模板方法

模版方法：通过实现类扩展的方法来完成业务逻辑。

1. 创建实例的模板

package designpattern;

public abstract class GenericWithCreate<T> {

    final T element;
    GenericWithCreate() {
        element = create();
    }

    abstract T create();
}

class X {}

2. X类创建的具体实现

package designpattern;

public class Creator extends GenericWithCreate<X> {

    @Override
    X create() {
        return new X();
    }

    void f() {
        System.out.println(element.getClass().getName());
    }
}

3. 测试代码

package designpattern;

public class CreatorGeneric {

    public static void main(String[] args) {
        Creator c = new Creator();
        c.f();
    }

}

//output
designpattern.X