remotecontrolwithundo.hpp

深入浅出设计模式（书配套c++源代码)。包含20个设计模式的c++实现。

#ifndef	_HFDP_CPP_COMMAND_REMOTE_CONTROL_WITH_UNDO_HPP_
#define _HFDP_CPP_COMMAND_REMOTE_CONTROL_WITH_UNDO_HPP_

#include "Undo.hpp"

namespace HeadFirstDesignPatterns {
namespace Command {
namespace Undo {

//
// This is the invoker
//
class RemoteControlWithUndo {

	private: static const int SLOTS = 7;

	private: Command* _onCommands[SLOTS];
	private: Command* _offCommands[SLOTS];
	private: Command* _noCommand;
	private: mutable Command* _undoCommand;

	public: RemoteControlWithUndo() {
		_noCommand = new NoCommand();
		for( int i = 0; i < SLOTS; i++ ) {
			_onCommands[i] = _noCommand;
			_offCommands[i] = _noCommand;
		}
		_undoCommand = _noCommand;
	}
	public: ~RemoteControlWithUndo() {
		delete _noCommand;
	}
	public: void setCommand( int slot, Command* onCommand, Command* offCommand ) { assert( slot <= SLOTS ); assert( onCommand ); assert( offCommand );
		_onCommands[slot]  = onCommand;
		_offCommands[slot] = offCommand;
	}
	public: void onButtonWasPushed( int slot ) const { assert( slot <= SLOTS );
		_onCommands[slot]->execute();
		_undoCommand = _onCommands[slot];
	}
	public: void offButtonWasPushed( int slot ) const { assert( slot <= SLOTS );
		_offCommands[slot]->execute();
		_undoCommand = _offCommands[slot];
	}
	public: void undoButtonWasPushed() const {
		_undoCommand->undo();
	}
	public: std::string toString() const {
		std::stringstream value;
		value << std::endl << "------ Remote Control -------" << std::endl;
		for( int i = 0; i < SLOTS; i++ ) {
			value << "[slot " << i << "] ";
			value << typeid( *_onCommands[i] ).name();
			value << "    ";
			value << typeid( *_offCommands[i] ).name();
			value << std::endl;
		}
		value << "[undo] " << typeid( *_undoCommand ).name() << std::endl;

		return value.str();
	}
};

} // namespace Undo
} // namespace Command
} // namespace HeadFirstDesignPatterns

#endif