Component Handlers

I saw a problem lurking which was the callback design for components. There was no way to know when an object was being destroyed unless the component sent a notification. The component could know that its instance is being destroyed but attached objects could not know.

I met this problem in FileToken where it wanted to point to an attached FileChunk instance but would not know if the FileChunk instance was destroyed.

I made a system-wide change. Before, components implemented specific callbacks for constructor, destructor and shutdown scenarios. Now a single handler can be set for each component in its initialization. The handler can receive messages from any component. The constructor, destructor and shutdown scenarios are now sent by CoreObject as messages to the component handler. But now there is a new message CORE_OBJECT_MESSAGE_DETACH which is sent to all attached objects when a object is being detached from it. This will be used by FileToken to know when FileChunk is being detached.

You can find the latest code collection at:
http://sourceforge.net/projects/screensos/files/screensos/packages_002.zip/download

When I hit a milestone, I will add a zip to the source forge files.