Refactoring IState - ISignal

Src/Myc.Core.Signals.pas

@@ -8,30 +8,29 @@ uses
     Myc.Signals;
 
 type
-    // TMycNullSignal implements a "null object" pattern for IMycState.
-    // This state is always considered "set".
+    // TMycNullSignal implements a "null object" pattern for ISignal.
     TMycNullSignal = class(TInterfacedObject, TSignal.ISignal)
     public
         function Subscribe(Subscriber: TSignal.ISubscriber): Pointer;
         procedure Unsubscribe(Tag: Pointer);
     end;
 
-    // TMycNullState implements a "null object" pattern for IMycState.
+    // TMycNullState implements a "null object" pattern for IState.
     // This state is always considered "set".
     TMycNullState = class(TInterfacedObject, TSignal.ISignal, TState.IState)
-    protected
-        // TState.IState
+    private
+        function GetSignal: TSignal;
         function GetIsSet: Boolean;
     public
         function Subscribe(Subscriber: TSignal.ISubscriber): Pointer;
         procedure Unsubscribe(Tag: Pointer);
+        property Signal: TSignal read GetSignal;
     end;
 
     // A state that acts as an event. It's state ist always set and it will always Trigger it's subscribers, if it gets notified by itself.
     TMycEvent = class(TInterfacedObject, TSignal.ISubscriber, TSignal.ISignal, TEvent.IEvent)
     strict private
         FSubscribers: TMycNotifyList<TSignal.ISubscriber>;
-    protected
         function GetSignal: TSignal;
         function GetIsSet: Boolean;
     public
@@ -69,7 +68,7 @@ type
         [volatile]
         FCount: Integer; // The internal countdown value for the latch.
         function GetState: TState; // Implementation for TLatch.ILatch.GetState and IFlag.GetState.
-    protected
+        function GetSignal: TSignal;
         function GetIsSet: Boolean;
     public
         // Creates the latch with an initial count.
@@ -103,11 +102,11 @@ type
         [volatile]
         FFlag: Boolean; // Internal state: true if dirty/set, false if clean/reset.
         function GetState: TState;
-    protected
+        function GetSignal: TSignal;
         function GetIsSet: Boolean;
     public
         // Creates a new dirty flag, initially set to dirty (true).
-        constructor Create;
+        constructor Create(AInit: Boolean);
         destructor Destroy; override;
 
         // Factory method to create a new TMycFlag instance.
@@ -166,6 +165,11 @@ begin
     Result := true; // Null state is always set.
 end;
 
+function TMycNullState.GetSignal: TSignal;
+begin
+    Result := Self;
+end;
+
 function TMycNullState.Subscribe(Subscriber: TSignal.ISubscriber): Pointer;
 begin
     // Since the state is always set, notify the subscriber immediately.
@@ -327,6 +331,11 @@ begin
     Result := FCount <= 0;
 end;
 
+function TMycLatch.GetSignal: TSignal;
+begin
+    Result := Self;
+end;
+
 function TMycLatch.GetState: TState;
 begin
     // TMycLatch itself implements TState.IState.
@@ -392,17 +401,17 @@ end;
 
 { TMycFlag }
 
-constructor TMycFlag.Create;
+constructor TMycFlag.Create(AInit: Boolean);
 begin
     inherited Create;
-    FFlag := false;
+    FFlag := AInit;
     FSubscribers.Create;
 end;
 
 class function TMycFlag.CreateDirty: TFlag.IFlag;
 begin
     // Factory method to create a new TMycFlag instance.
-    Result := TMycFlag.Create;
+    Result := TMycFlag.Create( true );
 end;
 
 destructor TMycFlag.Destroy;
@@ -423,6 +432,11 @@ begin
     Result := FFlag;
 end;
 
+function TMycFlag.GetSignal: TSignal;
+begin
+    Result := Self;
+end;
+
 function TMycFlag.GetState: TState;
 begin
     // TMycFlag itself implements TState.IState.
@@ -497,7 +511,7 @@ end;
 
 constructor TMycObserverFlag.Create(const ASignal: TSignal.ISignal);
 begin
-    inherited Create;
+    inherited Create( false );
     FSignal := ASignal;
 end;