visitor.h

   1 #ifndef _VISITOR_H_
   2 #define _VISITOR_H_
   3
   4 namespace odc {
   5
   6         class ShortPiece;
   7         class LongPiece;
   8
   9         /**
  10          * Visitor role of the Visitor design pattern.
  11          * Can be used to transform the document tree.
  12          */
  13         class Visitor {
  14                 public:
  15                 /**
  16                  * A "part" that can contain other elements starts here.
  17                  * This can be an StdTextModel or a ViewPiece or another container.
  18                  */
  19                 virtual void partStart() = 0;
  20                 /**
  21                  * A "part" ends here.
  22                  */
  23                 virtual void partEnd() = 0;
  24                 /**
  25                  * A left fold has been found.
  26                  * If the fold is collapsed, the first part that follows is the
  27                  * "hidden" part, otherwise the first part that follows is the
  28                  * "alternative" text. The rest is the vice versa.
  29                  * This is the main reason we even need a visitor.
  30                  * @param collapsed true if the fold is in collapsed form.
  31                  */
  32                 virtual void foldLeft(bool collapsed) = 0;
  33                 /**
  34                  * A right fold has been found.
  35                  */
  36                 virtual void foldRight() = 0;
  37                 /**
  38                  * A text piece has been found (8-bit characters).
  39                  */
  40                 virtual void textShortPiece(const ShortPiece *piece) = 0;
  41                 /**
  42                  * A text piece has been found (16-bit characters).
  43                  */
  44                 virtual void textLongPiece(const LongPiece *piece) = 0;
  45         };
  46 }
  47
  48 #endif // _VISITOR_H_