The concreteFilter serves as a base class for all filters that actually implement a filtering process. At the moment this includes all filters except
concreteFilter作为一个过滤器过滤过程,真正实现基类。目前,这包括所有除过滤器
类的对象----------Objects from the Class----------
Objects of this class should never be created directly. It serves only as a point of inheritance.
这个类的对象不应该被直接创建。它只是作为一个点的继承。
插槽----------Slots----------
filterId: The identifier associated with this class.
filterId:类与此相关的标识符。