public static SimpleIndex fromInputStream(DataInputStream in) throws IOException {
        int nEntries = in.readInt();
        LongObjectHashMap<Entry> dictionary = new LongObjectHashMap<>(nEntries);
        for (int i = 0; i < nEntries; i++) {
            long key = in.readLong();
            int[] docIds = SerializationHelper.readIntArray(in);
            int[] dataRefs = SerializationHelper.readIntArray(in);
            dictionary.put(key, new Entry(docIds, dataRefs));
        }
        dictionary.compact();
        return new SimpleIndex(dictionary);
    }
Retrieves a posting list for a given key

@param key the key to lookup
@return list of postings
predicate-search/src/main/java/com/yahoo/search/predicate/index/SimpleIndex.java