December 2000 - Zope-Dev

Re: [Geeks] Re: Interface Meta Data proposal
by Guido van Rossum 07 Dec '00

07 Dec '00

> I notice you mention post/pre conditions (something that UML obviously talks > about). I wonder if we want to do a bit of research on Eiffle and it's > contractual description. The only thing I wonder is if some of this is > actually useful programatically, if that makes sense? It's great info, but > is it useful at runtime? In Eiffel (I've never heard of Eiffle :-), pre- and post-conditions are turned into run-time checks, just like assertions. There are separate flags to turn code generation for pre- and post-conditions off. This is useful, as follows: while debugging your code, turn both on. When you've fully debugged an application, you turn both off. When you've fully debugged a library module, you create two versions: one with both turned off, for use in fully debugged applications, and one with pre-conditions on and post-conditions off, for use by other code that is still in need of debugging. I've heard that this works very well, and in Python 3000 (when we have optional static typing) I would love to add this to Python. If it's not feature bloat. --Guido van Rossum (home page: http://www.python.org/~guido/)

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(no subject)
by danchik 07 Dec '00

07 Dec '00

is there a way in zope to reference a document on a server without having it to be in the zope database??? if I want to display say a microsoft document, with content type of application/msword so that the Internet explorer displays it as formated word document and so that it can be saved back to server??? or is there other ways of accomplishing the same thing? thank you for any help Dan S.

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SQLAlias Memory Leak?
by Dyon Balding 06 Dec '00

06 Dec '00

Hi, I have an application that stores state data in a SQLServer database. The Zope and database servers run on different windows machines, using the ZODBCDA product to connect Zope to the ODBC machinery. What I have been observing is that the Zope client's memory usage increases consistently when ZSQL methods are being called. In the Debug screens, the culprit appears to be Shared.DC.ZRDB.RDB.SQLAlias. Here's a dump of the first few lines after hitting a ZSQL method a few hundred times using ab. The SQLAlias figures never seem to go down. Class December 5, 2000 1:58 pm December 5, 2000 2:01 pm Delta Shared.DC.ZRDB.RDB.SQLAlias 1048 4068 +3020 ZClasses.ZClass.ZClass 73 108 +35 OFS.DTMLMethod.DTMLMethod 63 94 +31 In fact most of our servers run out of memory and need to be restarted every couple of days when they get sufficient use. I've done a bit of a search of the mailing lists, and noone else appears to be having the same problem. So does anyone have an idea of what we might be doing differently to everyone else? We appear to have the latest versions installed. I've had a bit of a look through the code, and it appears that SQLAlias is used to case desensitize the column names of the returned data? Any pointers would be appreciated. thanks, d -- | Dyon Balding dyon(a)devcoder.com.au |

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ZUnit - feedback convocation
by Lalo Martins 06 Dec '00

06 Dec '00

Hi all I'trying to write a document on ZUnit and Unit Testing in general, following Michel's and Amos' documentation process. I wrote an outline, and now I'm stuck :-) anyone with a few free moments is welcome to take a look and send me some words. Also, anyone very interested in the subject is welcome to volunteer for editorial help (read the Process to know what this means). Thank you. (BTW, if you can't understand what an "outline" is, read the process too. Oh what the heck. If you haven't read it, then read it, it's very cool reading anyway.) []s, |alo +---- -- Hack and Roll ( http://www.hackandroll.org ) The biggest site for whatever-it-is-that-we-are. http://zope.gf.com.br/lalo mailto:lalo@hackandroll.org pgp key: http://zope.gf.com.br/lalo/pessoal/pgp Brazil of Darkness (RPG) --- http://zope.gf.com.br/BroDar

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ZPatterns & scalability...
by John Eikenberry 06 Dec '00

06 Dec '00

Just to get more opinions... we have a service coming up where we'd like to use a Zope/Zpatters solution. Its a feedback tool, with the potential of up to 50,000 entries. These would be stored in a Specialist/Rack/DataSkin combo, stored in a standard zodb/filestorage system. Using a ZCatalog for listings and the Specialist.getItem() for individual record retrieval. Any thoughts on scalability issues. Thanks in advance for any insights. -- John Eikenberry [jae(a)zhar.net - http://zhar.net] ______________________________________________________________ "A society that will trade a little liberty for a little order will deserve neither and lose both." --B. Franklin

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Implementing [XOR A] 1 object connections in ZPatterns
by Itai Tavor 06 Dec '00

06 Dec '00

Hi, Continuing the saga of my struggles with ZPatterns, I'm trying to work out the best way to implement an object that can be related to one of several other objects. For example, I have a Product class. A Product can come in different colors, so I also have a Color class. Products can have two photos of the product - small and large. Colors can also have a photo, showing the product in that particular color. So, a Photo object can be a large product photo, a small product photo, or a color photo. I can think of two ways to implement this: 1. Add small_photo_id, large_photo_id properties to Product, and photo_id property to Color. Then I do something like: Product.editInstanceForm: <dtml-if large_photo_id> <dtml-var "Photos.getItem(large_photo_id).viewInstance(...)"> <dtml-else> <form action="selectLargePhoto" method="post"> <dtml-var "Photos.selectPhotoSnippet(...)"> </form> </dtml-if> <method>Product.selectLargePhoto</method>: photo_id = self.Photos.selectPhoto(REQUEST) self.propertysheets.Basic.manage_changeProperties(large_photo_id=photo_id) 2. Add owner_id, photo_key properties to Photo. Then use: Product.editInstanceForm: <dtml-var "Photos.selectPhotoForOwner(Photos, REQUEST, owner_id=id, photo_key='large')"> Photos.selectPhotoForOwner: <dtml-let photo="defaultRack.getItemForKey(owner_id, photo_key)"> <dtml-if photo> <dtml-var "photo.viewInstance(...)" <dtml-else> ... code for selecting/creating photo ... </dtml-let> The 2nd way seems to go better with OO principles - all handling of photos is delegated to the Photos Specialist and the Product doesn't care if the photo exists or not, or where it comes from. But it also increases complexity in Photos, because I need to implement an efficient way to retrieve photos (with a Catalog, or SQL searches), and because it introduces the photo_key. Storing photo_id in Product eliminates these complexities, but it moves some of the responsibility for managing photos into Product. Can anyone add anything on making the choice? Or maybe a 3rd way I haven't thought of? Thanks, Itai -- Itai Tavor "Je sautille, donc je suis." C3Works itai(a)c3works.com - Kermit the Frog "If you haven't got your health, you haven't got anything"

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Re: ZPatterns, ObjectDomain, UML and all that.....
by Itai Tavor 05 Dec '00

05 Dec '00

Steve Spicklemire wrote: > >>>>> "RC" == RC Compaan <sparroy(a)adept.co.za> writes: > > RC> Hi Steve > > RC> I'm also a babe in the woods when it comes to object > RC> modelling, but here's my pennie's worth. Since code > RC> generation was not really required in the models I recently > RC> did for Zope Apps and the terrible exchange rate on the South > RC> African Rand I decided to use to very light weight Playground > RC> modelling tool. I agree with Steve Alexander that Coad > RC> notation serves ZPatterns *better* and this is exactly what > RC> Playground uses. > >Ahh.. alas Playground is Win only (if I'm thinking correctly that it's >the software that came in Coad's book), and I loaned tbe book and CD >to someone else ... grrrr... ;-) It is the software that comes with the book, and it is Win only. I started using it but switched to ConceptDraw because I got tired of turning my chair around to face the Windows machine every time I wanted to look at my object model. Like Roche said, you don't need code generation, so all you need is to be able to place classes and connect them. Playground is nice in that it actually knows about classes and lets you view class lists, create connections from the list and so on. ConceptDraw is just a drawing program so you won't have class lists, and the libraries aren't complete, but on the other hand, it works well on a Mac and, unlike Playground, it lets you do Coad, UML, Use Cases, activity diagrams, sequence diagrams, component diagrams, collaboration diagrams... Itai -- Itai Tavor "Je sautille, donc je suis." C3Works itai(a)c3works.com - Kermit the Frog "If you haven't got your health, you haven't got anything"

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Zope 2.3 plan updated...
by Brian Lloyd 05 Dec '00

05 Dec '00

Hi all - We're gearing up for getting a new feature release out so for those interested I've updated the Zope 2.3 plan at: http://dev.zope.org/Resources/zope_230_plan.html The main changes from the prior version are that it is much more detailed, some items have been added and the item for updating ZDOM to DOM level 2 has been dropped (until there is a clearer justification for it). I hope to make an alpha 1 release on Monday the 11th with the new Python Scripts and fixed user bootstrapping, among other things (see the plan for details). Brian Lloyd brian(a)digicool.com Software Engineer 540.371.6909 Digital Creations http://www.digicool.com

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FW: ZPatterns, ObjectDomain, UML and all that.....
by jimbo 05 Dec '00

05 Dec '00

I've been using DOmain Modeling Environment(DOME) for OOA/OOD recently. I use it because like ZOPE it has many features most important one being free. It has support for Coad notation and a list of others. IMHO it could be the default ZPatterns design tool of choice because you can extend it to include the ZPatterns concepts and it supports windows, and the PowerMac using VisualWorks. Has anybody out there had any experience with DOME ? DOME (the DOmain Modeling Environment) is a meta-CASE system suitable for building object oriented software models (Coad-Yourdon OOA and UML, for example), and more importantly, for building original types of models. It includes a graphical front-end, and a powerful back-end language for generating code, analyses and documentation. It is fully functional, tested, documented, and it is free, distributed under GNU General Public licenses. Download <a href="http://www.htc.honeywell.com/dome/download.htm">here</a> There is a Linux version and Smalltalk Source Code for VisualWorks 5i

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ZPatterns & ZEO?
by bens＠killersite.com 05 Dec '00

05 Dec '00

Has anyone used ZPatterns with ZEO? Is there any reason these 2 won't work well together? Will ZEO be able to send an "invalidate" message to all clients when an object changes in of them? Thanks

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