Re: Collection, enum or something else?
Lew wrote:
Mark Space wrote:
Todd wrote:
Hello,
Suppose one has a class called Shrub that has well-defined behavior
and state. Now suppose one wants to create references (pardon the
loose wording, hopefully this will become clear shortly) to shrubs of
the world by continent.
I think you might be over complicating things. What's the matter with:
public class Shrub
{
String name;
String continent;
or
Continent continent;
This type of reference is commonplace in ORM layers like Hibernate and
OpenJPA.
It's also a good example of avoiding primitive obsession.
Or something. I think you're over complicating things by using an
enum, for sure. There are probably not a finite list of shrubs that
you want to enumerate, and more will be discovered. My primary clue
here was that just a Shrub object was good enough inside your enum.
If it is, then you don't need the enum or a subclasse. "Prefer
composition to inheritance." And that's what I did. Rather than
subclass or make an enum, I just composed Shrug so that it had the
property needed.
I guess an enum for the continents makes sense though. Unlikely that
any new continents will come along.
Don't continents have attributes? Names, populaces, nations,
topographies, relationships to each other?
enum constants can have attributes too. Although, I do think that a
Java "enum" proper is a good fit for this.
This is not a challenge to Mark Space's excellent example, but an
illustration of how very amenable it is to enhancement, This sort of
functionality iteration is the heart of several very effective
development styles. Evolution is straightforward when you start with a
clean, robust design. Incremental advances are key, too - My suggestion
focused on only one detail, changing the type of 'continent'. I won't
even think about linking 'name' to Taxonomy until I'm sure Continent is
right.
After-the-fact linkups like this are harder with inheritance models than
with composition models.
--
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Legenda II.