teavm-gradle-plugin

Gradle plugin to compile jvm languages (bytecode) to Javascript (/Web assembly /C)

What is TeaVM?

TeaVM is a nice tool to compile (transpile? decompile? detrasnpile?) bytecode into JavaScript. You can find more details on its website: http://teavm.org/ Find examples in its git repo: https://github.com/konsoletyper/teavm or find this nice description in Java Magagzine: https://blogs.oracle.com/javamagazine/java-in-the-browser-with-teavm

How to use

apply plugin: 'java'
apply plugin: 'io.github.zebalu.teavm-gradle-plugin'

buildscript {
    repositories {
        jcenter()
    }

    dependencies {
        classpath 'io.github.zebalu:teavm-gradle-plugin:+'
    }
}

this is the minimal setup to use the plugin. (Compile task is teavmc.)

How to set up

By default the plugin adds teavmc task to your project. You can set it up by teavm extension object. source

It goes like this (every value is the default):

teavm {
   /** It a FileCollection object with all the calssfiles to use in compilation */
   classFiles = null;
   
   compileScopes = null;
   minifying = true;
   maxTopLevelNames = 10000;
   properties = null;
   debugInformationGenerated = false;
   sourceMapsGenerated = false;
   sourceFilesCopied = false;
   incremental = false;
   transformers = null;
   
   /** Where to save the result */
   targetDirectory = null;
   
   /** The directory to monitor to decide if compile is up-to-date or not
   sourceDirectory = null;
   
   /** How to name the result file. */
   targetFileName = "classes.js";
   
   /** Which class holds your public static void main(Strin[] args) method */
   mainClass = null;
   
   /** This will be the name of your main method after compilation. */
   entryPointName = 'main';
   
   classesToPreserve = null;
   stopOnErrors = true;
   optimizationLevel = "SIMPLE"; //org.teavm.vm.TeaVMOptimizationLevel.SIMPLE;
   fastGlobalAnalysis = false;
   targetType = "JAVASCRIPT"; //org.teavm.tooling.TeaVMTargetType.JAVASCRIPT;
   cacheDirectory = null;
   wasmVersion = "V_0x1"; //org.teavm.backend.wasm.render.WasmBinaryVersion.V_0x1;
   minHeapSize = 4;
   maxHeapSize = 128;
   outOfProcess = false;
   processMemory = 512;
   longjmpSupported = true;
   heapDump = false;
   
   /** Add name of configurations here where to look for jarfiles. */
   includeJarsFrom = ['runtimeClasspath'];
   
   /** FileCollection object which adds extra jars to compilation. */
   extraLibs = null;
   
   /** By default teavmc taskd epends on javaCompile task, unless this varaibale is true. */
   skipJavaCompile = false;       
}

All the undocumented stuff is unclear for me. I just use the original author's settings. (Sorry.)

How to create a custom task?

You should crate a TeavmCompileTask and every setting can be passed to the settings object:

task myCupOfTea(type: io.github.zebalue.gradle.teavm.TeavmCompileTask) {
    settings.skipJavaCompile=true
    settings.entryPointName='leEntry'
    /** etc. */
}