How to name factory like methods?

Question

I guess that most factory-like methods start with create. But why are they called \"create\"? Why not \"make\", \"produce\", \"build\", \"generate\" or something el

Answer 1

I'd point out that I've seen all of the verbs but produce in use in some library or other, so I wouldn't call create being an universal convention.

Now, create does sound better to me, evokes the precise meaning of the action.

So yes, it is a matter of (literary) taste.

Answer 2

Joshua Bloch in "Effective Java" suggests the following naming conventions

valueOf — Returns an instance that has, loosely speaking, the same value as its parameters. Such static factories are effectively type-conversion methods.

of — A concise alternative to valueOf, popularized by EnumSet (Item 32).

getInstance — Returns an instance that is described by the parameters but cannot be said to have the same value. In the case of a singleton, getInstance takes no parameters and returns the sole instance.

newInstance — Like getInstance, except that newInstance guarantees that each instance returned is distinct from all others.

getType — Like getInstance, but used when the factory method is in a different class. Type indicates the type of object returned by the factory method.

newType — Like newInstance, but used when the factory method is in a different class. Type indicates the type of object returned by the factory method.

Answer 3

"Create" and "make" are short, reasonably evocative, and not tied to other patterns in naming that I can think of. I've also seen both quite frequently and suspect they may be "de facto standards". I'd choose one and use it consistently at least within a project. (Looking at my own current project, I seem to use "make". I hope I'm consistent...)

Avoid "build" because it fits better with the Builder pattern and avoid "produce" because it evokes Producer/Consumer.

To really continue the metaphor of the "Factory" name for the pattern, I'd be tempted by "manufacture", but that's too long a word.

Answer 4

Partly convention, partly semantics.

Factory methods (signalled by the traditional create) should invoke appropriate constructors. If I saw buildURI, I would assume that it involved some computation, or assembly from parts (and I would not think there was a factory involved). The first thing that I thought when I saw generateURI is making something random, like a new personalized download link. They are not all the same, different words evoke different meanings; but most of them are not conventionalised.

Answer 5

Wanted to add a couple of points I don't see in other answers.

1. Although traditionally 'Factory' means 'creates objects', I like to think of it more broadly as 'returns me an object that behaves as I expect'. I shouldn't always have to know whether it's a brand new object, in fact I might not care. So in suitable cases you might avoid a 'Create...' name, even if that's how you're implementing it right now.

2. Guava is a good repository of factory naming ideas. It is popularising a nice DSL style. examples:

   Lists.newArrayListWithCapacity(100);
   ImmutableList.of("Hello", "World");