Question

I have a Gene class that keeps track of genes. Gene has a method for calculating the distance between two genes. Are there any reasons to make it static?

Which is better?

public static int geneDistance(Gene g0, Gene g1)

or

public int geneDistance(Gene other)

Arguments for/against making it static? I understand what it means for a member to be static, I’m just interested in its implications for maximum cleanliness/efficiency/etc.

I repeat the same pattern for returning trimmed versions of two genes, finding matches between genes, finding matches between animals (which contain collections of genes), etc.

Answer 1

Instance, not static

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For this case I think the second choice is clearly better. If you think about it, any method could be implemented as static if you are willing to pass the object to it, this only seems to be a special case because the other parameter is also an instance.

Therefore, our search for symmetry and abstraction is slightly offended by having to choose between the two instance objects for the dot operator. But if you look at .method as . then operator, it isn’t really a problem.

Plus, the only way to do functional-style chaining is with an attribute, i.e., instance method. You probably want thing.up.down.parent.next.distance(x) to work.