Java Code Examples for org.eclipse.rdf4j.query.algebra.Var#getValue()

@Override
protected void meetSP(final StatementPattern node) throws Exception {
    final StatementPattern sp = node.clone();
    final Var predVar = sp.getPredicateVar();

    final IRI pred = (IRI) predVar.getValue();
    final String predNamespace = pred.getNamespace();

    final Var objVar = sp.getObjectVar();
    final Var cntxtVar = sp.getContextVar();
    if (objVar != null &&
            !RDF.NAMESPACE.equals(predNamespace) &&
            !SESAME.NAMESPACE.equals(predNamespace) &&
            !RDFS.NAMESPACE.equals(predNamespace)
            && !EXPANDED.equals(cntxtVar)) {

        final IRI transPropIri = (IRI) predVar.getValue();
        if (inferenceEngine.isTransitiveProperty(transPropIri)) {
            node.replaceWith(new TransitivePropertySP(sp.getSubjectVar(), sp.getPredicateVar(), sp.getObjectVar(), sp.getContextVar()));
        }
    }
}
 

/**
 * Check whether any solution for the {@link StatementPattern} could be derived from
 * reflexive property inference, and if so, replace the pattern with a union of itself and the
 * reflexive solution.
 */
@Override
protected void meetSP(StatementPattern node) throws Exception {
    // Only applies when the predicate is defined and reflexive
    final Var predVar = node.getPredicateVar();
    if (predVar.getValue() != null && inferenceEngine.isReflexiveProperty((IRI) predVar.getValue())) {
        final StatementPattern originalSP = node.clone();
        // The reflexive solution is a ZeroLengthPath between subject and
        // object: they can be matched to one another, whether constants or
        // variables.
        final Var subjVar = node.getSubjectVar();
        final Var objVar = node.getObjectVar();
        final ZeroLengthPath reflexiveSolution = new ZeroLengthPath(subjVar, objVar);
        node.replaceWith(new InferUnion(originalSP, reflexiveSolution));
    }
}
 

private Collection<FuzzyEntry<Var>> transformVar(Var v) {
    Set<FuzzyEntry<Var>> vars = new HashSet<FuzzyEntry<Var>>();

    Value val = v.getValue();
    if (val != null && val instanceof IRI) {
        Collection<EquivalentIRI> uris =  getEquivalentURI(v);
        for(EquivalentIRI uri : uris)
        {
            Var v1 = transformVar(v,uri);
            vars.add(new FuzzyEntry<Var>(v1, uri.getProximity()));
        }
    }
    else {
        vars.add(new FuzzyEntry<Var>(v));
    }
    return vars;
}
 

@Override
protected void meetSP(final StatementPattern node) throws Exception {
    final StatementPattern currentNode = node.clone();
    final Var subVar = node.getSubjectVar();
    final Var predVar = node.getPredicateVar();
    final Var objVar = node.getObjectVar();
    final Var conVar = node.getContextVar();
    if (predVar != null && objVar != null && objVar.getValue() != null && RDF.TYPE.equals(predVar.getValue()) && !EXPANDED.equals(conVar)) {
        final List<Set<Resource>> intersections = inferenceEngine.getIntersectionsImplying((IRI) objVar.getValue());
        if (intersections != null && !intersections.isEmpty()) {
            final List<TupleExpr> joins = new ArrayList<>();
            for (final Set<Resource> intersection : intersections) {
                final Set<Resource> sortedIntersection = new TreeSet<>(new ResourceComparator());
                sortedIntersection.addAll(intersection);

                // Create a join tree of all statement patterns in the
                // current intersection.
                final TupleExpr joinTree = createJoinTree(new ArrayList<>(sortedIntersection), subVar, conVar);
                if (joinTree != null) {
                    joins.add(joinTree);
                }
            }

            if (!joins.isEmpty()) {
                // Combine all the intersection join trees for the type
                // together into a union tree.  This will be a join tree if
                // only one intersection exists.
                final TupleExpr unionTree = createUnionTree(joins);
                // Union the above union tree of intersections with the
                // original node.
                final Union union = new InferUnion(unionTree, currentNode);
                node.replaceWith(union);
                log.trace("Replacing node with inferred intersection union: " + union);
            }
        }
    }
}
 

private boolean isSameCtx(Var v1, Var v2) {
	if ((v1 != null && v1.getValue() != null) && (v2 != null && v2.getValue() != null)) {
		return v1.getValue().equals(v2.getValue());
	} else if ((v1 != null && v1.getName() != null) && (v2 != null && v2.getName() != null)) {
		return v1.getName().equals(v2.getName());
	}

	return false;
}
 

private Collection<EquivalentIRI> getEquivalentURI(Var v) {
    Value val = v.getValue();

    if (val != null && val instanceof IRI) {
        IRI uri = (IRI)val;
        return queryTransformation.retrieveEquivalentURIs(uri);
    }

    return Collections.emptySet();
}
 

protected Value getConstantValue(final Var var) {
    if (var != null) {
        return var.getValue();
    } else {
        return null;
    }
}
 

@Override
protected void meetSP(final StatementPattern node) throws Exception {
    final Var subVar = node.getSubjectVar();
    final Var predVar = node.getPredicateVar();
    final Var objVar = node.getObjectVar();
    final Var conVar = node.getContextVar();
    if (predVar != null && objVar != null && objVar.getValue() != null && objVar.getValue() instanceof Resource && RDF.TYPE.equals(predVar.getValue()) && !EXPANDED.equals(conVar)) {
        final Resource object = (Resource) objVar.getValue();
        if (inferenceEngine.isEnumeratedType(object)) {
            final Set<BindingSet> solutions = new LinkedHashSet<>();
            final Set<Resource> enumeration = inferenceEngine.getEnumeration(object);
            for (final Resource enumType : enumeration) {
                final QueryBindingSet qbs = new QueryBindingSet();
                qbs.addBinding(subVar.getName(), enumType);
                solutions.add(qbs);
            }

            if (!solutions.isEmpty()) {
                final BindingSetAssignment enumNode = new BindingSetAssignment();
                enumNode.setBindingSets(solutions);

                node.replaceWith(enumNode);
                log.trace("Replacing node with inferred one of enumeration: " + enumNode);
            }
        }
    }
}
 

/**
 * Checks whether the StatementPattern is a type query whose solutions could be inferred by
 * someValuesFrom inference, and if so, replaces the node with a union of itself and any
 * possible inference.
 */
@Override
protected void meetSP(StatementPattern node) throws Exception {
    final Var subjVar = node.getSubjectVar();
    final Var predVar = node.getPredicateVar();
    final Var objVar = node.getObjectVar();
    // Only applies to type queries where the type is defined
    if (predVar != null && RDF.TYPE.equals(predVar.getValue()) && objVar != null && objVar.getValue() instanceof Resource) {
        final Resource typeToInfer = (Resource) objVar.getValue();
        Map<Resource, Set<IRI>> relevantSvfRestrictions = inferenceEngine.getSomeValuesFromByRestrictionType(typeToInfer);
        if (!relevantSvfRestrictions.isEmpty()) {
            // We can infer the queried type if it is to a someValuesFrom restriction (or a
            // supertype of one), and the node in question (subjVar) is the subject of a triple
            // whose predicate is the restriction's property and whose object is an arbitrary
            // node of the restriction's value type.
            final Var valueTypeVar = new Var("t-" + UUID.randomUUID());
            final Var svfPredVar = new Var("p-" + UUID.randomUUID());
            final Var neighborVar = new Var("n-" + UUID.randomUUID());
            neighborVar.setAnonymous(true);
            final StatementPattern membershipPattern = new DoNotExpandSP(neighborVar,
                    new Var(RDF.TYPE.stringValue(), RDF.TYPE), valueTypeVar);
            final StatementPattern valuePattern = new StatementPattern(subjVar, svfPredVar, neighborVar);
            final InferJoin svfPattern = new InferJoin(membershipPattern, valuePattern);
            // Use a FixedStatementPattern to contain the appropriate (predicate, value type)
            // pairs, and check each one against the general pattern.
            final FixedStatementPattern svfPropertyTypes = new FixedStatementPattern(svfPredVar,
                    new Var(OWL.SOMEVALUESFROM.stringValue(), OWL.SOMEVALUESFROM), valueTypeVar);
            for (Resource svfValueType : relevantSvfRestrictions.keySet()) {
                for (IRI svfProperty : relevantSvfRestrictions.get(svfValueType)) {
                    svfPropertyTypes.statements.add(new NullableStatementImpl(svfProperty,
                            OWL.SOMEVALUESFROM, svfValueType));
                }
            }
            final InferJoin svfInferenceQuery = new InferJoin(svfPropertyTypes, svfPattern);
            node.replaceWith(new InferUnion(node.clone(), svfInferenceQuery));
        }
    }
}
 

private boolean isSameCtx(Var v1, Var v2) {
    if ((v1 != null && v1.getValue() != null) && (v2 != null && v2.getValue() != null)) {
        return v1.getValue().equals(v2.getValue());
    }
    else if ((v1 != null && v1.getName() != null) && (v2 != null && v2.getName() != null)) {
        return v1.getName().equals(v2.getName());
    }

    return false;
}
 

@Override
protected void meetSP(StatementPattern node) throws Exception {
    StatementPattern sp = node.clone();
    final Var predVar = sp.getPredicateVar();

    IRI pred = (IRI) predVar.getValue();
    String predNamespace = pred.getNamespace();

    final Var objVar = sp.getObjectVar();
    final Var cntxtVar = sp.getContextVar();
    if (objVar != null &&
            !RDF.NAMESPACE.equals(predNamespace) &&
            !SESAME.NAMESPACE.equals(predNamespace) &&
            !RDFS.NAMESPACE.equals(predNamespace)
            && !EXPANDED.equals(cntxtVar)) {
        /**
         *
         * { ?a ?pred ?b .}\n" +
         "       UNION " +
         "      { ?b ?pred ?a }
         */

        IRI predIri = (IRI) predVar.getValue();
        IRI invPropIri = inferenceEngine.findInverseOf(predIri);
        if (invPropIri != null) {
            Var subjVar = sp.getSubjectVar();
            Union union = new InferUnion();
            union.setLeftArg(sp);
            union.setRightArg(new StatementPattern(objVar, new Var(predVar.getName(), invPropIri), subjVar, cntxtVar));
            node.replaceWith(union);
        }
    }
}
 

private Value getVarValue(Var var, boolean fixedValue, BindingSet bindingSet) {
	Value v;
	if (fixedValue) {
		v = var.getValue();
		if (v == null) {
			v = this.bindings.getValue(var.getName());
		}
	} else {
		v = bindingSet.getValue(var.getName());
	}

	return v;
}
 

@Override
public void meet(Var node) throws RDFHandlerException {
	Value value;
	if (node.isConstant()) {
		value = node.getValue();
	} else {
		value = getVar(node.getName());
	}
	handler.handleStatement(valueFactory.createStatement(subject, predicate, value));
}
 

/**
 * Gets a value from a {@code Var} if it has a {@code Value}. If it does not then the method will attempt to get it
 * from the bindings using the name of the Var
 * @param var
 * @param bindings
 * @return the matching {@code Value} or {@code null} if var is {@code null}
 */
private static Value getVarValue(Var var, BindingSet bindings) {
    if (var == null) {
        return null;
    } else if (var.hasValue()) {
        return var.getValue();
    } else {
        return bindings.getValue(var.getName());
    }
}
 

private Set<String> getVariableNames() {
    final Set<String> vars = new HashSet<>();
    for (final StatementPattern pattern : patterns) {
        for (final Var var : pattern.getVarList()) {
            if (var.getValue() == null) {
                vars.add(var.getName());
            }
        }
    }
    return vars;
}
 

protected static Value toValue(Var var, BindingSet bindings) {
	if (var.hasValue())
		return var.getValue();
	
	if (bindings.hasBinding(var.getName()))	
		return bindings.getValue(var.getName());
	
	return null;			
}
 

private Value getValue(Var subjectVar) {
    return subjectVar.hasValue() ? subjectVar.getValue() : null;
}
 

@Override
public void meet(StatementPattern node) throws RepositoryException {
	StringBuilder builder = new StringBuilder();
	Scope scope = node.getScope();
	Var subj = node.getSubjectVar();
	Var pred = node.getPredicateVar();
	Var obj = node.getObjectVar();
	Var ctx = node.getContextVar();
	boolean cokay = ctx == null && scope.equals(Scope.DEFAULT_CONTEXTS)
			|| ctx != null && scope.equals(Scope.NAMED_CONTEXTS);
	boolean sokay = !subj.hasValue() || subj.isAnonymous() || subj.getValue() instanceof IRI;
	boolean ookay = !obj.hasValue() || obj.isAnonymous() || obj.getValue() instanceof IRI
			|| obj.getValue() instanceof Literal;
	if (cokay && sokay && ookay) {
		variables.clear();
		if (ctx != null) {
			builder.append("GRAPH ");
			appendVar(builder, ctx.getName());
			builder.append(" {\n");
		}
		appendVar(builder, subj);
		appendVar(builder, pred);
		appendVar(builder, obj);
		builder.append(" .");
		appendFilter(builder, subj);
		appendFilter(builder, pred);
		appendFilter(builder, obj);
		if (ctx != null) {
			if (ctx.hasValue()) {
				builder.append("\nFILTER sameTerm(");
				appendVar(builder, ctx.getName());
				builder.append(", ");
				writeValue(builder, ctx.getValue());
				builder.append(")\n");
			}
			builder.append("}");
		}
		this.pattern = builder.toString();
		this.patternNode = node;
	} else {
		this.patternNode = null; // NOPMD
	}
}
 

/**
 * Assigns BindingSet values for any {@link Var} whose {@link Value} is
 * null. Returns the {@link Value} associated with Var (if it has one),
 * otherwise returns the BindingSet Value corresponding to
 * {@link Var#getName()}. If no such Binding exits, this method returns
 * null.
 *
 * @param var
 * @param bindings
 * @return Value
 */
private Value getVarValue(final Var var, final BindingSet bindings) {
    if (var == null) {
        return null;
    } else if (var.hasValue()) {
        return var.getValue();
    } else {
        return bindings.getValue(var.getName());
    }
}
 

/**
 * Return the {@link Value} of the variable which is either taken from
 * the variable itself (bound) or from the bindingsset (unbound).
 * 
 * @param var
 * @param bindings
 * 			the bindings, must not be null, use {@link EmptyBindingSet} instead
 * 
 * @return
 * 		the value or null
 */
public static Value getVarValue(Var var, BindingSet bindings) {
	if (var == null) {
		return null;
	} else if (var.hasValue()) {
		return var.getValue();
	} else {
		return bindings.getValue(var.getName());
	}
}