Merge pull request #86 from viktorasl/feature/json-preprocessing

JSON preprocessing static method + docs

Author: matthewcheok

README.md

@@ -85,6 +85,16 @@ You should specify the inbound and outbound JSON mapping on your `RLMObject` sub
       };
     }
 
+JSON preprocessing can be done by implementing `jsonPreprocessing:` static method:
+
+```ObjC
+- (NSDictionary *)jsonPreprocessing:(NSDictionary *)dictionary {
+    NSMutableDictionary *dict = [[NSMutableDictionary alloc] initWithDictionary:dictionary];
+    dict[@"releaseCount"] = @(0);
+    return dict.copy;
+}
+```
+
 Leaving out either one of the above will result in a mapping that assumes camelCase for your properties which map to snake_case for the JSON equivalents.
 
 As you can do with Mantle, you can specify `NSValueTransformers` for your properties:

Realm+JSON.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name     = 'Realm+JSON'
-  s.version  = '0.2.14'
+  s.version  = '0.2.16'
   s.ios.deployment_target     = '7.0'
   s.osx.deployment_target     = '10.9'
   s.watchos.deployment_target = '2.0'

Realm+JSON/RLMObject+JSON.m

@@ -156,16 +156,24 @@ - (void)removeFromRealm {
 
 #pragma mark - Private
 
-+ (id)mc_createObjectFromJSONDictionary:(NSDictionary *)dictionary {
++ (id)mc_createObjectFromJSONDictionary:(NSDictionary *)origDict {
 	NSMutableDictionary *result = [NSMutableDictionary dictionary];
 	NSDictionary *mapping = [[self class] mc_inboundMapping];
 
+    NSDictionary *dictionary;
+    SEL preprocessingSel = NSSelectorFromString(@"preprocessedJSON:");
+    if ([self respondsToSelector:preprocessingSel]) {
+        dictionary = [self performSelector:preprocessingSel withObject:origDict];
+    } else {
+        dictionary = origDict;
+    }
+    
 	for (NSString *dictionaryKeyPath in mapping) {
 		NSString *objectKeyPath = mapping[dictionaryKeyPath];
-
+		
 		id value = [dictionary valueForKeyPath:dictionaryKeyPath];
 
-		if (value) {
+        if (value) {
 			Class propertyClass = [[self class] mc_classForPropertyKey:objectKeyPath];
 
 			NSValueTransformer *transformer = [[self class] mc_transformerForPropertyKey:objectKeyPath];