DDSLoader.h

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// This file is part of the "NcML Module" project, a BES module designed
// to allow NcML files to be used to be used as a wrapper to add
// AIS to existing datasets of any format.
//
// Copyright (c) 2009 OPeNDAP, Inc.
// Author: Michael Johnson  <m.johnson@opendap.org>
//
// For more information, please also see the main website: http://opendap.org/
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//
// Please see the files COPYING and COPYRIGHT for more information on the GLPL.
//
// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.
#ifndef __NCML_MODULE_DDSLOADER_H__
#define __NCML_MODULE_DDSLOADER_H__

#include <memory>
#include <string>

class BESDataHandlerInterface;
class BESContainer;
class BESContainerStorage;
class BESDapResponse;
class BESResponseObject;


namespace agg_util
{

class DDSLoader
{
private:

  // The dhi to use for the loading, passed in on creation.
  // Rep Invariant: the dhi state is the same on call exits as it was on call entry.
  BESDataHandlerInterface& _dhi;

  // whether we have actually hijacked the dhi, so restore knows.
  bool _hijacked;

  // The file we are laoding if we're hijacked
  std::string _filename;

  // Remember the store so we can pull the location out in restoreDHI on exception as well.
  BESContainerStorage* _store;

  // DHI state we hijack, for putting back on exception.
  std::string _containerSymbol;
  std::string _origAction;
  std::string _origActionName;
  BESContainer* _origContainer;
  BESResponseObject* _origResponse;

  // A counter we use to generate a "class-unique" symbol for containers internally.
  // Incremented by getNextContainerName().
  static long _gensymID;

public:

  enum ResponseType { eRT_RequestDDX = 0, eRT_RequestDataDDS, eRT_Num };

  DDSLoader(BESDataHandlerInterface &dhi);

  DDSLoader(const DDSLoader& proto);
  DDSLoader& operator=(const DDSLoader&);

  virtual ~DDSLoader();

  BESDataHandlerInterface& getDHI() const { return _dhi; }

  std::auto_ptr<BESDapResponse> load(const std::string& location, ResponseType type);

  void loadInto(const std::string& location, ResponseType type, BESDapResponse* pResponse);

  void cleanup() throw();


  static std::auto_ptr<BESDapResponse> makeResponseForType(ResponseType type);

  static std::string getActionForType(ResponseType type);

  static std::string getActionNameForType(ResponseType type);

  static bool checkResponseIsValidType(ResponseType type, BESDapResponse* pResponse);


private:

   void snapshotDHI();

   void restoreDHI();

   BESContainer* addNewContainerToStorage();

   void removeContainerFromStorage() throw();

   void ensureClean() throw();

   static std::string getNextContainerName();

  }; // class DDSLoader
} // namespace ncml_module

#endif /* __NCML_MODULE_DDSLOADER_H__ */