Example 17-1: Decorator

TOC

• Client
• Factory
• Component
• SalesTicket
• TicketDecorator
• Header1
• Header2
• Footer1
• Footer2

#pragma once
#include "Factory.h"
#include "Component.h"

class Client
{
public:
	Client(void);
public:
	~Client(void);
};

#include "Client.h"

Client::Client(void)
{
}

Client::~Client(void)
{
}

static void main ()
{
	Factory myFactory;
	Component *myComponent = myFactory.getComponent();
}

#pragma once
#include "Component.h"
#include "SalesTicket.h"
#include "Header1.h"
#include "Header2.h"
#include "Footer1.h"
#include "Footer2.h"

class Factory
{
public:
	Factory(void);
	Component* getComponent();
public:
	~Factory(void);
};

#include "Factory.h"

Factory::Factory(void)
{
}

Factory::~Factory(void)
{
}

Component *Factory::getComponent()
{
	bool doHeader1;
	bool doHeader2;
	bool doFooter1;
	bool doFooter2;

	// Put code here that sets doHeader1, doHeader2, doFooter1, doFooter2
	// One way could look up in a configuration file.
	// Here I'll hardcode an example that gives a footer1 and a header1
	doHeader1= true;
	doHeader2= false;
	doFooter1= true;
	doFooter2= false;

	Component *myComponent;
	myComponent = new SalesTicket;

	// Note that the chain is built backwards so the last one instantiated
	// is at the front of the list
	if (doFooter2) myComponent= new Footer2( myComponent);
	if (doFooter1) myComponent= new Footer1( myComponent);
	if (doHeader2) myComponent= new Header2( myComponent);
	if (doHeader1) myComponent= new Header1( myComponent);

	return (myComponent);
}

#pragma once

class Component
{
public:
	Component(void);
	virtual void prtTicket()= 0;
public:
	~Component(void);
};

#include "Component.h"

Component::Component(void)
{
}

Component::~Component(void)
{
}

#pragma once
#include "component.h"

class SalesTicket :	public Component
{
public:
	SalesTicket(void);
	void prtTicket();
public:
	~SalesTicket(void);
};

#include "SalesTicket.h"

SalesTicket::SalesTicket(void)
{
}

SalesTicket::~SalesTicket(void)
{
}

void SalesTicket::prtTicket(void)
{
	// place sales ticket printing code here
}

#pragma once
#include "component.h"

class TicketDecorator :	public Component
{
public:
	TicketDecorator(Component *myComponent);
	void callTrailer();
public:
	~TicketDecorator(void);
private:
	 Component *myTrailer;
};

#include "TicketDecorator.h"

TicketDecorator::TicketDecorator(Component *myComponent)
{
	myTrailer= myComponent;
}

TicketDecorator::~TicketDecorator(void)
{
}

void TicketDecorator::callTrailer()
{
	if (myTrailer != 0l) myTrailer->prtTicket();
}

#pragma once
#include "ticketdecorator.h"

class Header1 :	public TicketDecorator
{
public:
	Header1(Component *myComponent); 
	void prtTicket();
public:
	~Header1(void);
};

#include "Header1.h"

Header1::Header1(Component *myComponent) : TicketDecorator( myComponent)
{
}

Header1::~Header1(void)
{
}

void Header1::prtTicket()
{
	// place printing header 1 code here
	callTrailer();
}

#pragma once
#include "ticketdecorator.h"

class Header2 :	public TicketDecorator
{
public:
	Header2(Component *myComponent);
	void prtTicket();
public:
	~Header2(void);
};

#include "Header2.h"

Header2::Header2( Component *myComponent) : TicketDecorator( myComponent)
{
}

Header2::~Header2(void)
{
}

void Header2::prtTicket()
{
	// place printing header 2 code here
	callTrailer();
}

#pragma once
#include "ticketdecorator.h"

class Footer1 :	public TicketDecorator
{
public:
	Footer1(Component *myComponent);
	void prtTicket();
public:
	~Footer1(void);
};

#include "Footer1.h"

Footer1::Footer1(Component *myComponent) : TicketDecorator( myComponent)
{
}

Footer1::~Footer1(void)
{
}

void Footer1::prtTicket()
{
	callTrailer();
	// place printing footer 1 code here
}

#pragma once
#include "ticketdecorator.h"

class Footer2 :	public TicketDecorator
{
public:
	Footer2(Component *myComponent);
	void prtTicket();
public:
	~Footer2(void);
};

#include "Footer2.h"

Footer2::Footer2(Component *myComponent) : TicketDecorator( myComponent)
{
}

Footer2::~Footer2(void)
{
}

void Footer2::prtTicket()
{
	callTrailer();
	// place printing footer 2 code here
}