类别：

Creational Pattern

问题/动机：

如何创建一套父类的问题

情形一：混淆，且不能察觉

    // 下面这个方法本来是要建造一辆宝马汽车，但是因为零部件太多，粗心大意误用了奔驰的零件。
    public Car createBMWCar(){
        Part1 p1 = new com.bmw.Part1();
        [...]
        Part10000 p10000 = new com.benz.Part10000();
        [...]
    }

情形二：可完全避免混淆问题

import com.bmw.BMWFactory;
    [...]
    // 下面使用的是一个工厂，因为只引用了宝马工厂，所以不能可能出现奔驰的零件。
    public Car createBMWCar(){
        Part1 p1 = BMWFactory.getPart1();
        [...]
        Part10000 p10000 = BMWFactory.getPart10000();
        [...]
    }

方案：

https://en.wikipedia.org/wiki/Abstract_factory_pattern

示例：

public class AbstractFactoryPatternDemo {
    public static void main(String[] args) {

        GUIFactory guiFactory;
        Box box;
        Button button;

        // situation one:
        guiFactory = new WinFactory();
        box = guiFactory.createBox();
        box.paint();
        button = guiFactory.createButton();
        button.paint();

        // situation two:
        guiFactory = new MacOSFactory();
        box = guiFactory.createBox();
        box.paint();
        button = guiFactory.createButton();
        button.paint();
    }

}

// GUI Graphical User Interface
// https://docs.unity3d.com/ScriptReference/GUI.Button.html
// https://docs.unity3d.com/ScriptReference/GUI.Box.html

interface Button {
    void paint();
}

interface Box {
    void paint();
}

interface GUIFactory {
    public Button createButton();

    public Box createBox();
}

class WinFactory implements GUIFactory {
    @Override
    public Button createButton() {
        return new WinButton();
    }

    @Override
    public Box createBox() {
        return new WinBox();
    }
}

class MacOSFactory implements GUIFactory {
    @Override
    public Button createButton() {
        return new MacOSButton();
    }

    @Override
    public Box createBox() {
        return new MacOSBox();
    }
}

class WinButton implements Button {
    @Override
    public void paint() {
        System.out.println("WinButton");
    }
}

class MacOSButton implements Button {
    @Override
    public void paint() {
        System.out.println("macOS button");
    }
}

class WinBox implements Box {
    @Override
    public void paint() {
        System.out.println("WinBox");
    }
}

class MacOSBox implements Box {
    @Override
    public void paint() {
        System.out.println("macOS box");
    }
}