1、Objection 基本使用
例子：
1、Enginer
.h
@interface Enginer : NSObject
@end
.m
@implementation Enginer
objection_register(@"Enginer")
@end
2、Car
.h
@interface Car : NSObject
@property(nonatomic, strong) Enginer *mEnginer;
@end
.m
@implementation Car
objection_requires(@"mEnginer")
@end
3、ViewController
.h
@property (nonatomic, strong) Car *mCar;
.m
- (void)viewDidLoad
{
[super viewDidLoad];
self.mCar = [[JSObjection createInjector]getObject:[Car class]];
}
在ViewController里面获取的Car 的实体，并且，Car里面的Enginer也会自动创建。
Objection原理解析
Objection 通过传入class，通过class name 字符串化后创建一个JSObjectionInjectorEntry,并且以class name为key 保存到字典中，在获取的时候获取这个injectorEntry，获取到class 后，创建对象。
注册： objection_register(@"类名")
声明需要注入的参数： objection_requires(@"对象名")
注入： [[JSObjection createInjector]getObject:[Car class]]
ojbection_register()
#definde objection_register(value)
+(void)initialize{
if(self == [value class]){
[[JSObjection registerClass:[value class] scope: JSObjectionScopeNormal];
}
}
这个是到底做了什么呢？
static NSMutableDictionary *gObjectionContext
+（void）registerClass:(Class)theClass scope:(JSObjectionScope)scope
//核心代码
[gObjectionContext
setObject:[JSObjectionInjectorEntry entryWithClass: theClass scope:scope]
forKey: NSStringFromClass(theClass) ];
从上面可以看出来，实际上就是将一个JSObjectionInjectorEntry ，保存到一个以类名对应的一个字典里面。
那这个JSObjectionInjectorEntry 是什么东西呢？
typedef enum{
JSObjectionScopeNone = -1,
JSObjectionScopeNormal ,
JSObjecitonScopeSingleton
}
@interface JSObjectionInjectorEntry : JSObjectionEntry
@property (nonatomic, readonly) Class classEntry;
@end
@interface JSObjectionInjectorEntry ()
JSObjectionScope _lifeCycle;
id _storageCache;
@end
@implement
+ (id)entryWithClass: (Class) theClass scope:(JSObjectionScope)theLifeCycle{
return [[JSObjectionInjectorEntry alloc]initWithClass:theClass lifeCycle:thelifeCycle];
}
- (instancetype)initWithClass:(Class)theClass lifeCycle:(JSObjectionScope)theLifeCycle{
_lifeCycle = thelifeCycle;
_classEntry = theClass;
_storageCache = nil;
}
@end
从上面的代码可以看出来，JSObjectionInjectorEntry 保存了
1、class _ckassEntry
2、JSObjectionScope lifeCycle
从上面可以看出来，注册就是把class name 和 JSObjectionInjectiorEnry用字典保存到gObjectionContext ，Entry保存的了Class 和 lifeCycle.
2、 objection_requires()获取参数
这里就一个方法，会返回一个需要注入的参数列表
#define objection_requires(args...)
+(NSSet *)objectionRequires{
NSSet *requirements = [NSSet setWithObjects： args, nil];
return JSObjectionUtils.buildDependenciesForClass(self, requirements);
}
static NSSet *BuildDependenciesForClass(Class klass, NSSet*requirements){
Class superClass = class_getSuperclass([klass class]);
.....
retrunn requirements;
}
3、注入
通过class获取到注入器, 通过注入器获取到实例
JSObjectionInjector
-(id)getObjectWithArgs:(id)classOrProtocol,...{
va_list va_arguments;
va_start(va_arguments, classOrProtocol);
id object = [self getObject:classOrProtocol arguments:va_arguments];
va_end(va_arguments);
return object;
}
- (id)getObject:(id)classOrProtocol name:(NSString *)name initializer:(SEL)selector arguments:(NSArray *)argumentList {
1、通过classOrProtocol 获取key,及class name str
2、获取injectorEntry
injectorEntry = [JSObjectionInjectorEntry entryWithClass scope:JSObjectionScopeNormal];
injectorEntry.injector = self;
_context setObject:injectorEntry forKey：key
3、通过injectorEntry 获取实例对象
[injectorEntry extractObject：argumentList initializer:selector];
-(id)buidlObject:(NSArray *)arguments initializer:(SEL) initializer;
}
