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/// @file command.h
/// @details The abstract parent class for each class implementing a specific
/// command of the cloud editor.  This class is designed to be used with the
/// CommandQueue.
/// @author Yue Li and Matthew Hielsberg

#ifndef COMMAND_H_
#define COMMAND_H_

#include <pcl/apps/point_cloud_editor/localTypes.h>

/// @brief The abstract parent class of all the command classes. Commands are
/// non-copyable.
class Command
{
  public:
    /// @brief Destructor
    virtual ~Command ()
    {
    }

  protected:
    /// Allows command queues to be the only objects which are able to execute
    /// commands.
    friend class CommandQueue;

    /// @brief The default constructor.
    /// @details Derived commands are assumed to have undo by default.  Each
    /// is free to override this.
    Command () : has_undo_(true)
    {
    }

    /// @brief Returns true if the command has an undo function.
    inline
    bool
    hasUndo () const
    {
      return (has_undo_);
    }

    /// @brief Executes the command.
    virtual
    void
    execute () = 0;

    /// @brief Undos the command.
    virtual
    void
    undo () = 0;

    /// @brief a flag indicates whether the command has an undo function.
    bool has_undo_;

  private:
    /// @brief Copy Constructor - object is non-copyable
    Command (const Command&)
    {
      assert(false);
    }

    /// @brief Equal Operator - object is non-copyable
    Command&
    operator= (const Command&)
    {
      assert(false); return (*this);
    }
};
#endif //COMMAND_H_
