nullability.gradle

import groovy.io.FileType
import groovy.text.SimpleTemplateEngine

// Adapted from http://stancalau.ro/java_package-info_generator_gradle/
def generatedPackageInfoDir = "$buildDir/generated/package-info"

// Handle Android projects
if (project.plugins.hasPlugin("android")) {
    android.sourceSets.main.java.srcDirs generatedPackageInfoDir
}

// Handle Java projects
if (project.plugins.hasPlugin("java")) {
    sourceSets.main.java.srcDirs generatedPackageInfoDir
}

task generatePackageInfo << {
    println "generatePackageInfo"
    new File(generatedPackageInfoDir).deleteDir()

    def packages = [] as Set

    new File(".").eachFileRecurse(FileType.FILES) {
        if (it.name.endsWith(".java")) {
            packages = ((it.text =~ "package (.+);")[0][1])
        }
    }

    packages.each {
        def dir = mkdir(generatedPackageInfoDir + "/" + it.replaceAll("\\.", "/"))
        def outputFile = new File(dir.absolutePath, "package-info.java")
        String templateOutput = applyPackageInfoTemplate(it)
        outputFile << templateOutput
    }
}

def applyPackageInfoTemplate(packageName) {
    def engine = new SimpleTemplateEngine()
    def templateText = "@NonNull\n" +
        "package $packageName;\n" +
        "\n" +
        "import android.support.annotation.NonNull;"
    def templateParams = ["packageName": packageName]
    engine.createTemplate(templateText).make(templateParams).toString()
}

clean.finalizedBy(generatePackageInfo)