Java实现(02)——抽象工厂模式(Abstract Factory Pattern)

抽象工厂模式建立父类的工厂，通过父类创建子类工厂，通过子类工厂创建对象。

本例中有两个接口Shape和Color，通过两个子工厂，ShapeFactory和ColorFactory，父类工厂FactoryProducer生成相应的子类工厂。

public interface Shape {
void draw();
}

public class Square implements Shape{

@Override
public void draw() {
System.out.println("Inside Square::draw() method.");
}
}

public class Rectangle implements Shape {

@Override
public void draw() {
System.out.println("Inside Rectangle::draw() method.");
}
}

public class Circle implements Shape {

@Override
public void draw() {
System.out.println("Inside Circle::draw() method.");
}
}

public interface Color {
void fill();
}

public class Blue implements Color {

@Override
public void fill() {
System.out.println("Inside Blue::fill() method.");
}
}

public class Red implements Color {
@Override
public void fill() {
System.out.println("Inside Red::fill() method.");
}
}

public class Green implements Color {

@Override
public void fill() {
System.out.println("Inside Green::fill() method.");
}
}

public abstract class AbstractFactory {
abstract Color getColor(String color);
abstract Shape getShape(String shapeType);
}

public class ColorFactory extends AbstractFactory {
@Override
Color getColor(String color) {
if (color == null)
return null;
if (color.equalsIgnoreCase("RED"))
return new Red();
else if (color.equalsIgnoreCase("GREEN"))
return new Green();
else if (color.equalsIgnoreCase("BLUE"))
return new Blue();
return null;
}

@Override
Shape getShape(String shapeType) {
return null;
}
}

public class ShapeFactory extends AbstractFactory {
@Override
Color getColor(String color) {
return null;
}

@Override
public Shape getShape(String shapeType) {
if (shapeType == null) {
return null;
}
if (shapeType.equalsIgnoreCase("CIRCLE"))
return new Circle();
else if (shapeType.equalsIgnoreCase("RECTANGLE"))
return new Rectangle();
else if (shapeType.equalsIgnoreCase("SQUARE"))
return new Square();
return null;
}
}

public class FactoryProducer {
public static AbstractFactory getFactory(String choice) {
if (choice.equalsIgnoreCase("SHAPE"))
return new ShapeFactory();
else if (choice.equalsIgnoreCase("COLOR"))
return new ColorFactory();
return null;
}
}

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

AbstractFactory shapeFactory = FactoryProducer.getFactory("SHAPE");
Shape shape1 = shapeFactory.getShape("RECTANGLE");
shape1.draw();
Shape shape2 = shapeFactory.getShape("CIRCLE");
shape2.draw();

AbstractFactory colorFactory = FactoryProducer.getFactory("COLOR");
Color red = colorFactory.getColor("RED");
red.fill();
}
}

输出：

Inside Rectangle::draw() method.
Inside Circle::draw() method.
Inside Red::fill() method.