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

Example 31 with ValueExpr

use of org.eclipse.rdf4j.query.algebra.ValueExpr 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 ValueExpr

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

the class QueryModelBuilder method visit.

@Override
public SameTerm visit(ASTSameTerm node, Object data) throws VisitorException {
    ValueExpr leftArg = (ValueExpr) node.getLeftOperand().jjtAccept(this, null);
    ValueExpr rightArg = (ValueExpr) node.getRightOperand().jjtAccept(this, null);
    return new SameTerm(leftArg, rightArg);
}

Example 33 with ValueExpr

use of org.eclipse.rdf4j.query.algebra.ValueExpr 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);
}

Example 34 with ValueExpr

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

the class QueryModelBuilder method visit.

@Override
public ValueExpr visit(ASTAnd node, Object data) throws VisitorException {
    Iterator<ASTBooleanExpr> iter = node.getOperandList().iterator();
    ValueExpr result = (ValueExpr) iter.next().jjtAccept(this, null);
    while (iter.hasNext()) {
        ValueExpr operand = (ValueExpr) iter.next().jjtAccept(this, null);
        result = new And(result, operand);
    }
    return result;
}

Example 35 with ValueExpr

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

the class QueryModelBuilder method visit.

@Override
public Object visit(ASTFrom node, Object data) throws VisitorException {
    StatementPattern.Scope scope = StatementPattern.Scope.DEFAULT_CONTEXTS;
    Var contextVar = null;
    if (node.hasContextID()) {
        scope = StatementPattern.Scope.NAMED_CONTEXTS;
        ValueExpr contextID = (ValueExpr) node.getContextID().jjtAccept(this, null);
        if (contextID instanceof Var) {
            contextVar = (Var) contextID;
        } else if (contextID instanceof ValueConstant) {
            ValueConstant vc = (ValueConstant) contextID;
            contextVar = createConstantVar(vc.getValue());
        } else {
            throw new IllegalArgumentException("Unexpected contextID result type: " + contextID.getClass());
        }
    }
    graphPattern.setStatementPatternScope(scope);
    graphPattern.setContextVar(contextVar);
    node.getPathExpr().jjtAccept(this, null);
    return null;
}