Re: state of an object in setUp() of junit TestCase
On 10/30/2010 12:45 PM, markspace wrote:
On 10/30/2010 9:39 AM, Stanimir Stamenkov wrote:
... Relying on such default values, however, is generally
considered bad programming style.
I don't completely agree with the given statement, but then I can't come
up with arguments on any side. What do you think about it?
Lew's comment that an explicit initialization requires a second,
redundant and useless initialization is enough to counter Oracle's
statement.
I'd say precisely the opposite. The default values are 100% guaranteed
and deterministic, there's no reason not to rely on them, and it's
certainly not bad style. I'm sorry for whoever wrote that line in the
tutorial but I think they went off some place unknown to most
professionals.
This is a controversy. I sit somewhat in the middle - if the default initial
value carries algorithmic significance, e.g.,
private boolean initialized = false;
then the redundant initialization emphasizes that the algorithm depends on
that value, but if the usage pattern requires a call to some 'init()' or
'setup()' or 'prepare()' or such that sets the value before it's read, or if
otherwise there's nothing truly emphatic about the default value, then one
should follow markspace's advice.
private boolean initialized;
IME a need to emphasize initialization of member references to 'null' is rarer
than a need to emphasize initialization of primitives to their "zero-like" values.
Mind you, it is still completely unnecessary to initialize a member twice to
its default value just to make a point that a comment would make just as well,
private boolean initialized; // must start out 'false'
perhaps augmented with an invariant if you're anal retentive.
/** Constructor. */
public Foo()
{
// ... do all those lovely constructor things
assert ! initialized;
}
Now that makes the point and the JVM can help enforce it.
--
Lew
Anal expressive: like anal retentive but beneficially.
The anal expressive personality pays close attention to detail but is relaxed
about it.