presto-parser/src/main/java/io/prestosql/sql/ExpressionFormatter.java/ExpressionFormatter/visitSearchedCaseExpression
class ExpressionFormatter:        @Override
        protected String visitSearchedCaseExpression(SearchedCaseExpression node, Void context)
        {
            ImmutableList.Builder<String> parts = ImmutableList.builder();
            parts.add("CASE");
            for (WhenClause whenClause : node.getWhenClauses()) {
                parts.add(process(whenClause, context));
            }

            node.getDefaultValue()
                    .ifPresent((value) -> parts.add("ELSE").add(process(value, context)));

            parts.add("END");

            return "(" + Joiner.on(' ').join(parts.build()) + ")";
        }