@Override
      public boolean next() throws IOException {
        if (atEnd) return false;

        boolean b = delegate.next();
        if (!b) {
          return b;
        }
        // constrain the bottom.
        if (!top) {
          if (getComparator().compare(splitCell, getKey()) <= 0) {
            atEnd = true;
            return false;
          }
        }
        return true;
      }
Creates a half file reader for a hfile referred to by an hfilelink.
@param context   Reader context info
@param fileInfo  HFile info
@param cacheConf CacheConfig
@param r         original reference file (contains top or bottom)
@param conf      Configuration
hbase-server/src/main/java/org/apache/hadoop/hbase/io/HalfStoreFileReader.java