ProtoCache Java

Alternative flat binary format for Protobuf schema. It' works like FlatBuffers, but it's usually smaller and surpports map. Flat means no deserialization overhead. A benchmark shows the Protobuf has considerable deserialization overhead and significant reflection overhead. FlatBuffers is fast but wastes space. ProtoCache takes balance of data size and read speed, so it's useful in data caching.

	Protobuf	ProtoCache	FlatBuffers	Fury	Fury-Java
Data Size	574B	780B	1296B	989B	565B
Compressed Size	566B	571B	856B	852B	532B
Decode + Traverse	2624ns	902ns	1280ns	2646ns	1252ns
Decmpress	411ns	626ns	1323ns	851ns	443ns

Without zero-copy technique, the Java version is slow. Fury claims better performace than Protobuf and FlatBuffers, but our benchmark shows that's not truth unless giving up cross-language compatibility.

See detail in C++ version.

Code Gen

protoc --pcjv_out=. test.proto

A protobuf compiler plugin called protoc-gen-pcjv is available to generate java package. The generated files are short and human friendly. Don't mind to edit them if nessasery.

Basic APIs

pb.Main pb = pb.Main.parseFrom(raw);
raw = ProtoCache.serialize(pb);

pc.Main root = new pc.Main(raw);

Serializing a protobuf message with ProtoCache.serialize is the only way to create protocache binary at present. It's easy to access by wrapping the data with generated code.

Reflection

TODO