Add NIO helper methods

src/main/scala/com/github/mrpowers/spark/daria/utils/NioUtils.scala

@@ -0,0 +1,35 @@
+package com.github.mrpowers.spark.daria.utils
+
+import java.io.IOException
+import java.nio.file.{Files, Paths, Path, SimpleFileVisitor, FileVisitResult}
+import java.nio.file.attribute.BasicFileAttributes
+
+// Copied from StackOverflow: https://stackoverflow.com/a/47380288/1125159
+// Per Vladimir Matveev, it's best to use the Java NIO.2 API for modern Java I/O
+object NioUtils {
+
+  def remove(root: Path, deleteRoot: Boolean = true): Unit =
+    Files.walkFileTree(
+      root,
+      new SimpleFileVisitor[Path] {
+        override def visitFile(file: Path, attributes: BasicFileAttributes): FileVisitResult = {
+          Files.delete(file)
+          FileVisitResult.CONTINUE
+        }
+
+        override def postVisitDirectory(dir: Path, exception: IOException): FileVisitResult = {
+          if (deleteRoot) Files.delete(dir)
+          FileVisitResult.CONTINUE
+        }
+      }
+    )
+
+  def removeUnder(string: String): Unit = remove(Paths.get(string), deleteRoot = false)
+
+  def removeAll(string: String): Unit = remove(Paths.get(string))
+
+  def removeUnder(file: java.io.File): Unit = remove(file.toPath, deleteRoot = false)
+
+  def removeAll(file: java.io.File): Unit = remove(file.toPath)
+
+}