Added new demo that demonstrates how object interfaces in Object Pasc…

…al work.

Concepts.Registration.pas

@@ -76,6 +76,7 @@ implementation
   Concepts.System.VirtualMethodInterceptor.Form,
   Concepts.System.VirtualInterface.Form,
   Concepts.System.PublishedFields.Form,
+  Concepts.System.Interfaces.Form,
   {$ENDIF}
 
   {$IFDEF DEVEXPRESS}
@@ -392,6 +393,13 @@ class procedure TConcepts.RegisterSystemConcepts;
     'Demonstrates a form with components without published fields.',
     FCategoryColor
   );
+  ConceptManager.Register(
+    TfrmInterfaces,
+    'Interfaces',
+    'System',
+    'Demonstrates how object interfaces work.',
+    FCategoryColor
+  );
   {$ENDIF}
 end;
 

Concepts.dpr

@@ -79,20 +79,25 @@ uses
   Concepts.DevExpress.cxGridViewPresenter.Form in 'Forms\Concepts.DevExpress.cxGridViewPresenter.Form.pas' {frmcxGridViewPresenter},
   Concepts.VirtualTreeView.Form in 'Forms\Concepts.VirtualTreeView.Form.pas' {frmVirtualTreeView},
   Concepts.FireDAC.Form in 'Forms\Concepts.FireDAC.Form.pas' {frmFireDAC},
-  Concepts.System.PublishedFields.Form in 'Forms\Concepts.System.PublishedFields.Form.pas' {frmPublishedFields};
+  Concepts.System.PublishedFields.Form in 'Forms\Concepts.System.PublishedFields.Form.pas' {frmPublishedFields},
+  Concepts.System.Interfaces.DelegatedImplementation in 'Forms\Concepts.System.Interfaces.DelegatedImplementation.pas',
+  Concepts.System.Interfaces.Form in 'Forms\Concepts.System.Interfaces.Form.pas' {frmInterfaces},
+  Concepts.System.Interfaces.InterfacedObject in 'Forms\Concepts.System.Interfaces.InterfacedObject.pas',
+  Concepts.System.Interfaces.Interfaces in 'Forms\Concepts.System.Interfaces.Interfaces.pas',
+  Concepts.System.Interfaces.WeakReferences in 'Forms\Concepts.System.Interfaces.WeakReferences.pas';
 
 {$R *.res}
 
 { Used to directly start a concept by name. If empty a list will be shown with
   all registered concepts. }
 const
-//  EXECUTE_BY_NAME = '';
+  EXECUTE_BY_NAME = '';
   //EXECUTE_BY_NAME = 'ZeroMQ';
 //  EXECUTE_BY_NAME = 'FireDAC';
   //EXECUTE_BY_NAME = 'ORM';
   //EXECUTE_BY_NAME = 'TStringList';
   //EXECUTE_BY_NAME = 'Indy';
-  EXECUTE_BY_NAME = 'Parallel Library';
+  //EXECUTE_BY_NAME = 'Parallel Library';
 
 begin
   {$WARNINGS OFF}

Concepts.dproj

@@ -308,6 +308,14 @@
         <DCCReference Include="Forms\Concepts.System.PublishedFields.Form.pas">
             <Form>frmPublishedFields</Form>
         </DCCReference>
+        <DCCReference Include="Forms\Concepts.System.Interfaces.DelegatedImplementation.pas"/>
+        <DCCReference Include="Forms\Concepts.System.Interfaces.Form.pas">
+            <Form>frmInterfaces</Form>
+            <FormType>dfm</FormType>
+        </DCCReference>
+        <DCCReference Include="Forms\Concepts.System.Interfaces.InterfacedObject.pas"/>
+        <DCCReference Include="Forms\Concepts.System.Interfaces.Interfaces.pas"/>
+        <DCCReference Include="Forms\Concepts.System.Interfaces.WeakReferences.pas"/>
         <BuildConfiguration Include="Debug">
             <Key>Cfg_2</Key>
             <CfgParent>Base</CfgParent>

Forms/Concepts.System.Interfaces.DelegatedImplementation.pas

@@ -0,0 +1,115 @@
+{
+  Copyright (C) 2013-2018 Tim Sinaeve [email protected]
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+}
+
+{$I Concepts.inc}
+
+unit Concepts.System.Interfaces.DelegatedImplementation;
+
+interface
+
+uses
+  System.Classes,
+
+  Concepts.System.Interfaces.Interfaces,
+  Concepts.System.Interfaces.InterfacedObject;
+
+type
+  TInterfacedObject =
+    Concepts.System.Interfaces.InterfacedObject.TMyInterfacedObject;
+
+type
+  { This simple class descends from TObject and does not implement
+    IInnerInterface directly. An instance of this object will be used to
+    let an outer object implement IInnerInterface through the 'implements'
+    syntax. }
+  TInnerObject = class(TObject)
+ // TInnerObject = class(TInterfacedObject, IInnerInterface)
+  public
+    procedure InnerMethod;
+
+  end;
+
+  TOuterObject = class(TInterfacedObject, IOuterInterface, IInnerInterface)
+  private
+    FInnerObject    : TInnerObject;
+    //FInnerInterface : IInnerInterface;
+
+    //function GetInnerObject: IInnerInterface;
+
+    property InnerObject: TInnerObject
+      read FInnerObject implements IInnerInterface;
+
+  public
+    procedure BeforeDestruction; override;
+
+    constructor Create(
+      AIsRefCounted     : Boolean;
+      AOnAddRef         : TRefCountEvent = nil;
+      AOnRelease        : TRefCountEvent = nil;
+      AOnQueryInterface : TNotifyEvent = nil;
+      AOnDestroy        : TNotifyEvent = nil
+    ); override;
+
+    //procedure IInnerInterface.InnerMethod = MyInnerMethod;
+    procedure MyInnerMethod;
+
+    procedure OuterMethod;
+  end;
+
+implementation
+
+uses
+  Vcl.Dialogs;
+
+{ TInnerObject }
+
+procedure TInnerObject.InnerMethod;
+begin
+  ShowMessage('TInnerObject.InnerMethod called.');
+end;
+
+{ TOuterObject }
+
+procedure TOuterObject.BeforeDestruction;
+begin
+  FInnerObject.Free;
+  inherited BeforeDestruction;
+end;
+
+constructor TOuterObject.Create(AIsRefCounted: Boolean; AOnAddRef,
+  AOnRelease: TRefCountEvent; AOnQueryInterface, AOnDestroy: TNotifyEvent);
+begin
+  inherited Create(AIsRefCounted, AOnAddRef, AOnRelease, AOnQueryInterface, AOnDestroy);
+  FInnerObject := TInnerObject.Create;
+  //FInnerInterface := TInnerObject.Create(AIsRefCounted, AOnAddRef, AOnRelease, AOnQueryInterface, AOnDestroy);
+end;
+
+//function TOuterObject.GetInnerObject: IInnerInterface;
+//begin
+//  Result := FInnerInterface;
+//end;
+
+procedure TOuterObject.MyInnerMethod;
+begin
+  ShowMessage('TOuterObject.MyInnerMethod called.');
+end;
+
+procedure TOuterObject.OuterMethod;
+begin
+  ShowMessage('TOuterObject.OuterMethod called.');
+end;
+
+end.