code: package it.unibz.inf.ontop.model.term.functionsymbol.db.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.term.functionsymbol.db.DBFunctionSymbol;
  import it.unibz.inf.ontop.model.term.functionsymbol.db.DBFunctionSymbolSerializer;
  import it.unibz.inf.ontop.model.term.functionsymbol.impl.FunctionSymbolImpl;
  import it.unibz.inf.ontop.model.type.DBTermType;
  import it.unibz.inf.ontop.model.type.TermType;
  import it.unibz.inf.ontop.model.type.TermTypeInference;
  
  import javax.annotation.Nonnull;
  import java.util.Optional;
  import java.util.function.Function;
  
  public abstract class AbstractDBAggregationFunctionSymbol extends AbstractAggregationFunctionSymbol implements DBFunctionSymbol {
  
      private final DBFunctionSymbolSerializer serializer;
  
      protected AbstractDBAggregationFunctionSymbol(@Nonnull String name,
                                                    @Nonnull ImmutableList<TermType> expectedBaseTypes,
                                                    @Nonnull DBTermType targetType,
                                                    boolean isDistinct,
                                                    @Nonnull DBFunctionSymbolSerializer serializer) {
          super(name, expectedBaseTypes, targetType, isDistinct);
          this.serializer = serializer;
      }
  
      @Override
      public String getNativeDBString(ImmutableList<? extends ImmutableTerm> terms,
                                      Function<ImmutableTerm, String> termConverter, TermFactory termFactory) {
          return serializer.getNativeDBString(terms, termConverter, termFactory);
      }
  
      @Override
      protected ImmutableTerm buildTermAfterEvaluation(ImmutableList<ImmutableTerm> newTerms, TermFactory termFactory,
                                                       VariableNullability variableNullability) {
          if (getArity() >= 1) {
              ImmutableTerm newTerm = newTerms.get(0);
              return newTerm.isNull()
                      ? evaluateEmptyBag(termFactory)
                      : super.buildTermAfterEvaluation(newTerms, termFactory, variableNullability);
          }
          return super.buildTermAfterEvaluation(newTerms, termFactory, variableNullability);
      }
  
      @Override
      public boolean isPreferringToBePostProcessedOverBeingBlocked() {
          return false;
      }
  }
  