added simple observable implementation

src/nexus.core/IUpdatable.cs

@@ -0,0 +1,20 @@
+// Copyright Malachi Griffie
+// 
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+namespace nexus.core
+{
+ /// <summary>
+ /// Indicates that the provided value can be updated with new data <typeparamref name="T" />
+ /// </summary>
+ /// <typeparam name="T"></typeparam>
+ public interface IUpdatable<in T>
+ {
+ /// <summary>
+ /// Update this object with new data
+ /// </summary>
+ void Update( T value );
+ }
+}

src/nexus.core/Observable.cs

@@ -0,0 +1,96 @@
+// Copyright Malachi Griffie
+// 
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+using System;
+using System.Collections.Generic;
+
+namespace nexus.core
+{
+ /// <summary>
+ /// Simple implementation of <see cref="IObservable{T}" />
+ /// </summary>
+ public class Observable<T>
+ : IObservable<T>,
+ IUpdatable<T>,
+ IDisposable
+ {
+ private readonly List<IObserver<T>> m_observers;
+
+ /// <summary>
+ /// </summary>
+ public Observable()
+ {
+ m_observers = new List<IObserver<T>>();
+ }
+
+ /// <summary>
+ /// <c>true</c> if this observable has been disposed and can no longer be used or a <see cref="ObjectDisposedException" />
+ /// will be thrown
+ /// </summary>
+ public Boolean IsDisposed { get; private set; }
+
+ /// <inheritdoc />
+ public virtual void Dispose()
+ {
+ if(IsDisposed)
+ {
+ return;
+ }
+
+ IsDisposed = true;
+ var observers = new List<IObserver<T>>( m_observers );
+ foreach(var observer in observers)
+ {
+ observer.OnCompleted();
+ }
+ m_observers.Clear();
+ }
+
+ /// <inheritdoc />
+ public virtual void Error( Exception ex )
+ {
+ ThrowIfDisposed();
+
+ var observers = new List<IObserver<T>>( m_observers );
+ foreach(var observer in observers)
+ {
+ observer.OnError( ex );
+ }
+ }
+
+ /// <inheritdoc />
+ public virtual IDisposable Subscribe( IObserver<T> observer )
+ {
+ ThrowIfDisposed();
+
+ m_observers.Add( observer );
+ return new DisposeAction( () => m_observers.Remove( observer ) );
+ }
+
+ /// <inheritdoc />
+ public virtual void Update( T value )
+ {
+ ThrowIfDisposed();
+
+ var observers = new List<IObserver<T>>( m_observers );
+ foreach(var observer in observers)
+ {
+ observer.OnNext( value );
+ }
+ }
+
+ /// <summary>
+ /// Throw <see cref="ObjectDisposedException" /> if <see cref="IsDisposed" /> is <c>true</c>
+ /// </summary>
+ protected void ThrowIfDisposed()
+ {
+ if(IsDisposed)
+ {
+ throw new ObjectDisposedException( "Cannot perform operations on disposed {0}".F( GetType().Name ) );
+ }
+ }
+ }
+}

src/nexus.core/Observer.cs

@@ -17,16 +17,17 @@ public static class Observer
  /// <summary>
  /// Create a new observer using the provided methods to implement <see cref="IObserver{T}" />
  /// </summary>
- public static IObserver<T> Create<T>( Action<T> onNext, Action onComplete = null, Action<Exception> onError = null )
+ public static IObserver<T> Create<T>( Action<T> onNext, Action onComplete = null,
+ Action<Exception> onError = null )
  {
  return new FunctionObserver<T>( onNext, onComplete, onError );
  }
 
  /// <summary>
  /// Subscribe to this <paramref name="observable" /> using the provided methods to create a new <see cref="IObserver{T}" />
  /// </summary>
- public static IDisposable Subscribe<T>( this IObservable<T> observable, Action<T> onNext, Action onComplete = null,
- Action<Exception> onError = null )
+ public static IDisposable Subscribe<T>( this IObservable<T> observable, Action<T> onNext,
+ Action onComplete = null, Action<Exception> onError = null )
  {
  Contract.Requires( observable != null );
  return observable.Subscribe( Create( onNext, onComplete, onError ) );

src/nexus.core/nexus.core.csproj

@@ -44,7 +44,9 @@
  </ItemGroup>
  <ItemGroup>
  <Compile Include="ActionAsync.cs" />
+ <Compile Include="IUpdatable.cs" />
  <Compile Include="ObjectConverter.cs" />
+ <Compile Include="Observable.cs" />
  <Compile Include="Properties\BaseAssemblyInfo.cs" />
  <Compile Include="Bytes.cs" />
  <Compile Include="ByteUtils.cs" />