code: package it.unibz.inf.ontop.model.term.functionsymbol.db.impl;
  
  import com.google.common.collect.ImmutableList;
  import it.unibz.inf.ontop.model.term.ImmutableExpression;
  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.DBBooleanFunctionSymbol;
  import it.unibz.inf.ontop.model.type.DBTermType;
  
  import java.util.function.Function;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  
  public class RegexpLike3FunctionSymbol extends SimpleTypedDBFunctionSymbolImpl
          implements DBBooleanFunctionSymbol {
  
      private static final String REGEXP_LIKE_STR = "REGEXP_LIKE";
      private static final String FUNCTIONAL_TEMPLATE = "%s(%s)";
  
  
      protected RegexpLike3FunctionSymbol(DBTermType dbBooleanType, DBTermType rootDBTermType) {
          super(REGEXP_LIKE_STR, 3, dbBooleanType, false, rootDBTermType,
                  RegexpLike3FunctionSymbol::serialize);
      }
  
      @Override
      public boolean blocksNegation() {
          return true;
      }
  
      @Override
      public ImmutableExpression negate(ImmutableList<? extends ImmutableTerm> subTerms, TermFactory termFactory) {
          throw new UnsupportedOperationException();
      }
  
      public static String serialize(ImmutableList<? extends ImmutableTerm> terms,
                                                         Function<ImmutableTerm, String> termConverter, TermFactory termFactory) {
          /*
           * Normalizes the flag
           *   - DOT_ALL: s -> n
           */
          ImmutableTerm flagTerm = termFactory.getDBReplace(terms.get(2),
                  termFactory.getDBStringConstant("s"),
                  termFactory.getDBStringConstant("n"))
                  .simplify();
  
          String parameterString = Stream.of(terms.get(0), terms.get(1), flagTerm)
                  .map(termConverter)
                  .collect(Collectors.joining(","));
          return String.format(FUNCTIONAL_TEMPLATE, REGEXP_LIKE_STR, parameterString);
      }
  }
  