code: @Override
  	public void exists(final Runnable runnable) {
  		StringBuilder sql = new StringBuilder("select 1 from (")
  				.append(System.lineSeparator())
  				.append(aggregationSourceSql())
  				.append(System.lineSeparator())
  				.append(") t_");
  		context().setSql(sql.toString());
  		try (ResultSet rs = agent().query(context())) {
  			if (rs.next()) {
  				runnable.run();
  			}
  		} catch (final SQLException e) {
  			throw new EntitySqlRuntimeException(SqlKind.SELECT, e);
  		}
  	}
docs: {@inheritDoc}
  
  @see jp.co.future.uroborosql.fluent.SqlEntityQuery#exists(java.lang.Runnable)