JarCastinglightweight protobuf
A lightweight protocol buffer implementation for java.
Why not Google's official protobuf for java nor wire by Square?
Because those are a little heavy, I made this.
protobuf-javalite-3.15.8.jar is 694 kilo-bytes and uses reflection.
wire-runtime-3.7.0.jar is 189 kilo-bytes, uses reflection, and needs okio-2.8.0.jar, 243 kilo-bytes jar so in total 432 kilo-bytes.
I want to make protobuf implementation in less than 100 kilo-bytes.
There's comparison of fat-jar with shadow plugin at file-size-test/fat-sizes.txt
Limitations
Compared with Google's protobuf, there are various limitations.
- This doesn't support extensions.
- Currently, to make compiler easily, all fields are used as proto3's normal field. This means,
- No support for requires
- No hasField() for optionals
- No support for proto3's optionals
- No support for descriptors of anything like FileDescriptor.
How To Use
You can get runtime library from maven central. Here's example configuration for gradle.
repositories {
mavenCentral()
}
dependencies {
implementation("com.anatawa12.lightweight-protobuf:lightweight-protobuf:$lightWeightProtobufVersion")
}
You can also get jar version of protoc plugin from maven central. You can generate java files using protobuf-gradle-plugin.
protobuf {
plugins {
create("lw-java") {
artifact = "com.anatawa12.lightweight-protobuf:compiler:$lightWeightProtobufVersion:all@jar"
}
}
generateProtoTasks {
// use 'all().each {' for groovy
all().forEach {
it.plugins {
create("lw-java")
}
}
}
}
If you want to generate java files using protoc, you need to write wrapper script for each platform like this.
#!/bin/sh
exec java -jar /path/to/compiler-plugin.jar
@ECHO OFF
java -jar \path\to\compiler-plugin.jar
Status
- implement data struct compiler
- implement parser
- implement writer
- full support for proto2 and proto3
- proto3: packed by default
- proto3's optional
- proto2's optional
- proto2's required