code: @Override
    public void onTableProcessBegin(Table table, long tableProcessTime) {
  
      Preconditions.checkNotNull(table);
  
      if (!this.expectedHighWatermarks.hasPartitionWatermarks(tableKey(table))) {
        this.expectedHighWatermarks.setPartitionWatermarks(tableKey(table), Maps.<String, Long> newHashMap());
      }
    }
docs: Initializes the expected high watermarks for a {@link Table}
  {@inheritDoc}
  @see org.apache.gobblin.data.management.conversion.hive.watermarker.HiveSourceWatermarker#onTableProcessBegin(org.apache.hadoop.hive.ql.metadata.Table, long)