/Rx 1.0.10605/Source/Rxx/System/Reactive/PairedObservableExtensions.cs

using System.Diagnostics.Contracts;

using System.Reactive.Linq;



namespace System.Reactive

{

	/// <summary>

	/// Provides extension methods for <see cref="System.Reactive.IPairedObservable{TLeft,TRight}"/>.

	/// </summary>

	public static class PairedObservableExtensions

	{

		/// <summary>

		/// Notifies the observable that an observer is to receive notifications.

		/// </summary>

		/// <typeparam name="TLeft">Type of the left notification channel.</typeparam>

		/// <typeparam name="TRight">Type of the right notification channel.</typeparam>

		/// <param name="source">The observable for which a subscription is created.</param>

		/// <param name="onNextLeft">The handler of notifications in the left channel.</param>

		/// <param name="onNextRight">The handler of notifications in the right channel.</param>

		/// <returns>The observer's interface that enables cancelation of the subscription so that it stops receiving notifications.</returns>

		public static IDisposable SubscribePair<TLeft, TRight>(

			this IObservable<Either<TLeft, TRight>> source,

			Action<TLeft> onNextLeft,

			Action<TRight> onNextRight)

		{

			Contract.Requires(source != null);

			Contract.Requires(onNextLeft != null);

			Contract.Requires(onNextRight != null);

			Contract.Ensures(Contract.Result<IDisposable>() != null);



			var disposable = source.Subscribe(PairedObserver.Create(

				onNextLeft,

				onNextRight));



#if SILVERLIGHT

			Contract.Assume(disposable != null);

#endif



			return disposable;

		}



		/// <summary>

		/// Notifies the observable that an observer is to receive notifications.

		/// </summary>

		/// <typeparam name="TLeft">Type of the left notification channel.</typeparam>

		/// <typeparam name="TRight">Type of the right notification channel.</typeparam>

		/// <param name="source">The observable for which a subscription is created.</param>

		/// <param name="onNextLeft">The handler of notifications in the left channel.</param>

		/// <param name="onNextRight">The handler of notifications in the right channel.</param>

		/// <param name="onError">The handler of an error notification.</param>

		/// <returns>The observer's interface that enables cancelation of the subscription so that it stops receiving notifications.</returns>

		public static IDisposable SubscribePair<TLeft, TRight>(

			this IObservable<Either<TLeft, TRight>> source,

			Action<TLeft> onNextLeft,

			Action<TRight> onNextRight,

			Action<Exception> onError)

		{

			Contract.Requires(source != null);

			Contract.Requires(onNextLeft != null);

			Contract.Requires(onNextRight != null);

			Contract.Requires(onError != null);

			Contract.Ensures(Contract.Result<IDisposable>() != null);



			var disposable = source.Subscribe(PairedObserver.Create(

				onNextLeft,

				onNextRight,

				onError));



#if SILVERLIGHT

			Contract.Assume(disposable != null);

#endif



			return disposable;

		}



		/// <summary>

		/// Notifies the observable that an observer is to receive notifications.

		/// </summary>

		/// <typeparam name="TLeft">Type of the left notification channel.</typeparam>

		/// <typeparam name="TRight">Type of the right notification channel.</typeparam>

		/// <param name="source">The observable for which a subscription is created.</param>

		/// <param name="onNextLeft">The handler of notifications in the left channel.</param>

		/// <param name="onNextRight">The handler of notifications in the right channel.</param>

		/// <param name="onCompleted">The handler of a completion notification.</param>

		/// <returns>The observer's interface that enables cancelation of the subscription so that it stops receiving notifications.</returns>

		public static IDisposable SubscribePair<TLeft, TRight>(

			this IObservable<Either<TLeft, TRight>> source,

			Action<TLeft> onNextLeft,

			Action<TRight> onNextRight,

			Action onCompleted)

		{

			Contract.Requires(source != null);

			Contract.Requires(onNextLeft != null);

			Contract.Requires(onNextRight != null);

			Contract.Requires(onCompleted != null);

			Contract.Ensures(Contract.Result<IDisposable>() != null);



			var disposable = source.Subscribe(PairedObserver.Create(

				onNextLeft,

				onNextRight,

				onCompleted));



#if SILVERLIGHT

			Contract.Assume(disposable != null);

#endif



			return disposable;

		}



		/// <summary>

		/// Notifies the observable that an observer is to receive notifications.

		/// </summary>

		/// <typeparam name="TLeft">Type of the left notification channel.</typeparam>

		/// <typeparam name="TRight">Type of the right notification channel.</typeparam>

		/// <param name="source">The observable for which a subscription is created.</param>

		/// <param name="onNextLeft">The handler of notifications in the left channel.</param>

		/// <param name="onNextRight">The handler of notifications in the right channel.</param>

		/// <param name="onError">The handler of an error notification.</param>

		/// <param name="onCompleted">The handler of a completion notification.</param>

		/// <returns>The observer's interface that enables cancelation of the subscription so that it stops receiving notifications.</returns>

		public static IDisposable SubscribePair<TLeft, TRight>(

			this IObservable<Either<TLeft, TRight>> source,

			Action<TLeft> onNextLeft,

			Action<TRight> onNextRight,

			Action<Exception> onError,

			Action onCompleted)

		{

			Contract.Requires(source != null);

			Contract.Requires(onNextLeft != null);

			Contract.Requires(onNextRight != null);

			Contract.Requires(onError != null);

			Contract.Requires(onCompleted != null);

			Contract.Ensures(Contract.Result<IDisposable>() != null);



			var disposable = source.Subscribe(PairedObserver.Create(

				onNextLeft,

				onNextRight,

				onError,

				onCompleted));



#if SILVERLIGHT

			Contract.Assume(disposable != null);

#endif



			return disposable;

		}

	}

}