using System.Collections.Generic; namespace System.Reactive.Linq.ObservableImpl { internal sealed class Case<TValue, TResult> : Producer<TResult, Case<TValue, TResult>._>, IEvaluatableObservable<TResult> { internal sealed class _ : IdentitySink<TResult> { public _(IObserver<TResult> observer) : base(observer) { } public void Run(Case<TValue, TResult> parent) { IObservable<TResult> source; try { source = parent.Eval(); } catch (Exception error) { ForwardOnError(error); return; } Run(source); } } private readonly Func<TValue> _selector; private readonly IDictionary<TValue, IObservable<TResult>> _sources; private readonly IObservable<TResult> _defaultSource; public Case(Func<TValue> selector, IDictionary<TValue, IObservable<TResult>> sources, IObservable<TResult> defaultSource) { _selector = selector; _sources = sources; _defaultSource = defaultSource; } public IObservable<TResult> Eval() { if (_sources.TryGetValue(_selector(), out IObservable<TResult> value)) return value; return _defaultSource; } protected override _ CreateSink(IObserver<TResult> observer) { return new _(observer); } protected override void Run(_ sink) { sink.Run(this); } } }