code: @SuppressWarnings({"rawtypes"})
      @Override
      public void open(Map conf, TopologyContext context)
      {
          this.taskIndex = context.getThisTaskIndex();
          this.dataFileName = this.baseFileName + "_" + this.taskIndex;
          this.targetFile = new File(this.dataFileDir, this.dataFileName);
      }
docs: {@inheritDoc}