code: package it.unibz.inf.ontop.model.term.functionsymbol.impl;
  
  import com.google.common.collect.ImmutableList;
  import it.unibz.inf.ontop.iq.node.VariableNullability;
  import it.unibz.inf.ontop.model.term.ImmutableTerm;
  import it.unibz.inf.ontop.model.term.TermFactory;
  import it.unibz.inf.ontop.model.type.RDFDatatype;
  import it.unibz.inf.ontop.model.type.TermTypeInference;
  import it.unibz.inf.ontop.model.vocabulary.SPARQL;
  
  import java.util.Optional;
  
  public class NowSPARQLFunctionSymbolImpl extends SPARQLFunctionSymbolImpl {
  
      private final RDFDatatype xsdDatetimeType;
  
      protected NowSPARQLFunctionSymbolImpl(RDFDatatype xsdDatetimeType) {
          super("SP_NOW", SPARQL.NOW, ImmutableList.of());
          this.xsdDatetimeType = xsdDatetimeType;
      }
  
      @Override
      protected boolean tolerateNulls() {
          return false;
      }
  
      @Override
      public boolean isAlwaysInjectiveInTheAbsenceOfNonInjectiveFunctionalTerms() {
          return true;
      }
  
      @Override
      public Optional<TermTypeInference> inferType(ImmutableList<? extends ImmutableTerm> terms) {
          return Optional.of(TermTypeInference.declareTermType(xsdDatetimeType));
      }
  
      @Override
      public boolean canBePostProcessed(ImmutableList<? extends ImmutableTerm> arguments) {
          return false;
      }
  
      @Override
      protected ImmutableTerm buildTermAfterEvaluation(ImmutableList<ImmutableTerm> newTerms,
                                                       TermFactory termFactory, VariableNullability variableNullability) {
          return termFactory.getRDFFunctionalTerm(
                  termFactory.getConversion2RDFLexical(
                          termFactory.getDBNow(),
                          xsdDatetimeType),
                  termFactory.getRDFTermTypeConstant(xsdDatetimeType));
      }
  }
  