CQRS Call-Site Migration: Phase 2 Extension Handlers & Phase 3 Base Classes

src/Extensions/ACAT.Extensions.UI/Scanners/DashboardAppScanner.cs

@@ -4,6 +4,8 @@
 using ACAT.Core.PanelManagement.CommandDispatcher;
 using ACAT.Core.PanelManagement.Common;
 using ACAT.Core.PanelManagement.Interfaces;
+using ACAT.Core.Patterns.CQRS;
+using ACAT.Core.Patterns.CQRS.Samples;
 using ACAT.Core.UserControlManagement;
 using ACAT.Core.UserControlManagement.Interfaces;
 using ACAT.Core.Utility;
@@ -206,8 +208,19 @@ public bool ShowTalkPanel(WordPredictionModes mode)
                 PredictionMode = mode
             };
 
-            // create the panel instance
-            Form form = PanelManager.Instance.CreatePanel("TalkApplicationScanner", startupArg);
+            // CQRS: Use command handler instead of direct singleton access
+            var createPanelHandler = Context.ServiceProvider?.GetService(typeof(ICommandHandler<CreatePanelCommand>)) as ICommandHandler<CreatePanelCommand>;
+            Form form;
+            if (createPanelHandler != null)
+            {
+                var command = new CreatePanelCommand("TalkApplicationScanner", startupArg: startupArg);
+                createPanelHandler.Handle(command);
+                form = command.CreatedPanel as Form;
+            }
+            else
+            {
+                form = PanelManager.Instance.CreatePanel("TalkApplicationScanner", startupArg);
+            }
             if (form == null)
             {
                 _logger.LogError("Could not create TalkApplicationScanner panel.");

src/Libraries/ACATCore.Tests/CQRSHandlerTests.cs

@@ -0,0 +1,203 @@
+////////////////////////////////////////////////////////////////////////////
+//
+// Copyright 2013-2019; 2023 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+//
+//
+// CQRSHandlerTests.cs
+//
+// Unit tests for CQRS command handler resolution paths:
+//  1. Handler available via DI (DI path)
+//  2. Handler not available – caller falls back to legacy singleton (fallback path)
+//
+////////////////////////////////////////////////////////////////////////////
+
+using ACAT.Core.ActuatorManagement;
+using ACAT.Core.ActuatorManagement.Interfaces;
+using ACAT.Core.PanelManagement;
+using ACAT.Core.PanelManagement.Common;
+using ACAT.Core.PanelManagement.Interfaces;
+using ACAT.Core.Patterns.CQRS;
+using ACAT.Core.Patterns.CQRS.Samples;
+using ACATCore.Tests.Mocks;
+using Moq;
+using System.Windows.Forms;
+using Xunit;
+
+namespace ACATCore.Tests
+{
+    /// <summary>
+    /// Unit tests for the CQRS <see cref="CreatePanelCommandHandler"/> and
+    /// <see cref="HandleActuatorSwitchCommandHandler"/>, covering both the
+    /// DI-available and fallback (handler-null) resolution paths.
+    /// </summary>
+    public class CQRSHandlerTests
+    {
+        // ----------------------------------------------------------------
+        // CreatePanelCommandHandler – DI path
+        // ----------------------------------------------------------------
+
+        [Fact]
+        public void CreatePanelCommandHandler_WhenHandlerAvailable_CallsPanelManagerAndSetsCreatedPanel()
+        {
+            // Arrange
+            var mockPanel = new Mock<Form>();
+            var panelManagerMock = ManagerMocks.CreatePanelManager();
+            panelManagerMock
+                .Setup(m => m.CreatePanel(It.IsAny<string>()))
+                .Returns(mockPanel.Object);
+
+            var handler = new CreatePanelCommandHandler(panelManagerMock.Object);
+            var command = new CreatePanelCommand("TestScanner");
+
+            // Act
+            handler.Handle(command);
+
+            // Assert – panel manager was called with the correct class name
+            panelManagerMock.Verify(m => m.CreatePanel("TestScanner"), Times.Once);
+        }
+
+        [Fact]
+        public void CreatePanelCommandHandler_WithTitleAndStartupArg_CallsCorrectOverload()
+        {
+            // Arrange
+            var mockPanel = new Mock<Form>();
+            var startupArg = new StartupArg("TestScanner");
+            var panelManagerMock = ManagerMocks.CreatePanelManager();
+            panelManagerMock
+                .Setup(m => m.CreatePanel(
+                    It.IsAny<string>(),
+                    It.IsAny<string>(),
+                    It.IsAny<StartupArg>()))
+                .Returns(mockPanel.Object);
+
+            var handler = new CreatePanelCommandHandler(panelManagerMock.Object);
+            var command = new CreatePanelCommand("TestScanner", "My Title", startupArg);
+
+            // Act
+            handler.Handle(command);
+
+            // Assert – overload with title and startupArg was invoked
+            panelManagerMock.Verify(
+                m => m.CreatePanel("TestScanner", "My Title", startupArg),
+                Times.Once);
+        }
+
+        // ----------------------------------------------------------------
+        // CreatePanelCommandHandler – fallback path (handler is null)
+        // ----------------------------------------------------------------
+
+        [Fact]
+        public void CreatePanelCommand_WhenHandlerIsNull_CreatedPanelRemainsNull()
+        {
+            // Arrange – no handler, simulate the null-handler fallback path
+            ICommandHandler<CreatePanelCommand> handler = null;
+            var command = new CreatePanelCommand("TestScanner");
+
+            // Act – caller would use legacy fallback; here we just verify
+            // that the command remains in its initial state (CreatedPanel == null)
+            // and no exception is thrown when handler is not invoked.
+            if (handler != null)
+            {
+                handler.Handle(command);
+            }
+
+            // Assert
+            Assert.Null(command.CreatedPanel);
+        }
+
+        // ----------------------------------------------------------------
+        // HandleActuatorSwitchCommandHandler – DI path
+        // ----------------------------------------------------------------
+
+        [Fact]
+        public void HandleActuatorSwitchCommandHandler_Pause_CallsActuatorManagerPause()
+        {
+            // Arrange
+            var actuatorManagerMock = ManagerMocks.CreateActuatorManager();
+            var handler = new HandleActuatorSwitchCommandHandler(actuatorManagerMock.Object);
+            var command = new HandleActuatorSwitchCommand(ActuatorSwitchAction.Pause);
+
+            // Act
+            handler.Handle(command);
+
+            // Assert
+            actuatorManagerMock.Verify(m => m.Pause(), Times.Once);
+            actuatorManagerMock.Verify(m => m.Resume(), Times.Never);
+        }
+
+        [Fact]
+        public void HandleActuatorSwitchCommandHandler_Resume_CallsActuatorManagerResume()
+        {
+            // Arrange
+            var actuatorManagerMock = ManagerMocks.CreateActuatorManager();
+            var handler = new HandleActuatorSwitchCommandHandler(actuatorManagerMock.Object);
+            var command = new HandleActuatorSwitchCommand(ActuatorSwitchAction.Resume);
+
+            // Act
+            handler.Handle(command);
+
+            // Assert
+            actuatorManagerMock.Verify(m => m.Resume(), Times.Once);
+            actuatorManagerMock.Verify(m => m.Pause(), Times.Never);
+        }
+
+        // ----------------------------------------------------------------
+        // HandleActuatorSwitchCommandHandler – fallback path (handler is null)
+        // ----------------------------------------------------------------
+
+        [Fact]
+        public void HandleActuatorSwitchCommand_WhenHandlerIsNull_NoExceptionThrown()
+        {
+            // Arrange – simulate no DI handler available (null fallback path)
+            ICommandHandler<HandleActuatorSwitchCommand> handler = null;
+            var command = new HandleActuatorSwitchCommand(ActuatorSwitchAction.Pause);
+
+            // Act – caller would use legacy fallback; no exception should occur
+            // when the handler check is performed and handler is null.
+            var exceptionThrown = false;
+            try
+            {
+                if (handler != null)
+                {
+                    handler.Handle(command);
+                }
+                // legacy fallback would call Context.AppActuatorManager.Pause() here
+            }
+            catch
+            {
+                exceptionThrown = true;
+            }
+
+            // Assert
+            Assert.False(exceptionThrown);
+        }
+
+        // ----------------------------------------------------------------
+        // ActuatorBase property injection
+        // ----------------------------------------------------------------
+
+        [Fact]
+        public void ActuatorBase_CreatePanelHandlerProperty_CanBeSetAndRetrieved()
+        {
+            // Arrange
+            var panelManagerMock = ManagerMocks.CreatePanelManager();
+            var handlerMock = new Mock<ICommandHandler<CreatePanelCommand>>();
+            var actuator = new TestActuator();
+
+            // Act
+            actuator.CreatePanelHandler = handlerMock.Object;
+
+            // Assert
+            Assert.Same(handlerMock.Object, actuator.CreatePanelHandler);
+        }
+
+        /// <summary>
+        /// Minimal concrete actuator used only for unit tests.
+        /// </summary>
+        private class TestActuator : ActuatorBase
+        {
+            public override IActuatorSwitch CreateSwitch() => null;
+        }
+    }
+}

src/Libraries/ACATCore/ActuatorManagement/ActuatorBase.cs

@@ -21,6 +21,8 @@
 using ACAT.Core.Extensions;
 using ACAT.Core.PanelManagement;
 using ACAT.Core.PanelManagement.Interfaces;
+using ACAT.Core.Patterns.CQRS;
+using ACAT.Core.Patterns.CQRS.Samples;
 using ACAT.Core.PreferencesManagement.Interfaces;
 using ACAT.Core.Utility;
 using Microsoft.Extensions.Logging;
@@ -58,6 +60,11 @@ public abstract class ActuatorBase : IActuator
         /// </summary>
         private bool _disposed;
 
+        /// <summary>
+        /// Backing field for <see cref="CreatePanelHandler"/>.
+        /// </summary>
+        private ICommandHandler<CreatePanelCommand> _createPanelHandler;
+
         /// <summary>
         /// Initializes a new instance of the ActuatorBase class
         /// </summary>
@@ -166,6 +173,20 @@ public ICollection<IActuatorSwitch> Switches
         protected State actuatorState { get; set; }
         public Guid Id => Descriptor.Id;
 
+        /// <summary>
+        /// Injectable command handler for creating panels. When set, panel creation
+        /// uses CQRS instead of direct singleton access. Falls back to
+        /// <see cref="PanelManager.Instance"/> when not set.
+        /// Resolved lazily from <see cref="Context.ServiceProvider"/> if available.
+        /// </summary>
+        public ICommandHandler<CreatePanelCommand> CreatePanelHandler
+        {
+            get => _createPanelHandler ??
+                   (Context.ServiceProvider?.GetService(typeof(ICommandHandler<CreatePanelCommand>))
+                       as ICommandHandler<CreatePanelCommand>);
+            set => _createPanelHandler = value;
+        }
+
         /// <summary>
         /// Class factory to create a switch.  Override this in the
         /// derived classes to enable creating switches that are specific to the
@@ -658,7 +679,23 @@ protected bool ShowDefaultScanTimingsConfigureDialog()
                 return false;
             }
 
-            Form form = PanelManager.Instance.CreatePanel(CoreGlobals.AppPreferences.DefaultScanTimingsConfigurePanelName, "Adjust Scanning Speed");
+            Form form;
+            var handler = CreatePanelHandler;
+            if (handler != null)
+            {
+                var command = new CreatePanelCommand(
+                    CoreGlobals.AppPreferences.DefaultScanTimingsConfigurePanelName,
+                    "Adjust Scanning Speed");
+                handler.Handle(command);
+                form = command.CreatedPanel as Form;
+            }
+            else
+            {
+                form = PanelManager.Instance.CreatePanel(
+                    CoreGlobals.AppPreferences.DefaultScanTimingsConfigurePanelName,
+                    "Adjust Scanning Speed");
+            }
+
             if (form != null)
             {
                 Context.AppPanelManager.ShowDialog(form as IPanel);
@@ -675,7 +712,23 @@ protected bool ShowDefaultTryoutDialog()
                 return false;
             }
 
-            Form form = PanelManager.Instance.CreatePanel(CoreGlobals.AppPreferences.DefaultTryoutPanelName, "Switch Tryout");
+            Form form;
+            var handler = CreatePanelHandler;
+            if (handler != null)
+            {
+                var command = new CreatePanelCommand(
+                    CoreGlobals.AppPreferences.DefaultTryoutPanelName,
+                    "Switch Tryout");
+                handler.Handle(command);
+                form = command.CreatedPanel as Form;
+            }
+            else
+            {
+                form = PanelManager.Instance.CreatePanel(
+                    CoreGlobals.AppPreferences.DefaultTryoutPanelName,
+                    "Switch Tryout");
+            }
+
             if (form != null)
             {
                 Context.AppPanelManager.ShowDialog(form as IPanel);