From e236c29ef363237a876b2892747c3f1958648992 Mon Sep 17 00:00:00 2001
From: Rostislav Raykov <rostislav.raykov@infinno.eu>
Date: Tue, 29 Oct 2024 21:13:47 +0200
Subject: [PATCH] made the utility classes instantiable

---
 .../quickdrop/util/DataValidator.java          |  4 ++++
 .../quickdrop/util/FileEncryptionUtils.java    | 18 ++++++++----------
 .../rostislav/quickdrop/util/FileUtils.java    | 11 +++++++++++
 3 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/src/main/java/org/rostislav/quickdrop/util/DataValidator.java b/src/main/java/org/rostislav/quickdrop/util/DataValidator.java
index 0e282cb..4a69eba 100644
--- a/src/main/java/org/rostislav/quickdrop/util/DataValidator.java
+++ b/src/main/java/org/rostislav/quickdrop/util/DataValidator.java
@@ -1,6 +1,10 @@
 package org.rostislav.quickdrop.util;
 
 public class DataValidator {
+    private DataValidator() {
+        // To prevent instantiation
+    }
+
     public static boolean validateObjects(Object... objs) {
         for (Object temp : objs) {
             if (temp != null) {
diff --git a/src/main/java/org/rostislav/quickdrop/util/FileEncryptionUtils.java b/src/main/java/org/rostislav/quickdrop/util/FileEncryptionUtils.java
index c50c683..bca4d7a 100644
--- a/src/main/java/org/rostislav/quickdrop/util/FileEncryptionUtils.java
+++ b/src/main/java/org/rostislav/quickdrop/util/FileEncryptionUtils.java
@@ -1,5 +1,9 @@
 package org.rostislav.quickdrop.util;
 
+import javax.crypto.*;
+import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.PBEKeySpec;
+import javax.crypto.spec.SecretKeySpec;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
@@ -10,21 +14,15 @@ import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
 import java.security.spec.InvalidKeySpecException;
 
-import javax.crypto.BadPaddingException;
-import javax.crypto.Cipher;
-import javax.crypto.IllegalBlockSizeException;
-import javax.crypto.NoSuchPaddingException;
-import javax.crypto.SecretKey;
-import javax.crypto.SecretKeyFactory;
-import javax.crypto.spec.IvParameterSpec;
-import javax.crypto.spec.PBEKeySpec;
-import javax.crypto.spec.SecretKeySpec;
-
 public class FileEncryptionUtils {
     private static final String ALGORITHM = "AES/CBC/PKCS5Padding";
     private static final int ITERATION_COUNT = 65536;
     private static final int KEY_LENGTH = 128;
 
+    private FileEncryptionUtils() {
+        // To prevent instantiation
+    }
+
     public static SecretKey generateKeyFromPassword(String password, byte[] salt) throws NoSuchAlgorithmException, InvalidKeySpecException {
         PBEKeySpec spec = new PBEKeySpec(password.toCharArray(), salt, ITERATION_COUNT, KEY_LENGTH);
         SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
diff --git a/src/main/java/org/rostislav/quickdrop/util/FileUtils.java b/src/main/java/org/rostislav/quickdrop/util/FileUtils.java
index 986e5d9..8ae86bc 100644
--- a/src/main/java/org/rostislav/quickdrop/util/FileUtils.java
+++ b/src/main/java/org/rostislav/quickdrop/util/FileUtils.java
@@ -5,6 +5,9 @@ import org.rostislav.quickdrop.model.FileEntity;
 import org.springframework.ui.Model;
 
 public class FileUtils {
+    private FileUtils() {
+        // To prevent instantiation
+    }
 
     public static String formatFileSize(long size) {
         String[] units = {"B", "KB", "MB", "GB", "TB"};
@@ -17,6 +20,14 @@ public class FileUtils {
         return String.format("%.2f %s", sizeInUnits, units[unitIndex]);
     }
 
+    public static long bytesToMegabytes(long bytes) {
+        return bytes / 1024 / 1024;
+    }
+
+    public static long megabytesToBytes(long megabytes) {
+        return megabytes * 1024 * 1024;
+    }
+
     public static String getDownloadLink(HttpServletRequest request, FileEntity fileEntity) {
         return request.getScheme() + "://" + request.getServerName() + "/file/" + fileEntity.uuid;
     }