Java：模板类型的递归定义

Question

看看这个类的声明：

public abstract class AbstractTargetBuilder<T extends AbstractTargetBuilder<T, S>, S extends Target> {
...
}

类型T被定义为AbstractTargetBuilder<T,S>的子类型。这种模式有什么用？

此代码属于Spotlight库： https://github.com/TakuSemba/Spotlight/blob/master/spotlight/src/main/java/com/takusemba/spotlight/target/AbstractTargetBuilder.java