private boolean isLegalMeasurement(final String measurement) {
    try {
      PathUtils.isLegalPath("root." + measurement);
    } catch (final IllegalPathException e) {
      return false;
    }
    return measurement.startsWith("`") && measurement.endsWith("`") || !measurement.contains(".");
  }
{@link AggregateProcessor} is a {@link PipeProcessor} that can adopt different implementations of
{@link AbstractWindowingProcessor} as windowing strategy and use calculation methods from all the
{@link AbstractOperatorProcessor}s to calculate the given operators. Both the {@link
AbstractWindowingProcessor} and {@link AbstractOperatorProcessor} can be implemented by user and
loaded as a normal {@link PipeProcessor}
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/pipe/processor/aggregate/AggregateProcessor.java