namespace System.Reactive.Joins { internal class ActivePlan<T1, T2, T3, T4> : ActivePlan { private readonly Action<T1, T2, T3, T4> _onNext; private readonly JoinObserver<T1> _first; private readonly JoinObserver<T2> _second; private readonly JoinObserver<T3> _third; private readonly JoinObserver<T4> _fourth; internal ActivePlan(JoinObserver<T1> first, JoinObserver<T2> second, JoinObserver<T3> third, JoinObserver<T4> fourth, Action<T1, T2, T3, T4> onNext, Action onCompleted) : base(onCompleted) { _onNext = onNext; _first = first; _second = second; _third = third; _fourth = fourth; AddJoinObserver(first); AddJoinObserver(second); AddJoinObserver(third); AddJoinObserver(fourth); } internal override void Match() { if (_first.Queue.Count > 0 && _second.Queue.Count > 0 && _third.Queue.Count > 0 && _fourth.Queue.Count > 0) { Notification<T1> notification = _first.Queue.Peek(); Notification<T2> notification2 = _second.Queue.Peek(); Notification<T3> notification3 = _third.Queue.Peek(); Notification<T4> notification4 = _fourth.Queue.Peek(); if (notification.Kind == NotificationKind.OnCompleted || notification2.Kind == NotificationKind.OnCompleted || notification3.Kind == NotificationKind.OnCompleted || notification4.Kind == NotificationKind.OnCompleted) _onCompleted(); else { Dequeue(); _onNext(notification.Value, notification2.Value, notification3.Value, notification4.Value); } } } } }