final int length = directoryProviders.length;
IndexReader[] readers = new IndexReader[length];
ReaderProvider[] managers = new ReaderProvider[length];
for (int index = 0; index < length; index++) {
ReaderProvider indexReaderManager = directoryProviders[index].getIndexReaderManager();
IndexReader openIndexReader = indexReaderManager.openIndexReader();
readers[index] = openIndexReader;
managers[index] = indexReaderManager;
}
return ReaderProviderHelper.buildMultiReader( length, readers, managers );
}