content: /*
   * Copyright 2022 The FeatHub Authors
   *
   * Licensed 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
   *
   *     https://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 com.alibaba.feathub.flink.udf;
  
  import org.apache.flink.table.functions.ScalarFunction;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.text.ParseException;
  import java.text.SimpleDateFormat;
  import java.util.Date;
  import java.util.TimeZone;
  
  /** Convert the given date time string to number of milliseconds since epoch. */
  public class UnixTimestampMillis extends ScalarFunction {
  
      private static final Logger LOG = LoggerFactory.getLogger(UnixTimestampMillis.class);
      public static final String DEFAULT_FORMAT = "yyyy-MM-dd HH:mm:ss.SSS";
      private SimpleDateFormat formatter;
  
      public Long eval(String timestampStr, String zoneId) {
          return this.eval(timestampStr, DEFAULT_FORMAT, zoneId);
      }
  
      public Long eval(String timestampStr, String format, String zoneId) {
          // The UDF is only used by FeatHub internally. FeatHub guarantee that
          // the format and zoneId will not change across rows.
          if (formatter == null) {
              formatter = new SimpleDateFormat(format);
              formatter.setTimeZone(TimeZone.getTimeZone(zoneId));
          }
          try {
              Date date = formatter.parse(timestampStr);
              return date.getTime();
          } catch (ParseException e) {
              LOG.error(
                      String.format(
                              "Exception when parsing datetime string '%s' in format '%s'",
                              timestampStr, format),
                      e);
              return Long.MIN_VALUE;
          }
      }
  }
  