com.bigdata.rdf.sparql.ast

Class ArbitraryLengthPathNode

java.lang.Object

com.bigdata.bop.CoreBaseBOp

com.bigdata.bop.ModifiableBOpBase

com.bigdata.rdf.sparql.ast.ASTBase

com.bigdata.rdf.sparql.ast.QueryNodeBase

com.bigdata.rdf.sparql.ast.GroupMemberNodeBase<ArbitraryLengthPathNode>

com.bigdata.rdf.sparql.ast.ArbitraryLengthPathNode

All Implemented Interfaces:

BOp, IBindingProducerNode, IGroupMemberNode, IQueryNode, IReorderableNode, IVariableBindingRequirements, IPropertySet, Serializable, Cloneable

public class ArbitraryLengthPathNode
extends GroupMemberNodeBase<ArbitraryLengthPathNode>
implements IBindingProducerNode, IReorderableNode

A special kind of AST node that represents the SPARQL 1.1 arbitrary length path operator. This node has a single child arg - a JoinGroupNode consisting of other operators (the path) that must be run to fixed point. This node also has several annotations that define the schematics (the left and right sides and the lower and upper bounds) of the arbitrary length path.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ArbitraryLengthPathNode.Annotations

Field Summary

Fields inherited from class com.bigdata.bop.CoreBaseBOp

DEFAULT_INITIAL_CAPACITY

Fields inherited from interface com.bigdata.bop.BOp

NOANNS, NOARGS

Constructor Summary

Constructors

Constructor and Description
ArbitraryLengthPathNode(ArbitraryLengthPathNode op) Constructor required for com.bigdata.bop.BOpUtility#deepCopy(FilterNode).
ArbitraryLengthPathNode(BOp[] args, Map<String,Object> anns) Required shallow copy constructor.
ArbitraryLengthPathNode(TermNode left, TermNode right, VarNode tVarLeft, VarNode tVarRight, long lowerBound, long upperBound) Fully construct an arbitrary length path node with all required annotations.
ArbitraryLengthPathNode(TermNode left, TermNode right, VarNode tVarLeft, VarNode tVarRight, PathNode.PathMod mod) Fully construct an arbitrary length path node with all required annotations.

Method Summary

Methods

Modifier and Type	Method and Description
void	addDropVar(VarNode dropVar) Add a var that should be dropped after each round.
Set<VarNode>	dropVars() Get the vars that should be dropped after each round.
VarNode	edgeVar() Return the (optional) edge var.
Set<IVariable<?>>	getDefinitelyProducedBindings() Return the variables bound by the path - i.e.
Set<IVariable<?>>	getDesiredBound(StaticAnalysis sa) Get variables that are not required to be bound, but desired in the sense that we want them to be bound when evaluating the construct.
long	getEstimatedCardinality(StaticOptimizer opt) Return the estimated cardinality - either the range count of a statement pattern or some computed estimated cardinality for a join group.
Set<IVariable<?>>	getMaybeProducedBindings() Return the variables bound by the path - i.e.
Set<IVariable<?>>	getRequiredBound(StaticAnalysis sa) Return the variables used in the node that *must* be bound prior to evaluating the node.
Set<IVariable<?>>	getUsedVars() Return the set of variables used by this ALP node (statement pattern terms and inside filters).
boolean	isReorderable() The decision about whether to re-order can no longer be made simply by examining the type - individual instances of a particular type may or may not be reorderable.
TermNode	left() Returns the left term.
long	lowerBound() Return the lower bound.
TermNode	middle() Returns the (optional) middle term.
TermNode	right() Returns the right term.
void	setDropVars(Set<VarNode> dropVars) Set the vars that should be dropped after each round.
void	setEdgeVar(VarNode edgeVar, TermNode middle) Set the edge var and middle term.
JoinGroupNode	subgroup() Return the subgroup.
String	toString(int indent) The contract of this method at this level is under-specified.
VarNode	tVarLeft() Return the left transitivity var.
VarNode	tVarRight() Return the right transitivity var.
long	upperBound() Return the upper bound.

Methods inherited from class com.bigdata.rdf.sparql.ast.GroupMemberNodeBase

getContext, getParent, getParentGraphPatternGroup, getParentJoinGroup, setParent

Methods inherited from class com.bigdata.rdf.sparql.ast.QueryNodeBase

getQueryHints, toString

Methods inherited from class com.bigdata.rdf.sparql.ast.ASTBase

addExplainHint, getExplainHints, getQueryHint, getQueryHint, getQueryHintAsBoolean, getQueryHintAsBoolean, getQueryHintAsInteger, replaceAllWith, setQueryHint, setQueryHints

Methods inherited from class com.bigdata.bop.ModifiableBOpBase

addArg, addArg, addArgIfAbsent, annotations, annotationsEqual, argIterator, args, arity, clearProperty, copyAll, get, getProperty, indexOf, removeArg, replaceWith, setArg, setArgs, setId, setProperty, setUnboundProperty, toArray, toArray

Methods inherited from class com.bigdata.bop.CoreBaseBOp

annotationsEqual, annotationsToString, annotationsToString, annotationValueToString, checkArgs, clone, equals, getEvaluationContext, getId, getProperty, getRequiredProperty, hashCode, indent, isController, mutation, shortenName, toShortString

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.bigdata.rdf.sparql.ast.IGroupMemberNode

getContext, getParent, getParentGraphPatternGroup, getParentJoinGroup, setParent

Methods inherited from interface com.bigdata.bop.BOp

annotations, argIterator, args, arity, clone, get, getEvaluationContext, getId, getProperty, getRequiredProperty, isController, setProperty, toArray, toArray, toShortString, toString

Methods inherited from interface cutthecrap.utils.striterators.IPropertySet

getProperty

Constructor Detail

ArbitraryLengthPathNode

public ArbitraryLengthPathNode(ArbitraryLengthPathNode op)

Constructor required for com.bigdata.bop.BOpUtility#deepCopy(FilterNode).

ArbitraryLengthPathNode

public ArbitraryLengthPathNode(BOp[] args,
                       Map<String,Object> anns)

Required shallow copy constructor.

ArbitraryLengthPathNode

public ArbitraryLengthPathNode(TermNode left,
                       TermNode right,
                       VarNode tVarLeft,
                       VarNode tVarRight,
                       PathNode.PathMod mod)

Fully construct an arbitrary length path node with all required annotations.

ArbitraryLengthPathNode

public ArbitraryLengthPathNode(TermNode left,
                       TermNode right,
                       VarNode tVarLeft,
                       VarNode tVarRight,
                       long lowerBound,
                       long upperBound)

Fully construct an arbitrary length path node with all required annotations.

Method Detail

left

public TermNode left()

Returns the left term.

right

public TermNode right()

Returns the right term.

tVarLeft

public VarNode tVarLeft()

Return the left transitivity var.

tVarRight

public VarNode tVarRight()

Return the right transitivity var.

lowerBound

public long lowerBound()

Return the lower bound.

upperBound

public long upperBound()

Return the upper bound.

middle

public TermNode middle()

Returns the (optional) middle term.

edgeVar

public VarNode edgeVar()

Return the (optional) edge var.

setEdgeVar

public void setEdgeVar(VarNode edgeVar,
              TermNode middle)

Set the edge var and middle term. Only used by the ALP service when projecting edges.

setDropVars

public void setDropVars(Set<VarNode> dropVars)

Set the vars that should be dropped after each round.

See Also:

ArbitraryLengthPathNode.Annotations.DROP_VARS

addDropVar

public void addDropVar(VarNode dropVar)

Add a var that should be dropped after each round.

See Also:

ArbitraryLengthPathNode.Annotations.DROP_VARS

dropVars

public Set<VarNode> dropVars()

Get the vars that should be dropped after each round.

See Also:

ArbitraryLengthPathNode.Annotations.DROP_VARS

subgroup

public JoinGroupNode subgroup()

Return the subgroup.

getMaybeProducedBindings

public Set<IVariable<?>> getMaybeProducedBindings()

Return the variables bound by the path - i.e. what this node will attempt to bind when run.

getDefinitelyProducedBindings

public Set<IVariable<?>> getDefinitelyProducedBindings()

Return the variables bound by the path - i.e. what this node will attempt to bind when run.

getUsedVars

public Set<IVariable<?>> getUsedVars()

Return the set of variables used by this ALP node (statement pattern terms and inside filters). Used to determine what needs to be projected into the op.

toString

public String toString(int indent)

Description copied from class: CoreBaseBOp

The contract of this method at this level is under-specified. Sub-classes may choose between: - return a string representation of the object, similar to the use of CoreBaseBOp.toString() Or: - return a pretty-print representation of the object with indent Note that the former contract may or may not include recursive descent through a tree-like object, whereas the latter almost certainly does.

Specified by:

toString in interface BOp

Specified by:

toString in interface IQueryNode

Overrides:

toString in class CoreBaseBOp

Returns:

isReorderable

public boolean isReorderable()

Description copied from interface: IReorderableNode

The decision about whether to re-order can no longer be made simply by examining the type - individual instances of a particular type may or may not be reorderable.

Specified by:

isReorderable in interface IReorderableNode

getEstimatedCardinality

public long getEstimatedCardinality(StaticOptimizer opt)

Description copied from interface: IReorderableNode

Return the estimated cardinality - either the range count of a statement pattern or some computed estimated cardinality for a join group.

Specified by:

getEstimatedCardinality in interface IReorderableNode

Parameters:

opt - This optimizer can be used to help work out the estimate

getRequiredBound

public Set<IVariable<?>> getRequiredBound(StaticAnalysis sa)

Description copied from interface: IVariableBindingRequirements

Return the variables used in the node that *must* be bound prior to evaluating the node. For instance, when evaluation a SPARQL 1.1 service and the endpoint is specified through a variable, then this variable must be bound in order to identify the endpoint to which the query is to be sent. By *must* be bound we mean that, if it is possible to bring the variables in a join group in order such that they are bound when executing the construct (e.g., think of a FILTER), then we *must* consider that. However, when the IVariableBindingRequirements#getRequiredBound() interface cannot be satisified, the query may still be valid and return results (for the SPARQL 1.1 service example mentioned above, it may not, for the FILTER it may). The set of these variables must be disjoint from IVariableBindingRequirements#getRequiredUnound().

Specified by:

getRequiredBound in interface IVariableBindingRequirements

Returns:

the set of variables that must be bound prior to evaluation

getDesiredBound

public Set<IVariable<?>> getDesiredBound(StaticAnalysis sa)

Description copied from interface: IVariableBindingRequirements

Get variables that are not required to be bound, but desired in the sense that we want them to be bound when evaluating the construct. In general, the more variables are bound, the better, but this might differ for certain constructs. Should only report variables that are *not* reported through method IVariableBindingRequirements.getRequiredBound(StaticAnalysis).

Specified by:

getDesiredBound in interface IVariableBindingRequirements

Returns:

the set of variables that are desires to be bound, but not required