On 14/12/2012 09:41, Peter Levart wrote:
On 12/14/2012 10:06 AM, Peter Levart wrote:
On 12/14/2012 07:21 AM, David Holmes wrote:
Paul,
On 14/12/2012 9:46 AM, Paul Benedict wrote:
Lance,
Good questions. Someone with authority will surely answer, but here's
my armchair opinion...
If the Javadoc is to specify how the default method executes, than
that would naturally infer all default implementations must have a
stated contract. You can't document the default execution behavior in
the public API and then let a provider switch the behavior. The two go
hand-in-hand, imo.
I couldn't really make sense of that. :) The method has a contract.
The "default implementation" has to honor that contract. The question
is whether how the "default implementation" honors the method
contract is required to be part of a second contract.
I hope that made sense :)
I think that the answer is obvious. A default method provider has only
as much freedom in choosing the implementation of the default method
that particular implementation differences among various providers are
not observable by the "sane" usage of the API. The only soft aspect
might be performance. Any other behavioural difference should not be
allowed. Otherwise there will be in-compatibilities among platform
providers.
For example, the default Iterator.remove() is implemented in Oracle's
JDK as always throwing UnsupportedOperationException. The TCK should
test for that and the Javadoc should specify that.
Ok, I admit that in this particular case and other similar cases (where
the default method does nothing useful), the specification could
alternatively specify: "The default method behaviour is unspecified and
useless. Don't call that method or make sure it is always overridden if
you call it" - the TCK in that case doesn't test the behaviour of such
And forever more ever concrete Iterator implementation, that does not
support remove, will have to implement the remove method to throw UOE. I
think this is a big loss.
-Chris.
method.
Peter
As Joe said, default interface methods are no different than any other
overridable methods. They have a contract and behaviour. The behaviour
can be changed (overriden) within constraints defined by contract, but
the behaviour itself should also be specified and followed by
different providers.
Just my 2 cents.
Regards, Peter
David
-----
Paul
On Thu, Dec 13, 2012 at 5:30 PM, Lance Andersen - Oracle
<lance.ander...@oracle.com> wrote:
On Dec 13, 2012, at 6:16 PM, Leonid Arbuzov wrote:
Good point, Joe.
Those extra assertions for default methods can be checked
by regular API tests separately from signature tests.
I am not clear on this. See the message attached from David which
ask a similar question (from the attached email):
-------------------
2. It is not obvious to me that the JDK's choice for a default
implementation has to be _the_ only possible implementation choice.
In many/most cases there will be a very obvious choice, but that
doesn't mean that all suppliers of OpenJDK classes have to be
locked in to that choice.
-------------------
If everyone needs to implement the same default implementation then
great the JCK/TCK can test it and IMHO we should have a javadoc tag
for this.
If everyone is free to choose what the default behavior is, then we
cannot test it.
So has there been a decision WRT the requirements for default methods?
Best
Lance
Thanks,
-leonid
On 12/13/2012 1:05 PM, Joe Darcy wrote:
Hello,
As with concrete methods on abstract classes, I would expect the
specifications of the default methods to often contain text akin
to "This default implementation does x, y, and z" since if the
method is to be called by subtypes, the self-use patterns in the
default method need to be known.
Cheers,
-Joe
On 12/13/2012 11:24 AM, Leonid Arbouzov wrote:
Hello Lance,
My understanding would be that the signature test
should check that interface method is marked as default method
but do not track the code in its default body
(assuming that the body is not a part of a spec - API javadoc).
(I've confirmed that with the signature test developer)
Thanks,
-leonid
On 12/6/2012 9:01 AM, Lance Andersen - Oracle wrote:
Folks,
Will the signatures for interfaces that are recorded by the
TCKs for interfaces record the fact that a method includes a
default method? or will it just record the method definition?
I am assuming it will, but I know there has been discussion
that a implementor could choose a different default
implementation on one of the recent threads that was up for
review.
I am still trying to understand what our guidelines are, if any
for documenting the behavior of the supplied default methods
given the javadocs are part of the specification for many APIs
(and in some case the only spec).
Best
Lance
Lance Andersen| Principal Member of Technical Staff |
+1.781.442.2037
Oracle Java Engineering
1 Network Drive
Burlington, MA 01803
lance.ander...@oracle.com
Lance Andersen| Principal Member of Technical Staff | +1.781.442.2037
Oracle Java Engineering
1 Network Drive
Burlington, MA 01803
lance.ander...@oracle.com
