make Sha256 own Class

client/src/main/kotlin/org/hso/texturesyncclient/controller/net/InternalJsonModel.kt

@@ -2,6 +2,7 @@ package org.hso.texturesyncclient.controller.net
 
 // These types will be converted to the model.DataModel
 
+import org.hso.texturesyncclient.model.Sha256
 import org.hso.texturesyncclient.model.Texture
 import org.hso.texturesyncclient.model.TextureFormat
 import java.lang.Exception
@@ -32,7 +33,7 @@ internal data class InternalTexture(
             tex.addedOn.get(Calendar.MONTH), //
             tex.addedOn.get(Calendar.DAY_OF_MONTH)
         ),
-        texture_hash = bytes2hexString(tex.textureHash)
+        texture_hash = tex.textureHash.toString()
     )
 
     @Throws(ConnectionException::class)
@@ -50,24 +51,10 @@ internal data class InternalTexture(
                 },
                 resolution = Pair(resolution[0], resolution[1]),
                 addedOn = GregorianCalendar(added_on[0], added_on[1], added_on[2]),
-                textureHash = hexString2Bytes(texture_hash)
+                textureHash = Sha256(texture_hash)
             )
         } catch (e: Exception) { // i Know, but no time :[]
             throw ConnectionInvalidJsonException()
         }
     }
-}
-
-private fun bytes2hexString(bytes: ByteArray): String {
-    val s = StringBuilder(64)
-    for (byte in bytes) {
-        s.append(String.format("%02X"), byte)
-    }
-    return s.toString()
-}
-
-private fun hexString2Bytes(bytes: String): ByteArray {
-    return ByteArray(bytes.length / 2) { i ->
-        bytes.substring(i * 2, i * 2 + 2).toInt(16).toByte()
-    }
 }

client/src/main/kotlin/org/hso/texturesyncclient/model/DataModel.kt

@@ -1,6 +1,10 @@
 package org.hso.texturesyncclient.model
 
+import java.lang.IllegalArgumentException
 import java.util.*
+import java.security.MessageDigest
+
+
 
 class DataModel
 
@@ -16,5 +20,40 @@ data class Texture(
     val format : TextureFormat,
     val resolution : Pair<Int, Int>,
     val addedOn : Calendar,
-    val textureHash : ByteArray
+    val textureHash : Sha256
 )
+
+@Suppress("ArrayInDataClass")
+class Sha256 {
+
+    private val hashBytes : ByteArray
+
+    @Throws(IllegalArgumentException::class)
+    constructor(hex : String) {
+
+        if(hex.length != 64) {
+            throw IllegalArgumentException("Sha256 has wrong length.")
+        }
+
+        try {
+            hashBytes = ByteArray(hex.length / 2) { i ->
+                hex.substring(i * 2, i * 2 + 2).toInt(16).toByte()
+            }
+        }catch(n : NumberFormatException) {
+            throw IllegalArgumentException("Hash does not only Contain '0-9a-zA-Z'.")
+        }
+    }
+
+    constructor(data : ByteArray ) {
+        val digest = MessageDigest.getInstance("SHA-256")
+        hashBytes = digest.digest(data)
+    }
+
+    override fun toString(): String {
+        val s = StringBuilder(64)
+        for (byte in hashBytes) {
+            s.append(String.format("%02X"), byte)
+        }
+        return s.toString()
+    }
+}