FEAT FileUtils deleteDirectoryRecursively

src/main/java/de/nclazz/commons/io/FileUtils.java

@@ -0,0 +1,34 @@
+package de.nclazz.commons.io;
+
+import lombok.NonNull;
+
+import java.io.File;
+
+public abstract class FileUtils {
+
+    private FileUtils() { /* no-op */ }
+
+    /**
+     * Deletes a directory recursively.
+     * @param dir Directory to delete
+     * @throws NullPointerException if {@code dir} is {@code null}
+     * @throws IllegalArgumentException if {@code dir} is not a directory
+     */
+    public static void deleteDirectoryRecursively(@NonNull File dir) {
+        if(!dir.exists()) return;
+        if(!dir.isDirectory()) {
+            throw new IllegalArgumentException(String.format("File '%s' is not a directory!", dir.getAbsolutePath()));
+        }
+
+        for(File file : dir.listFiles()) {
+            if(file.isDirectory()) {
+                deleteDirectoryRecursively(file);
+            }else {
+                file.delete();
+            }
+        }
+
+        dir.delete();
+    }
+
+}

src/test/java/de/nclazz/commons/io/FileUtilsTests.java

@@ -0,0 +1,40 @@
+package de.nclazz.commons.io;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.io.File;
+import java.io.IOException;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class FileUtilsTests {
+
+    @Test
+    void testDeleteDirectoryRecursively() throws IOException {
+
+        File readmeFile = new File("README.md");
+        File dir = createDirectory();
+
+        assertTrue(dir.exists());
+        assertTrue(dir.isDirectory());
+
+        assertThrows(NullPointerException.class, () -> FileUtils.deleteDirectoryRecursively(null));
+        assertThrows(IllegalArgumentException.class, () -> FileUtils.deleteDirectoryRecursively(readmeFile));
+        assertDoesNotThrow(() -> FileUtils.deleteDirectoryRecursively(dir));
+
+        assertTrue(!dir.exists());
+    }
+
+    File createDirectory() throws IOException {
+        File dir = new File("target/tmp/subdirs/secondlevel");
+        dir.mkdirs();
+
+        for(int i = 0; i < 64; i++) {
+            new File(dir, "test_"+i+".txt").createNewFile();
+        }
+
+        return dir;
+    }
+
+}