using System.Collections.Generic; namespace System.Reactive.Joins { public abstract class Plan<TResult> { internal Plan() { } internal abstract ActivePlan Activate(Dictionary<object, IJoinObserver> externalSubscriptions, IObserver<TResult> observer, Action<ActivePlan> deactivate); internal static JoinObserver<TSource> CreateObserver<TSource>(Dictionary<object, IJoinObserver> externalSubscriptions, IObservable<TSource> observable, Action<Exception> onError) { JoinObserver<TSource> joinObserver = null; if (!externalSubscriptions.TryGetValue((object)observable, out IJoinObserver value)) { joinObserver = new JoinObserver<TSource>(observable, onError); externalSubscriptions.Add((object)observable, (IJoinObserver)joinObserver); } else joinObserver = (JoinObserver<TSource>)value; return joinObserver; } } }