@Override
  public boolean equals(Object o) {
    if (o instanceof BlockCacheKey) {
      BlockCacheKey k = (BlockCacheKey) o;
      return offset == k.offset
        && (hfileName == null ? k.hfileName == null : hfileName.equals(k.hfileName));
    } else {
      return false;
    }
  }
Construct a new BlockCacheKey
@param hfileName The name of the HFile this block belongs to.
@param offset    Offset of the block into the file
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/BlockCacheKey.java