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

Example 46 with TupleExpr

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

the class ConstructorBuilder method buildConstructor.

private TupleExpr buildConstructor(TupleExpr bodyExpr, TupleExpr constructExpr, boolean explicitConstructor, boolean distinct, boolean reduced) {
    TupleExpr result = bodyExpr;
    // Retrieve all StatementPattern's from the construct expression
    List<StatementPattern> statementPatterns = StatementPatternCollector.process(constructExpr);
    Set<Var> constructVars = getConstructVars(statementPatterns);
    // Finally, the spo-bindings are again filtered for duplicates.
    if (distinct || reduced) {
        // Create projection that removes all bindings that are not used in the
        // constructor
        ProjectionElemList projElemList = new ProjectionElemList();
        for (Var var : constructVars) {
            // the distinct
            if (!var.isAnonymous() && !var.hasValue()) {
                projElemList.addElement(new ProjectionElem(var.getName()));
            }
        }
        result = new Projection(result, projElemList);
        // Filter the duplicates from these projected bindings
        if (distinct) {
            result = new Distinct(result);
        } else {
            result = new Reduced(result);
        }
    }
    // Create BNodeGenerator's for all anonymous variables
    Map<Var, ExtensionElem> extElemMap = new HashMap<Var, ExtensionElem>();
    for (Var var : constructVars) {
        if (var.isAnonymous() && !extElemMap.containsKey(var)) {
            ValueExpr valueExpr = null;
            if (var.hasValue()) {
                valueExpr = new ValueConstant(var.getValue());
            } else if (explicitConstructor) {
                // only generate bnodes in case of an explicit constructor
                valueExpr = new BNodeGenerator();
            }
            if (valueExpr != null) {
                extElemMap.put(var, new ExtensionElem(valueExpr, var.getName()));
            }
        }
    }
    if (!extElemMap.isEmpty()) {
        result = new Extension(result, extElemMap.values());
    }
    // Create a Projection for each StatementPattern in the constructor
    List<ProjectionElemList> projections = new ArrayList<ProjectionElemList>();
    for (StatementPattern sp : statementPatterns) {
        ProjectionElemList projElemList = new ProjectionElemList();
        projElemList.addElement(new ProjectionElem(sp.getSubjectVar().getName(), "subject"));
        projElemList.addElement(new ProjectionElem(sp.getPredicateVar().getName(), "predicate"));
        projElemList.addElement(new ProjectionElem(sp.getObjectVar().getName(), "object"));
        projections.add(projElemList);
    }
    if (projections.size() == 1) {
        result = new Projection(result, projections.get(0));
    // Note: no need to apply the second duplicate elimination step if
    // there's just one projection
    } else if (projections.size() > 1) {
        result = new MultiProjection(result, projections);
        if (distinct) {
            // Add another distinct to filter duplicate statements
            result = new Distinct(result);
        } else if (reduced) {
            result = new Reduced(result);
        }
    } else {
        // Empty constructor
        result = new EmptySet();
    }
    return result;
}

Example 47 with TupleExpr

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

the class UpdateExprBuilder method visit.

@Override
public TupleExpr visit(ASTQuadsNotTriples node, Object data) throws VisitorException {
    GraphPattern parentGP = graphPattern;
    graphPattern = new GraphPattern();
    ValueExpr contextNode = (ValueExpr) node.jjtGetChild(0).jjtAccept(this, data);
    Var contextVar = mapValueExprToVar(contextNode);
    graphPattern.setContextVar(contextVar);
    graphPattern.setStatementPatternScope(Scope.NAMED_CONTEXTS);
    for (int i = 1; i < node.jjtGetNumChildren(); i++) {
        node.jjtGetChild(i).jjtAccept(this, data);
    }
    TupleExpr result = graphPattern.buildTupleExpr();
    parentGP.addRequiredTE(result);
    graphPattern = parentGP;
    return result;
}

Example 48 with TupleExpr

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

the class UpdateExprBuilder method visit.

@Override
public TupleExpr visit(ASTInsertClause node, Object data) throws VisitorException {
    TupleExpr result = (TupleExpr) data;
    // Collect insert clause triples
    GraphPattern parentGP = graphPattern;
    graphPattern = new GraphPattern();
    // inherit scope & context
    graphPattern.setStatementPatternScope(parentGP.getStatementPatternScope());
    graphPattern.setContextVar(parentGP.getContextVar());
    for (int i = 0; i < node.jjtGetNumChildren(); i++) {
        node.jjtGetChild(i).jjtAccept(this, data);
    }
    TupleExpr insertExpr = graphPattern.buildTupleExpr();
    graphPattern = parentGP;
    return insertExpr;
}

Example 49 with TupleExpr

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

the class UpdateExprBuilder method visit.

@Override
public TupleExpr visit(ASTDeleteClause node, Object data) throws VisitorException {
    TupleExpr result = (TupleExpr) data;
    // Collect construct triples
    GraphPattern parentGP = graphPattern;
    graphPattern = new GraphPattern();
    // inherit scope & context
    graphPattern.setStatementPatternScope(parentGP.getStatementPatternScope());
    graphPattern.setContextVar(parentGP.getContextVar());
    for (int i = 0; i < node.jjtGetNumChildren(); i++) {
        node.jjtGetChild(i).jjtAccept(this, data);
    }
    TupleExpr deleteExpr = graphPattern.buildTupleExpr();
    // FIXME we should adapt the grammar so we can avoid doing this in
    // post-processing.
    VarCollector collector = new VarCollector();
    deleteExpr.visit(collector);
    for (Var var : collector.getCollectedVars()) {
        if (var.isAnonymous() && !var.hasValue()) {
            // blank node in delete pattern, not allowed by SPARQL spec.
            throw new VisitorException("DELETE clause may not contain blank nodes");
        }
    }
    graphPattern = parentGP;
    return deleteExpr;
}

Example 50 with TupleExpr

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

the class UpdateExprBuilder method visit.

@Override
public Modify visit(ASTModify node, Object data) throws VisitorException {
    ASTWhereClause whereClause = node.getWhereClause();
    TupleExpr where = null;
    if (whereClause != null) {
        where = (TupleExpr) whereClause.jjtAccept(this, data);
    }
    TupleExpr delete = null;
    ASTDeleteClause deleteNode = node.getDeleteClause();
    if (deleteNode != null) {
        delete = (TupleExpr) deleteNode.jjtAccept(this, data);
    }
    TupleExpr insert = null;
    ASTInsertClause insertNode = node.getInsertClause();
    if (insertNode != null) {
        insert = (TupleExpr) insertNode.jjtAccept(this, data);
    }
    Modify modifyExpr = new Modify(delete, insert, where);
    return modifyExpr;
}