Add encryption option

src/main/kotlin/nl/astraeus/persistence/TransactionLog.kt

@@ -2,9 +2,11 @@ package nl.astraeus.persistence
 
 import java.io.File
 import java.io.ObjectInputStream
+import java.util.*
 
 class TransactionLog(
   directory: File,
+  val decryptionKey: String? = null,
 ) {
   val fileManager = FileManager(directory)
 
@@ -14,14 +16,15 @@ class TransactionLog(
 
       printer("Snapshot:")
       snapshot?.inputStream()?.use { input ->
-        ObjectInputStream(input).use { ois ->
+        ObjectInputStream(DecryptingInputStream(input, decryptionKey)).use { ois ->
           val versionNumber = ois.readInt()
           check(versionNumber == 1) {
             "Unsupported version number: $versionNumber"
           }
           val transactionNumber = ois.readLong()
           printer("[$versionNumber]  $transactionNumber")
-          val data = ois.readObject() as MutableMap<Class<*>, TypeData>
+          val dataObj = ois.readObject()
+          val data = dataObj as MutableMap<Class<*>, TypeData>
           printer("Data:")
           printer("\tClasses:")
           for ((cls, entries) in  data.entries) {
@@ -35,15 +38,26 @@ class TransactionLog(
       printer("Transactions:")
       transactions?.forEach { transaction ->
         transaction.inputStream().use { input ->
-          ObjectInputStream(input).use { ois ->
+          ObjectInputStream(DecryptingInputStream(input, decryptionKey)).use { ois ->
             val versionNumber = ois.readInt()
             check(versionNumber == 1) {
               "Unsupported version number: $versionNumber"
             }
             val transactionNumber = ois.readLong()
-            val actions = ois.readObject() as Set<Action>
+            val actions = ois.readObject()
+            val actionList = when(actions) {
+              is Set<*> -> {
+                LinkedList(actions as Set<Action>)
+              }
+              is List<*> -> {
+                actions as List<Action>
+              }
+              else -> {
+                emptyList()
+              }
+            }
             printer("\t[$transactionNumber]")
-            for (action in actions) {
+            for (action in actionList) {
               printer("\t\t- $action")
             }
           }