Add RegionSkins

BauSystem/BauSystem_Main/src/de/steamwar/bausystem/region/RegionBackups.java

@@ -20,8 +20,11 @@
 package de.steamwar.bausystem.region;
 
 import lombok.Getter;
+import lombok.NonNull;
 import lombok.RequiredArgsConstructor;
 
+import javax.annotation.CheckReturnValue;
+import javax.annotation.Nullable;
 import java.util.List;
 import java.util.Optional;
 
@@ -33,24 +36,33 @@ public interface RegionBackups {
         AUTOMATIC(20),
         ;
 
-        private final int maxBackups;
+        public final int maxBackups;
     }
 
     @RequiredArgsConstructor
     @Getter
     abstract class Backup {
+        @NonNull
         private final BackupType type;
+
+        @NonNull
         private final String name;
+
+        @NonNull
         private final FlagStorage flags;
 
+        @CheckReturnValue
         public abstract boolean load();
 
         public abstract void delete();
     }
 
+    @CheckReturnValue
     Optional<Backup> create(BackupType backupType);
 
+    @NonNull
     List<Backup> list();
 
+    @Nullable
     Backup get(String name);
 }