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Posted to woden-dev@ws.apache.org by "John Kaputin (gmail)" <ja...@gmail.com> on 2008/08/20 08:16:06 UTC
Re: equals method (was: Re: Questions about tests)
I have made the changes discussed in this thread in the woden209 branch and
would like those interested to review the changes prior to merging them into
trunk.
The WSDLComponent.equals method is deprecated and replaced with
WSLDComponent.isEquivalentTo. So far I have just replaced the existing
references to the equals method with calls to isEquivalentTo. There is
still further implementation of equivalence checking to be done for some of
the components (i.e. more implementations of isEquivalentTo are required).
regards,
John.
On Tue, Jul 8, 2008 at 11:57 PM, Lawrence Mandel <lm...@ca.ibm.com> wrote:
> +1
>
> We discussed this issue on today's Woden status call. (As a reminder, the
> call is open to all. Details can be found at [1].) John will implement the
> isEquivalentTo solution in a branch. We can then review the branch, see if
> revisions or another approach is required.
>
> [1] http://ws.apache.org/woden/dev/index.html#Weekly+Status+Call
>
> Lawrence
>
>
>
>
> From:
> "John Kaputin (gmail)" <ja...@gmail.com>
> To:
> woden-dev@ws.apache.org
> Date:
> 07/08/2008 08:06 AM
> Subject:
> Re: equals method (was: Re: Questions about tests)
>
>
>
> How about I assign JIRA Woden-209 (which is about equivalence) to myself
> and implement a solution based on isEquivalentTo() and update the tests as
> necessary? I can work in a branch rather than trunk, so we can review it
> before committing to trunk.
>
> John.
>
> On Tue, Jul 8, 2008 at 4:52 PM, Jeremy Hughes <hu...@apache.org> wrote:
> Arthur, I'm a bit confused. In a previous email in this thread you said:
>
> "I suggest using equals() to mean element equality"
>
> but below you're saying:
>
> "In general, it does not make sense to test two elements for equivalence."
>
> In any case, I'm starting to come round to the 'isEquivalentTo()' idea
> primarily because my proposal has a 'usability flaw'. If we were to
> implement component model equivalence in the equals() method of the
> org.apache.woden.internal.wsdl20.*Impl classes then this code does
> something unexpected:
>
> WSDLFactory factory = WSDLFactory.newInstance();
> descElem1 = factory.newDescription();
> descElem2 = factory.newDescription();
> // because the Impl class implements both Description and
> // DescriptionElement and there can only be one Object
> equals(Object)
> // method, if we decide to implement it as comparing at the
> component
> // model level then the following line of code does something
> unexpected
> // (compares at the component model not the element model)
> if (descElem1.equals(descElem2)) .......
>
> If what John summarizes your position to be [1] is correct then I'm +1
> for that too.
>
> [1] http://markmail.org/message/iskbhuoseuxxcqsl
>
> Regards,
> Jeremy
>
> 2008/7/8 Arthur Ryman <ar...@gmail.com>:
> > Sagara,
> >
> > Equivalence is only defined for components in the WSDL 2.0 spec. In
> > general, it does not make sense to test two elements for equivalence.
> > If an element maps to a component then it could be compared for
> > equivalence.
> >
> > Note that not all elements in the info map to components.
> >
> > Therefore, we should only add isEquivalentTo() to the Component
> interface.
> >
> > -- Arthur
> >
> > On Mon, Jul 7, 2008 at 4:48 PM, Jeremy Hughes <hu...@apache.org>
> wrote:
> >> Arthur,
> >>
> >> In this posting [1] I set out a few scenarios where .equals() would be
> >> useful for comparing components. I think XML / element model
> >> comparison will be less likely - I can see most applications would be
> >> manipulating WSDL at the component level. It really only needs XML /
> >> element model manipulation at the (de)serialization stage to get the
> >> WSDL into the correct file layout. I mentioned in the previous post
> >> that if there is a use case for comparing at the element model level
> >> then this is really equivalent to comparing at the XML level and can
> >> be done using something like XMLUnit on an xml stream / DOM object.
> >>
> >> [1]
>
> http://markmail.org/message/l6ors3ctmg4bjyco#query:+page:1+mid:l6ors3ctmg4bjyco+state:results
>
> >>
> >> Jeremy
> >>
> >> 2008/7/7 Arthur Ryman <ry...@ca.ibm.com>:
> >>>
> >>> John,
> >>>
> >>> I suggest using equals() to mean element equality (on both the Element
> and
> >>> Component objects) and using isEquivalentTo() for component equivance.
> >>>
> >>> Is there any technical problem with that?
> >>>
> >>> Arthur Ryman, Technical Executive (IBM DE)
> >>> Project and Program Management, Rational Division
> >>>
> >>> phone: +1-905-413-3077, TL 313-3077
> >>> assistant: +1-905-413-3831, TL 313-3831
> >>> fax: +1-905-413-4920, TL 313-4920
> >>> mobile: +1-416-939-5063
> >>>
> >>>
> >>> "John Kaputin (gmail)" <ja...@gmail.com>
> >>>
> >>> 07/07/2008 01:10 PM
> >>>
> >>> Please respond to
> >>> woden-dev@ws.apache.org
> >>> To
> >>> woden-dev@ws.apache.org
> >>> cc
> >>> Subject
> >>> Re: equals method (was: Re: Questions about tests)
> >>>
> >>>
> >>>
> >>>
> >>> Arthur,
> >>> there was some discussion last month on the original thread [1].
> Basically,
> >>> we have one set of Impl objects which implement two APIs (the
> Component and
> >>> Element APIs) and if we implement equals(Object) to test for logical
> >>> equivalence, there's confusion about which equivalence we are checking
> -
> >>> Component or Element. The spec just refers to Component equivalence
> and
> >>> Jeremy presented an argument in favour of implementing equals(Object)
> to
> >>> check for Component equivalence only.
> >>>
> >>> Currently, we declare the method WSDLComponent.equals(WSDLComponent)
> for the
> >>> Component API. It defaults to equality of object references in
> >>> WSDLComponentImpl and currently is only overridden in InterfaceImpl to
> check
> >>> for logical equivalence of Interface components (to handle Interface
> >>> inheritance). However, this equivalence checking for Interface
> inheritance
> >>> must still be implemented for InterfaceFault, InterfaceOperation,
> >>> InterfaceMessageReference and InterfaceFaultReference to complete the
> spec
> >>> requirements.
> >>>
> >>> I'm not so keen on equals(WSDLComponent) anymore. I think I prefer
> your
> >>> suggestion of WSDLComponent.isEquivalentTo(WSDLComponent). This would
> avoid
> >>> any confusion about what equals() methods mean in the Woden
> implementation.
> >>> It won't permit the use of collection methods like contains(), that
> rely on
> >>> a suitable implementation of equals(Object), but we don't use those
> methods
> >>> in the Woden implementation anyway. See how the equals(WSDLComponent)
> method
> >>> is currently used - we just loop through the collection of components,
> >>> checking each one for equivalence with equals(WSDLComponent). We could
> do
> >>> this just as well with an isEquivalentTo() method instead and it would
> >>> probably be more obvious too.
> >>>
> >>> [1]
> >>>
>
> http://mail-archives.apache.org/mod_mbox/ws-woden-dev/200806.mbox/%3c19a9f6be0806120420g677e1b5bwab97ffc984828d8c@mail.gmail.com%3e
>
> >>>
> >>> regards,
> >>> John
> >>>
> >>> On Tue, Jul 8, 2008 at 12:31 AM, Arthur Ryman <ry...@ca.ibm.com>
> wrote:
> >>>
> >>> Sagara,
> >>>
> >>> -1 on the use of the name Comparator. That should only be used for
> defining
> >>> a total ordering on objects, e.g. for when you sort them.
> >>>
> >>> Remind me why we can't have a standard equals() method? The topic of
> >>> component equivalence can be deferred and we can define an
> isEquivalentTo()
> >>> method later.
> >>>
> >>> Arthur Ryman, Technical Executive (IBM DE)
> >>> Project and Program Management, Rational Division
> >>>
> >>> phone: +1-905-413-3077, TL 313-3077
> >>> assistant: +1-905-413-3831, TL 313-3831
> >>> fax: +1-905-413-4920, TL 313-4920
> >>> mobile: +1-416-939-5063
> >>>
> >>> "Sagara Gunathunga" <sa...@gmail.com>
> >>>
> >>> 07/07/2008 12:02 PM
> >>>
> >>> Please respond to
> >>> woden-dev@ws.apache.org
> >>>
> >>> To
> >>> woden-dev@ws.apache.org
> >>> cc
> >>> Subject
> >>> Re: equals method (was: Re: Questions about tests)
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>> Hi guys,
> >>>
> >>> I like to add some ideas to this discussion, it seems like we couldn't
> come
> >>> up with a good solution for this dilemma quickly. But with our 1.0
> version
> >>> it is not a good thing to tell that we don't have a method to compare
> >>> equality of two WSDL component/element, it's always nice to have a
> solution
> >>> based on Object.equal() method , but in the users point of view most
> >>> important question is " is there any way to check equality of two
> WSDL
> >>> component/element ?? " . So my suggestion is to provide an alternative
> way
> >>> to compare WSDL component/elements until we find the ultimate
> solution.
> >>>
> >>> We can have a utility class called "WSDLComparator" to achieve this,
> >>> following method can be good candidate methods for this class.
> >>>
> >>> Public Boolean compare (WSDLCompnent com1, WSDLCompnent com2)
> >>>
> >>> Public Boolean compare (WSDLElemt ele2, WSDLElement ele2)
> >>>
> >>>
> >>>
> >>> Once we solve equal () method issue we can depreciate this class.
> >>> Meanwhile, I'm also facing this problem in my WSDLWritter test cases.
> I'm
> >>> planning to develop such a "WSDLComparator" class inside the test
> package
> >>> because there is no other way to compare WSDL components in my test
> cases.
> >>>
> >>> Thanks,
> >>>
> >>> On Wed, Jun 25, 2008 at 12:31 AM, Arthur Ryman <ry...@ca.ibm.com>
> wrote:
> >>>
> >>> Jeremy,
> >>>
> >>> I don't know off hand if we have test cases for that, but we should
> add them
> >>> if they are missing, and contribute them to W3C.
> >>>
> >>> There are a couple of assertions related to equivalence [1], [2].
> There are
> >>> a total of 5 test cases that cover these [3].
> >>>
> >>> [1] http://www.w3.org/TR/2007/REC-wsdl20-20070626/#InterfaceFault-1015
> >>> [2]
> http://www.w3.org/TR/2007/REC-wsdl20-20070626/#InterfaceOperation-1020
> >>> [3] http://dev.w3.org/2002/ws/desc/test-suite/Assertion-coverage.html
> >>>
> >>> Arthur Ryman, Technical Executive (IBM DE)
> >>> Project and Program Management, Rational Division
> >>>
> >>> phone: +1-905-413-3077, TL 313-3077
> >>> assistant: +1-905-413-3831, TL 313-3831
> >>> fax: +1-905-413-4920, TL 313-4920
> >>> mobile: +1-416-939-5063
> >>>
> >>> "Jeremy Hughes" <hu...@apache.org>
> >>> Sent by: jpjhughes@gmail.com
> >>>
> >>> 06/24/2008 09:55 AM
> >>>
> >>> Please respond to
> >>> woden-dev@ws.apache.org
> >>>
> >>> To
> >>> woden-dev@ws.apache.org
> >>> cc
> >>> Subject
> >>> Re: equals method (was: Re: Questions about tests)
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>> Hi Arthur,
> >>>
> >>> 2008/6/24 Arthur Ryman <ry...@ca.ibm.com>:
> >>>>
> >>>> Jeremy,
> >>>>
> >>>> The motivation for component equivalence was in fact the use case of
> >>>> "diamond" inheritence. Suppose you have four interfaces A, B, C, D,
> where
> >>>> B
> >>>> inherits A, C inherits A, and D inherits B and C. The D is getting
> all the
> >>>> operations from A twice, which is OK since they are equivalent. If B
> and C
> >>>> pointed to the same location for A there would be no problem, but if
> they
> >>>> point to different locations, then the parser must confirm that the
> >>>> definitions in each location are equivalent.
> >>>>
> >>>> A
> >>>> / \
> >>>> B C
> >>>> \ /
> >>>> D
> >>>>
> >>>
> >>> I wonder if we have a test that looks like this where we B gets the A
> >>> document from a different location to where C gets it ... and also a
> >>> negative test variation on that where the two instances of the A
> >>> document are different. In woden today I believe an
> >>> InterfaceImpl.equals() will compare the object IDs as it delegates to
> >>> Object.equals() and not compare the content of the two objects
> >>> representing A.
> >>>
> >>>> Arthur Ryman, Technical Executive (IBM DE)
> >>>> Project and Program Management, Rational Division
> >>>>
> >>>> phone: +1-905-413-3077, TL 313-3077
> >>>> assistant: +1-905-413-3831, TL 313-3831
> >>>> fax: +1-905-413-4920, TL 313-4920
> >>>> mobile: +1-416-939-5063
> >>>>
> >>>>
> >>>> "Jeremy Hughes" <hu...@apache.org>
> >>>> Sent by: jpjhughes@gmail.com
> >>>>
> >>>> 06/24/2008 06:36 AM
> >>>> Please respond to
> >>>> woden-dev@ws.apache.org
> >>>>
> >>>> To
> >>>> woden-dev@ws.apache.org
> >>>> cc
> >>>> Subject
> >>>> equals method (was: Re: Questions about tests)
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> Hi John,
> >>>>
> >>>> 2008/6/23 John Kaputin (gmail) <ja...@gmail.com>:
> >>>>> The WSDL 2 spec talks about equivalence between components. This is
> to do
> >>>>> with collapsing equivalent components derived from different parts
> of the
> >>>>> XML infoset into a single component in the Component model. I think
> there
> >>>>> are some assertions about it too. If I remember correctly, that was
> the
> >>>>> requirement behind having an equals() implementation that tested for
> the
> >>>>> logical equivalence of components and the equals(WSDLComponent)
> method
> >>>>
> >>>> I guess you're referring to section 2.15 of the core spec. I guess
> >>>> there isn't an interop as I don't think that would make sense - hence
> >>>> we haven't needed to get this to work so far. Also, I don't think we
> >>>> can be testing for equivalence in Woden today as the
> >>>> equals(WSDLComponent) method just delegates to Object.equals()
> >>>>
> >>>>> resulted because of the problem with implementing equals(Object) in
> an
> >>>>> Impl
> >>>>> class that implements both the Component and Element interfaces.
> >>>>>
> >>>>> For example, we wanted to override equals(Object) in
> DescriptionImpl, but
> >>>>> this implements both the Description component and the
> DescriptionElement
> >>>>> interfaces. The equivalence checking behavioiur for a Description
> >>>>> component
> >>>>> and a DescriptionElement are different, but at the DescriptionImpl
> level
> >>>>> we
> >>>>> can't tell which 'view' of the object the caller is seeing
> (component or
> >>>>> element).
> >>>>
> >>>> We could just define equals(Object) as comparing the two objects at
> >>>> the component model level. Then if you really want to compare at the
> >>>> XML level then you need to serialize both objects under comparison to
> >>>> XML and compare them using something like XMLUnit. We might be able
> to
> >>>> do something to simplify this with a layer on XMLUnit.
> >>>>
> >>>>>
> >>>>> We do need some form of equivalence checking to satisfy the spec and
> >>>>> while
> >>>>> implementing equals(WSDLComponent) across Woden might achieve this,
> it
> >>>>> will
> >>>>> break the transitivity of the Object equals() method as Jeremy says,
> >>>>> which
> >>>>> will limit the ability to make use of some aspects of Java (e.g. in
> the
> >>>>> collection classes).
> >>>>
> >>>> I've been trying to think of the use cases for the equals() method.
> >>>> For me it boils down to: does this WSDL (in object form) describe the
> >>>> same service as this other WSDL (in object form). Likely reasons
> you'd
> >>>> do this:
> >>>>
> >>>> a) you've read the WSDL from disc / URL twice and you want to see if
> >>>> they're the same. The DescriptionImpl objects will always be
> >>>> different, but the content will be equal.
> >>>>
> >>>> b) you've read WSDLs from two different locations and you want to see
> >>>> if they're the same - describe the same service, same service
> endpoint
> >>>> etc. Again the DescriptionImpl objects will have different object
> IDs.
> >>>> The WSDLs describe the same service if the component models are the
> >>>> same. The way in which a web service client interacts with the web
> >>>> service is the same whether it is using WSDL #1 or WSDL #2. i.e.
> there
> >>>> is nothing in the element model of the WSDLs that would cause the web
> >>>> service client to behave differently. If there was, then this should
> >>>> have been surfaced at the component model in some way. At least this
> >>>> has been my understanding, so if this is a false statement, please
> >>>> say.
> >>>>
> >>>> c) you've read WSDLs from two different locations and you want to see
> >>>> if they describe two different instances of the same web service -
> >>>> i.e. you have a choice of which the request should be sent to. For me
> >>>> this, and further variations on this theme (e.g. same web service,
> >>>> different transport) require the web service client to dig around in
> >>>> the WSDL a bit further than just calling equals(). I think this is
> >>>> possible today using the accessor methods we have today.
> >>>>
> >>>> d) you've read a WSDL and you want to split the WSDL into 2 - an
> >>>> interface and a service endpoint WSDL. Then you want to check that
> >>>> when you've done that, the result is semantically the same as what
> you
> >>>> started with. This is really a variation of b).
> >>>>
> >>>> So, based on this I think it the equals(Object) method should compare
> >>>> at the component model only. If there is a use case for comparing at
> >>>> the element model level then this is really equivalent to comparing
> at
> >>>> the XML level and can be done using something like XMLUnit on an xml
> >>>> stream / DOM object.
> >>>>
> >>>> So I propsose equals(Object) should compare at the component model
> only.
> >>>>
> >>>>>
> >>>>> Don't forget the issue still pending on the Woden wiki [1] about
> merging
> >>>>> the
> >>>>> Component and Element APIs into one API. This might simplify
> implementing
> >>>>> the equals(Object) method, but we will still need to test for
> Component
> >>>>> equivalence to satisfy the spec.
> >>>>
> >>>> What will merging the APIs really give us. I think that would be less
> >>>> intuitive. I guess I'd like to see how users of Woden wish to use it
> >>>> and what the shortfalls of the current APIs are.
> >>>>
> >>>>>
> >>>>> [1] http://wiki.apache.org/ws/FrontPage/Woden/APIReview/OneWsdlApi
> >>>>>
> >>>>> regards,
> >>>>> John.
> >>>>>
> >>>>> On Fri, Jun 13, 2008 at 11:39 PM, Jeremy Hughes <hu...@apache.org>
> >>>>> wrote:
> >>>>>>
> >>>>>> 2008/6/13 Jeff MAURY <je...@jeffmaury.com>:
> >>>>>> > Just to finish the discussion:
> >>>>>> >
> >>>>>> > 1) I agree that XMLUnint will solve the problem
> >>>>>> > 2) I think the equals method should work on the component level
> >>>>>> > because
> >>>>>> > Description is the component representation of the WSDL
> >>>>>> > 3) If the user wants to test equality at the element level, he
> should
> >>>>>> > use
> >>>>>> > the toElement methods and use equals on the results.
> >>>>>>
> >>>>>> That sounds like a nice idea, but both toElement() and
> toComponent()
> >>>>>> methods return 'this' ... so
> >>>>>>
> >>>>>> myDescription.toElement().equals(foo)
> >>>>>>
> >>>>>> will call the same equals() method on the same object as:
> >>>>>>
> >>>>>> myDescription.toComponent().equals(foo)
> >>>>>>
> >>>>>> but I can see your sentiment that the toElement() method should
> >>>>>> produce an object that effectively *is* the element model of the
> WSDL
> >>>>>> and so equals() method would test for equality at the element model
> >>>>>> level. I did have thoughts around the terminology we use - our
> meaning
> >>>>>> of the term "model" isn't quite the same (IMHO) as the meaning of
> the
> >>>>>> word "model" in the MVC pattern.
> >>>>>>
> >>>>>> I think if we starting thinking in terms of the MVC pattern then we
> >>>>>> would have a single model (in the MVC sense of the word) of the
> WSDL
> >>>>>> which would at least contain a representation of the XML (like
> >>>>>> DescriptionImpl does today) and optionally a calculated
> representation
> >>>>>> of WSDL in terms of what the spec calls *components*. This is
> pretty
> >>>>>> much what we have today in fact, except that we would just start
> >>>>>> saying we have *one* model. Then we would move to saying we have an
> >>>>>> "Element view" of the model and a "Component view" of the model.
> That
> >>>>>> way the equals() methods would be on the view and you would only
> ever
> >>>>>> compare an instance of one type of view of a WSDL with an instance
> of
> >>>>>> the same type of view of another WSDL.
> >>>>>>
> >>>>>> My only hesitation is that this is quite a significant change. Is
> it
> >>>>>> worth it just so that .equals() works? And we'd need hashCode() of
> >>>>>> course. It may provide further benefits - it would be easy enough
> to
> >>>>>> create other views on the model (if there was a use case for that).
> >>>>>>
> >>>>>> Regards,
> >>>>>> Jeremy
> >>>
> >>> ---------------------------------------------------------------------
> >>> To unsubscribe, e-mail: woden-dev-unsubscribe@ws.apache.org
> >>> For additional commands, e-mail: woden-dev-help@ws.apache.org
> >>>
> >>>
> >>>
> >>>
> >>>
> >>> --
> >>> Sagara Gunathunga
> >>>
> >>> Blog - ssagara.blogspot.com
> >>> Web - http://sagaras.awardspace.com/
> >>>
> >>>
> >>
> >> ---------------------------------------------------------------------
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> >> For additional commands, e-mail: woden-dev-help@ws.apache.org
> >>
> >>
> >
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> >
> >
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