code: @Override
      public void map(Key key, Value value, Context context)
              throws IOException,InterruptedException {
          writer.setContext(context);
          init();
  
          Record record = new Record();
          if (inputLabels != null) {
              int i = 0;
              for (ValueWritable vw : key.getGrouping()) {
                  vw.getLabel().set(inputLabels[i++]);
              }
              for (ValueWritable vw : value.getValues()) {
                  vw.getLabel().set(inputLabels[i++]);
              }
          }
          record.setKey(key);
          record.setValue(value);
  
          writer.setDefaultRecord(record);
          filter(record, writer);
      }
docs: {@inheritDoc}