I have a question concerning holding common code in a base class and having the derived class call it, even though the derived class's trigger method has been dispatched from the base. So, base->derived->base type call stack.
Is the following look OK, or does it smell? I have numbered the flow steps...
public abstract class LayerSuperType
{
public void DoSomething() // 1) Initial call from client
{
ImplementThis(); // 2) Polymorphic dispatch
}
protected abstract void ImplementThis();
protected void SomeCommonMethodToSaveOnDuplication(string key) // 4)
{
Configuration config = GetConfiguration(key);
}
}
public class DerivedOne : LayerSuperType
{
protected virtual void ImplementThis() // 2)
{
SomeCommonMethodToSaveOnDuplication("whatever"); // 3) Call method in base
}
}
public class DerivedTwo : LayerSuperType
{
protected virtual void ImplementThis() // 2)
{
SomeCommonMethodToSaveOnDuplication("something else"); // 3) Call method in base
}
}
Looks like a very simplified Template Method Pattern where your sub-classes do some specific kinds of things at the right points in the implementation of your algorithm, but the overall flow is directed by a method on the base class. You've also provided some services to your sub-classes in the form of base class methods; that's ok too as long as you're good as far as SOLID goes.