public void pageUp() {
    if (pageSize > 0 && currentPosition > 0) {
      currentPosition -= pageSize;
      if (currentPosition < 0) {
        currentPosition = 0;
      }
      keepConsistent();
    }
  }
Utility class for paging for the metrics.
hbase-hbtop/src/main/java/org/apache/hadoop/hbase/hbtop/screen/top/Paging.java