设计模式--工厂模式

简单工厂模式

披萨项目：要方便披萨品种的扩展、要便于维护、要能运行时扩展

简单工厂模式的设计方案：定义一个实例化披萨对象的类，封装创建对象的代码

简单工厂模式：定义了一个创建对象的类，由这个类来封装实例化对象的行为

代码如下：

package com.java.jikexueyuan.pizzastore.simplefactory;

import com.java.jikexueyuan.pizzastore.pizza.CheesePizza;
import com.java.jikexueyuan.pizzastore.pizza.GreekPizza;
import com.java.jikexueyuan.pizzastore.pizza.PepperPizza;
import com.java.jikexueyuan.pizzastore.pizza.Pizza;

public class SimplePizzaFactory {

    public Pizza CreatePizza(String ordertype) {
        Pizza pizza = null;

        if (ordertype.equals("cheese")) {
            pizza = new CheesePizza();
        } else if (ordertype.equals("greek")) {
            pizza = new GreekPizza();
        } else if (ordertype.equals("pepper")) {
            pizza = new PepperPizza();
        }
        return pizza;

    }

}

package com.java.jikexueyuan.pizzastore.pizza;

public abstract class Pizza {
    protected String name;
    
    public abstract void prepare();
    public void bake()
    {
        System.out.println(name+" baking;");
    }
    public void cut()
    {
        System.out.println(name+" cutting;");
    }
    public void box()
    {
        System.out.println(name+" boxing;");
    }
    public void setname(String name)
    {
        this.name=name;
    }
}

package com.java.jikexueyuan.pizzastore.pizza;

public class CheesePizza extends Pizza {

    @Override
    public void prepare() {
        // TODO Auto-generated method stub
        super.setname("CheesePizza");
        
        System.out.println(name+" preparing;");
    }

}

package com.java.jikexueyuan.pizzastore.simplefactory;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import com.java.jikexueyuan.pizzastore.pizza.CheesePizza;
import com.java.jikexueyuan.pizzastore.pizza.GreekPizza;
import com.java.jikexueyuan.pizzastore.pizza.PepperPizza;
import com.java.jikexueyuan.pizzastore.pizza.Pizza;

public class OrderPizza {
    SimplePizzaFactory mSimplePizzaFactory;

    public OrderPizza(SimplePizzaFactory mSimplePizzaFactory) {

        setFactory(mSimplePizzaFactory);
    }

    public void setFactory(SimplePizzaFactory mSimplePizzaFactory) {
        Pizza pizza = null;
        String ordertype;

        this.mSimplePizzaFactory = mSimplePizzaFactory;

        do {
            ordertype = gettype();
            pizza = mSimplePizzaFactory.CreatePizza(ordertype);
            if (pizza != null) {
                pizza.prepare();
                pizza.bake();
                pizza.cut();
                pizza.box();
            }

        } while (true);

    }

    private String gettype() {
        try {
            BufferedReader strin = new BufferedReader(new InputStreamReader(
                    System.in));
            System.out.println("input pizza type:");
            String str = strin.readLine();

            return str;
        } catch (IOException e) {
            e.printStackTrace();
            return "";
        }
    }

}

工厂方法模式

披萨项目加盟店

工厂方法模式设计方案：将披萨项目里的披萨对象实例化功能抽象成抽象方法，在不同加盟店具体实现功能。

工厂方法模式：定义了一个创建对象的抽象方法，由子类决定要实例化的类。 工厂方法模式将对象的实例化推迟到子类

代码如下

package com.java.jikexueyuan.pizzastore.method;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import com.java.jikexueyuan.pizzastore.pizza.CheesePizza;
import com.java.jikexueyuan.pizzastore.pizza.ChinesePizza;
import com.java.jikexueyuan.pizzastore.pizza.GreekPizza;
import com.java.jikexueyuan.pizzastore.pizza.PepperPizza;
import com.java.jikexueyuan.pizzastore.pizza.Pizza;

public abstract class OrderPizza {

    public OrderPizza() {
        Pizza pizza = null;
        String ordertype;

        do {
            ordertype = gettype();
            pizza = createPizza(ordertype);

            pizza.prepare();
            pizza.bake();
            pizza.cut();
            pizza.box();
        } while (true);
    }

    abstract Pizza createPizza(String ordertype);

    private String gettype() {
        try {
            BufferedReader strin = new BufferedReader(new InputStreamReader(
                    System.in));
            System.out.println("input pizza type:");
            String str = strin.readLine();

            return str;
        } catch (IOException e) {
            e.printStackTrace();
            return "";
        }
    }

}

package com.java.jikexueyuan.pizzastore.method;

import com.java.jikexueyuan.pizzastore.pizza.CheesePizza;
import com.java.jikexueyuan.pizzastore.pizza.GreekPizza;
import com.java.jikexueyuan.pizzastore.pizza.NYCheesePizza;
import com.java.jikexueyuan.pizzastore.pizza.NYPepperPizza;
import com.java.jikexueyuan.pizzastore.pizza.PepperPizza;
import com.java.jikexueyuan.pizzastore.pizza.Pizza;

public class NYOrderPizza extends OrderPizza {

    @Override
    Pizza createPizza(String ordertype) {
        Pizza pizza = null;

        if (ordertype.equals("cheese")) {
            pizza = new NYCheesePizza();
        } else if (ordertype.equals("pepper")) {
            pizza = new NYPepperPizza();
        }
        return pizza;

    }

}

package com.java.jikexueyuan.pizzastore.method;

import com.java.jikexueyuan.pizzastore.pizza.CheesePizza;
import com.java.jikexueyuan.pizzastore.pizza.GreekPizza;
import com.java.jikexueyuan.pizzastore.pizza.LDCheesePizza;
import com.java.jikexueyuan.pizzastore.pizza.LDPepperPizza;
import com.java.jikexueyuan.pizzastore.pizza.PepperPizza;
import com.java.jikexueyuan.pizzastore.pizza.Pizza;

public class LDOrderPizza extends OrderPizza {

    @Override
    Pizza createPizza(String ordertype) {
        Pizza pizza = null;

        if (ordertype.equals("cheese")) {
            pizza = new LDCheesePizza();
        } else if (ordertype.equals("pepper")) {
            pizza = new LDPepperPizza();
        }
        return pizza;

    }

}

抽象工厂模式

抽象工厂模式：定义了一个接口用于创建相关或有依赖关系的对象族，而无需明确指定具体类

package com.java.jikexueyuan.pizzastore.absfactory;

import com.java.jikexueyuan.pizzastore.pizza.Pizza;

public interface AbsFactory {
    public Pizza CreatePizza(String ordertype) ;
}

package com.java.jikexueyuan.pizzastore.absfactory;

import com.java.jikexueyuan.pizzastore.pizza.LDCheesePizza;
import com.java.jikexueyuan.pizzastore.pizza.LDPepperPizza;
import com.java.jikexueyuan.pizzastore.pizza.Pizza;

public class LDFactory implements AbsFactory {
    @Override
    public Pizza CreatePizza(String ordertype) {
        Pizza pizza = null;

        if (ordertype.equals("cheese")) {
            pizza = new LDCheesePizza();
        } else if (ordertype.equals("pepper")) {
            pizza = new LDPepperPizza();
        }
        return pizza;
    }
}

package com.java.jikexueyuan.pizzastore.absfactory;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import com.java.jikexueyuan.pizzastore.pizza.CheesePizza;
import com.java.jikexueyuan.pizzastore.pizza.GreekPizza;
import com.java.jikexueyuan.pizzastore.pizza.PepperPizza;
import com.java.jikexueyuan.pizzastore.pizza.Pizza;

public class OrderPizza {
    AbsFactory mFactory;

    public OrderPizza(AbsFactory mFactory) {

        setFactory(mFactory);
    }

    public void setFactory(AbsFactory mFactory) {
        Pizza pizza = null;
        String ordertype;

        this.mFactory = mFactory;

        do {
            ordertype = gettype();
            pizza = mFactory.CreatePizza(ordertype);
            if (pizza != null) {
                pizza.prepare();
                pizza.bake();
                pizza.cut();
                pizza.box();
            }

        } while (true);

    }

    private String gettype() {
        try {
            BufferedReader strin = new BufferedReader(new InputStreamReader(
                    System.in));
            System.out.println("input pizza type:");
            String str = strin.readLine();

            return str;
        } catch (IOException e) {
            e.printStackTrace();
            return "";
        }
    }

}

依赖抽象原则

　　变量不要持有具体类的引用

　　不要让类继承自具体类，要继承自抽象类或接口　

　　不要覆盖基类中已实现的方法