设计模式 - 工厂模式

工厂模式分为工厂方法和抽象工厂。

应用场景

实例化对象，代替new操作。如下图为工厂模式描述。

代码示例

public class ToyFactory {

    public static Toy produceToy(int toyName) throws ToyNameNotFoundException {
        switch (toyName) {
            case Toy.CHICKEN:
                return new ChickenToy();
            case Toy.DUCK:
                return new DuckToy();
            default:
                throw new ToyNameNotFoundException("Can't find toyname with " + toyName);

        }
    }

    public static void main(String[] args) {

        try {
            ToyFactory.produceToy(Toy.CHICKEN).saySomething();
            ToyFactory.produceToy(Toy.DUCK).saySomething();
            ToyFactory.produceToy(3).saySomething();
        } catch (ToyNameNotFoundException e) {
            e.printStackTrace();
        }
    }
}

class ToyNameNotFoundException extends Throwable {

    public ToyNameNotFoundException(String message) {
        super(message);
    }
}

interface Toy {

    public static int CHICKEN = 0x1;
    public static int DUCK = 0x2;

    // 定义Toy可以完成某些功能
    public void saySomething();
}

class DuckToy implements Toy {

    @Override
    public void saySomething() {
        System.out.println("呱呱");
    }
}

class ChickenToy implements Toy {

    @Override
    public void saySomething() {
        System.out.println("喔喔");
    }
}