code: public boolean exists(String key) {
          Path dir = getKeyDir(key);
          boolean res = false;
          try {
              _fs = dir.getFileSystem(_hadoopConf);
              res = _fs.exists(dir);
          } catch (IOException e) {
              LOG.warn("Exception checking for exists on: " + key);
          }
          return res;
      }
docs: Check if the key exists in the blob store.
  
  @param key the key to check for
  @return true if it exists else false.