@Override
  public void beforeStart(UDFParameters parameters, UDTFConfigurations configurations)
      throws Exception {
    configurations
        .setAccessStrategy(new SlidingSizeWindowAccessStrategy(Integer.MAX_VALUE))
        .setOutputDataType(Type.INT32);
  }
The function is used to compute the period of a numeric time series.
library-udf/src/main/java/org/apache/iotdb/library/dprofile/UDAFPeriod.java