namespace System.Reactive.Linq.ObservableImpl { internal sealed class MaxInt32 : Producer<int, MaxInt32._> { internal sealed class _ : IdentitySink<int> { private bool _hasValue; private int _lastValue; public _(IObserver<int> observer) : base(observer) { } public override void OnNext(int value) { if (_hasValue) { if (value > _lastValue) _lastValue = value; } else { _lastValue = value; _hasValue = true; } } public override void OnCompleted() { if (!_hasValue) ForwardOnError(new InvalidOperationException(Strings_Linq.NO_ELEMENTS)); else { ForwardOnNext(_lastValue); ForwardOnCompleted(); } } } private readonly IObservable<int> _source; public MaxInt32(IObservable<int> source) { _source = source; } protected override _ CreateSink(IObserver<int> observer) { return new _(observer); } protected override void Run(_ sink) { sink.Run(_source); } } }