我很难理解主题对象。无功扩展,主题<T>
考虑下面的代码:
var sub = new Subject<int>();
sub.Subscribe(x => Console.WriteLine(x)); //subscriber #1
sub.Subscribe(x => Console.WriteLine(x)); //subscriber #2
sub.OnNext(2);
我创建int类型的题目,当我执行OnNext它调用其它付费用户(#1和#2)。 我没有得到的东西是我读的那个主体意味着一个对象,它既是可观察的,又是观察者,但是这是如何解释为什么当我调用OnNext时,其他用户被调用。
我会理解,如果主题的OnNext会将其传播给所有订阅者=发布给所有其他人(这是有道理的),但是当我检查源代码时,我看不到任何内容,请参阅下文。
有人可能从下面的代码了解究竟是什么使OnNext(2)传播到其他订阅? (#1,#2)?
公共密封类主题:ISubject,ISubject,IObserver,的IObservable,IDisposable的 {// 领域 私人挥发性IObserver _observer;
// Methods
public Subject()
{
this._observer = NopObserver<T>.Instance;
}
public void Dispose()
{
this._observer = DisposedObserver<T>.Instance;
}
public void OnCompleted()
{
IObserver<T> comparand = null;
IObserver<T> completed = DoneObserver<T>.Completed;
do
{
comparand = this._observer;
}
while (((comparand != DisposedObserver<T>.Instance) && !(comparand is DoneObserver<T>)) && (Interlocked.CompareExchange<IObserver<T>>(ref this._observer, completed, comparand) != comparand));
comparand.OnCompleted();
}
public void OnError(Exception error)
{
if (error == null)
{
throw new ArgumentNullException("error");
}
IObserver<T> comparand = null;
DoneObserver<T> observer3 = new DoneObserver<T> {
Exception = error
};
DoneObserver<T> observer2 = observer3;
do
{
comparand = this._observer;
}
while (((comparand != DisposedObserver<T>.Instance) && !(comparand is DoneObserver<T>)) && (Interlocked.CompareExchange<IObserver<T>>(ref this._observer, observer2, comparand) != comparand));
comparand.OnError(error);
}
public void OnNext(T value)
{
this._observer.OnNext(value);
}
public IDisposable Subscribe(IObserver<T> observer)
{
if (observer == null)
{
throw new ArgumentNullException("observer");
}
IObserver<T> comparand = null;
IObserver<T> observer3 = null;
do
{
comparand = this._observer;
if (comparand == DisposedObserver<T>.Instance)
{
throw new ObjectDisposedException("");
}
if (comparand == DoneObserver<T>.Completed)
{
observer.OnCompleted();
return Disposable.Empty;
}
DoneObserver<T> observer4 = comparand as DoneObserver<T>;
if (observer4 != null)
{
observer.OnError(observer4.Exception);
return Disposable.Empty;
}
if (comparand == NopObserver<T>.Instance)
{
observer3 = observer;
}
else
{
Observer<T> observer5 = comparand as Observer<T>;
if (observer5 != null)
{
observer3 = observer5.Add(observer);
}
else
{
observer3 = new Observer<T>(new ImmutableList<IObserver<T>>(new IObserver<T>[] { comparand, observer }));
}
}
}
while (Interlocked.CompareExchange<IObserver<T>>(ref this._observer, observer3, comparand) != comparand);
return new Subscription<T>((Subject<T>) this, observer);
}
private void Unsubscribe(IObserver<T> observer)
{
IObserver<T> comparand = null;
IObserver<T> instance = null;
Label_0004:
comparand = this._observer;
if ((comparand != DisposedObserver<T>.Instance) && !(comparand is DoneObserver<T>))
{
Observer<T> observer4 = comparand as Observer<T>;
if (observer4 != null)
{
instance = observer4.Remove(observer);
}
else
{
if (comparand != observer)
{
return;
}
instance = NopObserver<T>.Instance;
}
if (Interlocked.CompareExchange<IObserver<T>>(ref this._observer, instance, comparand) != comparand)
{
goto Label_0004;
}
}
}
// Properties
public bool HasObservers
{
get
{
return (((this._observer != NopObserver<T>.Instance) && !(this._observer is DoneObserver<T>)) && (this._observer != DisposedObserver<T>.Instance));
}
}
// Nested Types
private class Subscription : IDisposable
{
// Fields
private IObserver<T> _observer;
private Subject<T> _subject;
// Methods
public Subscription(Subject<T> subject, IObserver<T> observer)
{
this._subject = subject;
this._observer = observer;
}
public void Dispose()
{
IObserver<T> observer = Interlocked.Exchange<IObserver<T>>(ref this._observer, null);
if (observer != null)
{
this._subject.Unsubscribe(observer);
this._subject = null;
}
}
}
}
顺便说一句,在复杂这里是[接收1.1/2.0的性能优化]的一部分(http://blogs.msdn.com/b/rxteam/archive/2012/03/12/reactive-extensions- v2-0-β-可供now.aspx)。 (§提高生产者速度)。 – 2014-09-09 20:13:03