root/juggler/tags/1.0.5/Kernel/vjConfigChunkHandler.h

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 * VR Juggler is (C) Copyright 1998, 1999, 2000 by Iowa State University
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 * Original Authors:
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 *   Patrick Hartling, Kevin Meinert,
 *   Carolina Cruz-Neira, Albert Baker
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#ifndef _VJ_CONFIG_CHUNK_HANDLER_H_
#define _VJ_CONFIG_CHUNK_HANDLER_H_

#include <vjConfig.h>
class vjConfigChunk;

//-----------------------------------------
//: Abstract base class for all classes that can handle config chunks
//
// This means that they can be "configured"
// and queried using the specified interface.
//
//
// The idea is that you override canHandle()
// to recognize chunks the derived class cares about.
// Then you over ride configAdd and configRemove
// to actually process those chunks.
// It is also possible to override configProcessPending although the 
// default one will work in most cases.
//---------------------------------------------
//! PUBLIC_API:
class vjConfigChunkHandler
{
public:
   //: Can the handler handle the given chunk?
   //! RETURNS: true - Can handle it
   //+          false - Can't handle it
   virtual bool configCanHandle(vjConfigChunk* chunk) = 0;

   //: Process any pending reconfiguration that we can deal with
   // This function processes each pending reconfiguration in configuration manager
   // The default implementation does the following. <br>
   // if(this->configCanHandle && passesDepCheck)
   //    configAdd/configRemove(chunk)
   // if(success)
   //   add/remove from pending
   //   remove/add from current
   //
   //! ARGS: lockIt - Should we lock the cfg_mgr pending list
   //+       defaults to true.  The only time this should be false is 
   //+       if you override this function and still want to make use of it's abilities
   //+         (ex.  The kernel needs to do this because if has to call configProcessPending on other managers in addition to itself)
   //! RETURNS: Number of chunks it actually processes
   virtual int configProcessPending(bool lockIt = true);

protected:
   //: Add the chunk to the configuration
   //! PRE: configCanHandle(chunk) == true
   //! RETURNS: success
   virtual bool configAdd(vjConfigChunk* chunk) = 0;

   //: Remove the chunk from the current configuration
   //! PRE: configCanHandle(chunk) == true
   //!RETURNS: success
   virtual bool configRemove(vjConfigChunk* chunk) = 0;
};


#endif