Improved code, refactored it a bit, implemented full null safety

QuasselDroidNG/src/main/java/de/kuschku/libquassel/events/LoginSuccessfulEvent.java

 package de.kuschku.libquassel.events;
 
+import android.support.annotation.NonNull;
+
+@SuppressWarnings("WeakerAccess")
 public class LoginSuccessfulEvent {
     public LoginSuccessfulEvent() {
     }
 
+    @NonNull
     @Override
     public String toString() {
         return "LoginSuccessfulEvent{}";

QuasselDroidNG/src/main/java/de/kuschku/libquassel/events/StatusMessageEvent.java

 package de.kuschku.libquassel.events;
 
+@SuppressWarnings("WeakerAccess")
 public class StatusMessageEvent {
     public final String scope;
     public final String message;

QuasselDroidNG/src/main/java/de/kuschku/libquassel/exceptions/UnknownTypeException.java

 package de.kuschku.libquassel.exceptions;
 
+import android.support.annotation.Nullable;
+
 public class UnknownTypeException extends IllegalArgumentException {
     public final String typeName;
 
@@ -7,6 +9,7 @@ public class UnknownTypeException extends IllegalArgumentException {
         this.typeName = typeName;
     }
 
+    @Nullable
     @Override
     public String getLocalizedMessage() {
         return getMessage();

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/FunctionType.java

 package de.kuschku.libquassel.functions;
 
+import android.support.annotation.NonNull;
+
 public enum FunctionType {
     INVALID(0),
     SYNC(1),
@@ -15,6 +17,7 @@ public enum FunctionType {
         this.id = id;
     }
 
+    @NonNull
     public static FunctionType fromId(int id) {
         switch (id) {
             case 1:

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/serializers/FunctionSerializer.java

 package de.kuschku.libquassel.functions.serializers;
 
+import android.support.annotation.NonNull;
+
 import java.util.List;
 
 public interface FunctionSerializer<T> {
-    List serialize(T data);
+    @NonNull
+    List serialize(@NonNull T data);
 
-    T deserialize(List packedFunc);
+    @NonNull
+    T deserialize(@NonNull List packedFunc);
 }

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/serializers/InitDataFunctionSerializer.java

 package de.kuschku.libquassel.functions.serializers;
 
+import android.support.annotation.NonNull;
+
 import java.util.List;
 
 import de.kuschku.libquassel.functions.types.InitDataFunction;
@@ -7,17 +9,20 @@ import de.kuschku.libquassel.functions.types.PackedInitDataFunction;
 import de.kuschku.libquassel.functions.types.UnpackedInitDataFunction;
 
 public class InitDataFunctionSerializer implements FunctionSerializer<InitDataFunction> {
+    @NonNull
     private static final InitDataFunctionSerializer serializer = new InitDataFunctionSerializer();
 
     private InitDataFunctionSerializer() {
     }
 
+    @NonNull
     public static InitDataFunctionSerializer get() {
         return serializer;
     }
 
+    @NonNull
     @Override
-    public List serialize(final InitDataFunction data) {
+    public List serialize(@NonNull final InitDataFunction data) {
         if (data instanceof UnpackedInitDataFunction) {
             return PackedInitDataFunctionSerializer.get().serialize((UnpackedInitDataFunction) data);
         } else if (data instanceof PackedInitDataFunction) {
@@ -27,8 +32,9 @@ public class InitDataFunctionSerializer implements FunctionSerializer<InitDataFu
         }
     }
 
+    @NonNull
     @Override
-    public InitDataFunction deserialize(final List packedFunc) {
+    public InitDataFunction deserialize(@NonNull final List packedFunc) {
         throw new IllegalArgumentException("Can not be applied to these arguments");
     }
 }

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/serializers/InitRequestFunctionSerializer.java

 package de.kuschku.libquassel.functions.serializers;
 
+import android.support.annotation.NonNull;
+
 import com.google.common.collect.Lists;
 
 import java.util.List;
@@ -9,19 +11,24 @@ import de.kuschku.libquassel.functions.types.InitRequestFunction;
 import de.kuschku.libquassel.primitives.types.QVariant;
 
 import static de.kuschku.libquassel.primitives.QMetaType.Type.QByteArray;
+import static de.kuschku.util.AndroidAssert.*;
 
+@SuppressWarnings("unchecked")
 public class InitRequestFunctionSerializer implements FunctionSerializer<InitRequestFunction> {
+    @NonNull
     private static final InitRequestFunctionSerializer serializer = new InitRequestFunctionSerializer();
 
     private InitRequestFunctionSerializer() {
     }
 
+    @NonNull
     public static InitRequestFunctionSerializer get() {
         return serializer;
     }
 
+    @NonNull
     @Override
-    public List serialize(final InitRequestFunction data) {
+    public List serialize(@NonNull final InitRequestFunction data) {
         return Lists.newArrayList(
                 FunctionType.INITREQUEST.id,
                 data.className,
@@ -30,7 +37,8 @@ public class InitRequestFunctionSerializer implements FunctionSerializer<InitReq
     }
 
     // TODO: Add this for all such serializers
-    public List serializePacked(final InitRequestFunction data) {
+    @NonNull
+    public List serializePacked(@NonNull final InitRequestFunction data) {
         return Lists.newArrayList(
                 new QVariant<>(FunctionType.INITREQUEST.id),
                 new QVariant<>(QByteArray, data.className),
@@ -38,11 +46,18 @@ public class InitRequestFunctionSerializer implements FunctionSerializer<InitReq
         );
     }
 
+    @NonNull
     @Override
-    public InitRequestFunction deserialize(final List packedFunc) {
+    public InitRequestFunction deserialize(@NonNull final List packedFunc) {
+        assertTrue(packedFunc.size() >= 2);
+
+        String className = (String) packedFunc.remove(0);
+        String objectName = (String) packedFunc.remove(0);
+        assertNotNull(className);
+
         return new InitRequestFunction(
-                (String) packedFunc.remove(0),
-                (String) packedFunc.remove(0)
+                className,
+                objectName
         );
     }
 }

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/serializers/PackedInitDataFunctionSerializer.java

 package de.kuschku.libquassel.functions.serializers;
 
+import android.support.annotation.NonNull;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -8,18 +10,24 @@ import de.kuschku.libquassel.functions.types.UnpackedInitDataFunction;
 import de.kuschku.libquassel.primitives.types.QVariant;
 import de.kuschku.libquassel.protocols.DatastreamPeer;
 
+import static de.kuschku.util.AndroidAssert.*;
+
+@SuppressWarnings({"unchecked", "ConstantConditions"})
 public class PackedInitDataFunctionSerializer implements FunctionSerializer<UnpackedInitDataFunction> {
+    @NonNull
     private static final PackedInitDataFunctionSerializer serializer = new PackedInitDataFunctionSerializer();
 
     private PackedInitDataFunctionSerializer() {
     }
 
+    @NonNull
     public static PackedInitDataFunctionSerializer get() {
         return serializer;
     }
 
+    @NonNull
     @Override
-    public List serialize(final UnpackedInitDataFunction data) {
+    public List serialize(@NonNull final UnpackedInitDataFunction data) {
         final List func = new ArrayList<>();
         func.add(FunctionType.INITDATA.id);
         func.add(data.className);
@@ -28,8 +36,11 @@ public class PackedInitDataFunctionSerializer implements FunctionSerializer<Unpa
         return func;
     }
 
+    @NonNull
     @Override
-    public UnpackedInitDataFunction deserialize(final List packedFunc) {
+    public UnpackedInitDataFunction deserialize(@NonNull final List packedFunc) {
+        assertTrue(packedFunc.size() >= 2);
+
         return new UnpackedInitDataFunction(
                 ((QVariant<String>) packedFunc.remove(0)).data,
                 ((QVariant<String>) packedFunc.remove(0)).data,

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/serializers/PackedRpcCallFunctionSerializer.java

 package de.kuschku.libquassel.functions.serializers;
 
+import android.support.annotation.NonNull;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -9,18 +11,24 @@ import de.kuschku.libquassel.primitives.QMetaType;
 import de.kuschku.libquassel.primitives.types.QVariant;
 import de.kuschku.libquassel.protocols.DatastreamPeer;
 
+import static de.kuschku.util.AndroidAssert.*;
+
+@SuppressWarnings({"unchecked", "ConstantConditions"})
 public class PackedRpcCallFunctionSerializer implements FunctionSerializer<RpcCallFunction> {
+    @NonNull
     private static final PackedRpcCallFunctionSerializer serializer = new PackedRpcCallFunctionSerializer();
 
     private PackedRpcCallFunctionSerializer() {
     }
 
+    @NonNull
     public static PackedRpcCallFunctionSerializer get() {
         return serializer;
     }
 
+    @NonNull
     @Override
-    public List serialize(final RpcCallFunction data) {
+    public List serialize(@NonNull final RpcCallFunction data) {
         final List func = new ArrayList<>();
         func.add(new QVariant<>(FunctionType.RPCCALL.id));
         func.add(new QVariant<>(QMetaType.Type.QByteArray, data.functionName));
@@ -28,8 +36,11 @@ public class PackedRpcCallFunctionSerializer implements FunctionSerializer<RpcCa
         return func;
     }
 
+    @NonNull
     @Override
-    public RpcCallFunction deserialize(final List packedFunc) {
+    public RpcCallFunction deserialize(@NonNull final List packedFunc) {
+        assertTrue(packedFunc.size() >= 1);
+
         return new RpcCallFunction(
                 ((QVariant<String>) packedFunc.remove(0)).data,
                 DatastreamPeer.unboxList(packedFunc)

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/serializers/PackedSyncFunctionSerializer.java

 package de.kuschku.libquassel.functions.serializers;
 
+import android.support.annotation.NonNull;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -9,18 +11,24 @@ import de.kuschku.libquassel.primitives.QMetaType;
 import de.kuschku.libquassel.primitives.types.QVariant;
 import de.kuschku.libquassel.protocols.DatastreamPeer;
 
-public class PackedSyncFunctionSerializer implements FunctionSerializer<SyncFunction> {
+import static de.kuschku.util.AndroidAssert.*;
+
+@SuppressWarnings({"unchecked", "ConstantConditions"})
+public class PackedSyncFunctionSerializer<T> implements FunctionSerializer<SyncFunction<T>> {
+    @NonNull
     private static final PackedSyncFunctionSerializer serializer = new PackedSyncFunctionSerializer();
 
     private PackedSyncFunctionSerializer() {
     }
 
+    @NonNull
     public static PackedSyncFunctionSerializer get() {
         return serializer;
     }
 
+    @NonNull
     @Override
-    public List serialize(final SyncFunction data) {
+    public List serialize(@NonNull final SyncFunction data) {
         final List func = new ArrayList<>();
         func.add(new QVariant<>(FunctionType.SYNC.id));
         func.add(new QVariant<>(QMetaType.Type.QByteArray, data.className));
@@ -30,9 +38,12 @@ public class PackedSyncFunctionSerializer implements FunctionSerializer<SyncFunc
         return func;
     }
 
+    @NonNull
     @Override
-    public SyncFunction deserialize(final List packedFunc) {
-        return new SyncFunction(
+    public SyncFunction<T> deserialize(@NonNull final List packedFunc) {
+        assertTrue(packedFunc.size() >= 3);
+
+        return new SyncFunction<>(
                 ((QVariant<String>) packedFunc.remove(0)).data,
                 ((QVariant<String>) packedFunc.remove(0)).data,
                 ((QVariant<String>) packedFunc.remove(0)).data,

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/serializers/UnpackedInitDataFunctionSerializer.java

 package de.kuschku.libquassel.functions.serializers;
 
+import android.support.annotation.NonNull;
+
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
@@ -8,18 +10,24 @@ import de.kuschku.libquassel.functions.FunctionType;
 import de.kuschku.libquassel.functions.types.PackedInitDataFunction;
 import de.kuschku.libquassel.primitives.types.QVariant;
 
+import static de.kuschku.util.AndroidAssert.*;
+
+@SuppressWarnings({"unchecked", "ConstantConditions"})
 public class UnpackedInitDataFunctionSerializer implements FunctionSerializer<PackedInitDataFunction> {
+    @NonNull
     private static final UnpackedInitDataFunctionSerializer serializer = new UnpackedInitDataFunctionSerializer();
 
     private UnpackedInitDataFunctionSerializer() {
     }
 
+    @NonNull
     public static UnpackedInitDataFunctionSerializer get() {
         return serializer;
     }
 
+    @NonNull
     @Override
-    public List serialize(final PackedInitDataFunction data) {
+    public List serialize(@NonNull final PackedInitDataFunction data) {
         final List func = new ArrayList<>();
         func.add(FunctionType.INITDATA.id);
         func.add(data.className);
@@ -28,8 +36,11 @@ public class UnpackedInitDataFunctionSerializer implements FunctionSerializer<Pa
         return func;
     }
 
+    @NonNull
     @Override
-    public PackedInitDataFunction deserialize(final List packedFunc) {
+    public PackedInitDataFunction deserialize(@NonNull final List packedFunc) {
+        assertTrue(packedFunc.size() >= 3);
+
         return new PackedInitDataFunction(
                 (String) packedFunc.remove(0),
                 (String) packedFunc.remove(0),

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/serializers/UnpackedRpcCallFunctionSerializer.java

 package de.kuschku.libquassel.functions.serializers;
 
+import android.support.annotation.NonNull;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -8,18 +10,24 @@ import de.kuschku.libquassel.functions.types.RpcCallFunction;
 import de.kuschku.libquassel.primitives.QMetaType;
 import de.kuschku.libquassel.primitives.types.QVariant;
 
+import static de.kuschku.util.AndroidAssert.*;
+
+@SuppressWarnings({"unchecked", "ConstantConditions"})
 public class UnpackedRpcCallFunctionSerializer implements FunctionSerializer<RpcCallFunction> {
+    @NonNull
     private static final UnpackedRpcCallFunctionSerializer serializer = new UnpackedRpcCallFunctionSerializer();
 
     private UnpackedRpcCallFunctionSerializer() {
     }
 
+    @NonNull
     public static UnpackedRpcCallFunctionSerializer get() {
         return serializer;
     }
 
+    @NonNull
     @Override
-    public List serialize(final RpcCallFunction data) {
+    public List serialize(@NonNull final RpcCallFunction data) {
         final List func = new ArrayList<>();
         func.add(new QVariant<>(FunctionType.RPCCALL.id));
         func.add(new QVariant<>(QMetaType.Type.QByteArray, data.functionName));
@@ -27,8 +35,11 @@ public class UnpackedRpcCallFunctionSerializer implements FunctionSerializer<Rpc
         return func;
     }
 
+    @NonNull
     @Override
-    public RpcCallFunction deserialize(final List packedFunc) {
+    public RpcCallFunction deserialize(@NonNull final List packedFunc) {
+        assertTrue(packedFunc.size() >= 1);
+
         return new RpcCallFunction(
                 (String) packedFunc.remove(0),
                 packedFunc

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/serializers/UnpackedSyncFunctionSerializer.java

 package de.kuschku.libquassel.functions.serializers;
 
+import android.support.annotation.NonNull;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -8,18 +10,24 @@ import de.kuschku.libquassel.functions.types.SyncFunction;
 import de.kuschku.libquassel.primitives.QMetaType;
 import de.kuschku.libquassel.primitives.types.QVariant;
 
-public class UnpackedSyncFunctionSerializer implements FunctionSerializer<SyncFunction> {
+import static de.kuschku.util.AndroidAssert.*;
+
+@SuppressWarnings({"unchecked", "ConstantConditions"})
+public class UnpackedSyncFunctionSerializer<T> implements FunctionSerializer<SyncFunction<T>> {
+    @NonNull
     private static final UnpackedSyncFunctionSerializer serializer = new UnpackedSyncFunctionSerializer();
 
     private UnpackedSyncFunctionSerializer() {
     }
 
+    @NonNull
     public static UnpackedSyncFunctionSerializer get() {
         return serializer;
     }
 
+    @NonNull
     @Override
-    public List serialize(final SyncFunction data) {
+    public List serialize(@NonNull final SyncFunction data) {
         final List func = new ArrayList<>();
         func.add(new QVariant<>(FunctionType.SYNC.id));
         func.add(new QVariant<>(QMetaType.Type.QByteArray, data.className));
@@ -29,9 +37,12 @@ public class UnpackedSyncFunctionSerializer implements FunctionSerializer<SyncFu
         return func;
     }
 
+    @NonNull
     @Override
-    public SyncFunction deserialize(final List packedFunc) {
-        return new SyncFunction(
+    public SyncFunction<T> deserialize(@NonNull final List packedFunc) {
+        assertTrue(packedFunc.size() >= 3);
+
+        return new SyncFunction<>(
                 (String) packedFunc.remove(0),
                 (String) packedFunc.remove(0),
                 (String) packedFunc.remove(0),

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/types/HandshakeFunction.java

 package de.kuschku.libquassel.functions.types;
 
+import android.support.annotation.NonNull;
+
 public class HandshakeFunction {
     public final Object data;
 
@@ -7,6 +9,7 @@ public class HandshakeFunction {
         this.data = data;
     }
 
+    @NonNull
     @Override
     public String toString() {
         return "HandshakeFunction{" +

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/types/InitRequestFunction.java

 package de.kuschku.libquassel.functions.types;
 
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+
 public class InitRequestFunction {
+    @NonNull
     public final String className;
+    @Nullable
     public final String objectName;
 
-    public InitRequestFunction(String className, String objectName) {
+    public InitRequestFunction(@NonNull String className, @Nullable String objectName) {
         this.className = className;
         this.objectName = objectName;
     }
 
+    @NonNull
     @Override
     public String toString() {
         return "InitRequestFunction{" +

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/types/PackedFunction.java

 package de.kuschku.libquassel.functions.types;
 
+import android.support.annotation.NonNull;
+
 import java.util.Map;
 
 import de.kuschku.libquassel.primitives.types.QVariant;
 
 public interface PackedFunction extends SerializedFunction<Map<String, QVariant>> {
+    @NonNull
     Map<String, QVariant> getData();
 }

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/types/PackedInitDataFunction.java

 package de.kuschku.libquassel.functions.types;
 
+import android.support.annotation.NonNull;
+
 import java.util.Map;
 
 import de.kuschku.libquassel.primitives.types.QVariant;
 
 public class PackedInitDataFunction extends InitDataFunction implements PackedFunction {
+    @NonNull
     private final Map<String, QVariant> data;
 
-    public PackedInitDataFunction(String className, String objectName, Map<String, QVariant> data) {
+    public PackedInitDataFunction(@NonNull String className, @NonNull String objectName, @NonNull Map<String, QVariant> data) {
         this.className = className;
         this.objectName = objectName;
         this.data = data;
     }
 
+    @NonNull
     @Override
     public Map<String, QVariant> getData() {
         return data;
     }
 
+    @NonNull
     @Override
     public String toString() {
         return "PackedInitDataFunction{" +

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/types/RpcCallFunction.java

 package de.kuschku.libquassel.functions.types;
 
+import android.support.annotation.NonNull;
+
 import java.util.Arrays;
 import java.util.List;
 
 public class RpcCallFunction {
+    @NonNull
     public final String functionName;
+    @NonNull
     public final List<Object> params;
 
-    public RpcCallFunction(String functionName, List<Object> params) {
+    public RpcCallFunction(@NonNull String functionName, @NonNull List<Object> params) {
         this.functionName = functionName;
         this.params = params;
     }
 
-    public RpcCallFunction(String functionName, Object... params) {
+    public RpcCallFunction(@NonNull String functionName, @NonNull Object... params) {
         this.functionName = functionName;
         this.params = Arrays.asList(params);
     }
 
+    @NonNull
     @Override
     public String toString() {
         return "RpcCallFunction{" +

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/types/SerializedFunction.java

 package de.kuschku.libquassel.functions.types;
 
+import android.support.annotation.NonNull;
+
 public interface SerializedFunction<T> {
+    @NonNull
     T getData();
 }

QuasselDroidNG/src/main/java/de/kuschku/libquassel/functions/types/SyncFunction.java

 package de.kuschku.libquassel.functions.types;
 
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+
 import java.util.List;
 
 public class SyncFunction<T> {
+    @NonNull
     public final String className;
+    @Nullable
     public final String objectName;
+    @NonNull
     public final String methodName;
+    @NonNull
     public final List<T> params;
 
-    public SyncFunction(String className, String objectName, String methodName, List<T> params) {
+    public SyncFunction(@NonNull String className, @Nullable String objectName, @NonNull String methodName, @NonNull List<T> params) {
         this.className = className;
         this.objectName = objectName;
         this.methodName = methodName;
         this.params = params;
     }
 
+    @NonNull
     @Override
     public String toString() {
         return "SyncFunction{" +