Unity Understanding Lifetime Managers

Unity默认提供了ContainerControlledLifetimeManager、TransientLifetimeManager、HierarchicalLifetimeManager、PerResolveLifetimeManager、PerThreadLifetimeManager和ExternallyControlledLifetimeManager。

ContainerControlledLifetimeManager 就是单例模式，在整个AppDomain中类型实例只有一个。

1 IUnityContainer unityContainer = new UnityContainer();
2 
3 unityContainer.RegisterType<TextWriter, StringWriter>(new ContainerControlledLifetimeManager(), new InjectionConstructor());
4 
5 TextWriter textWriter = unityContainer.Resolve<TextWriter>();
6 TextWriter textWriter2 = unityContainer.Resolve<TextWriter>();
7 
8 Console.WriteLine(Object.ReferenceEquals(textWriter, textWriter2));

TransientLifetimeManager 每次都会创建一个类型的新实例。

1 IUnityContainer unityContainer = new UnityContainer();
2 
3 unityContainer.RegisterType<TextWriter, StringWriter>(new TransientLifetimeManager(), new InjectionConstructor());
4 
5 TextWriter textWriter = unityContainer.Resolve<TextWriter>();
6 TextWriter textWriter2 = unityContainer.Resolve<TextWriter>();
7 
8 Console.WriteLine(Object.ReferenceEquals(textWriter, textWriter2));

HierarchicalLifetimeManager 单例模式，和ContainerControlledLifetimeManager不同的是子Container和祖先Container不共享类型实例。

1 IUnityContainer unityContainer = new UnityContainer();
2 IUnityContainer childUnityContainer = unityContainer.CreateChildContainer();
3 
4 unityContainer.RegisterType<TextWriter, StringWriter>(new HierarchicalLifetimeManager(), new InjectionConstructor());
5 
6 TextWriter textWriter = unityContainer.Resolve<TextWriter>();
7 TextWriter textWriter2 = childUnityContainer.Resolve<TextWriter>();

PerResolveLifetimeManager 和TransientLifetimeManager相同，每次调用Resolve函数都会返回新的类型实例。

1 IUnityContainer unityContainer = new UnityContainer();
2 IUnityContainer childUnityContainer = unityContainer.CreateChildContainer();
3 
4 unityContainer.RegisterType<TextWriter, StringWriter>(new PerResolveLifetimeManager(), new InjectionConstructor());
5 
6 TextWriter textWriter = unityContainer.Resolve<TextWriter>();
7 TextWriter textWriter2 = unityContainer.Resolve<TextWriter>();
8 
9 Console.WriteLine(Object.ReferenceEquals(textWriter, textWriter2));

PerThreadLifetimeManager 和ThreadStaticAttribute一样，同一个线程共享一个类型实例。

 1 IUnityContainer unityContainer = new UnityContainer();
 2 
 3 unityContainer.RegisterType<TextWriter, StringWriter>(new PerThreadLifetimeManager(), new InjectionConstructor());
 4 
 5 TextWriter textWriter = null;
 6 TextWriter textWriter2 = null;
 7 
 8 Semaphore semphore = new Semaphore(0, 2);
 9 
10 new Thread(() =>
11 {
12 　　textWriter = unityContainer.Resolve<TextWriter>();
13 　　semphore.Release();
14 }).Start();
15 
16 new Thread(() =>
17 {
18 　　textWriter2 = unityContainer.Resolve<TextWriter>();
19 　　semphore.Release();
20 }).Start();
21 
22 semphore.WaitOne();
23 
24 Console.WriteLine(Object.ReferenceEquals(textWriter, textWriter2));

ExternallyControlledLifetimeManager 类型共享同一个实例，内部对类型实例weak reference。类型实例的生命周期管理完全交给外部。

1 IUnityContainer unityContainer = new UnityContainer();
2 
3 unityContainer.RegisterType<TextWriter, StringWriter>(new ExternallyControlledLifetimeManager(), new InjectionConstructor());
4 
5 TextWriter textWriter = unityContainer.Resolve<TextWriter>();
6 TextWriter textWriter2 = unityContainer.Resolve<TextWriter>();
7 
8 Console.WriteLine(Object.ReferenceEquals(textWriter, textWriter2));