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

Example 31 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 32 with TupleExpr

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

the class SeRQLParser method parseQuery.

public ParsedQuery parseQuery(String queryStr, String baseURI) throws MalformedQueryException {
    try {
        ASTQueryContainer qc = SyntaxTreeBuilder.parseQuery(queryStr);
        // Replace deprecated NULL nodes with semantically equivalent
        // alternatives
        NullProcessor.process(qc);
        StringEscapesProcessor.process(qc);
        Map<String, String> namespaces = NamespaceDeclProcessor.process(qc);
        ProjectionProcessor.process(qc);
        qc.jjtAccept(new ProjectionAliasProcessor(), null);
        qc.jjtAccept(new AnonymousVarGenerator(), null);
        // TODO: check use of unbound variables?
        TupleExpr tupleExpr = QueryModelBuilder.buildQueryModel(qc, SimpleValueFactory.getInstance());
        ASTQuery queryNode = qc.getQuery();
        ParsedQuery query;
        if (queryNode instanceof ASTTupleQuery) {
            query = new ParsedTupleQuery(tupleExpr);
        } else if (queryNode instanceof ASTGraphQuery) {
            query = new ParsedGraphQuery(tupleExpr, namespaces);
        } else {
            throw new RuntimeException("Unexpected query type: " + queryNode.getClass());
        }
        return query;
    } catch (ParseException e) {
        throw new MalformedQueryException(e.getMessage(), e);
    } catch (TokenMgrError e) {
        throw new MalformedQueryException(e.getMessage(), e);
    } catch (VisitorException e) {
        throw new MalformedQueryException(e.getMessage(), e);
    }
}

Example 33 with TupleExpr

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

the class QueryModelBuilder method visit.

@Override
public TupleExpr visit(ASTGraphUnion node, Object data) throws VisitorException {
    TupleExpr leftArg = (TupleExpr) node.getLeftArg().jjtAccept(this, null);
    TupleExpr rightArg = (TupleExpr) node.getRightArg().jjtAccept(this, null);
    TupleExpr result = new Union(leftArg, rightArg);
    if (node.isDistinct()) {
        result = new Distinct(result);
    }
    return result;
}

Example 34 with TupleExpr

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

the class QueryModelBuilder method visit.

@Override
public TupleExpr visit(ASTGraphIntersect node, Object data) throws VisitorException {
    TupleExpr leftArg = (TupleExpr) node.getLeftArg().jjtAccept(this, null);
    TupleExpr rightArg = (TupleExpr) node.getRightArg().jjtAccept(this, null);
    return new Intersection(leftArg, rightArg);
}

Example 35 with TupleExpr

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

the class QueryModelBuilder method visit.

@Override
public CompareAll visit(ASTCompareAll node, Object data) throws VisitorException {
    ValueExpr valueExpr = (ValueExpr) node.getLeftOperand().jjtAccept(this, null);
    TupleExpr tupleExpr = (TupleExpr) node.getRightOperand().jjtAccept(this, null);
    CompareOp op = node.getOperator().getValue();
    return new CompareAll(valueExpr, tupleExpr, op);
}