Re: [forge-dev] reflection to access classes in project dependencies

I don't like it because it's not really optimal, but... I don't really see a better way forward that doesn't break every API we have. On Mon, Feb 18, 2013 at 9:43 PM, Lincoln Baxter, III < lincolnbaxter(a)gmail.com&gt; wrote: > Well, I actually meant refactor the entire JavaParser so that the types > are immutable by default, but modifiable when desired by doing an intanceof > and cast. This would, as John said, be a fairly invasive, with a fair > amount of downstream API impact, since all users of these APIs would now > need to reference these new types instead. It would mean refactoring all of > Forge. > > So from the perspective of Migration, it probably makes sense to do > something like add a method "isEditable()" > > > On Thu, Feb 14, 2013 at 2:19 PM, Thomas Frühbeck <fruehbeck(a)aon.at&gt;wrote: > >> If I understood Lincoln correctly, he meant adding an interface >> EditableJavaSource, so no change in the existing implementations necessary. >> So the boolean is substitutable by instanceof, your graceful error >> handling would be supported. >> >> Am 14.02.2013 20:10, schrieb John Franey: >> >> I would follow my object-oriented instinct to agree that a >> editable/non-editable parallel of the model would make sense. After all, >> an editable java source is kind of a non-editable java source, and adds >> editing behavior..... >> >> However, the parallel model seems to be a significant undertaking, and >> has a negative characteristic, in my opinion. Lets say there exists a >> method to search for and return a JavaClass, editable or not. In a use >> case where the JavaClass is to be modified, this method is inadequate. 1) >> The caller would have to check if the result is instance of >> EditableJavaClass, then cast, or 2) an alternate query method would be >> provided to return only EditableJavaClass and since methods cannot be >> overridden by return type the alternate query method would have to be >> defined in a different interface. Not taht either of these are difficult >> to overcome, but I think the parallel model would increase overall >> complexity a little and add to the level of effort, and the benefit gained >> is merely type protection against the runtime error of attempting to modify >> a non-editable java component. >> >> To go against that impulse just a second, consider the option of a >> property on the base class, a boolean: editable. This would avoid the >> parallel model, avoid casting and support polymorphic calls. The runtime >> error of attempting to modify a non-editable component can be handled in a >> few different ways: 1) a runtime exception, 2) a quiet no-op. Without the >> editable property, I would not use a runtime exception. There would be no >> chance for the forge plugin programmer to avoid the error gracefully. With >> the property, the error is the programmer's and a runtime exception could >> be appropriate. >> >> Regards, >> John >> >> >> >> On Thu, Feb 14, 2013 at 1:11 PM, Lincoln Baxter, III < >> lincolnbaxter(a)gmail.com&gt; wrote: >> >>> As I understood it, we need a way of explicitly noting when a >>> JavaSource instance is mutable or not. Perhaps splitting the API into a >>> JavaSource an EditableJavaSource parallel. >>> >>> It was also my understanding that proxies were going to be used to do >>> lazy-classloading for any JARs brought in via this system. I'm not sure we >>> need to worry about this just yet. We can get it working then think about >>> performance implications. >>> >>> >>> On Thu, Feb 14, 2013 at 12:23 PM, John Franey <jjfraney(a)gmail.com&gt;wrote: >>> >>>> I have no intention of providing a way to modify the class >>>> definition of a java class defined within a dependency of the user's >>>> project. >>>> >>>> Putting the question another way: >>>> >>>> To date, the forge java model today supports only modifiable java >>>> components. This effort introduces non-modifiable java components to the >>>> forge java model. This raises the question: Would the non-modifiable >>>> java components be inspected with the same api that supports the modifiable >>>> java components (JavaClass, and others). If no, what api is used to >>>> inspect the non-modifiable java components? >>>> >>>> My naive answer is: the non-modifiable java components would be >>>> inspected using the same api as the modifiable java components. Methods of >>>> that api that expressly modify the java component would be inert for >>>> non-modifiable java components. >>>> >>>> John >>>> >>>> >>>> >>>> On Thu, Feb 14, 2013 at 12:05 PM, Thomas Frühbeck <fruehbeck(a)aon.at&gt;wrote: >>>> >>>>> Hmm, I expect loading of JARs not to the problem, is it? So the >>>>> loading and reflecting on the "external" class should be possible. >>>>> I was thinking of the next step, implementing kind of writable >>>>> JavaClass not just ignoring the changes, but making the modified class >>>>> available to the project. >>>>> Sorry if I misunderstood your quest? =) >>>>> >>>>> Thomas >>>>> >>>>> Am 14.02.2013 17:37, schrieb John Franey: >>>>> >>>>> Thomas, >>>>> >>>>> I have minimal exposure to proxy due to experience with hibernate, >>>>> but my understanding is not adequate to understand how they would apply. >>>>> Do I understand correctly that the benefit of a dynamic proxy is high when >>>>> a temporary class implementation is needed, and when a method of the proxy >>>>> is invoked, some action is taken, perhaps instantiating another >>>>> implementation of the interface. In this use case, we don't need to invoke >>>>> the methods of a project's class, we need to inspect the methods (and other >>>>> members) of the class, right? >>>>> >>>>> John >>>>> >>>>> >>>>> >>>>> >>>>> On Thu, Feb 14, 2013 at 11:22 AM, Thomas Frühbeck <fruehbeck(a)aon.at&gt;wrote: >>>>> >>>>>> exactly what I was looking for :-)) >>>>>> Thanks George! >>>>>> >>>>>> Am 14.02.2013 16:55, schrieb George Gastaldi: >>>>>> >>>>>> Hi Thomas, >>>>>> >>>>>> Have a look in Forge 2.0 source code. We're using javassist at >>>>>> it's best in the proxy module >>>>>> >>>>>> >>>>>> >>>>>> Em 14/02/2013, às 13:53, Thomas Frühbeck <fruehbeck(a)aon.at&gt; >>>>>> escreveu: >>>>>> >>>>>> Hi John, >>>>>> >>>>>> my two cents: >>>>>> - this feature is a must-have, if Forge should be more than a >>>>>> tool to iniitialize projects, really great idea >>>>>> - being pragmatic I would say this calls for proxy classes, >>>>>> similar to CDI decorators or the copy-on-write strategy >>>>>> >>>>>> (AFAIK the downside to CDI decorators is that they need interfaces >>>>>> on the base classes, thus again requiring changes of the classes if they >>>>>> hadnt been designed for it firstplace.) >>>>>> >>>>>> I have a very similar problem I am currently trying to solve with >>>>>> silly wrapper classes and was starting to think about dynamic proxy >>>>>> generation - unfortunately I have _no_ experience with such technology >>>>>> other than being simple user :-/ >>>>>> >>>>>> Have you thought about javassist? Is it an option at all? >>>>>> >>>>>> Thomas >>>>>> >>>>>> >>>>>> Am 14.02.2013 16:21, schrieb John Franey: >>>>>> >>>>>> My motivation for this email is to satisfy FORGE-773. However, this >>>>>> is also related to FORGE-563 and FORGE-424, and resolution could enable >>>>>> other features. >>>>>> >>>>>> I have written a prototype: >>>>>> 1) an implementation of the forge java api interfaces which >>>>>> delegates to java's reflection, offering a read only perspective of java >>>>>> components. >>>>>> 2) a forge module, currently a facet, to search for a given binary >>>>>> class in the project's dependencies and returns the result wrapped in the >>>>>> above delegate. >>>>>> >>>>>> These are demonstrable in a unit test. >>>>>> >>>>>> My dilemma now is how to integrate these into the forge project. >>>>>> There are a few different areas, but I'll start with this: >>>>>> >>>>>> >>>>>> For some callers, a java class is a java class, whether it >>>>>> originates as source code (from the current forge project) or is a class >>>>>> from the dependency set. For example, scaffolding primarily is a read only >>>>>> operation. In this use case, it would be simpler for these clients to have >>>>>> a single interface to resolve classes because whether a class is source or >>>>>> binary is not relevant to the use case. >>>>>> >>>>>> On the other hand, there is a set of classes in a user's project >>>>>> that are modifiable. In these cases, a java class is not a java class. >>>>>> Forge components might want the distinction somehow. There ought the be >>>>>> some distinction of which class is modifiable and which is not. >>>>>> >>>>>> Naively, I took the first thinking that the existing forge java >>>>>> model would be adequate. To have separate java api for read-only and >>>>>> read-write java model objects seems a fundamental addition to the java >>>>>> model which requires much more effort. In absence of such a model, I >>>>>> though to implement 'no-op' for those code changing methods (e.g., >>>>>> Named.setName() would be inert). I assumed that forge component that >>>>>> change source code would have necessary context to know when it is >>>>>> operating on a source code module, avoiding attempts to modify a binary >>>>>> class. >>>>>> >>>>>> So, I'm looking for discussion and consensus on the above. Any >>>>>> thoughts? >>>>>> >>>>>> Regards, >>>>>> John >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> forge-dev mailing listforge-dev@lists.jboss.orghttps://lists.jboss.org/mailman/listinfo/forge-dev >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> forge-dev mailing list >>>>>> forge-dev(a)lists.jboss.org >>>>>> https://lists.jboss.org/mailman/listinfo/forge-dev >>>>>> >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> forge-dev mailing listforge-dev@lists.jboss.orghttps://lists.jboss.org/mailman/listinfo/forge-dev >>>>>> >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> forge-dev mailing list >>>>>> forge-dev(a)lists.jboss.org >>>>>> https://lists.jboss.org/mailman/listinfo/forge-dev >>>>>> >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> forge-dev mailing listforge-dev@lists.jboss.orghttps://lists.jboss.org/mailman/listinfo/forge-dev >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> forge-dev mailing list >>>>> forge-dev(a)lists.jboss.org >>>>> https://lists.jboss.org/mailman/listinfo/forge-dev >>>>> >>>> >>>> >>>> _______________________________________________ >>>> forge-dev mailing list >>>> forge-dev(a)lists.jboss.org >>>> https://lists.jboss.org/mailman/listinfo/forge-dev >>>> >>> >>> >>> >>> -- >>> Lincoln Baxter, III >>> http://ocpsoft.org >>> "Simpler is better." >>> >>> _______________________________________________ >>> forge-dev mailing list >>> forge-dev(a)lists.jboss.org >>> https://lists.jboss.org/mailman/listinfo/forge-dev >>> >> >> >> >> _______________________________________________ >> forge-dev mailing listforge-dev@lists.jboss.orghttps://lists.jboss.org/mailman/listinfo/forge-dev >> >> >> >> _______________________________________________ >> forge-dev mailing list >> forge-dev(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/forge-dev >> > > > > -- > Lincoln Baxter, III > http://ocpsoft.org > "Simpler is better." > -- Lincoln Baxter, III http://ocpsoft.org "Simpler is better." _______________________________________________ forge-dev mailing list forge-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/forge-dev