Why is hashing stateless? about zero-allocation-hashing HOT 3 OPEN

Removing the currently-present API (single method calls) and making users to emulate it would be a bad decision, because requiring people to call three methods when just one suffices 95% of the time doesn't make sense.

Augmenting the current API with support for chaining is possible.

from zero-allocation-hashing.

Agreed, removing / breaking the current API would be a mistake. Doing a bit of refactoring to enable chaining seems like a better move as you suggest.

from zero-allocation-hashing.

Streaming version api (with state) can be use to wrap a hash function as a OutputStream. It will reduce the overall allocations when we hash an object, which is the real scene in many RPC servers.

With stateless api, hashing the object will perform many allocations on the serialization step:

ByteBuffer/byte[] ser_results = do_serialization(obj);
long h = long_function.hash64(ser_results);

Meanwhile, the streaming api will be friendly for less allocations:

HashOutputStream hash_stream = wrap_streaming_hash(long_function_streaming);
do_serialization_to_a_stream(ser_results, hash_stream);
long h=hash_stream.finalize();

from zero-allocation-hashing.