Fixed handling of null representables in ReprUtil

src/main/java/org/cryptimeleon/math/serialization/annotations/internal/ArrayRepresentationHandler.java

@@ -51,6 +51,9 @@ public static boolean canHandle(Type type) {
 
     @Override
     public Object deserializeFromRepresentation(Representation repr, Function<String, RepresentationRestorer> getRegisteredRestorer) {
+        if (repr == null)
+            return null;
+
         //Create array
         Object result = Array.newInstance(elementType, repr.list().size());
 
@@ -64,6 +67,9 @@ public Object deserializeFromRepresentation(Representation repr, Function<String
 
     @Override
     public Representation serializeToRepresentation(Object obj) {
+        if (obj == null)
+            return null;
+
         ListRepresentation repr = new ListRepresentation();
 
         for (int i=0; i<Array.getLength(obj); i++)

src/main/java/org/cryptimeleon/math/serialization/annotations/internal/DependentRepresentationHandler.java

@@ -38,11 +38,15 @@ public static boolean canHandle(Type type) {
 
     @Override
     public Object deserializeFromRepresentation(Representation repr, Function<String, RepresentationRestorer> getRegisteredRestorer) {
+        if (repr == null)
+            return null;
         return getRegisteredRestorer.apply(restorerString).restoreFromRepresentation(typeToRestore, repr);
     }
 
     @Override
     public Representation serializeToRepresentation(Object object) {
+        if (object == null)
+            return null;
         return ((Representable) object).getRepresentation();
     }
 }

src/main/java/org/cryptimeleon/math/serialization/annotations/internal/ListAndSetRepresentationHandler.java

@@ -88,8 +88,10 @@ public static boolean canHandle(Type collectionType) { //handles List|Set<anythi
 
     @SuppressWarnings({"rawtypes", "unchecked"})
     @Override
-    public Object deserializeFromRepresentation(Representation repr,
-                                                Function<String, RepresentationRestorer> getRegisteredRestorer) {
+    public Object deserializeFromRepresentation(Representation repr, Function<String, RepresentationRestorer> getRegisteredRestorer) {
+        if (repr == null)
+            return null;
+
         Collection result = null;
 
         //Try to call default constructor to create collection.
@@ -130,12 +132,19 @@ public Object deserializeFromRepresentation(Representation repr,
 
     @Override
     public Representation serializeToRepresentation(Object obj) {
+        if (obj == null)
+            return null;
+
         if (!(obj instanceof List || obj instanceof Set))
             throw new IllegalArgumentException("Cannot handle representation of "+obj.getClass().getName());
+
+        if (!(obj instanceof List)) { //shuffle elements to avoid order leak
+            obj = Arrays.asList(((Set<?>) obj).toArray());
+            Collections.shuffle((List<?>) obj);
+        }
+
         ListRepresentation repr = new ListRepresentation();
         for (Object inner : (Iterable<?>) obj) {
-            //TODO sort elements in case of a Set type to avoid leaking something.
-            // Or is that done by the Converter? No, cannot.
             repr.put(elementHandler.serializeToRepresentation(inner));
         }
         return repr;

src/main/java/org/cryptimeleon/math/serialization/annotations/internal/MapRepresentationHandler.java

@@ -112,6 +112,9 @@ public static boolean canHandle(Type mapType) { //handles Map<anything>.
     @SuppressWarnings({"rawtypes", "unchecked"})
     @Override
     public Object deserializeFromRepresentation(Representation repr, Function<String, RepresentationRestorer> getRegisteredRestorer) {
+        if (repr == null)
+            return null;
+
         Map result = null;
 
         // Try to call default constructor to create collection.
@@ -141,8 +144,11 @@ public Object deserializeFromRepresentation(Representation repr, Function<String
 
     @Override
     public Representation serializeToRepresentation(Object obj) {
+        if (obj == null)
+            return null;
         if (!(obj instanceof Map))
             throw new IllegalArgumentException("Cannot handle representation of "+obj.getClass().getName());
+
         MapRepresentation repr = new MapRepresentation();
         ((Map<?,?>) obj).forEach(
                 (k, v) -> repr.put(

src/main/java/org/cryptimeleon/math/serialization/annotations/internal/StandaloneRepresentationHandler.java

@@ -44,8 +44,7 @@ public static boolean canHandle(Type type) {
     }
 
     @Override
-    public Object deserializeFromRepresentation(Representation repr,
-                                                Function<String, RepresentationRestorer> getRegisteredRestorer) {
+    public Object deserializeFromRepresentation(Representation repr, Function<String, RepresentationRestorer> getRegisteredRestorer) {
         if (repr == null) {
             return null;
         }