Fragile Base Class
The fragile base class problem is a fundamental architectural problem of object-oriented programming systems where base classes (superclasses) are considered "fragile" because seemingly safe modifications to a base class, when inherited by the derived classes, may cause the derived classes to malfunction. The programmer cannot determine whether a base class change is safe simply by examining in isolation the methods of the base class.
One possible solution is to make instance variables private to their defining class and force subclasses to use accessors to modify superclass states. A language could also make it so that subclasses can control which inherited methods are exposed publicly. These changes prevent subclasses from relying on implementation details of superclasses and allow subclasses to expose only those superclass methods that are applicable to themselves.
Another alternative solution could be to have an interface instead of superclass.
Read more about Fragile Base Class: Solutions
Famous quotes containing the words fragile, base and/or class:
“At twenty you have many desires which hide the truth, but beyond forty there are only real and fragile truths—your abilities and your failings.”
—Gérard Depardieu (b. 1948)
“Jealousy is both reasonable and belongs to reasonable men, while envy is base and belongs to the base, for the one makes himself get good things by jealousy, while the other does not allow his neighbour to have them through envy.”
—Aristotle (384–322 B.C.)
“God of justice, save the people
From the clash of race and creed,
From the strife of class and faction,
Make our nation free indeed;”
—William Pierson Merrill (1867–1954)