one of three context scopes: all contexts, null context only, or named contexts only.

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
ZeroLengthPath()
ZeroLengthPath(StatementPattern.Scope scope, Var subject, Var object)	Creates a zero-length path that matches a subject-, predicate- and object variable against statements from the specified context scope.
ZeroLengthPath(StatementPattern.Scope scope, Var subjVar, Var objVar, Var conVar)	Creates a zero-length path that matches a subject-, predicate-, object- and context variable against statements from the specified context scope.
ZeroLengthPath(Var subject, Var object)	Creates a zero-length path that matches a subject-, predicate- and object variable against statements from all contexts.
ZeroLengthPath(Var subject, Var object, Var context)	Creates a zero-length path that matches a subject-, predicate-, object- and context variable against statements from all contexts.

Method Summary

Modifier and Type	Method	Description
ZeroLengthPath	clone()	Returns a (deep) clone of this query model node.
boolean	equals(Object other)	Returns true if this query model node and its children are recursively equal to o and its children.
Set<String>	getAssuredBindingNames()	Gets the names of the bindings that are guaranteed to be present in the results produced by this tuple expression.
Set<String>	getBindingNames()	Gets the names of the bindings that are, or can be, returned by this tuple expression when it is evaluated.
Var	getContextVar()	Returns the context variable, if available.
Var	getObjectVar()
StatementPattern.Scope	getScope()	Gets the context scope for the zero-length path.
String	getSignature()	Default implementation of QueryModelNode.getSignature() that prints the name of the node's class.
Var	getSubjectVar()
List<Var>	getVarList()
<L extends Collection<Var>> L	getVars(L varCollection)	Adds the variables of this statement pattern to the supplied collection.
int	hashCode()
void	replaceChildNode(QueryModelNode current, QueryModelNode replacement)	Default implementation of QueryModelNode.replaceChildNode(QueryModelNode, QueryModelNode) that throws an IllegalArgumentException indicating that current is not a child node of this node.
void	setContextVar(Var context)
void	setObjectVar(Var object)
void	setScope(StatementPattern.Scope scope)	Sets the context scope for the zero-length path
void	setSubjectVar(Var subject)
<X extends Exception> void	visit(QueryModelVisitor<X> visitor)	Visits this node.
<X extends Exception> void	visitChildren(QueryModelVisitor<X> visitor)	Dummy implementation of QueryModelNode.visitChildren(org.eclipse.rdf4j.query.algebra.QueryModelVisitor<X>) that does nothing.

Methods inherited from class org.eclipse.rdf4j.query.algebra.AbstractQueryModelNode

getCardinality, getCostEstimate, getParentNode, getResultSizeActual, getResultSizeEstimate, getTotalTimeNanosActual, isCardinalitySet, isGraphPatternGroup, isVariableScopeChange, nullEquals, replaceNodeInList, replaceWith, resetCardinality, setCardinality, setCostEstimate, setGraphPatternGroup, setParentNode, setResultSizeActual, setResultSizeEstimate, setTotalTimeNanosActual, setVariableScopeChange, shouldCacheCardinality, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eclipse.rdf4j.query.algebra.QueryModelNode

getCostEstimate, getParentNode, getResultSizeActual, getResultSizeEstimate, getTotalTimeNanosActual, replaceWith, setCostEstimate, setParentNode, setResultSizeActual, setResultSizeEstimate, setTotalTimeNanosActual, toString

Constructor Details

ZeroLengthPath

public ZeroLengthPath()

ZeroLengthPath

public ZeroLengthPath(Var subject,
 Var object)

Creates a zero-length path that matches a subject-, predicate- and object variable against statements from all contexts.

ZeroLengthPath

public ZeroLengthPath(StatementPattern.Scope scope,
 Var subject,
 Var object)

Creates a zero-length path that matches a subject-, predicate- and object variable against statements from the specified context scope.

ZeroLengthPath

public ZeroLengthPath(Var subject,
 Var object,
 Var context)

Creates a zero-length path that matches a subject-, predicate-, object- and context variable against statements from all contexts.

ZeroLengthPath

public ZeroLengthPath(StatementPattern.Scope scope,
 Var subjVar,
 Var objVar,
 Var conVar)

Creates a zero-length path that matches a subject-, predicate-, object- and context variable against statements from the specified context scope.

Method Details

getScope

public StatementPattern.Scope getScope()

Gets the context scope for the zero-length path.

setScope

public void setScope(StatementPattern.Scope scope)

Sets the context scope for the zero-length path

getSubjectVar

public Var getSubjectVar()

setSubjectVar

public void setSubjectVar(Var subject)

getObjectVar

public Var getObjectVar()

setObjectVar

public void setObjectVar(Var object)

getContextVar

public Var getContextVar()

Returns the context variable, if available.

setContextVar

public void setContextVar(Var context)

getBindingNames

public Set<String> getBindingNames()

Description copied from interface: TupleExpr

Gets the names of the bindings that are, or can be, returned by this tuple expression when it is evaluated.

Specified by:

getBindingNames in interface TupleExpr

Returns:

A set of binding names.

getAssuredBindingNames

public Set<String> getAssuredBindingNames()

Description copied from interface: TupleExpr

Gets the names of the bindings that are guaranteed to be present in the results produced by this tuple expression.

Specified by:

getAssuredBindingNames in interface TupleExpr

Returns:

A set of binding names.

getVarList

public List<Var> getVarList()

getVars

public <L extends Collection<Var>> L getVars(L varCollection)

Adds the variables of this statement pattern to the supplied collection.

visit

public <X extends Exception> void visit(QueryModelVisitor<X> visitor)
                                 throws X

Description copied from interface: QueryModelNode

Visits this node. The node reports itself to the visitor with the proper runtime type.

Specified by:

visit in interface QueryModelNode

Throws:

X extends Exception

visitChildren

public <X extends Exception> void visitChildren(QueryModelVisitor<X> visitor)
                                         throws X

Description copied from class: AbstractQueryModelNode

Dummy implementation of QueryModelNode.visitChildren(org.eclipse.rdf4j.query.algebra.QueryModelVisitor<X>) that does nothing. Subclasses should override this method when they have child nodes.

Specified by:

visitChildren in interface QueryModelNode

Overrides:

visitChildren in class AbstractQueryModelNode

Throws:

X extends Exception

replaceChildNode

public void replaceChildNode(QueryModelNode current,
 QueryModelNode replacement)

Description copied from class: AbstractQueryModelNode

Default implementation of QueryModelNode.replaceChildNode(QueryModelNode, QueryModelNode) that throws an IllegalArgumentException indicating that current is not a child node of this node.

Specified by:

replaceChildNode in interface QueryModelNode

Overrides:

replaceChildNode in class AbstractQueryModelNode

Parameters:

current - The current child node.

replacement - The new child node.

getSignature

public String getSignature()

Description copied from class: AbstractQueryModelNode

Default implementation of QueryModelNode.getSignature() that prints the name of the node's class.

Specified by:

getSignature in interface QueryModelNode

Overrides:

getSignature in class AbstractQueryModelNode

Returns:

The node's signature, e.g. SLICE (offset=10, limit=10).

equals

public boolean equals(Object other)

Description copied from interface: QueryModelNode

Returns true if this query model node and its children are recursively equal to o and its children.

Specified by:

equals in interface QueryModelNode

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

clone

public ZeroLengthPath clone()

Description copied from interface: QueryModelNode

Returns a (deep) clone of this query model node. This method recursively clones the entire node tree, starting from this nodes.

Specified by:

clone in interface QueryModelNode

Specified by:

clone in interface TupleExpr

Overrides:

clone in class AbstractQueryModelNode

Returns:

A deep clone of this query model node.