A potential disadvantage of factory methods is that clients might have to
subclass the Creator class just to create a particular ConcreteProduct object.
Subclassing is fine when the client has to subclass the Creator class anyway,
but otherwise the client now must deal with another point of evolution.
工厂方法的一个潜在缺点在于客户可能仅仅为了创建一个特定的ConcreteProduct, 就不得不创建Creator子类。当Creator子类不必需时,客户现在必然要处理类演化的其他方面;但当客户无论如何必须创建Creator子类时,创建子类也是可行的。
前半句好理解,后面半句,无论是英文版还是翻译,都不懂什么意思,求解释:
(1)Creator在工厂方法中难道可以不要吗?为何在这里提到必需和不必需的情况?
(2)类的演化的其他方面是什么?怎么说的感觉跟有关部门一样神秘!