private Map<String, Path> generateSnapshotToRestoreDirMapping(Collection<String> snapshots,
    Path baseRestoreDir) {
    Map<String, Path> rtn = Maps.newHashMap();

    for (String snapshotName : snapshots) {
      Path restoreSnapshotDir =
        new Path(baseRestoreDir, snapshotName + "__" + UUID.randomUUID().toString());
      rtn.put(snapshotName, restoreSnapshotDir);
    }

    return rtn;
  }
Generate a random path underneath baseRestoreDir for each snapshot in snapshots and return a
map from the snapshot to the restore directory.
@param snapshots      collection of snapshot names to restore
@param baseRestoreDir base directory under which all snapshots in snapshots will be restored
@return a mapping from snapshot name to the directory in which that snapshot has been restored
hbase-mapreduce/src/main/java/org/apache/hadoop/hbase/mapreduce/MultiTableSnapshotInputFormatImpl.java