大话设计模式--装饰者模式 Decorator -- C++实现实例

1.装饰者模式 Decorator

动态地给一个对象添加一个额外的职责， 就添加功能来说， 装饰模式比生成子类更为灵活。

每个装饰对象的实现和如何使用这个对象分离，  每个装饰对象只关心自己的功能，不需要关心如何被添加到对象链中。

实例：

人和衣服的装饰关系。

person.h   Person类

#ifndef PERSON_H
#define PERSON_H

#include <string>
#include <iostream>
using namespace std;

class Person
{
public:
    Person();
    Person(string name);
    void virtual show();

private:
    string name;

};

#endif // PERSON_H

person.cpp

#include "person.h"

Person::Person()
{
}

Person::Person(string name)
{
    this->name = name;
}

void Person::show()
{
    cout << " <-name-> " << name << endl;
}

finery.h

#ifndef FINERY_H
#define FINERY_H

#include "person.h"

class Finery : public Person
{
public:
    Finery();
    void Decorate(Person *person);
    void show();

protected:
    Person *person;

};

#endif // FINERY_H

finery.cpp

#include "finery.h"

Finery::Finery()
{
}

void Finery::Decorate(Person* person)
{
    this->person = person;
}

void Finery::show()
{
    if(person != NULL)
        person->show();
}

tshirts.h 装饰者

#ifndef TSHIRTS_H
#define TSHIRTS_H

#include "finery.h"

class TShirts : public Finery
{
public:
    TShirts();
    void show();
};

#endif // TSHIRTS_H

tshirts.cpp

#include "tshirts.h"

TShirts::TShirts()
{
}

void TShirts::show()
{
    cout << " TShirts " << endl;
    Finery::show();
}

bigtrouser.h

#ifndef BIGTROUSER_H
#define BIGTROUSER_H

#include "finery.h"

class BigTrouser : public Finery
{
public:
    BigTrouser();
    void show();
};

#endif // BIGTROUSER_H

bigtrouser.cpp

#include "bigtrouser.h"

BigTrouser::BigTrouser()
{
}

void BigTrouser::show()
{
    cout << " BigTrouser " << endl;
    Finery::show();
}

main.cpp

#include <iostream>
#include "tshirts.h"
#include "bigtrouser.h"
#include "person.h"

using namespace std;

int main()
{
    cout << "Hello World!" << endl;

    Person *person = new Person("kevin");

    TShirts *tshirt = new TShirts();
    BigTrouser *bigT = new BigTrouser();

    tshirt->Decorate(person);
    bigT->Decorate(tshirt);
    bigT->show();

    return 0;
}