Terrific feedbacks - like always! - Matt, thanks a lot, very appreciated!!! We do - at least, I - love you! :D
> on. I can only surmise that the Oracle (?) compiler may take the > subsequent method calls into account when trying to infer type > parameters from arguments, perhaps. I am using the Apple's JDK: Apache Maven 3.0.4 (r1232337; 2012-01-17 09:44:56+0100) Maven home: /Applications/apache-maven-3.0.4 Java version: 1.6.0_29, vendor: Apple Inc. Java home: /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home Default locale: en_US, platform encoding: MacRoman OS name: "mac os x", version: "10.7.2", arch: "x86_64", family: "mac" > however one thing that springs to mind is to take the > CommonsGraph fluent APIs and move them to some typed interface, then > have each level of the interface hierarchy define a public static > final instance of this fluent interface that knows how to behave > appropriately for that type...? Not sure if this would work properly > in practice, but the best idea I'm likely to come up with. this is what I tried to do indeed, CommonsGraph#findMaxFlow returns an interface where generic types are inferred depending on the graph input. Thanks *a lot* for your kind help, always much more than appreciated!!! -Simo http://people.apache.org/~simonetripodi/ http://simonetripodi.livejournal.com/ http://twitter.com/simonetripodi http://www.99soft.org/ On Thu, Jan 26, 2012 at 5:08 PM, Matt Benson <gudnabr...@gmail.com> wrote: > Whew... I hope you guys love me. :P I decided to take a look just > because I've had to play with Eclipse before on issues like this. > What I typically find is that Eclipse has a sane reason for > complaining where it does. This time I *really* thought Eclipse was > wrong... but check this out: > > In the FordFulkersonTestCase, if you break this down statement by > statement, what Eclipse is complaining about is "findMaxFlow(graph);". > Now, if you use Eclipse's 'Assign to local variable' quick assist, > you find that it creates a variable of type: > > FromHeadBuilder<BaseLabeledVertex, Object, > BaseLabeledWeightedEdge<Integer>, > DirectedMutableWeightedGraph<BaseLabeledVertex, > BaseLabeledWeightedEdge<Integer>, Integer>> > > Note that it has calculated the W type parameter to be Object. > > I am reasonably sure that the reason for this is that > CommonsGraph.findMaxFlow's <G> type parameter is declared as "G > extends DirectedGraph<V, WE>". Thus the fact that our > DirectedMutableWeightedGraph 'graph' has its W type parameter assigned > as Integer is completely irrelevant as far as #findMaxFlow() is > concerned. There is no way for the compiler to infer that > #findMaxFlow<W> should be Integer in the context of the fully chained > call. By contrast, simply changing Object to Integer in the signature > of Eclipse's generated local variable gives the compiler enough to go > on. I can only surmise that the Oracle (?) compiler may take the > subsequent method calls into account when trying to infer type > parameters from arguments, perhaps. > > So that's my diagnosis. How to cope with it while retaining fluency > is another story. I'm not familiar enough with the domain or the API > to be able to make any recommendation that would probably be terribly > useful; however one thing that springs to mind is to take the > CommonsGraph fluent APIs and move them to some typed interface, then > have each level of the interface hierarchy define a public static > final instance of this fluent interface that knows how to behave > appropriately for that type...? Not sure if this would work properly > in practice, but the best idea I'm likely to come up with. > > HTH, > Matt > > On Thu, Jan 26, 2012 at 8:42 AM, Simone Tripodi > <simonetrip...@apache.org> wrote: >> Hi Claudio!!! >> >> thanks for reporting, I have indeed the same issue - even if I thought >> was just an Eclipse bug! >> I honestly don't know how to fix the problem, I hope someone in the ML >> can provide a solution as well - same behavior met in IntelliJ!!! >> >> All the best, >> -Simo >> >> http://people.apache.org/~simonetripodi/ >> http://simonetripodi.livejournal.com/ >> http://twitter.com/simonetripodi >> http://www.99soft.org/ >> >> >> >> On Thu, Jan 26, 2012 at 3:33 PM, Claudio Squarcella >> <squar...@dia.uniroma3.it> wrote: >>> P.S. for completeness: >>> >>> Eclipse version: Indigo Service Release 1 >>> Build id: 20110916-0149 >>> OS: Mac OS X Lion >>> >>> Cheers, >>> Claudio >>> >>> >>> On 26/01/2012 15:30, Claudio Squarcella wrote: >>>> >>>> Hi all, >>>> >>>> I am experiencing a rather annoying issue with the latest version of >>>> commons-graph on Eclipse. Compiling with javac (maven, command line) it >>>> works fine, but the editor still complains: e.g. line 72 of the new >>>> FordFulkersonTestCase[1] gives a list of errors[2]. >>>> >>>> Now, I know from googling that Eclipse is not new to strange behavior, but >>>> I wanted to know if anyone on the ML has a nice answer, solution or >>>> workaround (other than standard answers like "use another IDE"), or at >>>> least >>>> experiences the same issue with the code. >>>> >>>> Thank you, >>>> Claudio >>>> >>>> --- >>>> >>>> [1] >>>> https://svn.apache.org/viewvc/commons/sandbox/graph/trunk/src/test/java/org/apache/commons/graph/flow/FordFulkersonTestCase.java?revision=1235827&view=markup >>>> [2] Multiple markers at this line >>>> - Bound mismatch: The generic method applyingFordFulkerson(OM) of type >>>> MaxFlowAlgorithmSelector<V,W,WE,G> is not applicable for the arguments >>>> (IntegerWeight). The >>>> inferred type IntegerWeight is not a valid substitute for the bounded >>>> parameter <OM extends OrderedMonoid<Object>> >>>> - Type mismatch: cannot convert from Object to Integer >>>> - Bound mismatch: The generic method findMaxFlow(G) of type >>>> CommonsGraph<V,E,G> is not applicable for the arguments >>>> >>>> (DirectedMutableWeightedGraph<BaseLabeledVertex,BaseLabeledWeightedEdge<Integer>,Integer>). >>>> The inferred type BaseLabeledWeightedEdge<Integer> is not a valid >>>> substitute >>>> for the bounded parameter <WE extends WeightedEdge<W>> >>>> >>> >>> -- >>> Claudio Squarcella >>> PhD student at Roma Tre University >>> E-mail address: squar...@dia.uniroma3.it >>> Phone: +39-06-57333215 >>> Fax: +39-06-57333612 >>> http://www.dia.uniroma3.it/~squarcel >>> >>> >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org >>> For additional commands, e-mail: dev-h...@commons.apache.org >>> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org >> For additional commands, e-mail: dev-h...@commons.apache.org >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > For additional commands, e-mail: dev-h...@commons.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
