lucene/src/main/java/com/twitter/elephantbird/mapreduce/input/LuceneIndexRecordReader.java
protected IndexReader openIndex(Path path, Configuration conf) throws IOException {
    return DirectoryReader.open(new LuceneHdfsDirectory(path, path.getFileSystem(conf)));
  }
protected IndexReader openIndex(Path path, Configuration conf) throws IOException {
    return DirectoryReader.open(new LuceneHdfsDirectory(path, path.getFileSystem(conf)));
  }
Open an index stored in path
Override if you want more control over how indexes are opened

@param path path to the index
@param conf job conf
@return an IndexReader of the index in path
@throws IOException