ObjectMap.h

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/***************************************************************************
 *
 * Copyright (C) 2009-2011 Cassio Neri Moreira
 *
 * This file is part of the KeyValue library.
 *
 * The KeyValue library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or (at
 * your option) any later version.
 *
 * The KeyValue 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 General
 * Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with KeyValue. If not, see <http://www.gnu.org/licenses/>.
 *
 * If you modify this library, or any covered work, by linking or combining
 * it with Excel (or a modified version of that program), containing parts
 * covered by the terms of End-User License Agreement for Microsoft
 * Software, the licensors of KeyValue grant you additional permission to
 * convey the resulting work.
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 **************************************************************************/

#ifndef KEYVALUE_KEY_MAP_OBJECTMAP_H_
#define KEYVALUE_KEY_MAP_OBJECTMAP_H_

#include <boost/utility.hpp>

#include "keyvalue/extern/String.h"
#include "keyvalue/frontend/LexicalToolKit.h"
#include "keyvalue/mngt/BuilderFrom.h"
#include "keyvalue/mngt/DataSet.h"
#include "keyvalue/mngt/ProcessorMngr.h"
#include "keyvalue/mngt/Repository.h"
#include "keyvalue/sys/exception/Exception.h"
#include "keyvalue/sys/exception/KV_ASSERT.h"
#include "keyvalue/util/Global.h"
#include "keyvalue/value/Variant.h"

namespace keyvalue {
namespace key {

template <typename ObjectType>
class ObjectMap :

  private ::boost::noncopyable {

public:

  typedef typename value::PtrTraits<ObjectType>::Type_ OutputType_;

  OutputType_
  map(const value::Variant& variant) const;

private:

  virtual string
  getName() const = 0;

}; // class ObjectMap

/*--------------------------------------------------------------------------
 * map()
 *------------------------------------------------------------------------*/

template <typename ObjectType>
typename ObjectMap<ObjectType>::OutputType_
ObjectMap<ObjectType>::map(const value::Variant& variant) const {

  string name;

  // Try to get object by its name.

  if (variant.is<string>(frontend::LexicalToolKit::input)) {

    name = variant.get<string>(frontend::LexicalToolKit::input);

    try {
      shared_ptr<const DataSet>
        data(util::Global<Repository>::get()->getDataSet(name));
      return data->build<ObjectType>();
    }

    catch(Repository::NotFound& error) {
      if (error.getName() != name)
        throw;
    }
  }

  // Try to build directly from variant.

  const AbstractBuilder* const builder =
      util::Global<ProcessorMngr>::get()->findBuilder(typeid(ObjectType));

  if (!builder) {
    if (name.empty())
      throw RuntimeError() & "No builder can build object expected by key "
        "'" & getName() & "'. (Value is '" & variant & "'.)";
    else
      throw RuntimeError() & "No object named '" & name & "' exists and no "
        "builder can build object expected by key '" & getName() & "' from "
        "this string.";
  }

  typedef BuilderFrom<ObjectType, value::Variant> const BuilderFromVariant;

  const BuilderFromVariant* bfv(dynamic_cast<BuilderFromVariant*>(builder));

  if (!bfv)
    throw RuntimeError() & "Builder '" & builder->getName() & "' needs a "
      "data set. It cannot satisfy key '" & getName() & "' and build from "
      "input '" & variant & "'.";

  return bfv->getObject(variant);
}

} // namespace key
} // namespace keyvalue

#endif // KEYVALUE_KEY_MAP_OBJECTMAP_H_