lesson_3

README.md

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+Паттерн "Декоратор" динамически наделяет объект новыми возможностями и является гибкой альтернативой субклассированию в области расширения функциональности (поведения).
+
+Типы декораторов соответствуют типам декорируемых компонентов (соответствие достигается посредством наследования или реализации интерфейса). Декораторы изменяют поведение компонентов, добавляя новую функциональность до и (или) после (или даже вместо) вызовов методов компонентов. Компонент может декорироваться любым количеством декораторов. Декораторы обычно прозрачны для клиентов компонента (если клиентский код не зависит от конкретного типа компонента).
+
+*Принцип:*
+- Согласно принципу открытости/закрытости системы должны проектироваться так, чтобы их закрытые компоненты были изолированы от новых расширений.

lesson_3/Beverage.hpp

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+/*
+ * Beverage.hpp
+ *
+ *  Created on: 1 нояб. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include <string>
+
+class Beverage
+{
+public:
+    enum Size {TALL, GRANDE, VENTI};
+    Size size = Size::TALL;
+    std::string description = "Unknown Beverage";
+
+    virtual std::string getDescription() const
+    {
+        return description;
+    }
+
+    virtual void setSize(Size size)
+    {
+        this->size = size;
+    }
+
+    virtual Size getSize() const
+    {
+        return size;
+    }
+
+    virtual double cost() const = 0;
+
+    virtual ~Beverage() {}
+};

lesson_3/CondimentDecorator.hpp

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+/*
+ * CondimentDecorator.hpp
+ *
+ *  Created on: 1 нояб. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include "Beverage.hpp"
+#include <iostream>
+
+class CondimentDecorator: public Beverage
+{
+public:
+    Beverage *beverage;
+
+    CondimentDecorator(Beverage *beverage): beverage(beverage) {}
+
+    virtual std::string getDescription() const = 0;
+
+    ~CondimentDecorator()
+    {
+        delete beverage;
+    }
+};

lesson_3/DarkRoast.hpp

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+/*
+ * DarkRoast.hpp
+ *
+ *  Created on: 1 нояб. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include "Beverage.hpp"
+
+class DarkRoast: public Beverage
+{
+public:
+    DarkRoast()
+    {
+        description = "Dark Roast";
+    }
+
+    double cost() const override
+    {
+        return 0.99;
+    }
+};

lesson_3/Decaf.hpp

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+/*
+ * Decaf.hpp
+ *
+ *  Created on: 1 нояб. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include "Beverage.hpp"
+
+class Decaf: public Beverage
+{
+public:
+    Decaf()
+    {
+        description = "Decaf";
+    }
+
+    double cost() const override
+    {
+        return 1.05;
+    }
+};

lesson_3/Espresso.hpp

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+/*
+ * Espresso.hpp
+ *
+ *  Created on: 1 нояб. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include "Beverage.hpp"
+
+class Espresso: public Beverage
+{
+public:
+    Espresso()
+    {
+        description = "Espresso";
+    }
+
+    double cost() const override
+    {
+        return 1.99;
+    }
+};

lesson_3/HouseBlend.hpp

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+/*
+ * HouseBlend.hpp
+ *
+ *  Created on: 1 нояб. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include "Beverage.hpp"
+
+class HouseBlend: public Beverage
+{
+public:
+    HouseBlend()
+    {
+        description = "House Blend";
+    }
+
+    double cost() const override
+    {
+        return 0.89;
+    }
+};

lesson_3/Milk.hpp

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+/*
+ * Milk.hpp
+ *
+ *  Created on: 1 нояб. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include "CondimentDecorator.hpp"
+
+class Milk: public CondimentDecorator
+{
+public:
+    Milk(Beverage *beverage): CondimentDecorator(beverage) {}
+
+    std::string getDescription() const override
+    {
+        return beverage->getDescription() + ", Milk";
+    }
+
+    double cost() const override
+    {
+        return 0.10 + beverage->cost();
+    }
+};

lesson_3/Mocha.hpp

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+/*
+ * Mocha.hpp
+ *
+ *  Created on: 1 нояб. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include "CondimentDecorator.hpp"
+
+class Mocha: public CondimentDecorator
+{
+public:
+    Mocha(Beverage *beverage): CondimentDecorator(beverage) {}
+
+    std::string getDescription() const override
+    {
+        return beverage->getDescription() + ", Mocha";
+    }
+
+    double cost() const override
+    {
+        return 0.20 + beverage->cost();
+    }
+};

lesson_3/Soy.hpp

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+/*
+ * Soy.hpp
+ *
+ *  Created on: 1 нояб. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include "CondimentDecorator.hpp"
+
+class Soy: public CondimentDecorator
+{
+public:
+    Soy(Beverage *beverage) : CondimentDecorator(beverage) {}
+
+    std::string getDescription() const override
+    {
+        return beverage->getDescription() + ", Soy";
+    }
+
+    double cost() const override
+    {
+        double cost = 0.15 + beverage->cost();
+
+        if (beverage->getSize() == Size::TALL)
+        {
+            cost += .10;
+        }
+        else if (beverage->getSize() == Size::GRANDE)
+        {
+            cost += .15;
+        }
+        else if (beverage->getSize() == Size::VENTI)
+        {
+            cost += .20;
+        }
+
+        return cost;
+    }
+};

lesson_3/Whip.hpp

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+/*
+ * Whip.hpp
+ *
+ *  Created on: 1 нояб. 2021 г.
+ *      Author: alexander
+ */
+
+#pragma once
+
+#include "CondimentDecorator.hpp"
+
+class Whip: public CondimentDecorator
+{
+public:
+    Whip(Beverage *beverage): CondimentDecorator(beverage) {}
+
+    std::string getDescription() const override
+    {
+        return beverage->getDescription() + ", Whip";
+    }
+
+    double cost() const override
+    {
+        return 0.10 + beverage->cost();
+    }
+};

lesson_3/main.cpp

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+/*
+ * main.cpp
+ *
+ *  Created on: 1 нояб. 2021 г.
+ *      Author: alexander
+ */
+
+#include "Beverage.hpp"
+#include "Espresso.hpp"
+#include "DarkRoast.hpp"
+#include "Mocha.hpp"
+#include "Whip.hpp"
+#include "HouseBlend.hpp"
+#include "Soy.hpp"
+#include "Decaf.hpp"
+#include "Milk.hpp"
+#include <iostream>
+
+int main()
+{
+    Beverage *beverage = new Espresso();
+    std::cout << beverage->getDescription() << " $" << beverage->cost() << std::endl;
+
+    Beverage *beverage2 = new DarkRoast();
+    beverage2 = new Mocha(beverage2);
+    beverage2 = new Mocha(beverage2);
+    beverage2 = new Whip(beverage2);
+    std::cout << beverage2->getDescription() << " $" << beverage2->cost() << std::endl;
+
+    Beverage *beverage3 = new HouseBlend();
+    beverage3->setSize(Beverage::Size::VENTI);
+    beverage3 = new Soy(beverage3);
+    beverage3 = new Mocha(beverage3);
+    beverage3 = new Whip(beverage3);
+    std::cout << beverage3->getDescription() << " $" << beverage3->cost() << std::endl;
+
+    Beverage *beverage4 = new Decaf();
+    beverage4 = new Mocha(beverage4);
+    beverage4 = new Mocha(beverage4);
+    beverage4 = new Milk(beverage4);
+    std::cout << beverage4->getDescription() << " $" << beverage4->cost() << std::endl;
+
+    delete beverage;
+    delete beverage2;
+    delete beverage3;
+
+    return 0;
+}