IEntryObservable

IEntryObservable is interface for observing state changes.

/// <summary>Observable entry</summary>
public interface IEntryObservable : IEntry, IObservable<EntryEvent> { }

/// <summary>Describes state transition. Events are dispatched after newStatus has applied.</summary>
public struct EntryEvent
{
    /// <summary>Sending entry.</summary>
    public IEntry Sender;
    /// <summary>State before change.</summary>
    public EntryState OldState;
    /// <summary>State after change.</summary>
    public EntryState NewState;
}

.Subscribe(observer) subscribes to state changes.

// Create entry in unassigned state
IEntry<string> entry = new Entry<string>();
// Create observer
IObserver<EntryEvent> observer = new Observer();
// Subscribe to changes
entry.Subscribe(observer);
// Modify state
entry.SetValue("Hello");
// Dispose
((IDisposable)entry).Dispose();
// OnNext((Value, Hello, , None))
// OnNext((Disposed, Hello, , None))
// OnCompleted

public class Observer : IObserver<EntryEvent>
{
    public void OnCompleted() => WriteLine("OnCompleted");
    public void OnError(Exception error) => WriteLine($"OnError({error})");
    public void OnNext(EntryEvent @event) => WriteLine($"OnNext({@event.NewState})");
}

.Subscribe(delegate) subscribes an Action<EntryEvent>.

// Create entry in unassigned state
IEntry<string> entry = new Entry<string>();
// Subsribe with delegate
((IEntryObservable)entry).Subscribe(@event => WriteLine(@event));
// Modify state
entry.SetValue("Hello");

Full Example

Full example

using System;
using Avalanche.Service;
using static System.Console;

public class entry_observable
{
    public static void Run()
    {
        {
            // <01>
            // Create entry in unassigned state
            IEntry<string> entry = new Entry<string>();
            // Create observer
            IObserver<EntryEvent> observer = new Observer();
            // Subscribe to changes
            entry.Subscribe(observer);
            // Modify state
            entry.SetValue("Hello");
            // Dispose
            ((IDisposable)entry).Dispose();
            // OnNext((Value, Hello, , None))
            // OnNext((Disposed, Hello, , None))
            // OnCompleted
            // </01>
        }
        {
            // <02>
            // Create entry in unassigned state
            IEntry<string> entry = new Entry<string>();
            // Subsribe with delegate
            ((IEntryObservable)entry).Subscribe(@event => WriteLine(@event));
            // Modify state
            entry.SetValue("Hello");
            // </02>
        }
    }

    // <99>
    public class Observer : IObserver<EntryEvent>
    {
        public void OnCompleted() => WriteLine("OnCompleted");
        public void OnError(Exception error) => WriteLine($"OnError({error})");
        public void OnNext(EntryEvent @event) => WriteLine($"OnNext({@event.NewState})");
    }
    // </99>
}