The cleaner for all gradle projects on a disc.

main.kt

import java.io.File

interface IProjectDetector {
    fun isProjectRootFolder(folder: File): Boolean
}

interface IProjectCleaner {
    fun clean(folder: File)
}

interface IProjectManager : IProjectDetector, IProjectCleaner

class GradleProjectManager : IProjectManager {

    override fun isProjectRootFolder(folder: File): Boolean {
        return File(folder, "build.gradle").exists()
                && File(folder, "gradlew").exists()
                && File(folder, "gradlew.bat").exists()
    }

    override fun clean(folder: File) {
        println("cleaning $folder")
        File(folder, ".gradle").deleteRecursively()
        File(folder, "build").deleteRecursively()
        folder
                .listFiles()
                .filter { it.isDirectory }
                .forEach { File(it, "build").deleteRecursively() }

    }
}

fun main(args: Array<String>) {
    val projectManagers: List<IProjectManager> = listOf(GradleProjectManager())

    File("C:\\")
            .walkTopDown()
            .filter { it.isDirectory }
            .forEach { folder ->
                projectManagers
                        .filter { it.isProjectRootFolder(folder) }
                        .forEach {  it.clean(folder) }
            }
}