Expression.h

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/*  Copyright (C) 2008 National Institute For Space Research (INPE) - Brazil.
 
    This file is part of the TerraLib - a Framework for building GIS enabled applications.
 
    TerraLib 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 3 of the License,
    or (at your option) any later version.
 
    TerraLib 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 TerraLib. See COPYING. If not, write to
    TerraLib Team at <terralib-team@terralib.org>.
 */
 
/*!
  \file terralib/dataaccess/query/Expression.h
  
  \brief This is an abstract class that models a query expression.
*/
 
#ifndef __TERRALIB_DATAACCESS_INTERNAL_EXPRESSION_H
#define __TERRALIB_DATAACCESS_INTERNAL_EXPRESSION_H
 
// TerraLib
#include "../../common/BaseVisitable.h"
#include "QueryVisitor.h"
 
namespace te
{
  namespace da
  {
    /*!
      \class Expression
      
      \brief This is an abstract class that models a query expression.
 
      An expression is a combination of one or more
      functions, literals or property names that can be evaluated.
 
      \sa PropertyName, Function, Literal
    */
    class TEDATAACCESSEXPORT Expression : public te::common::BaseVisitable<QueryVisitor>
    {
      public:
 
        TE_DEFINE_VISITABLE
 
        /*! \brief Default constructor. */
        Expression() {}
 
        /*! \brief Virtual destructor. */
        virtual ~Expression() {}
 
        /*! \brief It creates a new copy of this expression. */
        virtual Expression* clone() const = 0;
    };
 
    /*! \brief For use with boost conteiners. */
    inline Expression* new_clone(const Expression& a)
    {
      return a.clone();
    }
 
  } // end namespace da
}   // end namespace te
 
TEDATAACCESSEXPORT te::da::Expression* operator==(const te::da::Expression& e1, const te::da::Expression& e2);
TEDATAACCESSEXPORT te::da::Expression* operator!=(const te::da::Expression& e1, const te::da::Expression& e2);
TEDATAACCESSEXPORT te::da::Expression* operator&&(const te::da::Expression& e1, const te::da::Expression& e2);
TEDATAACCESSEXPORT te::da::Expression* operator||(const te::da::Expression& e1, const te::da::Expression& e2);
TEDATAACCESSEXPORT te::da::Expression* operator~(const te::da::Expression& e);
TEDATAACCESSEXPORT te::da::Expression* operator>(const te::da::Expression& e1, const te::da::Expression& e2);
TEDATAACCESSEXPORT te::da::Expression* operator>=(const te::da::Expression& e1, const te::da::Expression& e2);
TEDATAACCESSEXPORT te::da::Expression* operator<(const te::da::Expression& e1, const te::da::Expression& e2);
TEDATAACCESSEXPORT te::da::Expression* operator<=(const te::da::Expression& e1, const te::da::Expression& e2);
 
#endif  // __TERRALIB_DATAACCESS_INTERNAL_EXPRESSION_H