Examples with Var org.eclipse.rdf4j.query.algebra.Var used on opensource projects

Example 41 with Var

use of org.eclipse.rdf4j.query.algebra.Var in project rdf4j by eclipse.

the class TupleExprBuilder method processHavingClause.

private TupleExpr processHavingClause(ASTHavingClause havingNode, TupleExpr tupleExpr, Group group) throws VisitorException {
    if (havingNode != null) {
        // create an implicit group
        if (group == null) {
            group = new Group(tupleExpr);
        }
        ValueExpr expr = (ValueExpr) havingNode.jjtGetChild(0).jjtAccept(this, tupleExpr);
        // retrieve any aggregate operators from the expression.
        AggregateCollector collector = new AggregateCollector();
        collector.meetOther(expr);
        // replace operator occurrences with an anonymous var, and alias it
        // to the group
        Extension extension = new Extension();
        for (AggregateOperator operator : collector.getOperators()) {
            Var var = createAnonVar();
            // replace occurrence of the operator in the filter expression
            // with the variable.
            AggregateOperatorReplacer replacer = new AggregateOperatorReplacer(operator, var);
            replacer.meetOther(expr);
            String alias = var.getName();
            // create an extension linking the operator to the variable
            // name.
            ExtensionElem pe = new ExtensionElem(operator, alias);
            extension.addElement(pe);
            // add the aggregate operator to the group.
            GroupElem ge = new GroupElem(alias, operator);
            // FIXME quite often the aggregate in the HAVING clause will be
            // a duplicate of an aggregate in the projection. We could
            // perhaps
            // optimize for that, to avoid having to evaluate twice.
            group.addGroupElement(ge);
        }
        extension.setArg(group);
        tupleExpr = new Filter(extension, expr);
    }
    return tupleExpr;
}

Example 42 with Var

use of org.eclipse.rdf4j.query.algebra.Var in project rdf4j by eclipse.

the class QueryBuilderFactory method describe.

/**
 * Create a QueryBuilder for creating a describe query
 *
 * @param theVars
 *        the variables to be described
 * @param theValues
 *        the specific bound URI values to be described
 * @return a describe query builder
 */
public static QueryBuilder<ParsedGraphQuery> describe(String[] theVars, Resource... theValues) {
    QueryBuilder<ParsedGraphQuery> aBuilder = new AbstractQueryBuilder<ParsedGraphQuery>(new ParsedDescribeQuery());
    aBuilder.reduced();
    aBuilder.addProjectionVar("descr_subj", "descr_pred", "descr_obj");
    GroupBuilder<?, ?> aGroup = aBuilder.group();
    if (theVars != null) {
        for (String aVar : theVars) {
            Var aVarObj = new Var(aVar);
            aVarObj.setAnonymous(true);
            aGroup.filter().or(new SameTerm(aVarObj, new Var("descr_subj")), new SameTerm(aVarObj, new Var("descr_obj")));
        }
    }
    if (theValues != null) {
        for (Resource aVar : theValues) {
            Var aSubjVar = new Var("descr_subj");
            aSubjVar.setAnonymous(true);
            Var aObjVar = new Var("descr_obj");
            aObjVar.setAnonymous(true);
            aGroup.filter().or(new SameTerm(new ValueConstant(aVar), aSubjVar), new SameTerm(new ValueConstant(aVar), aObjVar));
        }
    }
    aGroup.atom("descr_subj", "descr_pred", "descr_obj");
    return aBuilder;
}

Example 43 with Var

use of org.eclipse.rdf4j.query.algebra.Var in project rdf4j by eclipse.

the class ContextCollector method binaryOpMeet.

private void binaryOpMeet(TupleExpr theCurrentExpr, TupleExpr theLeftExpr, TupleExpr theRightExpr) throws Exception {
    theLeftExpr.visit(this);
    Var aLeftCtx = mContexts.get(theLeftExpr);
    theRightExpr.visit(this);
    Var aRightCtx = mContexts.get(theRightExpr);
    sameCtxCheck(theCurrentExpr, theLeftExpr, aLeftCtx, theRightExpr, aRightCtx);
}

Example 44 with Var

use of org.eclipse.rdf4j.query.algebra.Var in project rdf4j by eclipse.

the class TupleExprBuilder method visit.

@Override
public Object visit(ASTPathSequence pathSeqNode, Object data) throws VisitorException {
    ValueExpr subject = (ValueExpr) data;
    Var subjVar = mapValueExprToVar(subject);
    // check if we should invert subject and object.
    boolean invertSequence = checkInverse(pathSeqNode);
    @SuppressWarnings("unchecked") List<ValueExpr> objectList = (List<ValueExpr>) getObjectList(pathSeqNode).jjtAccept(this, null);
    List<ASTPathElt> pathElements = pathSeqNode.getPathElements();
    int pathLength = pathElements.size();
    GraphPattern pathSequencePattern = new GraphPattern(graphPattern);
    Scope scope = pathSequencePattern.getStatementPatternScope();
    Var contextVar = pathSequencePattern.getContextVar();
    Var startVar = subjVar;
    for (int i = 0; i < pathLength; i++) {
        ASTPathElt pathElement = pathElements.get(i);
        ASTPathMod pathMod = pathElement.getPathMod();
        long lowerBound = Long.MIN_VALUE;
        long upperBound = Long.MIN_VALUE;
        if (pathMod != null) {
            lowerBound = pathMod.getLowerBound();
            upperBound = pathMod.getUpperBound();
            if (upperBound == Long.MIN_VALUE) {
                upperBound = lowerBound;
            } else if (lowerBound == Long.MIN_VALUE) {
                lowerBound = upperBound;
            }
        }
        if (pathElement.isNegatedPropertySet()) {
            // create a temporary negated property set object and set the
            // correct subject and object vars to continue
            // the path sequence.
            NegatedPropertySet nps = new NegatedPropertySet();
            nps.setScope(scope);
            nps.setSubjectVar(startVar);
            nps.setContextVar(contextVar);
            for (Node child : pathElement.jjtGetChildren()) {
                if (child instanceof ASTPathMod) {
                    // skip the modifier
                    continue;
                }
                nps.addPropertySetElem((PropertySetElem) child.jjtAccept(this, data));
            }
            Var[] objVarReplacement = null;
            if (i == pathLength - 1) {
                if (objectList.contains(subjVar)) {
                    // See SES-1685
                    Var objVar = mapValueExprToVar(objectList.get(objectList.indexOf(subjVar)));
                    objVarReplacement = new Var[] { objVar, createAnonVar() };
                    objectList.remove(objVar);
                    objectList.add(objVarReplacement[1]);
                } else {
                    nps.setObjectList(objectList);
                }
            } else {
                // not last element in path.
                Var nextVar = createAnonVar();
                List<ValueExpr> nextVarList = new ArrayList<ValueExpr>();
                nextVarList.add(nextVar);
                nps.setObjectList(nextVarList);
                startVar = nextVar;
            }
            // convert the NegatedPropertySet to a proper TupleExpr
            TupleExpr te = createTupleExprForNegatedPropertySet(nps, i);
            if (objVarReplacement != null) {
                SameTerm condition = new SameTerm(objVarReplacement[0], objVarReplacement[1]);
                pathSequencePattern.addConstraint(condition);
            }
            for (ValueExpr object : objectList) {
                Var objVar = mapValueExprToVar(object);
                te = handlePathModifiers(scope, subjVar, te, objVar, contextVar, lowerBound, upperBound);
            }
            pathSequencePattern.addRequiredTE(te);
        } else if (pathElement.isNestedPath()) {
            GraphPattern parentGP = graphPattern;
            graphPattern = new GraphPattern(parentGP);
            if (i == pathLength - 1) {
                // last element in the path
                pathElement.jjtGetChild(0).jjtAccept(this, startVar);
                TupleExpr te = graphPattern.buildTupleExpr();
                for (ValueExpr object : objectList) {
                    Var objVar = mapValueExprToVar(object);
                    if (objVar.equals(subjVar)) {
                        // see SES-1685
                        Var objVarReplacement = createAnonVar();
                        te = handlePathModifiers(scope, startVar, te, objVarReplacement, contextVar, lowerBound, upperBound);
                        SameTerm condition = new SameTerm(objVar, objVarReplacement);
                        pathSequencePattern.addConstraint(condition);
                    } else {
                        te = handlePathModifiers(scope, startVar, te, objVar, contextVar, lowerBound, upperBound);
                    }
                    pathSequencePattern.addRequiredTE(te);
                }
            } else {
                // not the last element in the path, introduce an anonymous
                // var
                // to connect.
                Var nextVar = createAnonVar();
                pathElement.jjtGetChild(0).jjtAccept(this, startVar);
                TupleExpr te = graphPattern.buildTupleExpr();
                // replace all object list occurrences with the intermediate
                // var.
                te = replaceVarOccurrence(te, objectList, nextVar);
                te = handlePathModifiers(scope, startVar, te, nextVar, contextVar, lowerBound, upperBound);
                pathSequencePattern.addRequiredTE(te);
                startVar = nextVar;
            }
            graphPattern = parentGP;
        } else {
            ValueExpr pred = (ValueExpr) pathElement.jjtAccept(this, data);
            Var predVar = mapValueExprToVar(pred);
            TupleExpr te;
            if (i == pathLength - 1) {
                // objects
                for (ValueExpr object : objectList) {
                    Var objVar = mapValueExprToVar(object);
                    boolean replaced = false;
                    // to avoid problems in cyclic paths
                    if (objVar.equals(subjVar)) {
                        objVar = createAnonVar();
                        replaced = true;
                    }
                    Var endVar = objVar;
                    if (invertSequence) {
                        endVar = subjVar;
                        if (startVar.equals(subjVar)) {
                            // inverted path sequence of length 1.
                            startVar = objVar;
                        }
                    }
                    if (pathElement.isInverse()) {
                        te = new StatementPattern(scope, endVar, predVar, startVar, contextVar);
                        te = handlePathModifiers(scope, endVar, te, startVar, contextVar, lowerBound, upperBound);
                    } else {
                        te = new StatementPattern(scope, startVar, predVar, endVar, contextVar);
                        te = handlePathModifiers(scope, startVar, te, endVar, contextVar, lowerBound, upperBound);
                    }
                    if (replaced) {
                        SameTerm condition = new SameTerm(objVar, mapValueExprToVar(object));
                        pathSequencePattern.addConstraint(condition);
                    }
                    pathSequencePattern.addRequiredTE(te);
                }
            } else {
                // not the last element in the path, introduce an anonymous
                // var
                // to connect.
                Var nextVar = createAnonVar();
                if (invertSequence && startVar.equals(subjVar)) {
                    // sequence
                    for (ValueExpr object : objectList) {
                        Var objVar = mapValueExprToVar(object);
                        startVar = objVar;
                        if (pathElement.isInverse()) {
                            Var temp = startVar;
                            startVar = nextVar;
                            nextVar = temp;
                        }
                        te = new StatementPattern(scope, startVar, predVar, nextVar, contextVar);
                        te = handlePathModifiers(scope, startVar, te, nextVar, contextVar, lowerBound, upperBound);
                        pathSequencePattern.addRequiredTE(te);
                    }
                } else {
                    if (pathElement.isInverse()) {
                        final Var oldStartVar = startVar;
                        startVar = nextVar;
                        nextVar = oldStartVar;
                    }
                    te = new StatementPattern(scope, startVar, predVar, nextVar, contextVar);
                    te = handlePathModifiers(scope, startVar, te, nextVar, contextVar, lowerBound, upperBound);
                    pathSequencePattern.addRequiredTE(te);
                }
                // set the subject for the next element in the path.
                startVar = (pathElement.isInverse() ? startVar : nextVar);
            }
        }
    }
    // add the created path sequence to the graph pattern.
    for (TupleExpr te : pathSequencePattern.getRequiredTEs()) {
        graphPattern.addRequiredTE(te);
    }
    if (pathSequencePattern.getConstraints() != null) {
        for (ValueExpr constraint : pathSequencePattern.getConstraints()) {
            graphPattern.addConstraint(constraint);
        }
    }
    return null;
}

Example 45 with Var

use of org.eclipse.rdf4j.query.algebra.Var in project rdf4j by eclipse.

the class TupleExprBuilder method visit.

@Override
public Object visit(ASTPropertyList propListNode, Object data) throws VisitorException {
    ValueExpr subject = (ValueExpr) data;
    ValueExpr predicate = (ValueExpr) propListNode.getVerb().jjtAccept(this, null);
    @SuppressWarnings("unchecked") List<ValueExpr> objectList = (List<ValueExpr>) propListNode.getObjectList().jjtAccept(this, null);
    Var subjVar = mapValueExprToVar(subject);
    Var predVar = mapValueExprToVar(predicate);
    for (ValueExpr object : objectList) {
        Var objVar = mapValueExprToVar(object);
        graphPattern.addRequiredSP(subjVar, predVar, objVar);
    }
    ASTPropertyList nextPropList = propListNode.getNextPropertyList();
    if (nextPropList != null) {
        nextPropList.jjtAccept(this, subject);
    }
    return graphPattern.buildTupleExpr();
}