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  • Namespaces combined with TFS / Source Control explanation

    - by Christian
    As an ISV company we slowly run into the "structure your code"-issue. We mainly develop using Visual Studio 2008 and 2010 RC. Languages c# and vb.net. We have our own Team Foundation Server and of course we use Source Control. When we started developing based on the .NET Framework, we also begun using Namespaces in a primitive way. With the time we 'became more mature', i mean we learned to use the namespaces and we structured the code more and more, but only in the solution scope. Now we have about 100 different projects and solutions in our Source Safe. We realized that many of our own classes are coded very redundant, i mean, a Write2Log, GetExtensionFromFilename or similar Function can be found between one and 20 times in all these projects and solutions. So my idea is: Creating one single kind of root folder in Source Control and start an own namespace-hierarchy-structure below this root, let's name it CompanyName. A Write2Log class would then be found in CompanyName.System.Logging. Whenever we create a new solution or project and we need a log function, we will 'namespace' that solution and place it accordingly somewhere below the CompanyName root folder. To have the logging functionality we then import (add) the existing project to the solution. Those 20+ projects/solutions with the write2log class can then be maintained in one single place. To my questions: - is that a good idea, the philosophy of namespaces and source control? - There must be a good book explaining the Namespaces combined with Source Control, yes? any hints/directions/tips? - how do you manage your 50+ projects?

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  • How to ask BeanUtils to ignore null values

    - by Calm Storm
    Using Commons beanUtils I would like to know how to ask any converter say the Dateconverter to ignore null values and use null as default. As an example consider a public class, public class X { private Date date1; private String string1; //add public getters and setters } and my convertertest as, public class Apache { @Test public void testSimple() throws Exception { X x1 = new X(), x2 = new X(); x1.setString1("X"); x1.setDate1(null); org.apache.commons.beanutils.BeanUtils.copyProperties(x2, x1); //throws ConversionException System.out.println(x2.getString1()); System.out.println(x2.getDate1()); } } The above throws a NPE since the date happens to be null. This looks a very primitive scenario to me which should be handled by default (as in, I would expect x2 to have null value for date1). The doco tells me that I can ask the converter to do this. Can someone point me as to the best way for doing this ? I dont want to get hold of the Converter and isUseDefault() to be true because then I have to do it for all Date, Enum and many other converters !

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  • Flex / Flash builder : no returning data using database

    - by Tristan
    Hello, i'm following some flex tutorials everything's working as wanted expected for one thing : When i use my function getServerByBrand($brand) there is no returned data into my datagrid and i don't know why because it uses the same schema as getAllserver() which is working . I don't know whether it's cause by the function itselft or the configuration in flash builder : protected function RechercheGSP_clickHandler(event:MouseEvent):void { getServerByBrandResult.token = dbClass.getServerByBrand(SearchInput.text); } Here's what i've got in Data/Services : getServerByBrand(brand : string) : Object And finally the function : public function getServerByBrand($brand) { $stmt = mysqli_prepare($this->connection, "SELECT DISTINCT * FROM $this->tablename where GSP_nom=? "); $this->throwExceptionOnError(); mysqli_stmt_execute($stmt); $this->throwExceptionOnError(); $rows = array(); mysqli_stmt_bind_result($stmt, $row->idServ, $row->GSP_nom, $row->IPserv, $row->port, $row->tickrate, $row->membre, $row->nomPays, $row->finContrat, $row->actif, $row->timestamp, $row->type, $row->jeux, $row->slot, $row->ipClient, $row->essai, $row->reussite, $row->echec, $row->valide, $row->email); while (mysqli_stmt_fetch($stmt)) { $row->timestamp = new DateTime($row->timestamp); $rows[] = $row; $row = new stdClass(); mysqli_stmt_bind_result($stmt, $row->idServ, $row->GSP_nom, $row->IPserv, $row->port, $row->tickrate, $row->membre, $row->nomPays, $row->finContrat, $row->actif, $row->timestamp, $row->type, $row->jeux, $row->slot, $row->ipClient, $row->essai, $row->reussite, $row->echec, $row->valide, $row->email); } mysqli_stmt_free_result($stmt); mysqli_close($this->connection); return $rows; } I tested the settings with configure return type and it tells me : "the operation returned a primitive "object". test settings : Parameters (brand) / Input type (String) / Value (woop) To conclude, there is no returned object at all. Do you see the problem ? Thanks

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  • CQRS - The query side

    - by mattcodes
    A lot of the blogsphere articles related to CQRS (command query repsonsibility) seperation seem to imply that all screens/viewmodels are flat. e.g. Name, Age, Location Of Birth etc.. and thus the suggestion that implementation wise we stick them into fast read source etc.. single table per view mySQL etc.. and pull them out with something like primitive SqlDataReader, kick that nasty nhibernate ORM etc.. However, whilst I agree that domain models dont mapped well to most screens, many of the screens that I work with are more dimensional, and Im sure this is pretty common in LOB apps. So my question is how are people handling screen where by for example it displays a summary of customer details and then a list of their orders with a [more detail] link etc.... I thought about keeping with the straight forward SQL query to the Query Database breaking off the outer join so can build a suitable ViewModel to View but it seems like overkill? Alternatively (this is starting to feel yuck) in CustomerSummaryView table have a text/big (whatever the type is in your DB) column called Orders, and the columns for the Order summary screen grid are seperated by , and rows by |. Even with XML datatype it still feeel dirty. Any thoughts on an optimal practice?

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  • Non RBAC User Roles and Permissions System: checking the user's City

    - by micha12
    We are currently designing a User Roles and Permissions System in our web application (ASP.NET), and it seems that we have several cases that do no fit within the classical Role-Based Access Control (RBAC). I will post several questions, each devoted to a particular case, this being the first post. We have the following case: not to allow a user view a certain page if the user lives in a particular city. This is a simple case that is coded in the following way: if (User.City == “Moscow”) // Allow the user to view the page. else // Do not allow the user to view this page. Though this case is very simple and straightforward, it has nothing to do with the RBAC. On StackOverflow, someone called this an Attribute-based Access Control. Under the classical RBAC, it seems that this case should be designed like this: introduce a permission “City where the person lives”, this permission will have a property City. Then create a role, add a permission of type “City = Moscow” to it and the assign the role to the user. Looks extremely cumbersome. The question is whether it is acceptable to introduce such non-RBAC approaches to our permissions system – does that break the design or not? This might seem a primitive question, but we found that most applications use pure RBAC, and we started to think that we might be doing something wrong. Thank you.

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  • How to implement RSA-CBC?(I have uploaded the request document)

    - by tq0fqeu
    I don't konw more about cipher, I just want to implement RSA-CBC which maybe mean that the result of RSA encrypt in CBC mode, and I have implemented RSA. any code languages will be ok, java will be appreciated thx I copy the request as follow(maybe has spelling wrong), but that's French I don't konw that: Pr´esentation du mini-projet Le but du mini-projet est d’impl´ementer une version ´el´ementaire du chi?rement d’un bloc par RSA et d’inclure cette primitive dans un systeme de chi?rement par bloc avec chaˆinage de blocs et IV (Initial Vector ) al´eatoire. Dans ce systeme, un texte clair (`a chi?rer) est d´ecompos´e en blocs de taille t (?x´ee par l’utilisa- teur), chaque bloc (clair) est chi?r´e par RSA en un bloc crypt´e de mˆeme taille, puis le cryptogramme associ´e au texte clair initial est obtenu en chaˆinant les blocs crypt´es par la m´ethode CBC (cipher- block chaining) d´ecrite dans le cours (voir poly “Block Ciphers”) Votre programme devra demander a l’utilisateur la taille t, puis, apres g´en´eration des cl´es publique et priv´ee, lui proposer de chi?rer ou d´echi?rer un (court) ?chier ASCII. Il est indispensable que votre programme soit au moins capable de traiter le cas (tres peu r´ealiste du point de vue de la s´ecurit´e) t = 32. Pour les traiter des blocs plus grands, il vous faudra impl´ementer des routines d’arithm´etique multi-pr´ecision ; pour cela, je vous conseille de faire appela des bibliotheques libres comme GMP (GNU Multiprecision Library). Pour la g´en´eration al´eatoire des nombres premiers p et q, vous pouvez ´egalement faire appela des bibliotheques sp´ecialis´ees,a condition de me donner toutes les pr´ecisions n´ecessaires. Vous devez m’envoyer (avant une date qui reste a ?xer)a mon adresse ´electronique ([email protected]) un courriel (sujet : [MI1-crypto] : devoir, corps du message : les noms des ´etudiants ayant travaill´e sur le mini-projet) auquel sera attach´e un dossier compress´e regroupant vos sources C ou Java comment´ees, votre programme ex´ecutable, et un ?chier texte ou PDF donnant toutes les pr´ecisions sur les biblioth`eques utilis´ees, vos choix algorithmiques et d’impl´ementation, et les raisons de ces choix (complexit´e algorithmique, robus- tesse, facilit´e d’impl´ementation, etc.). Vous pouvez travailler en binˆome ou en trinˆome, mais je serai nettement plus exigeant avec les trinˆomes I have uploaded the request at http://uploading.com/files/22emmm6b/enonce_projet.pdf/ thx

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  • Model relationships in ASP.NET MVC

    - by Fabiano
    Hi I recently started evaluating ASP.NET MVC. While it is really easy and quick to create Controllers and Views for Models with only primitive properties (like shown in the starter videos from the official page) I didn't find any good way to work with references to complex types. Let's say, I have these Models: public class Customer { public int Id { get; set; } public string Name { get; set; } public Address Address { get; set; } public IList<Order> Orders { get; set; } } public class Address { public int Id { get; set; } public string ..... ..... } public class Order { public int Id { get; set; } public Customer Customer { get; set; } public string OrderName { get; set; } ..... } Note that I don't have foreign keys in the models (like it's typical for LINQ to SQL, which is also used in the sample video) but an object reference. How can I handle such references in asp.net mvc? Does someone has some good tips or links to tutorials about this problem? maybe including autobinding with complex types.

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  • What are the most interesting equivalences arising from the Curry-Howard Isomorphism?

    - by Tom
    I came upon the Curry-Howard Isomorphism relatively late in my programming life, and perhaps this contributes to my being utterly fascinated by it. It implies that for every programming concept there exists a precise analogue in formal logic, and vice versa. Here's an "obvious" list of such analogies, off the top of my head: program/definition | proof type/declaration | proposition inhabited type | theorem function | implication function argument | hypothesis/antecedent function result | conclusion/consequent function application | modus ponens recursion | induction identity function | tautology non-terminating function | absurdity tuple | conjunction (and) disjoint union | exclusive disjunction (xor) parametric polymorphism | universal quantification So, to my question: what are some of the more interesting/obscure implications of this isomorphism? I'm no logician so I'm sure I've only scratched the surface with this list. For example, here are some programming notions for which I'm unaware of pithy names in logic: currying | "((a & b) => c) iff (a => (b => c))" scope | "known theory + hypotheses" And here are some logical concepts which I haven't quite pinned down in programming terms: primitive type? | axiom set of valid programs? | theory ? | disjunction (or)

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  • Textured Primitives in XNA with a first person camera

    - by 131nary
    So I have a XNA application set up. The camera is in first person mode, and the user can move around using the keyboard and reposition the camera target with the mouse. I have been able to load 3D models fine, and they appear on screen no problem. Whenever I try to draw any primitive (textured or not), it does not show up anywhere on the screen, no matter how I position the camera. In Initialize(), I have: quad = new Quad(Vector3.Zero, Vector3.UnitZ, Vector3.Up, 2, 2); quadVertexDecl = new VertexDeclaration(this.GraphicsDevice, VertexPositionNormalTexture.VertexElements); In LoadContent(), I have: quadTexture = Content.Load<Texture2D>(@"Textures\brickWall"); quadEffect = new BasicEffect(this.GraphicsDevice, null); quadEffect.AmbientLightColor = new Vector3(0.8f, 0.8f, 0.8f); quadEffect.LightingEnabled = true; quadEffect.World = Matrix.Identity; quadEffect.View = Matrix.CreateLookAt(cameraPosition, cameraTarget, Vector3.Up); quadEffect.Projection = this.Projection; quadEffect.TextureEnabled = true; quadEffect.Texture = quadTexture; And in Draw() I have: this.GraphicsDevice.VertexDeclaration = quadVertexDecl; quadEffect.Begin(); foreach (EffectPass pass in quadEffect.CurrentTechnique.Passes) { pass.Begin(); GraphicsDevice.DrawUserIndexedPrimitives<VertexPositionNormalTexture>( PrimitiveType.TriangleList, quad.Vertices, 0, 4, quad.Indexes, 0, 2); pass.End(); } quadEffect.End(); I think I'm doing something wrong in the quadEffect properties, but I'm not quite sure what.

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  • Which PHP library I should choose to work with CouchDB?

    - by Guss
    I want to try playing with CouchDB for a new project I'm writing (as a hobby, not part of my job). I'm well versed in PHP, but I haven't programmed with CouchDB at all, and also I have little experience with non-SQL databases. From looking at CouchDB's "Getting Started with PHP" document they recommend using a third-party library or writing your own client using their RESTful HTTP API. I think I'd rather not mess with writing protocol implementations myself at this point, but what is your experience with writing PHP to work with CouchDB? I haven't tested any of the alternatives yet, but I looked at: PHPillow : I'm interested in the way they implement ORM. I wasn't planning to do ORM, but my problem domain probably map well to that method. PHP Object Freezer: seems like a poor man's ORM - I can use it to implement an actual ORM, or just as an easy store/retrieve document API but it seems too primitive. PHP-on-Couch : Also a bit simple, but they have an interesting API for views and from the documentation it looks usable enough. PHP CouchDB Extension : From the listed options this looks like it has the best chance of making it into the PHP mainline itself, and also has the most complete API. Any opinion one wish to share on each library is welcome.

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  • Python c_types .dll functions (pari library)

    - by silinter
    Alright, so a couple days ago I decided to try and write a primitive wrapper for the PARI library. Ever since then I've been playing with ctypes library in loading the dll and accessing the functions contained using code similar to the following: from ctypes import * libcyg=CDLL("<path/cygwin1.dll") #It needs cygwin to be loaded. Not sure why. pari=CDLL("<path>/libpari-gmp-2.4.dll") print pari.fibo #fibonacci function #prints something like "<_FuncPtr object at 0x00BA5828>" So the functions are there and they can potentially be accessed, but I always recieve an access violation no matter what I try. For example: pari.fibo(5) #access violation pari.fibo(c_int(5)) #access violation pari.fibo.argtypes=[c_long] #setting arguments manually pari.fibo.restype=long #set the return type pari.fibo(byref(c_int(5))) #access violation reading 0x04 consistently and any variation on that, including setting argtypes to receive pointers. The Pari .dll is written in C and the fibonacci function's syntax within the library is GEN fibo(long x) (docs @http://pari.math.u-bordeaux.fr/dochtml/html/Arithmetic_functions.html#fibonacci, I need more rep it seems). Could it be the return type that's causing these errors, as it is not a standard int or long but a GEN type, which is unique to the PARI library? Any help would be appreciated. If anyone is able to successfully load the library and use ANY function from within python, please tell; I've been at this for hours now.

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  • JDBC/OSGi and how to dynamically load drivers without explicitly stating dependencies in the bundle?

    - by Chris
    Hi, This is a biggie. I have a well-structured yet monolithic code base that has a primitive modular architecture (all modules implement interfaces yet share the same classpath). I realize the folly of this approach and the problems it represents when I go to deploy on application servers that may have different conflicting versions of my library. I'm dependent on around 30 jars right now and am mid-way though bnding them up. Now some of my modules are easy to declare the versioned dependencies of, such as my networking components. They statically reference classes within the JRE and other BNDded libraries but my JDBC related components instantiate via Class.forName(...) and can use one of any number of drivers. I am breaking everything up into OSGi bundles by service area. My core classes/interfaces. Reporting related components. Database access related components (via JDBC). etc.... I wish for my code to be able to still be used without OSGi via single jar file with all my dependencies and without OSGi at all (via JARJAR) and also to be modular via the OSGi meta-data and granular bundles with dependency information. How do I configure my bundle and my code so that it can dynamically utilize any driver on the classpath and/or within the OSGi container environment (Felix/Equinox/etc.)? Is there a run-time method to detect if I am running in an OSGi container that is compatible across containers (Felix/Equinox/etc.) ? Do I need to use a different class loading mechanism if I am in a OSGi container? Am I required to import OSGi classes into my project to be able to load an at-bundle-time-unknown JDBC driver via my database module? I also have a second method of obtaining a driver (via JNDI, which is only really applicable when running in an app server), do I need to change my JNDI access code for OSGi-aware app servers?

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  • Why does autoboxing in Java allow me to have 3 possible values for a boolean?

    - by John
    Reference: http://java.sun.com/j2se/1.5.0/docs/guide/language/autoboxing.html If your program tries to autounbox null, it will throw a NullPointerException. javac will give you a compile-time error if you try to assign null to a boolean. makes sense. assigning null to a Boolean is a-ok though. also makes sense, i guess. but let's think about the fact that you'll get a NPE when trying to autounbox null. what this means is that you can't safely perform boolean operations on Booleans without null-checking or exception handling. same goes for doing math operations on an Integer. for a long time, i was a fan of autoboxing in java1.5+ because I thought it got java closer to be truly object-oriented. but, after running into this problem last night, i gotta say that i think this sucks. the compiler giving me an error when I'm trying to do stuff with an uninitialized primitive is a good thing. I think I may be misunderstanding the point of autoboxing, but at the same time I will never accept that a boolean should be able to have 3 values. can anyone explain this? what am i not getting?

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  • Why does gcc generate verbose assembly code?

    - by Jared Nash
    I have a question about assembly code generated by GCC (-S option). Since, I am new to assembly language and know very little about it, the question will be very primitive. Still, I hope somebody will answer: Suppose, I have this C code: main(){ int x = 15; int y = 6; int z = x - y; return 0; } If we look at the assembly code (especially the part corresponding to int z = x - y ), we see: main: ... subl $16, %esp movl $15, -4(%ebp) movl $6, -8(%ebp) movl -8(%ebp), %eax movl -4(%ebp), %edx movl %edx, %ecx subl %eax, %ecx movl %ecx, %eax movl %eax, -12(%ebp) ... Why doesn't GCC generate something like this, which is less copying things around. main: ... movl $15, -4(%ebp) movl $6, -8(%ebp) movl -8(%ebp), %edx movl -4(%ebp), %eax subl %edx, %eax movl %eax, -12(%ebp) ... P.S. Linux zion-5 2.6.32-21-generic #32-Ubuntu SMP Fri Apr 16 08:10:02 UTC 2010 i686 GNU/Linux gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5)

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  • Why do my raytraced spheres have dark lines when lit with multiple light sources?

    - by Curyous
    I have a simple raytracer that only works back up to the first intersection. The scene looks OK with two different light sources, but when both lights are in the scene, there are dark shadows where the lit area from one ends, even if in the middle of a lit area from the other light source (particularly noticeable on the green ball). The transition from the 'area lit by both light sources' to the 'area lit by just one light source' seems to be slightly darker than the 'area lit by just one light source'. The code where I'm adding the lighting effects is: // trace lights for ( int l=0; l<primitives.count; l++) { Primitive* p = [primitives objectAtIndex:l]; if (p.light) { Sphere * lightSource = (Sphere *)p; // calculate diffuse shading Vector3 *light = [[Vector3 alloc] init]; light.x = lightSource.centre.x - intersectionPoint.x; light.y = lightSource.centre.y - intersectionPoint.y; light.z = lightSource.centre.z - intersectionPoint.z; [light normalize]; Vector3 * normal = [[primitiveThatWasHit getNormalAt:intersectionPoint] retain]; if (primitiveThatWasHit.material.diffuse > 0) { float illumination = DOT(normal, light); if (illumination > 0) { float diff = illumination * primitiveThatWasHit.material.diffuse; // add diffuse component to ray color colour.red += diff * primitiveThatWasHit.material.colour.red * lightSource.material.colour.red; colour.blue += diff * primitiveThatWasHit.material.colour.blue * lightSource.material.colour.blue; colour.green += diff * primitiveThatWasHit.material.colour.green * lightSource.material.colour.green; } } [normal release]; [light release]; } } How can I make it look right?

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  • Design PDF template and populate data at runtime using java,xml etc..

    - by Samant
    well i have been looking for a java based PDF solutions...we dont have a clean way i guess-still.. all solutions are primitive and kind of workarounds... No easy solution for this requirement - 1. Designing a PDF template using a IDE (eg. Livecycle designer ..which is not free) 2. Then at runtime using java, populate data into this PDF template...either using xml or other datasources... such a simple requirement and NONE has a good "open-source and free" solution yet ! Is anyone aware of any ? I have been searching for since 3-4 years now..for a clean way out... Eclipse BIRT comes close.. but does not handle Barcode elements ..OOB. Jasper - ireport is also good but that tool does not have a table concept and is kind of annoying ! Also barcode support is not good. XSL-FO has not free IDE for design . Looking for a better answer .. got one ?

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  • Why am I having this InstantiationException in Java when accessing final local variables?

    - by Oscar Reyes
    I was playing with some code to make a "closure like" construct ( not working btw ) Everything looked fine but when I tried to access a final local variable in the code, the exception InstantiationException is thrown. If I remove the access to the local variable either by removing it altogether or by making it class attribute instead, no exception happens. The doc says: InstantiationException Thrown when an application tries to create an instance of a class using the newInstance method in class Class, but the specified class object cannot be instantiated. The instantiation can fail for a variety of reasons including but not limited to: - the class object represents an abstract class, an interface, an array class, a primitive type, or void - the class has no nullary constructor What other reason could have caused this problem? Here's the code. comment/uncomment the class attribute / local variable to see the effect (lines:5 and 10 ). import javax.swing.*; import java.awt.event.*; import java.awt.*; class InstantiationExceptionDemo { //static JTextField field = new JTextField();// works if uncommented public static void main( String [] args ) { JFrame frame = new JFrame(); JButton button = new JButton("Click"); final JTextField field = new JTextField();// fails if uncommented button.addActionListener( new _(){{ System.out.println("click " + field.getText()); }}); frame.add( field ); frame.add( button, BorderLayout.SOUTH ); frame.pack();frame.setVisible( true ); } } class _ implements ActionListener { public void actionPerformed( ActionEvent e ){ try { this.getClass().newInstance(); } catch( InstantiationException ie ){ throw new RuntimeException( ie ); } catch( IllegalAccessException ie ){ throw new RuntimeException( ie ); } } } Is this a bug in Java? edit Oh, I forgot, the stacktrace ( when thrown ) is: Caused by: java.lang.InstantiationException: InstantiationExceptionDemo$1 at java.lang.Class.newInstance0(Class.java:340) at java.lang.Class.newInstance(Class.java:308) at _.actionPerformed(InstantiationExceptionDemo.java:25)

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  • general learning methodology

    - by momo
    just wanted to hear on the different general learning paths people embark on when learning a new language/framework. the one i currently use, which is how i learned bash and am currently learning python, is: instant hacking tutorial (very short tutorial introducing the basic syntax, variable declaration, loops, data types, etc. and how they are generally used) in depth tutorial with good programming style and slightly topic-specific (e.g. Mark Pilgrim's Dive into Python), important topics for me personally are regex methods, file IO, and ways the different data types are utilized best (i wrote a very primitive bayesian spam filter using python's dictionaries to keep track of word occurrences) spaced-repition of syntax or short recipes (i use anki, with questions like 'create dictionary with filename and filesize metadata, human-readable' or simpler ones like 'match 0 - 3 occurences of the letter M in a string', or 'return/create an iterator from two sequences') the use of spaced-repitition has been invaluable, and i credit it with the ease that i can recall/create python algorithms. however, i've recently started looking into django, and i've found that spaced-repitition, at least in my case, doesn't work very well for learning a framework, it works best with short code recipes (either that or i should start looking into more basic django framework tutorials). the problem i'm encountering is that since framework programming is not only algorithms, but actually learning the API, which can be quite complex since you have to learn all the methods, modules, the places where they are stored, and the sequence of which things have to be done. for ex. in django to start a project that deals with polls (from the django tutorial), one has to create the project, edit the settings.py file, create the polls app, edit the models.py file (which requires knowing the classes that are present in the module models), edit the urls.py file, etc. i found that my spaced-repition method didn't work very well for this type of learning, so i wanted to ask you guys what method(s) you use for learning the different frameworks/APIs.

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  • What is the best method for updating all changed data in EF 4?

    - by Soul_Master
    I try to create some method that can update any changed data from changed Data object (this object is generated by ASP.NET MVC) to old Data object (this object is retrieved from current data in DBMS) like the following code. public static bool UpdateSomeData(SomeEntities context, SomeModelType changedData) { var oldData = GetSomeModelTypeById(context, changedData.ID); UpdateModel(oldData, changedData); return context.SaveChanges() > 0; } I try to create method for saving any changed data without affects other unchanged data like the following source code. public static void UpdateModel<TModel>(TModel oldData, TModel changedData) { foreach (var pi in typeof(TModel).GetProperties() .Where ( // Ignore Change ID property for security reason x => x.Name.ToUpper() != "ID" && x.CanRead && x.CanWrite && ( // It must be primitive type or Guid x.PropertyType.FullName.StartsWith("System") && !x.PropertyType.FullName.StartsWith("System.Collection") && !x.PropertyType.FullName.StartsWith("System.Data.Entity.DynamicProxies") ) ) { var oldValue = pi.GetValue(oldData, null); var newValue = pi.GetValue(changedData, null); if (!oldValue.Equals(newValue)) { pi.SetValue(oldData, newValue, null); } } } I am not sure about the above method because it is so ugly method for updating data. From recent bug, it realizes me that if you update some property like Navigation Properties (related data from other table), it will remove current record from database. I don't understand why it happened. But it is very dangerous for me. So, do you have any idea for this question to ensure me about updating data from ASP.NET MVC? Thanks,

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  • What's a good Java-based Master-Slave communication mechanism?

    - by plecong
    I'm creating a Java application that requires master-slave communication between JVMs, possibly residing on the same physical machine. There will be a "master" server running inside a JEE application server (i.e. JBoss) that will have "slave" clients connect to it and dynamically register itself for communication (that is the master will not know the IP addresses/ports of the slaves so cannot be configured in advance). The master server acts as a controller that will dole work out to the slaves and the slaves will periodically respond with notifications, so there would be bi-directional communication. I was originally thinking of RPC-based systems where each side would be a server, but it could get complicated, so I'd prefer a mechanism where there's an open socket and they talk back and forth. I'm looking for a communication mechanism that would be low-latency where the messages would be mostly primitive types, so no serious serialization is necessary. Here's what I've looked at: RMI JMS: Built-in to Java, the "slave" clients would connect to the existing ConnectionFactory in the application server. JAX-WS/RS: Both master and slave would be servers exposing an RPC interface for bi-directional communication. JGroups/Hazelcast: Use shared distributed data structures to facilitate communication. Memcached/MongoDB: Use these as "queues" to facilitate communication, though the clients would have to poll so there would be some latency. Thrift: This does seem to keep a persistent connection, but not sure how to integrate/embed a Thrift server into JBoss WebSocket/Raw Socket: This would work, but require a lot more custom code than I'd like. Is there any technology I'm missing? Edit: Also looked at: JMX: Have the client connect to JBoss' JMX server and receive JMX notifications for bidirectional comms.

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  • How to create a generic C free function .

    - by nomemory
    I have some C structures related to a 'list' data structure. They look like this. struct nmlist_element_s { void *data; struct nmlist_element_s *next; }; typedef struct nmlist_element_s nmlist_element; struct nmlist_s { void (*destructor)(void *data); int (*cmp)(const void *e1, const void *e2); unsigned int size; nmlist_element *head; nmlist_element *tail; }; typedef struct nmlist_s nmlist; This way I can have different data types being hold in "nmlist_element-data" . The "constructor" (in terms of OOP) has the following signature: nmlist *nmlist_alloc(void (*destructor)(void *data)); Where "destructor" is specific function that de-allocated "data" (being hold by the nmlist_element). If I want to have a list containing integers as data, my "destructor" would like this: void int_destructor(void *data) { free((int*)data); } Still i find it rather "unfriendly" for me to write a destructor functions for every simple primitive data type. So is there a trick to write something like this ? (for primitives): void "x"_destructor(void *data, "x") { free(("x" *)data); } PS: I am not a macro fan myself, and in my short experience regarding C, i don't use them, unless necessary.

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  • Why is debugging better in an IDE?

    - by Bill Karwin
    I've been a software developer for over twenty years, programming in C, Perl, SQL, Java, PHP, JavaScript, and recently Python. I've never had a problem I could not debug using some careful thought, and well-placed debugging print statements. I respect that many people say that my techniques are primitive, and using a real debugger in an IDE is much better. Yet from my observation, IDE users don't appear to debug faster or more successfully than I can, using my stone knives and bear skins. I'm sincerely open to learning the right tools, I've just never been shown a compelling advantage to using visual debuggers. Moreover, I have never read a tutorial or book that showed how to debug effectively using an IDE, beyond the basics of how to set breakpoints and display the contents of variables. What am I missing? What makes IDE debugging tools so much more effective than thoughtful use of diagnostic print statements? Can you suggest resources (tutorials, books, screencasts) that show the finer techniques of IDE debugging? Sweet answers! Thanks much to everyone for taking the time. Very illuminating. I voted up many, and voted none down. Some notable points: Debuggers can help me do ad hoc inspection or alteration of variables, code, or any other aspect of the runtime environment, whereas manual debugging requires me to stop, edit, and re-execute the application (possibly requiring recompilation). Debuggers can attach to a running process or use a crash dump, whereas with manual debugging, "steps to reproduce" a defect are necessary. Debuggers can display complex data structures, multi-threaded environments, or full runtime stacks easily and in a more readable manner. Debuggers offer many ways to reduce the time and repetitive work to do almost any debugging tasks. Visual debuggers and console debuggers are both useful, and have many features in common. A visual debugger integrated into an IDE also gives you convenient access to smart editing and all the other features of the IDE, in a single integrated development environment (hence the name).

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  • Detection of negative integers using bit operations

    - by Nawaz
    One approach to check if a given integer is negative or not, could be this: (using bit operations) int num_bits = sizeof(int) * 8; //assuming 8 bits per byte! int sign_bit = given_int & (1 << (num_bits-1)); //sign_bit is either 1 or 0 if ( sign_bit ) { cout << "given integer is negative"<<endl; } else { cout << "given integer is positive"<<endl; } The problem with this solution is that number of bits per byte couldn't be 8, it could be 9,10, 11 even 16 or 40 bits per byte. Byte doesn't necessarily mean 8 bits! Anyway, this problem can be easily fixed by writing, //CHAR_BIT is defined in limits.h int num_bits = sizeof(int) * CHAR_BIT; //no assumption. It seems fine now. But is it really? Is this Standard conformant? What if the negative integer is not represented as 2's complement? What if it's representation in a binary numeration system that doesn't necessitate only negative integers to have 1 in it's most significant bit? Can we write such code that will be both portable and standard conformant? Related topics: Size of Primitive data types Why is a boolean 1 byte and not 1 bit of size?

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  • EF/LINQ: Where() against a property of a subtype

    - by ladenedge
    I have a set of POCOs, all of which implement the following simple interface: interface IIdObject { int Id { get; set; } } A subset of these POCOs implement this additional interface: interface IDeletableObject : IIdObject { bool IsDeleted { get; set; } } I have a repository hierarchy that looks something like this: IRepository<T <: BasicRepository<T <: ValidatingRepository<T (where T is IIdObject) I'm trying to add a FilteringRepository to the hierarchy such that all of the POCOs that implement IDeletableObject have a Where(p => p.IsDeleted == false) filter applied before any other queries take place. My goal is to avoid duplicating the hierarchy solely for IDeletableObjects. My first attempt looked like this: public override IQueryable<T> Query() { return base.Query().Where(t => ((IDeletableObject)t).IsDeleted == false); } This works well with LINQ to Objects, but when I switch to an EF backend I get: "LINQ to Entities only supports casting Entity Data Model primitive types." I went on to try some fancier parameterized solutions, but they ultimately failed because I couldn't make T covariant in the following case for some reason I don't quite understand: interface IQueryFilter<out T> // error { Expression<Func<T, bool>> GetFilter(); } I'd be happy to go into more detail on my more complicated solutions if it would help, but I think I'll stop here for now in hope that someone might have an idea for me to try. Thanks very much in advance!

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  • To use the 'I' prefix for interfaces or not to

    - by ng
    That is the question? So how big a sin is it not to use this convention when developing a c# project? This convention is widely used in the .NET class library. However, I am not a fan to say the least, not just for asthetic reasons but I don't think it makes any contribution. For example is IPSec an interface of PSec? Is IIOPConnection An interface of IOPConnection, I usually go to the definition to find out anyway. So would not using this convention cause confusion? Are there any c# projects or libraries of note that drop this convention? Do any c# projects that mix conventions, as unfortunately Apache Wicket does? The Java class libraries have existed without this for many years, I don't feel I have ever struggled to read code without it. Also, should the interface not be the most primitive description? I mean IList<T> as an interface for List<T> in c#, is it not better to have List<T> and LinkedList<T> or ArrayList<T> or even CopyOnWriteArrayList<T>? The classes describe the implementation? I think I get more information here, than I do from List<T> in c#.

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