Class ContextCollector

java.lang.Object

org.eclipse.rdf4j.query.algebra.helpers.AbstractQueryModelVisitor<Exception>

org.eclipse.rdf4j.queryrender.sparql.ContextCollector

All Implemented Interfaces:

QueryModelVisitor<Exception>

public class ContextCollector
extends AbstractQueryModelVisitor<Exception>

Visitor implementation for the query algebra which walks the tree and figures out the context for nodes in the algebra. The context for a node is set on the highest node in the tree. That is, everything below it shares the same context.

Field Summary

Fields

Modifier and Type	Field	Description
private final Map<TupleExpr, Var>	mContexts	Maps TupleExpr to contexts.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	ContextCollector()

Method Summary

Modifier and Type	Method	Description
private void	binaryOpMeet(TupleExpr theCurrentExpr, TupleExpr theLeftExpr, TupleExpr theRightExpr)
(package private) static Map<TupleExpr, Var>	collectContexts(TupleExpr theTupleExpr)
private boolean	isSameCtx(Var v1, Var v2)
void	meet(Difference theOp)
void	meet(Filter theFilter)
void	meet(Intersection theOp)
void	meet(Join theJoin)
void	meet(LeftJoin theJoin)
void	meet(StatementPattern thePattern)
void	meet(Union theOp)
private void	sameCtxCheck(TupleExpr theCurrentExpr, TupleExpr theLeftExpr, Var theLeftCtx, TupleExpr theRightExpr, Var theRightCtx)

Methods inherited from class AbstractQueryModelVisitor

meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meet, meetBinaryTupleOperator, meetBinaryValueOperator, meetCompareSubQueryValueOperator, meetNAryValueOperator, meetNode, meetOther, meetSubQueryValueOperator, meetUnaryTupleOperator, meetUnaryValueOperator, meetUpdateExpr

Methods inherited from class Object

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

Field Details

mContexts

private final Map<TupleExpr, Var> mContexts

Maps TupleExpr to contexts. This map contains only top-level expression elements that share the given context (i.e., all elements below share the same context) -- this is because of where contexts are being introduced into a SPARQL query -- all elements sharing the same contexts are grouped together with a "GRAPH { ... }" clause.

Constructor Details

ContextCollector

private ContextCollector()

Method Details

collectContexts

static Map<TupleExpr, Var> collectContexts(TupleExpr theTupleExpr)
                                    throws Exception

Throws:

Exception

meet

public void meet(Join theJoin)
          throws Exception

Specified by:

meet in interface QueryModelVisitor<Exception>

Overrides:

meet in class AbstractQueryModelVisitor<Exception>

Throws:

Exception

meet

public void meet(LeftJoin theJoin)
          throws Exception

Specified by:

meet in interface QueryModelVisitor<Exception>

Overrides:

meet in class AbstractQueryModelVisitor<Exception>

Throws:

Exception

meet

public void meet(Union theOp)
          throws Exception

Specified by:

meet in interface QueryModelVisitor<Exception>

Overrides:

meet in class AbstractQueryModelVisitor<Exception>

Throws:

Exception

meet

public void meet(Difference theOp)
          throws Exception

Specified by:

meet in interface QueryModelVisitor<Exception>

Overrides:

meet in class AbstractQueryModelVisitor<Exception>

Throws:

Exception

meet

public void meet(Intersection theOp)
          throws Exception

Specified by:

meet in interface QueryModelVisitor<Exception>

Overrides:

meet in class AbstractQueryModelVisitor<Exception>

Throws:

Exception

meet

public void meet(Filter theFilter)
          throws Exception

Specified by:

meet in interface QueryModelVisitor<Exception>

Overrides:

meet in class AbstractQueryModelVisitor<Exception>

Throws:

Exception

binaryOpMeet

private void binaryOpMeet(TupleExpr theCurrentExpr,
 TupleExpr theLeftExpr,
 TupleExpr theRightExpr)
                   throws Exception

Throws:

Exception

meet

public void meet(StatementPattern thePattern)
          throws Exception

Specified by:

meet in interface QueryModelVisitor<Exception>

Overrides:

meet in class AbstractQueryModelVisitor<Exception>

Throws:

Exception

sameCtxCheck

private void sameCtxCheck(TupleExpr theCurrentExpr,
 TupleExpr theLeftExpr,
 Var theLeftCtx,
 TupleExpr theRightExpr,
 Var theRightCtx)

isSameCtx

private boolean isSameCtx(Var v1,
 Var v2)