deveel · tsutomi · Oct 16, 2023
@@ -48,9 +48,15 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Deveel.Repository.Manager.X
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Deveel.Repository.Manager.DynamicLinq", "src\Deveel.Repository.Manager.DynamicLinq\Deveel.Repository.Manager.DynamicLinq.csproj", "{638851EF-B000-490C-9035-A962279A3E9B}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Deveel.Repository.Manager.EasyCaching", "src\Deveel.Repository.Manager.EasyCaching\Deveel.Repository.Manager.EasyCaching.csproj", "{84D55BE2-7DAD-4CA3-A3E2-EFB4D41FA3CA}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Deveel.Repository.Manager.EasyCaching", "src\Deveel.Repository.Manager.EasyCaching\Deveel.Repository.Manager.EasyCaching.csproj", "{84D55BE2-7DAD-4CA3-A3E2-EFB4D41FA3CA}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Deveel.Repository.Manager.EasyCaching.XUnit", "test\Deveel.Repository.Manager.EasyCaching.XUnit\Deveel.Repository.Manager.EasyCaching.XUnit.csproj", "{F47C196B-758D-4C05-8918-FB63C61649EB}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Deveel.Repository.Manager.EasyCaching.XUnit", "test\Deveel.Repository.Manager.EasyCaching.XUnit\Deveel.Repository.Manager.EasyCaching.XUnit.csproj", "{F47C196B-758D-4C05-8918-FB63C61649EB}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Deveel.Repository.MartenDb", "src\Deveel.Repository.MartenDb\Deveel.Repository.MartenDb.csproj", "{96284897-30DC-4F27-866C-355F06D02DFB}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Deveel.Repository.MartenDb.XUnit", "test\Deveel.Repository.MartenDb.XUnit\Deveel.Repository.MartenDb.XUnit.csproj", "{8CAC793C-A886-42C8-B754-7E5F7D8DE1F2}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Deveel.Repository.Aggregate.Model", "src\Deveel.Repository.Aggregate.Model\Deveel.Repository.Aggregate.Model.csproj", "{D7403F7B-AD31-4F06-876B-1D97103B931A}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -126,6 +132,18 @@ Global
 		{F47C196B-758D-4C05-8918-FB63C61649EB}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{F47C196B-758D-4C05-8918-FB63C61649EB}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{F47C196B-758D-4C05-8918-FB63C61649EB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{96284897-30DC-4F27-866C-355F06D02DFB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{96284897-30DC-4F27-866C-355F06D02DFB}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{96284897-30DC-4F27-866C-355F06D02DFB}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{96284897-30DC-4F27-866C-355F06D02DFB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{8CAC793C-A886-42C8-B754-7E5F7D8DE1F2}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{8CAC793C-A886-42C8-B754-7E5F7D8DE1F2}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{8CAC793C-A886-42C8-B754-7E5F7D8DE1F2}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{8CAC793C-A886-42C8-B754-7E5F7D8DE1F2}.Release|Any CPU.Build.0 = Release|Any CPU
+		{D7403F7B-AD31-4F06-876B-1D97103B931A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{D7403F7B-AD31-4F06-876B-1D97103B931A}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{D7403F7B-AD31-4F06-876B-1D97103B931A}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{D7403F7B-AD31-4F06-876B-1D97103B931A}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -148,6 +166,9 @@ Global
 		{638851EF-B000-490C-9035-A962279A3E9B} = {2860FD4D-510F-43C8-870E-5559B90D0CAD}
 		{84D55BE2-7DAD-4CA3-A3E2-EFB4D41FA3CA} = {2860FD4D-510F-43C8-870E-5559B90D0CAD}
 		{F47C196B-758D-4C05-8918-FB63C61649EB} = {50434E05-0F21-4871-AFB3-A483CEE4A300}
+		{96284897-30DC-4F27-866C-355F06D02DFB} = {2860FD4D-510F-43C8-870E-5559B90D0CAD}
+		{8CAC793C-A886-42C8-B754-7E5F7D8DE1F2} = {50434E05-0F21-4871-AFB3-A483CEE4A300}
+		{D7403F7B-AD31-4F06-876B-1D97103B931A} = {2860FD4D-510F-43C8-870E-5559B90D0CAD}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {01FD9B16-84B3-4D99-80C1-11B2F3D65B56}

@@ -0,0 +1,73 @@
+namespace Deveel.Data {
+	/// <summary>
+	/// Provides a base implementation of an object
+	/// that aggregates a stream of events to form
+	/// its state.
+	/// </summary>
+	public abstract class Aggregate {
+		/// <summary>
+		/// Constructs the aggregate from the initial set of
+		/// committed events.
+		/// </summary>
+		/// <param name="committedEvents"></param>
+		protected Aggregate(IEnumerable<object>? committedEvents = null) {
+			Events = new EventCollection(this, committedEvents);
+
+			foreach (var @event in Events.Committed) {
+				ApplyEvent(@event);
+			}
+		}
+
+		/// <summary>
+		/// Gets the stream of events that are applied to
+		/// the aggregate.
+		/// </summary>
+		public EventCollection Events { get; }
+
+		/// <summary>
+		/// Gets the version of the aggregate.
+		/// </summary>
+		/// <remarks>
+		/// The default implementation returns the total number
+		/// of events in the stream.
+		/// </remarks>
+		[Version]
+		public virtual int Version => Events.Count;
+
+		/// <summary>
+		/// Applies the given event to the aggregate, changing
+		/// its state and incrementing the version.
+		/// </summary>
+		/// <param name="event">
+		/// The event to apply to the aggregate.
+		/// </param>
+		public void Apply(object @event) {
+			ArgumentNullException.ThrowIfNull(@event, nameof(@event));
+
+			ApplyEvent(@event);
+
+			Events.Add(@event);
+		}
+
+		/// <summary>
+		/// When overridden in a derived class, applies the given
+		/// event to the aggregate, changing its state.
+		/// </summary>
+		/// <param name="event">
+		/// The event to apply to the aggregate.
+		/// </param>
+		protected virtual void ApplyEvent(object @event) {
+		}
+
+		/// <summary>
+		/// Commits the current stream of events to the aggregate.
+		/// </summary>
+		public void Commit() => Events.Commit();
+
+		/// <summary>
+		/// Rolls back the current stream of uncommitted events 
+		/// to the aggregate.
+		/// </summary>
+		public void Rollback() => Events.Clear();
+	}
+}
@@ -0,0 +1,143 @@
+using System.Collections;
+
+namespace Deveel.Data {
+	/// <summary>
+	/// A collection of events that are applied to an aggregate.
+	/// </summary>
+	public sealed class EventCollection : IReadOnlyCollection<object> {
+		private readonly List<EventState> events;
+
+		/// <summary>
+		/// Constructs the collection from the initial
+		/// set of committed events.
+		/// </summary>
+		/// <param name="aggregate">
+		/// The aggregate that the events are applied to.
+		/// </param>
+		/// <param name="committedEvents">
+		/// The initial set of events that are committed to
+		/// form the aggregate.
+		/// </param>
+		internal EventCollection(Aggregate aggregate, IEnumerable<object>? committedEvents = null) {
+			ArgumentNullException.ThrowIfNull(aggregate, nameof(aggregate));
+
+			Aggregate = aggregate;
+
+			events = new List<EventState>();
+
+			if (committedEvents != null) {
+				foreach (var @event in committedEvents) {
+					events.Add(new EventState(@event, true));
+				}
+			}
+		}
+
+		/// <summary>
+		/// Gets the aggregate that the events are applied to.
+		/// </summary>
+		public Aggregate Aggregate { get; }
+
+		/// <summary>
+		/// Gets the total number of events in the collection.
+		/// </summary>
+		public int Count {
+			get {
+				lock (events) {
+					return events.Count;
+				}
+			}
+		}
+
+		/// <inheritdoc/>
+		public IReadOnlyList<object> Committed {
+			get {
+				lock (events) {
+					return events.Where(x => x.IsCommitted).Select(x => x.Event).ToArray();
+				}
+			}
+		}
+
+		/// <inheritdoc/>
+		public IReadOnlyList<object> Uncommitted {
+			get {
+				lock (events) {
+					return events.Where(x => !x.IsCommitted).Select(x => x.Event).ToArray();
+				}
+			}
+		}
+
+		/// <summary>
+		/// Adds a new event to the collection as uncommitted.
+		/// </summary>
+		/// <param name="event">
+		/// The event to add to the collection.
+		/// </param>
+		/// <remarks>
+		/// The event is added to the collection as uncommitted,
+		/// that means that it is not yet part of the aggregate
+		/// and that can be removed or cleared.
+		/// </remarks>
+		internal void Add(object @event) {
+			lock (events) {
+				events.Add(new EventState(@event, false));
+			}
+		}
+
+		/// <summary>
+		/// Clears all the uncommitted events from the collection.
+		/// </summary>
+		internal void Clear() {
+			lock (events) {
+				for (var i = events.Count - 1; i >= 0; i--) {
+					if (!events[i].IsCommitted)
+						events.RemoveAt(i);
+				}
+			}
+		}
+
+		internal void Commit() {
+			lock (events) {
+				for (var i = events.Count - 1; i >= 0; i--) {
+					if (!events[i].IsCommitted)
+						events[i] = new EventState(events[i].Event, true);
+				}
+			}
+		}
+
+		/// <summary>
+		/// Checks if the given event is contained in the collection.
+		/// </summary>
+		/// <param name="event">
+		/// The event to check.
+		/// </param>
+		/// <returns>
+		/// Returns <c>true</c> if the event is contained in the
+		/// collection, otherwise <c>false</c>.
+		/// </returns>
+		public bool Contains(object @event) {
+			lock (events) {
+				return events.Any(x => x.Event.Equals(@event));
+			}
+		}
+
+		/// <inheritdoc/>
+		public IEnumerator<object> GetEnumerator() {
+			lock (events) {
+				return events.Select(x => x.Event).GetEnumerator();
+			}
+		}
+
+		IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+
+		private readonly struct EventState {
+			internal EventState(object @event, bool isCommitted) {
+				Event = @event;
+				IsCommitted = isCommitted;
+			}
+
+			public object Event { get; }
+
+			public bool IsCommitted { get; }
+		}
+	}
+}
@@ -0,0 +1,9 @@
+namespace Deveel.Data {
+	/// <summary>
+	/// An attribute that is used to identify a property of an
+	/// aggregate that is used to obtain its version.
+	/// </summary>
+	[AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
+	public sealed class VersionAttribute : Attribute {
+	}
+}