抽象工厂
抽象工厂模式，先将所有工厂需要的操作抽象出来形成一个抽象工厂类（AbstractFactory）。
所以工厂类都继承AbstractFactory。
后续通过FactoryProduct创建工厂类，返回的类型为AbstractFactory，（所有工厂类都是抽象工厂的子类）
最后通过具体的工厂类创建对象。
Shape接口
public interface Shape { public void draw(); }
Shape接口实现类：
Circle.java
public class Circle implements Shape{ @Override public void draw() { System.out.println("draw cilcle"); } }
Color接口
public interface Color { public void fill(); }
Color接口的实现类
Red.java
public class Red implements Color{ @Override public void fill() { System.out.println("fill red"); } }
以上是工厂模式。
AbstractFactory
定义了获取Shape和获取Color的方法，（将所有工厂中的创建操作抽取出来）
public abstract class AbstractFactory { public abstract Shape getShape(String shape); public abstract Color getColor(String color); }
ShapeFactory 继承AbastractFactory （具体的工厂类继承抽象工厂）
public class ShapeFactory extends AbstractFactory{ @Override public Shape getShape(String shape) { if("circle".equals(shape)) { return new Circle(); } return null; } @Override public Color getColor(String color) { return null; } }
ShapeFactory根据String shape实施化对应对象。
ColorFactroy 继承AbastractFactory
public class ColorFactory extends AbstractFactory{ @Override public Shape getShape(String shape) { return null; } @Override public Color getColor(String color) { if("red".equals(color)) { return new Red(); } return null; } }
根据color实例化对应对象。
FactoryProducer 根据factory获取对应的工厂，后续通过工厂实例化对应对象。（FactoryProduct用于创建工厂类）
public class FactroyProducer { public static AbstractFactory getFactory(String factory) { if("shape".equals(factory)) { return new ShapeFactory(); }else if("color".equals(factory)) { return new ColorFactory(); } return null; } }
Main
public class Main { public static void main(String[] args) { AbstractFactory shapeFactory = FactroyProducer.getFactory("shape"); //获取shape工厂 Shape circle = shapeFactory.getShape("circle"); //使用shape工厂实例化circle circle.draw(); AbstractFactory colorFactory = FactroyProducer.getFactory("color"); //获取color工厂 Color red = colorFactory.getColor("red"); //获取颜色 red.fill(); } }
运行结果：
draw cilcle
fill red
上述获取工厂，以及从工厂过去对象都是通过字符串进行判断，而且采用if else后续分支过多可读写不强。
可采用枚举类型配合switch语句扩展。
ShapeEnum
enum ShapeEnum { CIRCLE,RECTANGLE,SQUARE }
ColorEnum
public enum ColorEnum { RED,BULE }
FactoryEnum
public enum FactoryEnum { SHAPE,COLOR }
ShapeFactory
public class ShapeFactory extends AbstractFactory{ @Override public Shape getShape(ShapeEnum shape) { switch (shape) { case CIRCLE: return new Circle(); default: //没有找到类则抛出异常 try { throw new ClassNotFoundException(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return null; } @Override public Color getColor(ColorEnum color) { return null; } }
ColorFactory
public class ColorFactory extends AbstractFactory{ @Override public Shape getShape(ShapeEnum shape) { return null; } @Override public Color getColor(ColorEnum color) { switch(color) { case RED: return new Red(); default : try { throw new ClassNotFoundException(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return null; } }
FactoryProduct
public class FactroyProducer { public static AbstractFactory getFactory(FactoryEnum factory) { switch (factory) { case SHAPE: return new ShapeFactory(); case COLOR: return new ColorFactory(); default: try { throw new ClassNotFoundException(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return null; } }
Main
public class Main { public static void main(String[] args) { AbstractFactory shapeFactory = FactroyProducer.getFactory(FactoryEnum.SHAPE); Shape circle = shapeFactory.getShape(ShapeEnum.CIRCLE); circle.draw(); AbstractFactory colorFactory = FactroyProducer.getFactory(FactoryEnum.COLOR); Color red = colorFactory.getColor(ColorEnum.RED); red.fill(); } }
运行结果：
draw cilcle
fill red
参考资料：
http://www.runoob.com/design-pattern/abstract-factory-pattern.html
原文：https://www.cnblogs.com/huang-changfan/p/10710498.html