restamp

Restamp is a library for applying access transformers to java source code files.

Overview

Restamp can be used to apply access transformers to closed/forked projects, enabling developers to access fields, methods and classes in the project that were previously not accessible.

Installation & Usage

For both library and cli usage it is important that a full classpath of the project is supplied to the project. This includes a jar of the project itself if only a subset of its classes are read/parsed by restamp (which is almost always the case).

As a library

Gradle (Kotlin DSL)

repositories {
    maven("https://repo.papermc.io/repository/maven-public/")
}

dependencies {
    compileOnly("io.papermc.restamp:restamp:1.1.0")
}

java {
    toolchain.languageVersion.set(JavaLanguageVersion.of(17))
}

Maven

<repository>
    <id>papermc</id>
    <url>https://repo.papermc.io/repository/maven-public/</url>
</repository>

<dependency>
    <groupId>io.papermc.restamp</groupId>
    <artifactId>restamp</artifactId>
    <version>1.1.0</version>
</dependency>

You may use restamp by first constructing a RestampContextConfiguration via its builder:

RestampContextConfiguration.builder()
    .accessTransformers(Path.of("/path/to/the/at/file"))
    [...]
    .build();

The configuration may then be parsed into the inputs to restamp via RestampInput.parseFrom(contextConfiguration). This process parses the java source files as specified in the context configuration. As such it is not a cheap process and should be called as few times as possible.

After constructing inputs, restamp can be executed using Restamp.run(inputs), yielding back the changeset of all applied access transformers for further usage by your jvm-based project.

As a CLI

You can download the cli from the GitHub Releases page or you can build it with ./gradlew build which produces the cli in restamp-cli/build/libs/restamp-cli-*-final.jar.

More information on the CLI's expected parameters can be found via the --help flag. A sample execution may look like this:

java -jar restamp.jar \
  -cp "lib/guava.jar;lib/joml.jar;[...]" \
  --source-path src/main/java \
  -at at.at

which applies all access transformers found in the at.at file to the relevant sources found under src/main/java while using all classes found in the jars supposed to -cp as a semicolon separated array.

PaperMC / restamp