--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancStone/Sources/Messages/ICallable.h	Tue Jul 07 16:21:02 2020 +0200
@@ -0,0 +1,95 @@
+/**
+ * Stone of Orthanc
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2020 Osimis S.A., Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Affero General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#pragma once
+
+#include "IMessage.h"
+#include "IObserver.h"
+
+#include <Logging.h>
+
+#include <boost/noncopyable.hpp>
+#include <boost/weak_ptr.hpp>
+
+#include <string>
+#include <stdint.h>
+
+namespace OrthancStone 
+{
+  // This is referencing an object and member function that can be notified
+  // by an IObservable.  The object must derive from IO
+  // The member functions must be of type "void Method(const IMessage& message)" or reference a derived class of IMessage
+  class ICallable : public boost::noncopyable
+  {
+  public:
+    virtual ~ICallable()
+    {
+    }
+
+    virtual void Apply(const IMessage& message) = 0;
+
+    virtual const MessageIdentifier& GetMessageIdentifier() = 0;
+
+    // TODO - Is this needed?
+    virtual boost::weak_ptr<IObserver> GetObserver() const = 0;
+  };
+
+
+  template <typename TObserver,
+            typename TMessage>
+  class Callable : public ICallable
+  {
+  private:
+    typedef void (TObserver::* MemberMethod) (const TMessage&);
+
+    boost::weak_ptr<IObserver>  observer_;
+    MemberMethod                function_;
+
+  public:
+    Callable(boost::shared_ptr<TObserver> observer,
+             MemberMethod function) :
+      observer_(observer),
+      function_(function)
+    {
+    }
+
+    virtual void Apply(const IMessage& message)
+    {
+      boost::shared_ptr<IObserver> lock(observer_);
+      if (lock)
+      {
+        TObserver& observer = dynamic_cast<TObserver&>(*lock);
+        const TMessage& typedMessage = dynamic_cast<const TMessage&>(message);
+        (observer.*function_) (typedMessage);
+      }
+    }
+
+    virtual const MessageIdentifier& GetMessageIdentifier()
+    {
+      return TMessage::GetStaticIdentifier();
+    }
+
+    virtual boost::weak_ptr<IObserver> GetObserver() const
+    {
+      return observer_;
+    }
+  };
+}