Feat: Better Reducer

src/EntityDb.Abstractions/Reducers/IReducer.cs

@@ -0,0 +1,15 @@
+namespace EntityDb.Abstractions.Reducers;
+
+/// <summary>
+///     Represents a type that can reduce one state into another state.
+/// </summary>
+/// <typeparam name="TState">The state to be reduced.</typeparam>
+public interface IReducer<TState>
+{
+    /// <summary>
+    ///     Returns a new <see cref="TState"/> that incorporates this object into input <see cref="TState"/>.
+    /// </summary>
+    /// <param name="state">The state to be reduced.</param>
+    /// <returns></returns>
+    TState Reduce(TState state);
+}

src/EntityDb.Abstractions/Transactions/ITransactionRepository.cs

@@ -1,5 +1,4 @@
 using EntityDb.Abstractions.Annotations;
-using EntityDb.Abstractions.Commands;
 using EntityDb.Abstractions.Disposables;
 using EntityDb.Abstractions.Leases;
 using EntityDb.Abstractions.Queries;
@@ -86,7 +85,7 @@ public interface ITransactionRepository<TEntity> : IDisposableResource
     /// </summary>
     /// <param name="commandQuery">The command query.</param>
     /// <returns>The commands which are found by <paramref name="commandQuery" />.</returns>
-    Task<ICommand<TEntity>[]> GetCommands(ICommandQuery commandQuery);
+    Task<object[]> GetCommands(ICommandQuery commandQuery);
 
     /// <summary>
     ///     Returns the leases which are found by a lease query.
@@ -107,7 +106,7 @@ public interface ITransactionRepository<TEntity> : IDisposableResource
     /// </summary>
     /// <param name="commandQuery">The command query.</param>
     /// <returns>The annotated commands which are found by <paramref name="commandQuery" />.</returns>
-    Task<IEntityAnnotation<ICommand<TEntity>>[]> GetAnnotatedCommands(ICommandQuery commandQuery);
+    Task<IEntityAnnotation<object>[]> GetAnnotatedCommands(ICommandQuery commandQuery);
 
     /// <summary>
     ///     Inserts a single transaction with an atomic commit.

src/EntityDb.Abstractions/Transactions/Steps/ICommandTransactionStep.cs

@@ -1,6 +1,4 @@
-using EntityDb.Abstractions.Commands;
-
-namespace EntityDb.Abstractions.Transactions.Steps;
+namespace EntityDb.Abstractions.Transactions.Steps;
 
 /// <summary>
 ///     Represents a modification to an entity's state.
@@ -11,7 +9,7 @@ public interface ICommandTransactionStep<TEntity> : ITransactionStep<TEntity>
     /// <summary>
     ///     The modifier.
     /// </summary>
-    ICommand<TEntity> Command { get; }
+    object Command { get; }
 
     /// <summary>
     ///     A snapshot of the entity before the command.

src/EntityDb.Common/Entities/IEntity.cs

@@ -20,4 +20,11 @@ public interface IEntity<out TEntity>
     /// </summary>
     /// <returns></returns>
     ulong GetVersionNumber();
+
+    /// <summary>
+    ///     Returns a new <typeparamref name="TEntity" /> that incorporates the commands.
+    /// </summary>
+    /// <param name="commands">The commands</param>
+    /// <returns>A new <typeparamref name="TEntity" /> that incorporates <paramref name="commands"/>.</returns>
+    TEntity Reduce(params object[] commands);
 }

src/EntityDb.Common/Transactions/Builders/SingleEntityTransactionBuilder.cs

@@ -1,5 +1,4 @@
-using EntityDb.Abstractions.Commands;
-using EntityDb.Abstractions.Leases;
+using EntityDb.Abstractions.Leases;
 using EntityDb.Abstractions.Tags;
 using EntityDb.Abstractions.Transactions;
 using EntityDb.Common.Entities;
@@ -52,7 +51,7 @@ public bool IsEntityKnown()
     /// <returns>The transaction builder.</returns>
     /// <remarks>
     ///     Call this method to load an entity that already exists before calling
-    ///     <see cref="Append(ICommand{TEntity})"/>.
+    ///     <see cref="Append(object)"/>.
     /// </remarks>
     public SingleEntityTransactionBuilder<TEntity> Load(TEntity entity)
     {
@@ -62,11 +61,11 @@ public SingleEntityTransactionBuilder<TEntity> Load(TEntity entity)
     }
 
     /// <summary>
-    ///     Adds a transaction step that appends a single <see cref="ICommand{TEntity}"/>.
+    ///     Adds a transaction step that appends a single command.
     /// </summary>
     /// <param name="command">The new command that modifies the <typeparamref name="TEntity"/>.</param>
     /// <returns>The transaction builder.</returns>
-    public SingleEntityTransactionBuilder<TEntity> Append(ICommand<TEntity> command)
+    public SingleEntityTransactionBuilder<TEntity> Append(object command)
     {
         _transactionBuilder.Append(EntityId, command);
 

src/EntityDb.Common/Transactions/Builders/TransactionBuilder.cs

@@ -1,5 +1,4 @@
 using EntityDb.Abstractions.Agents;
-using EntityDb.Abstractions.Commands;
 using EntityDb.Abstractions.Leases;
 using EntityDb.Abstractions.Tags;
 using EntityDb.Abstractions.Transactions;
@@ -50,7 +49,7 @@ private void ConstructIfNotKnown(Guid entityId)
         _knownEntities.Add(entityId, entity);
     }
 
-    private void AddGeneralTransactionStep(Guid entityId, ICommand<TEntity> command)
+    private void AddGeneralTransactionStep(Guid entityId, object command)
     {
         ConstructIfNotKnown(entityId);
 
@@ -149,7 +148,7 @@ public bool IsEntityKnown(Guid entityId)
     /// <returns>The transaction builder.</returns>
     /// <remarks>
     ///     Call this method to load an entity that already exists before calling
-    ///     <see cref="Append(Guid, ICommand{TEntity})" />.
+    ///     <see cref="Append(Guid, object)" />.
     /// </remarks>
     public TransactionBuilder<TEntity> Load(Guid entityId, TEntity entity)
     {
@@ -164,12 +163,12 @@ public TransactionBuilder<TEntity> Load(Guid entityId, TEntity entity)
     }
 
     /// <summary>
-    ///     Adds a transaction step that appends a single <see cref="ICommand{TEntity}"/> associated with a given entity id.
+    ///     Adds a transaction step that appends a single command associated with a given entity id.
     /// </summary>
     /// <param name="entityId">The id associated with the <typeparamref name="TEntity"/>.</param>
     /// <param name="command">The new command that modifies the <typeparamref name="TEntity"/>.</param>
     /// <returns>The transaction builder.</returns>
-    public TransactionBuilder<TEntity> Append(Guid entityId, ICommand<TEntity> command)
+    public TransactionBuilder<TEntity> Append(Guid entityId, object command)
     {
         AddGeneralTransactionStep(entityId, command);
 

src/EntityDb.Common/Transactions/Steps/CommandTransactionStep.cs

@@ -1,13 +1,12 @@
-using EntityDb.Abstractions.Commands;
-using EntityDb.Abstractions.Transactions.Steps;
+using EntityDb.Abstractions.Transactions.Steps;
 using System;
 
 namespace EntityDb.Common.Transactions.Steps;
 
 internal sealed record CommandTransactionStep<TEntity> : ICommandTransactionStep<TEntity>
 {
     public Guid EntityId { get; init; }
-    public ICommand<TEntity> Command { get; init; } = default!;
+    public object Command { get; init; } = default!;
     public TEntity PreviousEntitySnapshot { get; init; } = default!;
     public ulong PreviousEntityVersionNumber { get; init; }
     public TEntity NextEntitySnapshot { get; init; } = default!;

src/EntityDb.Common/Transactions/TransactionRepositoryWrapper.cs

@@ -1,5 +1,4 @@
 using EntityDb.Abstractions.Annotations;
-using EntityDb.Abstractions.Commands;
 using EntityDb.Abstractions.Leases;
 using EntityDb.Abstractions.Queries;
 using EntityDb.Abstractions.Tags;
@@ -64,7 +63,7 @@ public Task<object[]> GetAgentSignatures(IAgentSignatureQuery agentSignatureQuer
         return WrapQuery(_transactionRepository.GetAgentSignatures(agentSignatureQuery));
     }
 
-    public Task<ICommand<TEntity>[]> GetCommands(ICommandQuery commandQuery)
+    public Task<object[]> GetCommands(ICommandQuery commandQuery)
     {
         return WrapQuery(_transactionRepository.GetCommands(commandQuery));
     }
@@ -79,7 +78,7 @@ public Task<ITag[]> GetTags(ITagQuery tagQuery)
         return WrapQuery(_transactionRepository.GetTags(tagQuery));
     }
 
-    public Task<IEntityAnnotation<ICommand<TEntity>>[]> GetAnnotatedCommands(ICommandQuery commandQuery)
+    public Task<IEntityAnnotation<object>[]> GetAnnotatedCommands(ICommandQuery commandQuery)
     {
         return WrapQuery(_transactionRepository.GetAnnotatedCommands(commandQuery));
     }

src/EntityDb.MongoDb/Transactions/MongoDbTransactionRepository.cs

@@ -1,5 +1,4 @@
 using EntityDb.Abstractions.Annotations;
-using EntityDb.Abstractions.Commands;
 using EntityDb.Abstractions.Leases;
 using EntityDb.Abstractions.Queries;
 using EntityDb.Abstractions.Tags;
@@ -90,11 +89,11 @@ public Task<object[]> GetAgentSignatures(IAgentSignatureQuery agentSignatureQuer
             .GetData<AgentSignatureDocument, object>();
     }
 
-    public Task<ICommand<TEntity>[]> GetCommands(ICommandQuery commandQuery)
+    public Task<object[]> GetCommands(ICommandQuery commandQuery)
     {
         return CommandDocument
             .GetQuery(_mongoSession, commandQuery)
-            .GetData<CommandDocument, ICommand<TEntity>>();
+            .GetData<CommandDocument, object>();
     }
 
     public Task<ILease[]> GetLeases(ILeaseQuery leaseQuery)
@@ -111,11 +110,11 @@ public Task<ITag[]> GetTags(ITagQuery tagQuery)
             .GetData<TagDocument, ITag>();
     }
 
-    public Task<IEntityAnnotation<ICommand<TEntity>>[]> GetAnnotatedCommands(ICommandQuery commandQuery)
+    public Task<IEntityAnnotation<object>[]> GetAnnotatedCommands(ICommandQuery commandQuery)
     {
         return CommandDocument
             .GetQuery(_mongoSession, commandQuery)
-            .GetEntityAnnotation<CommandDocument, ICommand<TEntity>>();
+            .GetEntityAnnotation<CommandDocument, object>();
     }
 
     private async Task ExecuteCommandTransactionStep(ITransaction<TEntity> transaction, ICommandTransactionStep<TEntity> commandTransactionStep)

src/EntityDb.Void/Transactions/VoidTransactionRepository.cs

@@ -1,5 +1,4 @@
 using EntityDb.Abstractions.Annotations;
-using EntityDb.Abstractions.Commands;
 using EntityDb.Abstractions.Leases;
 using EntityDb.Abstractions.Queries;
 using EntityDb.Abstractions.Tags;
@@ -57,9 +56,9 @@ public Task<object[]> GetAgentSignatures(IAgentSignatureQuery agentSignatureQuer
         return Task.FromResult(Array.Empty<object>());
     }
 
-    public Task<ICommand<TEntity>[]> GetCommands(ICommandQuery commandQuery)
+    public Task<object[]> GetCommands(ICommandQuery commandQuery)
     {
-        return Task.FromResult(Array.Empty<ICommand<TEntity>>());
+        return Task.FromResult(Array.Empty<object>());
     }
 
     public Task<ILease[]> GetLeases(ILeaseQuery leaseQuery)
@@ -72,9 +71,9 @@ public Task<ITag[]> GetTags(ITagQuery tagQuery)
         return Task.FromResult(Array.Empty<ITag>());
     }
 
-    public Task<IEntityAnnotation<ICommand<TEntity>>[]> GetAnnotatedCommands(ICommandQuery commandQuery)
+    public Task<IEntityAnnotation<object>[]> GetAnnotatedCommands(ICommandQuery commandQuery)
     {
-        return Task.FromResult(Array.Empty<IEntityAnnotation<ICommand<TEntity>>>());
+        return Task.FromResult(Array.Empty<IEntityAnnotation<object>>());
     }
 
     public Task<bool> PutTransaction(ITransaction<TEntity> transaction)

test/EntityDb.Common.Tests/Entities/EntityTests.cs

@@ -1,5 +1,4 @@
-using EntityDb.Abstractions.Commands;
-using EntityDb.Abstractions.Entities;
+using EntityDb.Abstractions.Entities;
 using EntityDb.Abstractions.Queries;
 using EntityDb.Abstractions.Snapshots;
 using EntityDb.Abstractions.Transactions;
@@ -53,7 +52,7 @@ public async Task GivenExistingEntityWithNoSnapshot_WhenGettingEntity_ThenGetCom
 
         var entityId = Guid.NewGuid();
 
-        var commands = new List<ICommand<TransactionEntity>>();
+        var commands = new List<object>();
 
         var transactionRepositoryMock = new Mock<ITransactionRepository<TransactionEntity>>(MockBehavior.Strict);
 
@@ -204,7 +203,7 @@ public async Task GivenSnapshotAndNewCommands_WhenGettingSnapshotOrDefault_ThenR
 
         var snapshot = new TransactionEntity(1);
 
-        var newCommands = new ICommand<TransactionEntity>[]
+        var newCommands = new object[]
         {
             new DoNothing(),
             new DoNothing()

test/EntityDb.Common.Tests/Implementations/Commands/Count.cs

@@ -1,9 +1,9 @@
-using EntityDb.Abstractions.Commands;
+using EntityDb.Abstractions.Reducers;
 using EntityDb.Common.Tests.Implementations.Entities;
 
 namespace EntityDb.Common.Tests.Implementations.Commands;
 
-public record Count(int Number) : ICommand<TransactionEntity>
+public record Count(int Number) : IReducer<TransactionEntity>
 {
     public TransactionEntity Reduce(TransactionEntity entity)
     {

test/EntityDb.Common.Tests/Implementations/Commands/DoNothing.cs

@@ -1,9 +1,9 @@
-using EntityDb.Abstractions.Commands;
+using EntityDb.Abstractions.Reducers;
 using EntityDb.Common.Tests.Implementations.Entities;
 
 namespace EntityDb.Common.Tests.Implementations.Commands;
 
-public record DoNothing : ICommand<TransactionEntity>
+public record DoNothing : IReducer<TransactionEntity>
 {
     public TransactionEntity Reduce(TransactionEntity entity)
     {