[GitHub] carbondata pull request #1565: [CARBONDATA-1518][Pre-Aggregate]Support creat...

[jackylk <gi...@git.apache.org>]

Github user jackylk commented on a diff in the pull request:

    https://github.com/apache/carbondata/pull/1565#discussion_r154988752
  
    --- Diff: core/src/main/java/org/apache/carbondata/core/preagg/TimeSeriesUDF.java ---
    @@ -0,0 +1,127 @@
    +/*
    + * Licensed to the Apache Software Foundation (ASF) under one or more
    + * contributor license agreements.  See the NOTICE file distributed with
    + * this work for additional information regarding copyright ownership.
    + * The ASF licenses this file to You under the Apache License, Version 2.0
    + * (the "License"); you may not use this file except in compliance with
    + * the License.  You may obtain a copy of the License at
    + *
    + *    http://www.apache.org/licenses/LICENSE-2.0
    + *
    + * Unless required by applicable law or agreed to in writing, software
    + * distributed under the License is distributed on an "AS IS" BASIS,
    + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    + * See the License for the specific language governing permissions and
    + * limitations under the License.
    + */
    +package org.apache.carbondata.core.preagg;
    +
    +import java.sql.Timestamp;
    +import java.util.ArrayList;
    +import java.util.Calendar;
    +import java.util.GregorianCalendar;
    +import java.util.List;
    +
    +/**
    + * class for applying timeseries udf
    + */
    +public class TimeSeriesUDF {
    +
    +  public final List<String> TIMESERIES_FUNCTION = new ArrayList<>();
    +
    +  // thread local for keeping calender instance
    +  private ThreadLocal<Calendar> calanderThreadLocal = new ThreadLocal<>();
    +
    +  /**
    +   * singleton instance
    +   */
    +  public static final TimeSeriesUDF INSTANCE = new TimeSeriesUDF();
    +
    +  private TimeSeriesUDF() {
    +    initialize();
    +  }
    +
    +  /**
    +   * Below method will be used to apply udf on data provided
    +   * Method will work based on below logic.
    +   * Data: 2016-7-23 01:01:30,10
    +   * Year Level UDF will return: 2016-1-1 00:00:00,0
    +   * Month Level UDF will return: 2016-7-1 00:00:00,0
    +   * Day Level UDF will return: 2016-7-23 00:00:00,0
    +   * Hour Level UDF will return: 2016-7-23 01:00:00,0
    +   * Minute Level UDF will return: 2016-7-23 01:01:00,0
    +   * Second Level UDF will return: 2016-7-23 01:01:30,0
    +   * If function does not match with any of the above functions
    +   * it will throw exception
    --- End diff --
    
    mention it is IllegalArgumentException explicitly


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