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• Presenting MVC to Old C++ Spaghetti Coders?

  - by leeand00

  I wish to present the idea of MVC to a bunch of old C++ spaghetti coders (at my local computer club). One of them that has alot of influence on the rest of the group seems to finally be getting the idea of encapsulation (largely due in part to this website). I was hoping that I could also point him in the right direction by showing him Model View Controller, but I need to do it in a way that makes sense to him, as well as it probably needs to be written in C/C++! I realize that MVC is a very old architectural pattern so it would seem to me that there should be something out there that would do the job. I'm more of a web developer, so I was wondering if anybody out there who is a good C/C++ coder could tell me what it is that made the MVC light switch turn on in your head.

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• Future proof Primary Key design in postgresql

  - by John P

  I've always used either auto_generated or Sequences in the past for my primary keys. With the current system I'm working on there is the possibility of having to eventually partition the data which has never been a requirement in the past. Knowing that I may need to partition the data in the future, is there any advantage of using UUIDs for PKs instead of the database's built-in sequences? If so, is there a design pattern that can safely generate relatively short keys (say 6 characters instead of the usual long one e6709870-5cbc-11df-a08a-0800200c9a66)? 36^6 keys per-table is more than sufficient for any table I could imagine. I will be using the keys in URLs so conciseness is important.

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• How can the javascript plugin architecture in raphael/jquery be done?

  - by TimDog

  I'm looking for a barebones javascript example that demonstrates how the javascript plugin architecture works with large javascript libraries (such as raphael or jquery). In either scenario, you build plugins by ensuring your custom plugin follows this pattern: jQuery.fn.pluginName -- so assume I have a library: myLibrary = (function() { //my fancy javascript code return function() { //my return object }; }); How would fn be incorporated into the above myLibrary object to ensure that he resulting plugin is callable? I instantiate myLibrary like so: var lib = new myLibrary(); And now I have included a reference to my plugin in my page: myLibrary.fn.simplePlugin = function() { //more fancy code } So finally, I can just call: lib.simplePlugin(); Basically, what magic is actually occuring when the .fn is used during the creation of the plugin?

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• lock file so that it cannot be deleted

  - by JoeCool

  I'm working with two independent c/c++ applications on Windows where one of them constantly updates an image on disk (from a webcam) and the other reads that image for processing. This works fine and dandy 99.99% of the time, but every once in a while the reader app is in the middle of reading the image when the writer deletes it to refresh it with a new one. The obvious solution to me seems to be to have the reader put some sort of a lock on the file so that the writer can see that it can't delete it and thus spin-lock on it until it can delete and update. Is there anyway to do this? Or is there another simple design pattern I can use to get the same sort of constant image refreshing between two programs? Thanks, -Robert

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• How do I format positional argument help using Python's optparse?

  - by cdleary

  As mentioned in the docs the optparse.OptionParser uses an IndentedHelpFormatter to output the formatted option help, for which which I found some API documentation. I want to display a similarly formatted help text for the required, positional arguments in the usage text. Is there an adapter or a simple usage pattern that can be used for similar positional argument formatting? Clarification Preferably only using the stdlib. Optparse does great except for this one formatting nuance, which I feel like we should be able to fix without importing whole other packages. :-)

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• how to call any method of Project from classlibrary?

  - by Pankaj Mishra

  Hello I have Class Library Where a class of multithreading Of Producer and consumer based. private void WorkDeQueue() { while (true) { string Url = null; lock (locker) { if (queueList.Count > 0) { Url = queueList.Dequeue(); /* return if a null is found in the queue */ if (Url == null) return; } } if (Url != null) { /* if a job was found then process it */ GetData(Url); //This Is a Method } else { /* if a job was not found (meaning list is empty) then * wait till something is added to it*/ wh.WaitOne(); } } } this GetData method has no body on that class. How can i call any method of my project in palace of getdata. I tried with factory Pattern and also with reflection. but both didn't worked for me. So plz tell me how can i call any method of my project from here.

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• TextBox.TextChanged & ICommandSource

  - by Brad Leach

  I am following the M-V-VM pattern for my WPF UI. I would like to hook up a command to the TextChanged event of a TextBox to a command that is in my ViewModel class. The only way I can conceive of completing this task is to inherit from the TextBox control, and implement ICommandSource. I can then instruct the command to be fired from the TextChanged event. This seems to be too much work for something which appears to be so simple. Is there an easier way (than subclassing the TextBox and implementing ICommandSource) to hook up the TextChanged event to my ViewModel class?

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• How do I run a vim script that alters the current buffer?

  - by Dan

  I'm trying to write a beautify.vim script that makes C-like code adhere to a standard that I can easily read. My file contains only substitution commands that all begin with %s/... However, when I try to run the script with my file open, in the manner :source beautify.vim, or :runtime beautify.vim, it runs but all the substitute commands state that their pattern wasn't found (patterns were tested by entering them manually and should work). Is there some way to make vim run the commands in the context of the current buffer? beautify.vim: " add spaces before open braces sil! :%s/\%>1c>\s\@<!{/ {/g " beautify for sil! :%s/for *( *\([^;]*\) *; *\([^;]*\) *; *\([^;]*\) *)/for (\1; \2; \3)/ " add spaces after commas sil! :%s/,\s\@!/, /g In my tests the first :s command should match (it matches when applied manually).

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• Iphone -- init method of an abstract class

  - by William Jockusch

  I want to create classes Car, Vehicle, and Airplane with the following properties: Car and Airplane are both subclasses of Vehicle. Car and Airplane both have an initWithString method. The acceptable input strings for Car's and Airplane's initWithString methods do not overlap. Vehicle is "almost abstract", in the sense that any initialized instance should be either a Car or an Airplane. It is possible to pass a string into Vehicle and get back an instance of Car, an instance of Airplane, or nil, depending on the input string. Any particular design pattern I should prefer? In particular for Vehicle's initWithString and/or newVehicleWithString methods.

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• Ant 1.8 include or import with nested resource collection

  - by Danny

  I'd like to have Ant automatically include or import resources matching a particular pattern, but I'm really struggling with the syntax. Here's what I've tried: <import> <fileset dir="${basedir}" includes="*-graph.xml" /> </import> However, I just get the error message import requires file attribute or at least one nested resource The documentation for import (and include) both say that you can use a nested resource collection, and the documentation for resource collections says <fileset> is a resource collection. I've Googled and can't find any useful examples at all. I'm using Ant 1.8.1 (verified with ant -version)

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• Activator.CreateInstance(string) and Activator.CreateInstance<T>() difference

  - by Juan Manuel Formoso

  No, this is not a question about generics. I have a Factory pattern with several classes with internal constructors (I don't want them being instantiated if not through the factory). My problem is that CreateInstance fails with a "No parameterless constructor defined for this object" error unless I pass "true" on the non-public parameter. Example // Fails Activator.CreateInstance(type); // Works Activator.CreateInstance(type, true); I wanted to make the factory generic to make it a little simpler, like this: public class GenericFactory<T> where T : MyAbstractType { public static T GetInstance() { return Activator.CreateInstance<T>(); } } However, I was unable to find how to pass that "true" parameter for it to accept non-public constructors (internal). Did I miss something or it isn't possible?

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• Scala match question

  - by javier

  Hello to everyone. I came across with an error on my Scala code that I cannot solve by myself (I am new at Scala). I have the following code: def myFunction(list: List[Any]): String = { var strItems : String = ""; list.foreach(item => { strItems += item match { case x:JsonSerializable => x.toJson() case y:String => ("\"" + y + "\"") case _ => item.toString } if(item != list.last) strItems += ","; }) strItems; } The error I am getting is: error: pattern type is incompatible with expected type; found : String required: Unit case y:String = ("\"" + y + "\"") Any idea why? PS: is there a more performant way to code myFunction

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• Another Java vs. Scala perspective - is this typical?

  - by Alex R

  I have been reading about Scala for a while and even wrote some small programs to better understand some of the more exoteric features. Today I decided to do my first "real project", translating some 60 lines of ugly Java code to Scala to rewrite it using the better pattern-matching features (why? because the Java version was becoming hard to maintain due to excessive combination of regex and conditionals). About halfway through the editing process, Eclipse thew up this error: I get the general impression that the Scala IDE in Eclipse is a lot buggier and less complete than its Java equivalent. Is this correct or do I just have a bad installation? Is there a better IDE for Scala?

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• Nesting Patterns Algorithms / Cutting Waste Problem

  - by WedTM

  First off, I'd like to say that I'm already looking into the "Cutting Stock Problem" algorithm, however I feel that I need a bit more clarification, and possibly some help with some of the math (Not my strong point). What I need to do is have an offset pattern that causes the circle to fit in the crevasse created by having the two circular dies sitting next to each other on the previous line, like so: O O O O O O O O O O O O O O O O O I'm hoping someone can point me towards the right algorithm for this! Thanks!

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• How to study programming with C language

  - by gurugio

  I am using only C for 5 years. So I am sure that I know C grammer, but I have no idea how to advance programming skills. There are many books for modern languages (such as C++, Java) to study programming skills like the refactoring or pattern, software architecture. But no book is written with C language. The book author say that his/her book is not language-dependent, but I don't think so. How can I advance my programming skills? I have to study modern language and read the books? Are there books about software design or programming skill written with C?

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• UISplitViewController: how to get toolbar if details controller is UITableView?

  - by Krumelur

  Hi, I checked out Apple's example on how to exchange detail views in the UISplitViewController (http://developer.apple.com/library/ios/#samplecode/MultipleDetailViews/Introduction/Intro.html#//apple_ref/doc/uid/DTS40009775) and it seems that they put the UIToolbar in every detail controller. Then, if the device is rotated, they hide the toolbar or show it and add a popover button which will show the root controller. I'd like to adopt this pattern to show my root controller in a popover using a button in the toolbar, but unfortunately, my detail controllers are all UITableViewControllers and they do not allow adding other UI elements than a table view. So how do I deal with that? Is there an example around? René

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• First time unit testing (in silverlight)

  - by Jakob

  Hi I've searched some other posts, but most of them assumed that people knew what they were doing in their unit testing, and frankly I don't. I see the idea behind unit testing, and I'm coding an silverlight application much in the blind right now, and I'd like to write some unit tests to kind of be sure I'm on the right path. I'd like to be able to use the SL4 vs 2010 silverlight unit test project template, to keep it simple and not use external tools. So what I need an answer for are questions like: what are the methods of unit testing? what are the differences between unit tests, and automated unit tests? How do I meaningfully unit test in silverlight? What should I be aware of while unit testing (in silverlight) ? Also should I implement some kind of IRepository pattern in my silverlight app to make unit testing easier?

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• Binding command to button in silverlight 4 using mvvm

  - by Archie

  Hello, I have a user control called HomePage.xaml. I'm creating a model instance (using MVVM pattern) in the code behind file in the constructor of page as MainViewModel model = new MainViewModel(); I have a button in HomePage.xaml which I want to bind to the command inside MainViewModel called GetData() and want to populate the data in datagrid. MainViewModel has an ObservableCollection which I would use to bind the data in datagrid. Populating the data in datagrid without binding command works fine. I'm binding the button as: <StackPanel x:Name="stkPanelInput" Orientation="Horizontal" VerticalAlignment="Center" HorizontalAlignment="Center"> <Button x:Name="buttonGetData" Width="70" Content="GetData" Command="{Binding GetData}" Click="buttonGetData_Click"/> </StackPanel> How shall I bind the command using MVVM? Thanks.

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• Separate functionality depending on Role in ASP.NET MVC

  - by Andrew Bullock

  I'm looking for an elegant pattern to solve this problem: I have several user roles in my system, and for many of my controller actions, I need to deal with slightly different data. For example, take /Users/Edit/1 This allows a Moderator to edit a users email address, but Administrators to edit a user's email address and password. I'd like a design for separating the two different bits of action code for the GET and the POST. Solutions I've come up with so far are: Switch inside each method, however this doesn't really help when i want different model arguments on the POST :( Custom controller factory which chooses a UsersController_ForModerators and UsersController_ForAdmins instead of just UsersController from the controller name and current user role Custom action invoker which choose the Edit_ForModerators method in a similar way to above Have an IUsersController and register a different implementation of it in my IoC container as a named instance based on Role Build an implementation of the controller at runtime using Castle DynamicProxy and manipulate the methods to those from role-based implementations Im preferring the named IoC instance route atm as it means all my urls/routing will work seamlessly. Ideas? Suggestions?

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• preg_match problem

  - by Biroka

  I'm trying to get some stuff from a string in php. In RegexBuddy and Regular expression tester (firefox addon) it works good, but php gives me the following: Warning: preg_match() [function.preg-match]: Compilation failed: unmatched parentheses at offset 34 in D:\path\example.php on line 62 my pattern is "/.{4}_tmp\\([A-Za-z0-9.\\]*)\(([0-9]*)\) : (.*)/i" an example string: C:\Temp\browseide\projects\32\821C_tmp\SourceFiles\main.c(8) : error C2143: syntax error : missing ';' before 'for' what RegexBuddy gets: 821C_tmp\SourceFiles\main.c(8) : error C2143: syntax error : missing ';' before 'for' Group 1: SourceFiles\main.c Group 2: 8 Group 3: error C2143: syntax error : missing ';' before 'for'

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• Compressing large text data before storing into db?

  - by Steel Plume

  Hello, I have application which retrieves many large log files from a system LAN. Currently I put all log files on Postgresql, the table has a column type TEXT and I don't plan any search on this text column because I use another external process which nightly retrieves all files and scans for sensitive pattern. So the column value could be also a BLOB or a CLOB, but now my question is the following, the database has already its compression system, but could I improve this compression manually like with common compressor utilities? And above all WHAT IF I manually pre-compress the large file and then I put as binary into the data table, is it unuseful as database system provides its internal compression?

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• Which syntax is better for return value?

  - by Omar Kooheji

  I've been doing a massive code review and one pattern I notice all over the place is this: public bool MethodName() { bool returnValue = false; if (expression) { // do something returnValue = MethodCall(); } else { // do something else returnValue = Expression; } return returnValue; } This is not how I would have done this I would have just returned the value when I knew what it was. which of these two patterns is more correct? I stress that the logic always seems to be structured such that the return value is assigned in one plave only and no code is executed after it's assigned.

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• Scraping paginated items from a website using scrapy

  - by Mridang Agarwalla

  I'm using scrapy to scrape items from a site. I'm not being able to implement this scraping pattern. The site I'm trying to scrape is a forum and I scrape the site once a day. Each page has a table containing posts. New posts are added to the top of the table and as more and more posts are posted to the site, the older posts go further into the pages due to pagination. This is a very simple scenario and we will assume that the order of the posts never change. I would like to scrape this site and scrape all the "new" records until the last scraped post from yesterday is encountered. I have configured my spider to paginate endlessly and when it encounters yesterday's last scraped post, it should stop. How can implement this? (My Scrapy installation works with my Django installation using django-dynamic-scraper )

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• Does the WCF framework support the XSD IDREF restriction?

  - by Gerard

  A nice feature in XSD is the IDREF restriction, e.g.: <xs:restriction base="xs:IDREF"> <xs:pattern value="[0-9a-zA-Z\-]+"/> </xs:restriction> I used this restriction with great benefit in a Java JAXWS-project. An object serialized in a SOAP XML datamodel can hold a reference (pointer) to another object in the same SOAP message. I want to try the same approach in a C# WCF-project, can it be done? On the web site Data Contract Schema Reference I can see e.g. Id ignored, Ref forbidden, but I am not sure whether I understand what that means.

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• Assigning an @Annotation enum a value

  - by h2g2java

  I created enum Restrictions{ none, enumeration, fractionDigits, length, maxExclusive, maxInclusive, maxLength, minExclusive, minInclusive, minLength, pattern, totalDigits, whiteSpace; public Restrictions setValue(int value){ this.value = value; return this; } public int value; } So that I could happily do something like this, which is perfectly legal syntax. Restrictions r1 = Restrictions.maxLength.setValue(64); The reason being is, I am using enum to restrict the type of restriction that could be used, and be able to assign a value to that restriction. However, my actual motivation is to use that restriction in an @annotation. @Retention(RetentionPolicy.RUNTIME) @Target({ElementType.TYPE, ElementType.FIELD, ElementType.METHOD}) public @interface Presentable { Restrictions[] restrictions() default Restrictions.none; } So that, I intended to do this: @Presentable(restrictions=Restrictions.maxLength.setValue(64)) public String userName; to which, the compiler croaks The value for annotation enum attribute must be an enum constant expression. Is there a way to accomplish what I wish to accomplish

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