YYKit源码探究（四十二） —— NSObject分类之YYModel（一）

版本记录

版本号	时间
V1.0	2018.03.30

前言

iOS圈内有几个人大家基本都知道，比如说王巍、唐巧，还有YYKit框架的作者现任职于滴滴的郭曜源 - ibireme等。这里有一篇唐巧对他的专访，还有他的 GitHub - Yaoyuan 和 博客，这里贴出来框架YYKit 框架。接下来几篇我们就一起来看一下这个框架。感兴趣的可以看上面写的几篇。
1. YYKit源码探究（一） —— 基本概览
2. YYKit源码探究（二） —— NSString分类之Hash（一）
3. YYKit源码探究（三） —— NSString分类之Encode and decode（二）
4. YYKit源码探究（四） —— NSString分类之Drawing（三）
5. YYKit源码探究（五） —— NSString分类之Regular Expression（四）
6. YYKit源码探究（六） —— NSString分类之NSNumber Compatible（五）
7. YYKit源码探究（七） —— NSString分类之Utilities（六）
8. YYKit源码探究（八） —— NSNumber分类（一）
9. YYKit源码探究（九） —— UIFont分类之架构分析和Font Traits（一）
10. YYKit源码探究（十） —— UIFont分类之Create font（二）
11. YYKit源码探究（十一） —— UIFont分类之Load and unload font（三）
12. YYKit源码探究（十二） —— UIFont分类之Dump font data（四）
13. YYKit源码探究（十三） —— UIImage分类之框架结构和Create image部分（一）
14. YYKit源码探究（十四） —— UIImage分类之Image Info（二）
15. YYKit源码探究（十五） —— UIImage分类之Modify Image（三）
16. YYKit源码探究（十六） —— UIImage分类之Image Effect（四）
17. YYKit源码探究（十七） —— UIImageView分类之架构和image部分（一）
18. YYKit源码探究（十八） —— UIImageView分类之highlight image部分（二）
19. YYKit源码探究（十九） —— UIScreen分类（一）
20. YYKit源码探究（二十） —— UIScrollView分类（一）
21. YYKit源码探究（二十一） —— UITableView分类（一）
22. YYKit源码探究（二十二） —— UITextField分类（一）
23. YYKit源码探究（二十三） —— UIView分类（一）
24. YYKit源码探究（二十四） —— UIPasteboard分类（一）
25. YYKit源码探究（二十五） —— UIGestureRecognizer分类（一）
26. YYKit源码探究（二十六） —— UIDevice分类框架及Device Information（一）
27. YYKit源码探究（二十七） —— UIDevice分类之Network Information（二）
28. YYKit源码探究（二十八） —— UIDevice分类之Disk Space（三）
29. YYKit源码探究（二十九） —— UIDevice分类之Memory Information（四）
30. YYKit源码探究（三十） —— UIDevice分类之CPU Information（五）
31. YYKit源码探究（三十一） —— UIControl分类（一）
32. YYKit源码探究（三十二） —— UIColor分类之Create a UIColor Object（一）
33. YYKit源码探究（三十三） —— UIColor分类之Get color's description（二）
34. YYKit源码探究（三十四） —— UIColor分类之Retrieving Color Information（三）
35. YYKit源码探究（三十五） —— UIButton分类之image（一）
36. YYKit源码探究（三十六） —— UIButton分类之background image（二）
37. YYKit源码探究（三十七） —— UIBezierPath分类（一）
38. YYKit源码探究（三十八） —— UIBarButtonItem分类（一）
39. YYKit源码探究（三十九） —— UIApplication分类（一）
40. YYKit源码探究（四十） —— NSTimer分类（一）
41. YYKit源码探究（四十一） —— NSParagraphStyle分类（一）

回顾

上一篇主要介绍了NSParagraphStyle分类，这一篇主要看一下NSObject分类YYModel部分。

---

API

下面我们一起来看一下API文档。

YYModel协议

/**
 If the default model transform does not fit to your model class, implement one or
 more method in this protocol to change the default key-value transform process.
 There's no need to add '' to your class header.
 */
@protocol YYModel 
@optional

/**
 Custom property mapper.
 
 @discussion If the key in JSON/Dictionary does not match to the model's property name,
 implements this method and returns the additional mapper.
 
 Example:
    
    json: 
        {
            "n":"Harry Pottery",
            "p": 256,
            "ext" : {
                "desc" : "A book written by J.K.Rowling."
            },
            "ID" : 100010
        }
 
    model:
        @interface YYBook : NSObject
        @property NSString *name;
        @property NSInteger page;
        @property NSString *desc;
        @property NSString *bookID;
        @end
        
        @implementation YYBook
        + (NSDictionary *)modelCustomPropertyMapper {
            return @{@"name"  : @"n",
                     @"page"  : @"p",
                     @"desc"  : @"ext.desc",
                     @"bookID": @[@"id", @"ID", @"book_id"]};
        }
        @end
 
 @return A custom mapper for properties.
 */
+ (nullable NSDictionary *)modelCustomPropertyMapper;

/**
 The generic class mapper for container properties.
 
 @discussion If the property is a container object, such as NSArray/NSSet/NSDictionary,
 implements this method and returns a property->class mapper, tells which kind of 
 object will be add to the array/set/dictionary.
 
  Example:
        @class YYShadow, YYBorder, YYAttachment;
 
        @interface YYAttributes
        @property NSString *name;
        @property NSArray *shadows;
        @property NSSet *borders;
        @property NSDictionary *attachments;
        @end
 
        @implementation YYAttributes
        + (NSDictionary *)modelContainerPropertyGenericClass {
            return @{@"shadows" : [YYShadow class],
                     @"borders" : YYBorder.class,
                     @"attachments" : @"YYAttachment" };
        }
        @end
 
 @return A class mapper.
 */
+ (nullable NSDictionary *)modelContainerPropertyGenericClass;

/**
 If you need to create instances of different classes during json->object transform,
 use the method to choose custom class based on dictionary data.
 
 @discussion If the model implements this method, it will be called to determine resulting class
 during `+modelWithJSON:`, `+modelWithDictionary:`, conveting object of properties of parent objects 
 (both singular and containers via `+modelContainerPropertyGenericClass`).
 
 Example:
        @class YYCircle, YYRectangle, YYLine;
 
        @implementation YYShape

        + (Class)modelCustomClassForDictionary:(NSDictionary*)dictionary {
            if (dictionary[@"radius"] != nil) {
                return [YYCircle class];
            } else if (dictionary[@"width"] != nil) {
                return [YYRectangle class];
            } else if (dictionary[@"y2"] != nil) {
                return [YYLine class];
            } else {
                return [self class];
            }
        }

        @end

 @param dictionary The json/kv dictionary.
 
 @return Class to create from this dictionary, `nil` to use current class.

 */
+ (nullable Class)modelCustomClassForDictionary:(NSDictionary *)dictionary;

/**
 All the properties in blacklist will be ignored in model transform process.
 Returns nil to ignore this feature.
 
 @return An array of property's name.
 */
+ (nullable NSArray *)modelPropertyBlacklist;

/**
 If a property is not in the whitelist, it will be ignored in model transform process.
 Returns nil to ignore this feature.
 
 @return An array of property's name.
 */
+ (nullable NSArray *)modelPropertyWhitelist;

/**
 This method's behavior is similar to `- (BOOL)modelCustomTransformFromDictionary:(NSDictionary *)dic;`, 
 but be called before the model transform.
 
 @discussion If the model implements this method, it will be called before
 `+modelWithJSON:`, `+modelWithDictionary:`, `-modelSetWithJSON:` and `-modelSetWithDictionary:`.
 If this method returns nil, the transform process will ignore this model.
 
 @param dic  The json/kv dictionary.
 
 @return Returns the modified dictionary, or nil to ignore this model.
 */
- (NSDictionary *)modelCustomWillTransformFromDictionary:(NSDictionary *)dic;

/**
 If the default json-to-model transform does not fit to your model object, implement
 this method to do additional process. You can also use this method to validate the 
 model's properties.
 
 @discussion If the model implements this method, it will be called at the end of
 `+modelWithJSON:`, `+modelWithDictionary:`, `-modelSetWithJSON:` and `-modelSetWithDictionary:`.
 If this method returns NO, the transform process will ignore this model.
 
 @param dic  The json/kv dictionary.
 
 @return Returns YES if the model is valid, or NO to ignore this model.
 */
- (BOOL)modelCustomTransformFromDictionary:(NSDictionary *)dic;

/**
 If the default model-to-json transform does not fit to your model class, implement
 this method to do additional process. You can also use this method to validate the
 json dictionary.
 
 @discussion If the model implements this method, it will be called at the end of
 `-modelToJSONObject` and `-modelToJSONString`.
 If this method returns NO, the transform process will ignore this json dictionary.
 
 @param dic  The json dictionary.
 
 @return Returns YES if the model is valid, or NO to ignore this model.
 */
- (BOOL)modelCustomTransformToDictionary:(NSMutableDictionary *)dic;

@end

如果默认的模型转换不能适合你的模型类，实现协议中的一个或者更多的方法来改变默认的键值转换过程，不用在你的类的头文件中添加。

下面我们就一起详细的看一下这个协议。

1. + (nullable NSDictionary *)modelCustomPropertyMapper;

如果JSON/Dictionary中的key不能匹配模型中属性名字，实现这个方法并返回映射。

注意里面中的例子。

2. + (nullable NSDictionary *)modelContainerPropertyGenericClass;

容器属性的泛型类映射器。

如果属性是一个容器对象，如NSArray / NSSet / NSDictionary，实现此方法并返回一个property->class映射器，告诉哪种对象将被添加到array/set/dictionary。

3. + (nullable Class)modelCustomClassForDictionary:(NSDictionary *)dictionary;

如果你需要在json-> object转换过程中创建不同类的实例，使用该方法根据字典数据选择自定义类。

如果模型实现了这个方法，它将被调用来确定结果类在+ modelWithJSON：，+ modelWithDictionary：期间，传递父对象属性的对象（通过+ modelContainerPropertyGenericClass包含单数和容器）。

4. + (nullable NSArray *)modelPropertyBlacklist;

在模型转换过程中，所有黑名单中的属性将被忽略，返回值就是一组属性名称。

5. + (nullable NSArray *)modelPropertyWhitelist;

如果属性不在白名单中，它将在模型转换过程中被忽略。

6. - (NSDictionary *)modelCustomWillTransformFromDictionary:(NSDictionary *)dic;

该方法与- (BOOL)modelCustomTransformFromDictionary:(NSDictionary *)dic;类似，但是是在模型转换之前调用的。

如果模型实现了这个方法，它就会在+modelWithJSON:, +modelWithDictionary:, -modelSetWithJSON: and -modelSetWithDictionary:之前进行调用，如果这个方法返回nil，转换过程将会忽略这个模型。

7. - (BOOL)modelCustomTransformFromDictionary:(NSDictionary *)dic;

如果默认的json-to-model转换不适合你的模型对象，实现这个方法进行进一步的处理，你也可以使用这个方法验证模型属性。

如果模型实现了这个方法，它将会在+modelWithJSON:, +modelWithDictionary:, -modelSetWithJSON: and -modelSetWithDictionary:后进行调用，如果方法返回NO，转换过程将会忽略这个模型。

8. - (BOOL)modelCustomTransformToDictionary:(NSMutableDictionary *)dic;

如果默认的model-to-json转换不适合你的模型对象，实现这个方法进行进一步的处理，你也可以使用这个方法验证模型属性。

如果模型实现了这个方法，它将会在 -modelToJSONObject and -modelToJSONString后进行调用，如果方法返回NO，转换过程将会忽略这个模型。

NSArray (YYModel)

下面我们就看一下这个API

/**
 Provide some data-model method for NSArray.
 */
@interface NSArray (YYModel)

/**
 Creates and returns an array from a json-array.
 This method is thread-safe.
 
 @param cls  The instance's class in array.
 @param json  A json array of `NSArray`, `NSString` or `NSData`.
              Example: [{"name","Mary"},{name:"Joe"}]
 
 @return A array, or nil if an error occurs.
 */
+ (nullable NSArray *)modelArrayWithClass:(Class)cls json:(id)json;

@end

1. + (nullable NSArray *)modelArrayWithClass:(Class)cls json:(id)json;

该方法的作用就是从json-array创建并返回一个数组。

方法实现

+ (NSArray *)modelArrayWithClass:(Class)cls json:(id)json {
    if (!json) return nil;
    NSArray *arr = nil;
    NSData *jsonData = nil;
    if ([json isKindOfClass:[NSArray class]]) {
        arr = json;
    } else if ([json isKindOfClass:[NSString class]]) {
        jsonData = [(NSString *)json dataUsingEncoding : NSUTF8StringEncoding];
    } else if ([json isKindOfClass:[NSData class]]) {
        jsonData = json;
    }
    if (jsonData) {
        arr = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:NULL];
        if (![arr isKindOfClass:[NSArray class]]) arr = nil;
    }
    return [self modelArrayWithClass:cls array:arr];
}

+ (NSArray *)modelArrayWithClass:(Class)cls array:(NSArray *)arr {
    if (!cls || !arr) return nil;
    NSMutableArray *result = [NSMutableArray new];
    for (NSDictionary *dic in arr) {
        if (![dic isKindOfClass:[NSDictionary class]]) continue;
        NSObject *obj = [cls modelWithDictionary:dic];
        if (obj) [result addObject:obj];
    }
    return result;
}

NSDictionary (YYModel)

下面我们就看一下这个API

/**
 Provide some data-model method for NSDictionary.
 */
@interface NSDictionary (YYModel)

/**
 Creates and returns a dictionary from a json.
 This method is thread-safe.
 
 @param cls  The value instance's class in dictionary.
 @param json  A json dictionary of `NSDictionary`, `NSString` or `NSData`.
              Example: {"user1":{"name","Mary"}, "user2": {name:"Joe"}}
 
 @return A dictionary, or nil if an error occurs.
 */
+ (nullable NSDictionary *)modelDictionaryWithClass:(Class)cls json:(id)json;
@end

1. + (nullable NSDictionary *)modelDictionaryWithClass:(Class)cls json:(id)json;

该方法的作用就是从json创建并返回一个字典。

方法实现

+ (NSDictionary *)modelDictionaryWithClass:(Class)cls json:(id)json {
    if (!json) return nil;
    NSDictionary *dic = nil;
    NSData *jsonData = nil;
    if ([json isKindOfClass:[NSDictionary class]]) {
        dic = json;
    } else if ([json isKindOfClass:[NSString class]]) {
        jsonData = [(NSString *)json dataUsingEncoding : NSUTF8StringEncoding];
    } else if ([json isKindOfClass:[NSData class]]) {
        jsonData = json;
    }
    if (jsonData) {
        dic = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:NULL];
        if (![dic isKindOfClass:[NSDictionary class]]) dic = nil;
    }
    return [self modelDictionaryWithClass:cls dictionary:dic];
}

+ (NSDictionary *)modelDictionaryWithClass:(Class)cls dictionary:(NSDictionary *)dic {
    if (!cls || !dic) return nil;
    NSMutableDictionary *result = [NSMutableDictionary new];
    for (NSString *key in dic.allKeys) {
        if (![key isKindOfClass:[NSString class]]) continue;
        NSObject *obj = [cls modelWithDictionary:dic[key]];
        if (obj) result[key] = obj;
    }
    return result;
}

NSObject (YYModel)

下面我们就看一下这个API

@interface NSObject (YYModel)

/**
 Creates and returns a new instance of the receiver from a json.
 This method is thread-safe.
 
 @param json  A json object in `NSDictionary`, `NSString` or `NSData`.
 
 @return A new instance created from the json, or nil if an error occurs.
 */
+ (nullable instancetype)modelWithJSON:(id)json;

/**
 Creates and returns a new instance of the receiver from a key-value dictionary.
 This method is thread-safe.
 
 @param dictionary  A key-value dictionary mapped to the instance's properties.
 Any invalid key-value pair in dictionary will be ignored.
 
 @return A new instance created from the dictionary, or nil if an error occurs.
 
 @discussion The key in `dictionary` will mapped to the reciever's property name,
 and the value will set to the property. If the value's type does not match the
 property, this method will try to convert the value based on these rules:
 
     `NSString` or `NSNumber` -> c number, such as BOOL, int, long, float, NSUInteger...
     `NSString` -> NSDate, parsed with format "yyyy-MM-dd'T'HH:mm:ssZ", "yyyy-MM-dd HH:mm:ss" or "yyyy-MM-dd".
     `NSString` -> NSURL.
     `NSValue` -> struct or union, such as CGRect, CGSize, ...
     `NSString` -> SEL, Class.
 */
+ (nullable instancetype)modelWithDictionary:(NSDictionary *)dictionary;

/**
 Set the receiver's properties with a json object.
 
 @discussion Any invalid data in json will be ignored.
 
 @param json  A json object of `NSDictionary`, `NSString` or `NSData`, mapped to the
 receiver's properties.
 
 @return Whether succeed.
 */
- (BOOL)modelSetWithJSON:(id)json;

/**
 Set the receiver's properties with a key-value dictionary.
 
 @param dic  A key-value dictionary mapped to the receiver's properties.
 Any invalid key-value pair in dictionary will be ignored.
 
 @discussion The key in `dictionary` will mapped to the reciever's property name,
 and the value will set to the property. If the value's type doesn't match the
 property, this method will try to convert the value based on these rules:
 
     `NSString`, `NSNumber` -> c number, such as BOOL, int, long, float, NSUInteger...
     `NSString` -> NSDate, parsed with format "yyyy-MM-dd'T'HH:mm:ssZ", "yyyy-MM-dd HH:mm:ss" or "yyyy-MM-dd".
     `NSString` -> NSURL.
     `NSValue` -> struct or union, such as CGRect, CGSize, ...
     `NSString` -> SEL, Class.
 
 @return Whether succeed.
 */
- (BOOL)modelSetWithDictionary:(NSDictionary *)dic;

/**
 Generate a json object from the receiver's properties.
 
 @return A json object in `NSDictionary` or `NSArray`, or nil if an error occurs.
 See [NSJSONSerialization isValidJSONObject] for more information.
 
 @discussion Any of the invalid property is ignored.
 If the reciver is `NSArray`, `NSDictionary` or `NSSet`, it just convert
 the inner object to json object.
 */
- (nullable id)modelToJSONObject;

/**
 Generate a json string's data from the receiver's properties.
 
 @return A json string's data, or nil if an error occurs.
 
 @discussion Any of the invalid property is ignored.
 If the reciver is `NSArray`, `NSDictionary` or `NSSet`, it will also convert the 
 inner object to json string.
 */
- (nullable NSData *)modelToJSONData;

/**
 Generate a json string from the receiver's properties.
 
 @return A json string, or nil if an error occurs.
 
 @discussion Any of the invalid property is ignored.
 If the reciver is `NSArray`, `NSDictionary` or `NSSet`, it will also convert the 
 inner object to json string.
 */
- (nullable NSString *)modelToJSONString;

/**
 Copy a instance with the receiver's properties.
 
 @return A copied instance, or nil if an error occurs.
 */
- (nullable id)modelCopy;

/**
 Encode the receiver's properties to a coder.
 
 @param aCoder  An archiver object.
 */
- (void)modelEncodeWithCoder:(NSCoder *)aCoder;

/**
 Decode the receiver's properties from a decoder.
 
 @param aDecoder  An archiver object.
 
 @return self
 */
- (id)modelInitWithCoder:(NSCoder *)aDecoder;

/**
 Get a hash code with the receiver's properties.
 
 @return Hash code.
 */
- (NSUInteger)modelHash;

/**
 Compares the receiver with another object for equality, based on properties.
 
 @param model  Another object.
 
 @return `YES` if the reciever is equal to the object, otherwise `NO`.
 */
- (BOOL)modelIsEqual:(id)model;

/**
 Description method for debugging purposes based on properties.
 
 @return A string that describes the contents of the receiver.
 */
- (NSString *)modelDescription;

@end

下面我们就详细的看一下这个API

1. + (nullable instancetype)modelWithJSON:(id)json;

从json创建并返回一个实例，该方法是线程安全的。

方法实现

+ (instancetype)modelWithJSON:(id)json {
    NSDictionary *dic = [self _yy_dictionaryWithJSON:json];
    return [self modelWithDictionary:dic];
}

2. + (nullable instancetype)modelWithDictionary:(NSDictionary *)dictionary;

从字典创建并返回一个实例，该方法是线程安全的。

这里注意，在给对象的属性进行赋值的时候，如果值类型和属性类型不符合的话，该方法会按照下面规则进行适当的转换。

`NSString` or `NSNumber` -> c number, such as BOOL, int, long, float, NSUInteger...
 `NSString` -> NSDate, parsed with format "yyyy-MM-dd'T'HH:mm:ssZ", "yyyy-MM-dd HH:mm:ss" or "yyyy-MM-dd".
 `NSString` -> NSURL.
 `NSValue` -> struct or union, such as CGRect, CGSize, ...
 `NSString` -> SEL, Class.

方法实现

+ (instancetype)modelWithDictionary:(NSDictionary *)dictionary {
    if (!dictionary || dictionary == (id)kCFNull) return nil;
    if (![dictionary isKindOfClass:[NSDictionary class]]) return nil;
    
    Class cls = [self class];
    _YYModelMeta *modelMeta = [_YYModelMeta metaWithClass:cls];
    if (modelMeta->_hasCustomClassFromDictionary) {
        cls = [cls modelCustomClassForDictionary:dictionary] ?: cls;
    }
    
    NSObject *one = [cls new];
    if ([one modelSetWithDictionary:dictionary]) return one;
    return nil;
}

3. - (BOOL)modelSetWithJSON:(id)json;

判断model和JSON之间的转换是否成功。

方法实现

- (BOOL)modelSetWithJSON:(id)json {
    NSDictionary *dic = [NSObject _yy_dictionaryWithJSON:json];
    return [self modelSetWithDictionary:dic];
}

4. - (BOOL)modelSetWithDictionary:(NSDictionary *)dic;

用给定的字典设置接受者的属性。

字典中的key会映射到接受者的属性名称上，值将被设置给属性，如果值类型和属性类型不相符，这个方法将会按照下面规则进行转换。

`NSString`, `NSNumber` -> c number, such as BOOL, int, long, float, NSUInteger...
`NSString` -> NSDate, parsed with format "yyyy-MM-dd'T'HH:mm:ssZ", "yyyy-MM-dd HH:mm:ss" or "yyyy-MM-dd".
`NSString` -> NSURL.
`NSValue` -> struct or union, such as CGRect, CGSize, ...
`NSString` -> SEL, Class.

方法实现

- (BOOL)modelSetWithDictionary:(NSDictionary *)dic {
    if (!dic || dic == (id)kCFNull) return NO;
    if (![dic isKindOfClass:[NSDictionary class]]) return NO;
    
    _YYModelMeta *modelMeta = [_YYModelMeta metaWithClass:object_getClass(self)];
    if (modelMeta->_keyMappedCount == 0) return NO;
    
    if (modelMeta->_hasCustomWillTransformFromDictionary) {
        dic = [((id)self) modelCustomWillTransformFromDictionary:dic];
        if (![dic isKindOfClass:[NSDictionary class]]) return NO;
    }
    
    ModelSetContext context = {0};
    context.modelMeta = (__bridge void *)(modelMeta);
    context.model = (__bridge void *)(self);
    context.dictionary = (__bridge void *)(dic);
    
    if (modelMeta->_keyMappedCount >= CFDictionaryGetCount((CFDictionaryRef)dic)) {
        CFDictionaryApplyFunction((CFDictionaryRef)dic, ModelSetWithDictionaryFunction, &context);
        if (modelMeta->_keyPathPropertyMetas) {
            CFArrayApplyFunction((CFArrayRef)modelMeta->_keyPathPropertyMetas,
                                 CFRangeMake(0, CFArrayGetCount((CFArrayRef)modelMeta->_keyPathPropertyMetas)),
                                 ModelSetWithPropertyMetaArrayFunction,
                                 &context);
        }
        if (modelMeta->_multiKeysPropertyMetas) {
            CFArrayApplyFunction((CFArrayRef)modelMeta->_multiKeysPropertyMetas,
                                 CFRangeMake(0, CFArrayGetCount((CFArrayRef)modelMeta->_multiKeysPropertyMetas)),
                                 ModelSetWithPropertyMetaArrayFunction,
                                 &context);
        }
    } else {
        CFArrayApplyFunction((CFArrayRef)modelMeta->_allPropertyMetas,
                             CFRangeMake(0, modelMeta->_keyMappedCount),
                             ModelSetWithPropertyMetaArrayFunction,
                             &context);
    }
    
    if (modelMeta->_hasCustomTransformFromDictionary) {
        return [((id)self) modelCustomTransformFromDictionary:dic];
    }
    return YES;
}

5. - (nullable id)modelToJSONObject;

根据接受者属性生成一个json对象。

如果接受者是NSArray, NSDictionary or NSSet，那么它仅将内部对象转化为json对象。

方法实现

- (id)modelToJSONObject {
    /*
     Apple said:
     The top level object is an NSArray or NSDictionary.
     All objects are instances of NSString, NSNumber, NSArray, NSDictionary, or NSNull.
     All dictionary keys are instances of NSString.
     Numbers are not NaN or infinity.
     */
    id jsonObject = ModelToJSONObjectRecursive(self);
    if ([jsonObject isKindOfClass:[NSArray class]]) return jsonObject;
    if ([jsonObject isKindOfClass:[NSDictionary class]]) return jsonObject;
    return nil;
}

6. - (nullable NSData *)modelToJSONData;

根据接受者属性生成一个json data。

如果接受者是NSArray, NSDictionary or NSSet，那么它仅将内部对象转化为json字符串。

方法实现

- (NSData *)modelToJSONData {
    id jsonObject = [self modelToJSONObject];
    if (!jsonObject) return nil;
    return [NSJSONSerialization dataWithJSONObject:jsonObject options:0 error:NULL];
}

7. - (nullable NSString *)modelToJSONString;

根据接受者属性，生成一个json字符串。

如果接受者是NSArray, NSDictionary or NSSet，那么它仅将内部对象转化为json字符串。

方法实现

- (NSString *)modelToJSONString {
    NSData *jsonData = [self modelToJSONData];
    if (jsonData.length == 0) return nil;
    return [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}

8. - (nullable id)modelCopy;

根据接受者属性，生成一个实例。

方法实现

- (id)modelCopy{
    if (self == (id)kCFNull) return self;
    _YYModelMeta *modelMeta = [_YYModelMeta metaWithClass:self.class];
    if (modelMeta->_nsType) return [self copy];
    
    NSObject *one = [self.class new];
    for (_YYModelPropertyMeta *propertyMeta in modelMeta->_allPropertyMetas) {
        if (!propertyMeta->_getter || !propertyMeta->_setter) continue;
        
        if (propertyMeta->_isCNumber) {
            switch (propertyMeta->_type & YYEncodingTypeMask) {
                case YYEncodingTypeBool: {
                    bool num = ((bool (*)(id, SEL))(void *) objc_msgSend)((id)self, propertyMeta->_getter);
                    ((void (*)(id, SEL, bool))(void *) objc_msgSend)((id)one, propertyMeta->_setter, num);
                } break;
                case YYEncodingTypeInt8:
                case YYEncodingTypeUInt8: {
                    uint8_t num = ((bool (*)(id, SEL))(void *) objc_msgSend)((id)self, propertyMeta->_getter);
                    ((void (*)(id, SEL, uint8_t))(void *) objc_msgSend)((id)one, propertyMeta->_setter, num);
                } break;
                case YYEncodingTypeInt16:
                case YYEncodingTypeUInt16: {
                    uint16_t num = ((uint16_t (*)(id, SEL))(void *) objc_msgSend)((id)self, propertyMeta->_getter);
                    ((void (*)(id, SEL, uint16_t))(void *) objc_msgSend)((id)one, propertyMeta->_setter, num);
                } break;
                case YYEncodingTypeInt32:
                case YYEncodingTypeUInt32: {
                    uint32_t num = ((uint32_t (*)(id, SEL))(void *) objc_msgSend)((id)self, propertyMeta->_getter);
                    ((void (*)(id, SEL, uint32_t))(void *) objc_msgSend)((id)one, propertyMeta->_setter, num);
                } break;
                case YYEncodingTypeInt64:
                case YYEncodingTypeUInt64: {
                    uint64_t num = ((uint64_t (*)(id, SEL))(void *) objc_msgSend)((id)self, propertyMeta->_getter);
                    ((void (*)(id, SEL, uint64_t))(void *) objc_msgSend)((id)one, propertyMeta->_setter, num);
                } break;
                case YYEncodingTypeFloat: {
                    float num = ((float (*)(id, SEL))(void *) objc_msgSend)((id)self, propertyMeta->_getter);
                    ((void (*)(id, SEL, float))(void *) objc_msgSend)((id)one, propertyMeta->_setter, num);
                } break;
                case YYEncodingTypeDouble: {
                    double num = ((double (*)(id, SEL))(void *) objc_msgSend)((id)self, propertyMeta->_getter);
                    ((void (*)(id, SEL, double))(void *) objc_msgSend)((id)one, propertyMeta->_setter, num);
                } break;
                case YYEncodingTypeLongDouble: {
                    long double num = ((long double (*)(id, SEL))(void *) objc_msgSend)((id)self, propertyMeta->_getter);
                    ((void (*)(id, SEL, long double))(void *) objc_msgSend)((id)one, propertyMeta->_setter, num);
                } // break; commented for code coverage in next line
                default: break;
            }
        } else {
            switch (propertyMeta->_type & YYEncodingTypeMask) {
                case YYEncodingTypeObject:
                case YYEncodingTypeClass:
                case YYEncodingTypeBlock: {
                    id value = ((id (*)(id, SEL))(void *) objc_msgSend)((id)self, propertyMeta->_getter);
                    ((void (*)(id, SEL, id))(void *) objc_msgSend)((id)one, propertyMeta->_setter, value);
                } break;
                case YYEncodingTypeSEL:
                case YYEncodingTypePointer:
                case YYEncodingTypeCString: {
                    size_t value = ((size_t (*)(id, SEL))(void *) objc_msgSend)((id)self, propertyMeta->_getter);
                    ((void (*)(id, SEL, size_t))(void *) objc_msgSend)((id)one, propertyMeta->_setter, value);
                } break;
                case YYEncodingTypeStruct:
                case YYEncodingTypeUnion: {
                    @try {
                        NSValue *value = [self valueForKey:NSStringFromSelector(propertyMeta->_getter)];
                        if (value) {
                            [one setValue:value forKey:propertyMeta->_name];
                        }
                    } @catch (NSException *exception) {}
                } // break; commented for code coverage in next line
                default: break;
            }
        }
    }
    return one;
}

9. - (void)modelEncodeWithCoder:(NSCoder *)aCoder;

将接受者属性编码到coder。

方法实现

- (void)modelEncodeWithCoder:(NSCoder *)aCoder {
    if (!aCoder) return;
    if (self == (id)kCFNull) {
        [((id)self)encodeWithCoder:aCoder];
        return;
    }
    
    _YYModelMeta *modelMeta = [_YYModelMeta metaWithClass:self.class];
    if (modelMeta->_nsType) {
        [((id)self)encodeWithCoder:aCoder];
        return;
    }
    
    for (_YYModelPropertyMeta *propertyMeta in modelMeta->_allPropertyMetas) {
        if (!propertyMeta->_getter) return;
        
        if (propertyMeta->_isCNumber) {
            NSNumber *value = ModelCreateNumberFromProperty(self, propertyMeta);
            if (value) [aCoder encodeObject:value forKey:propertyMeta->_name];
        } else {
            switch (propertyMeta->_type & YYEncodingTypeMask) {
                case YYEncodingTypeObject: {
                    id value = ((id (*)(id, SEL))(void *)objc_msgSend)((id)self, propertyMeta->_getter);
                    if (value && (propertyMeta->_nsType || [value respondsToSelector:@selector(encodeWithCoder:)])) {
                        if ([value isKindOfClass:[NSValue class]]) {
                            if ([value isKindOfClass:[NSNumber class]]) {
                                [aCoder encodeObject:value forKey:propertyMeta->_name];
                            }
                        } else {
                            [aCoder encodeObject:value forKey:propertyMeta->_name];
                        }
                    }
                } break;
                case YYEncodingTypeSEL: {
                    SEL value = ((SEL (*)(id, SEL))(void *)objc_msgSend)((id)self, propertyMeta->_getter);
                    if (value) {
                        NSString *str = NSStringFromSelector(value);
                        [aCoder encodeObject:str forKey:propertyMeta->_name];
                    }
                } break;
                case YYEncodingTypeStruct:
                case YYEncodingTypeUnion: {
                    if (propertyMeta->_isKVCCompatible && propertyMeta->_isStructAvailableForKeyedArchiver) {
                        @try {
                            NSValue *value = [self valueForKey:NSStringFromSelector(propertyMeta->_getter)];
                            [aCoder encodeObject:value forKey:propertyMeta->_name];
                        } @catch (NSException *exception) {}
                    }
                } break;
                    
                default:
                    break;
            }
        }
    }
}

10. - (id)modelInitWithCoder:(NSCoder *)aDecoder;

将接受者属性进行解码。

方法实现

- (id)modelInitWithCoder:(NSCoder *)aDecoder {
    if (!aDecoder) return self;
    if (self == (id)kCFNull) return self;    
    _YYModelMeta *modelMeta = [_YYModelMeta metaWithClass:self.class];
    if (modelMeta->_nsType) return self;
    
    for (_YYModelPropertyMeta *propertyMeta in modelMeta->_allPropertyMetas) {
        if (!propertyMeta->_setter) continue;
        
        if (propertyMeta->_isCNumber) {
            NSNumber *value = [aDecoder decodeObjectForKey:propertyMeta->_name];
            if ([value isKindOfClass:[NSNumber class]]) {
                ModelSetNumberToProperty(self, value, propertyMeta);
                [value class];
            }
        } else {
            YYEncodingType type = propertyMeta->_type & YYEncodingTypeMask;
            switch (type) {
                case YYEncodingTypeObject: {
                    id value = [aDecoder decodeObjectForKey:propertyMeta->_name];
                    ((void (*)(id, SEL, id))(void *) objc_msgSend)((id)self, propertyMeta->_setter, value);
                } break;
                case YYEncodingTypeSEL: {
                    NSString *str = [aDecoder decodeObjectForKey:propertyMeta->_name];
                    if ([str isKindOfClass:[NSString class]]) {
                        SEL sel = NSSelectorFromString(str);
                        ((void (*)(id, SEL, SEL))(void *) objc_msgSend)((id)self, propertyMeta->_setter, sel);
                    }
                } break;
                case YYEncodingTypeStruct:
                case YYEncodingTypeUnion: {
                    if (propertyMeta->_isKVCCompatible) {
                        @try {
                            NSValue *value = [aDecoder decodeObjectForKey:propertyMeta->_name];
                            if (value) [self setValue:value forKey:propertyMeta->_name];
                        } @catch (NSException *exception) {}
                    }
                } break;
                    
                default:
                    break;
            }
        }
    }
    return self;
}

11. - (NSUInteger)modelHash;

获取接收者属性的hash code

方法实现

- (NSUInteger)modelHash {
    if (self == (id)kCFNull) return [self hash];
    _YYModelMeta *modelMeta = [_YYModelMeta metaWithClass:self.class];
    if (modelMeta->_nsType) return [self hash];
    
    NSUInteger value = 0;
    NSUInteger count = 0;
    for (_YYModelPropertyMeta *propertyMeta in modelMeta->_allPropertyMetas) {
        if (!propertyMeta->_isKVCCompatible) continue;
        value ^= [[self valueForKey:NSStringFromSelector(propertyMeta->_getter)] hash];
        count++;
    }
    if (count == 0) value = (long)((__bridge void *)self);
    return value;
}

12. - (BOOL)modelIsEqual:(id)model;

基于属性，比较接受者和另外一个对象是否相等。

方法实现

- (BOOL)modelIsEqual:(id)model {
    if (self == model) return YES;
    if (![model isMemberOfClass:self.class]) return NO;
    _YYModelMeta *modelMeta = [_YYModelMeta metaWithClass:self.class];
    if (modelMeta->_nsType) return [self isEqual:model];
    if ([self hash] != [model hash]) return NO;
    
    for (_YYModelPropertyMeta *propertyMeta in modelMeta->_allPropertyMetas) {
        if (!propertyMeta->_isKVCCompatible) continue;
        id this = [self valueForKey:NSStringFromSelector(propertyMeta->_getter)];
        id that = [model valueForKey:NSStringFromSelector(propertyMeta->_getter)];
        if (this == that) continue;
        if (this == nil || that == nil) return NO;
        if (![this isEqual:that]) return NO;
    }
    return YES;
}

13. - (NSString *)modelDescription;

返回接受者内容的描述字符串。

方法实现

- (NSString *)modelDescription {
    return ModelDescription(self);
}

/// Generaate a description string
static NSString *ModelDescription(NSObject *model) {
    static const int kDescMaxLength = 100;
    if (!model) return @"";
    if (model == (id)kCFNull) return @"";
    if (![model isKindOfClass:[NSObject class]]) return [NSString stringWithFormat:@"%@",model];
    
    
    _YYModelMeta *modelMeta = [_YYModelMeta metaWithClass:model.class];
    switch (modelMeta->_nsType) {
        case YYEncodingTypeNSString: case YYEncodingTypeNSMutableString: {
            return [NSString stringWithFormat:@"\"%@\"",model];
        }
        
        case YYEncodingTypeNSValue:
        case YYEncodingTypeNSData: case YYEncodingTypeNSMutableData: {
            NSString *tmp = model.description;
            if (tmp.length > kDescMaxLength) {
                tmp = [tmp substringToIndex:kDescMaxLength];
                tmp = [tmp stringByAppendingString:@"..."];
            }
            return tmp;
        }
            
        case YYEncodingTypeNSNumber:
        case YYEncodingTypeNSDecimalNumber:
        case YYEncodingTypeNSDate:
        case YYEncodingTypeNSURL: {
            return [NSString stringWithFormat:@"%@",model];
        }
            
        case YYEncodingTypeNSSet: case YYEncodingTypeNSMutableSet: {
            model = ((NSSet *)model).allObjects;
        } // no break
            
        case YYEncodingTypeNSArray: case YYEncodingTypeNSMutableArray: {
            NSArray *array = (id)model;
            NSMutableString *desc = [NSMutableString new];
            if (array.count == 0) {
                return [desc stringByAppendingString:@"[]"];
            } else {
                [desc appendFormat:@"[\n"];
                for (NSUInteger i = 0, max = array.count; i < max; i++) {
                    NSObject *obj = array[i];
                    [desc appendString:@"    "];
                    [desc appendString:ModelDescriptionAddIndent(ModelDescription(obj).mutableCopy, 1)];
                    [desc appendString:(i + 1 == max) ? @"\n" : @";\n"];
                }
                [desc appendString:@"]"];
                return desc;
            }
        }
        case YYEncodingTypeNSDictionary: case YYEncodingTypeNSMutableDictionary: {
            NSDictionary *dic = (id)model;
            NSMutableString *desc = [NSMutableString new];
            if (dic.count == 0) {
                return [desc stringByAppendingString:@"{}"];
            } else {
                NSArray *keys = dic.allKeys;
                
                [desc appendFormat:@"{\n"];
                for (NSUInteger i = 0, max = keys.count; i < max; i++) {
                    NSString *key = keys[i];
                    NSObject *value = dic[key];
                    [desc appendString:@"    "];
                    [desc appendFormat:@"%@ = %@",key, ModelDescriptionAddIndent(ModelDescription(value).mutableCopy, 1)];
                    [desc appendString:(i + 1 == max) ? @"\n" : @";\n"];
                }
                [desc appendString:@"}"];
            }
            return desc;
        }
        
        default: {
            NSMutableString *desc = [NSMutableString new];
            [desc appendFormat:@"<%@: %p>", model.class, model];
            if (modelMeta->_allPropertyMetas.count == 0) return desc;
            
            // sort property names
            NSArray *properties = [modelMeta->_allPropertyMetas
                                   sortedArrayUsingComparator:^NSComparisonResult(_YYModelPropertyMeta *p1, _YYModelPropertyMeta *p2) {
                                       return [p1->_name compare:p2->_name];
                                   }];
            
            [desc appendFormat:@" {\n"];
            for (NSUInteger i = 0, max = properties.count; i < max; i++) {
                _YYModelPropertyMeta *property = properties[i];
                NSString *propertyDesc;
                if (property->_isCNumber) {
                    NSNumber *num = ModelCreateNumberFromProperty(model, property);
                    propertyDesc = num.stringValue;
                } else {
                    switch (property->_type & YYEncodingTypeMask) {
                        case YYEncodingTypeObject: {
                            id v = ((id (*)(id, SEL))(void *) objc_msgSend)((id)model, property->_getter);
                            propertyDesc = ModelDescription(v);
                            if (!propertyDesc) propertyDesc = @"";
                        } break;
                        case YYEncodingTypeClass: {
                            id v = ((id (*)(id, SEL))(void *) objc_msgSend)((id)model, property->_getter);
                            propertyDesc = ((NSObject *)v).description;
                            if (!propertyDesc) propertyDesc = @"";
                        } break;
                        case YYEncodingTypeSEL: {
                            SEL sel = ((SEL (*)(id, SEL))(void *) objc_msgSend)((id)model, property->_getter);
                            if (sel) propertyDesc = NSStringFromSelector(sel);
                            else propertyDesc = @"";
                        } break;
                        case YYEncodingTypeBlock: {
                            id block = ((id (*)(id, SEL))(void *) objc_msgSend)((id)model, property->_getter);
                            propertyDesc = block ? ((NSObject *)block).description : @"";
                        } break;
                        case YYEncodingTypeCArray: case YYEncodingTypeCString: case YYEncodingTypePointer: {
                            void *pointer = ((void* (*)(id, SEL))(void *) objc_msgSend)((id)model, property->_getter);
                            propertyDesc = [NSString stringWithFormat:@"%p",pointer];
                        } break;
                        case YYEncodingTypeStruct: case YYEncodingTypeUnion: {
                            NSValue *value = [model valueForKey:property->_name];
                            propertyDesc = value ? value.description : @"{unknown}";
                        } break;
                        default: propertyDesc = @"";
                    }
                }
                
                propertyDesc = ModelDescriptionAddIndent(propertyDesc.mutableCopy, 1);
                [desc appendFormat:@"    %@ = %@",property->_name, propertyDesc];
                [desc appendString:(i + 1 == max) ? @"\n" : @";\n"];
            }
            [desc appendFormat:@"}"];
            return desc;
        }
    }
}

后记

本篇主要介绍了NSObject的一个分类，感兴趣的给个赞或者关注~~~