builder.c

design_patterns code设计模式书中的源码 对学习设计模式的人很有帮助的

/*
*/

#include "C++/MazeParts.H"
#include "C++/MazeGame.H"
#include <iostream.h>
/*
*/
class MazeBuilder {
public:
    virtual void BuildMaze() { }
    virtual void BuildRoom(int room) { }
    virtual void BuildDoor(int roomFrom, int roomTo) { }

    virtual Maze* GetMaze() { return 0; }
protected:
    MazeBuilder();
};
/*
*/
Maze* MazeGame::CreateMaze (MazeBuilder& builder) {
    builder.BuildMaze();

    builder.BuildRoom(1);
    builder.BuildRoom(2);
    builder.BuildDoor(1, 2);

    return builder.GetMaze();
}
/*
*/
Maze* MazeGame::CreateComplexMaze (MazeBuilder& builder) {
    builder.BuildRoom(1);
    // ...
    builder.BuildRoom(1001);

    return builder.GetMaze();
}
/*
*/
class StandardMazeBuilder : public MazeBuilder {
public:
    StandardMazeBuilder();
/*
*/
    virtual void BuildMaze();
    virtual void BuildRoom(int);
    virtual void BuildDoor(int, int);
/*
*/
    virtual Maze* GetMaze();
private:
    Direction CommonWall(Room*, Room*);
    Maze* _currentMaze;
};

/*
*/
StandardMazeBuilder::StandardMazeBuilder () {
    _currentMaze = 0;
}
/*
*/
void StandardMazeBuilder::BuildMaze () {
    _currentMaze = new Maze;
}
/*
*/
Maze *StandardMazeBuilder::GetMaze () {
    Maze* maze =  _currentMaze;
    return maze;
}
/*
*/
void StandardMazeBuilder::BuildRoom (int n) {
    if (!_currentMaze->RoomNo(n)) {
        Room* room = new Room(n);
        _currentMaze->AddRoom(room);
/*
*/
        room->SetSide(North, new Wall);
        room->SetSide(South, new Wall);
        room->SetSide(East, new Wall);
        room->SetSide(West, new Wall);
    }
}
/*
*/
void StandardMazeBuilder::BuildDoor (int n1, int n2) {
    Room* r1 = _currentMaze->RoomNo(n1);
    Room* r2 = _currentMaze->RoomNo(n2);
    Door* d = new Door(r1, r2);
/*
*/
    r1->SetSide(CommonWall(r1,r2), d);
    r2->SetSide(CommonWall(r2,r1), d);
}
/*
*/
void dummy() {
/*
*/
Maze* maze;
MazeGame game;
StandardMazeBuilder builder;

game.CreateMaze(builder);
maze = builder.GetMaze();
/*
*/
}
/*
*/
class CountingMazeBuilder : public MazeBuilder {
public:
    CountingMazeBuilder();
/*
*/
    virtual void BuildMaze();
    virtual void BuildRoom(int);
    virtual void BuildDoor(int, int);
    virtual void AddWall(int, Direction);
/*
*/
    void GetCounts(int&, int&) const;
private:
    int _doors;
    int _rooms;
};
/*
*/
CountingMazeBuilder::CountingMazeBuilder () {
    _rooms = _doors = 0;
}
/*
*/
void CountingMazeBuilder::BuildRoom (int) {
    _rooms++;
}
/*
*/
void CountingMazeBuilder::BuildDoor (int, int) {
    _doors++;
}
/*
*/
void CountingMazeBuilder::GetCounts (
    int& rooms, int& doors
) const {
    rooms = _rooms;
    doors = _doors;
}
/*
*/
void dummy1() {
/*
*/
int rooms, doors;
MazeGame game;
CountingMazeBuilder builder;

game.CreateMaze(builder);
builder.GetCounts(rooms, doors);

cout << "The maze has "
     << rooms << " rooms and "
     << doors << " doors" << endl;
/*
*/
}
/*
*/