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• javascript open window references

  - by duckofrubber

  Hi, I'm having some issues understanding how to reference new browser windows after opening them. As an example, if I created 3 new windows from a main one (index.html): var one = window.open( 'one.html', 'one',"top=10,left=10,width=100,height=100,location=no,menubar=no,scrollbars=no,status=no,toolbar=no,resizable=no"); var two = window.open( 'two.html', 'two',"top=100,left=10,width=100,height=100,location=no,menubar=no,scrollbars=no,status=no,toolbar=no,resizable=no"); var three = window.open( 'three.html', 'three',"top=200,left=10,width=100,height=100,location=no,menubar=no,scrollbars=no,status=no,toolbar=no,resizable=no"); two.focus(); How could I programmatically focus on (or just refer to) browser "three" if browser "two" is currently in focus?

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• Java: Best practices for turning foreign horror-code into clean API...?

  - by java.is.for.desktop

  Hello, everyone! I have a project (related to graph algorithms). It is written by someone else. The code is horrible: public fields, no getters/setters huge methods, all public some classes have over 20 fields some classes have over 5 constructors (which are also huge) some of those constructors just left many fields null (so I can't make some fields final, because then every second constructor signals errors) methods and classes rely on each other in both directions I have to rewrite this into a clean and understandable API. Problem is: I myself don't understand anything in this code. Please give me hints on analyzing and understanding such code. I was thinking, perhaps, there are tools which perform static code analysis and give me call graphs and things like this.

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• Implementing password hashing/salting algorithm from crackstation.net

  - by Mason240

  I am trying to implement a password hashing/salting algorithm from crackstation.net, but I am unsure how implement it. Storing the password upon user registration seems to be as simple as passing the password into create_hash(). $password = create_hash($_POST['Password']; I'm not following how to validate upon user login. validate_password($password, $good_hash) returns either true or false, and takes $password as parameter, so it seems like a no brainer except for the second parameter $good_hash. Where does this param come from? It is my understanding that password is turned into a hash value every time its used, and that the hash value is what is stored and compared. So why would I have both the $password and $good_hash values? Quick overview of the functions: function create_hash($password){ calls pbkdf2() } function validate_password($password, $good_hash){ calls pbkdf2() calls slow_equals() } function slow_equals($a, $b){ } function pbkdf2($algorithm, $password, $salt, $count, $key_length, $raw_output = false){ } Of course a different, better method for this would also be just as helpful. Thank you

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• Entity Framework VS LINQ to SQL VS ADO.NET with stored procedures?

  - by BritishDeveloper

  How would you rate each of them in terms of: Performance Speed of development Neat, intuitive, maintainable code Flexibility Overall I like my SQL and so have always been a die-hard fan of ADO.NET and stored procedures but I recently had a play with Linq to SQL and was blown away by how quickly I was writing out my DataAccess layer and have decided to spend some time really understanding either Linq to SQL or EF... or neither? I just want to check, that there isn't a great flaw in any of these technologies that would render my research time useless. E.g. performance is terrible, it's cool for simple apps but can only take you so far

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• Preserving original StackTrace/LineNumbers in .NET Exceptions

  - by Sam

  Understanding the difference between throw ex and throw, why is the original StackTrace preserved in this example: static void Main(string[] args) { try { LongFaultyMethod(); } catch (System.Exception ex) { Console.WriteLine(ex.StackTrace); } } static void LongFaultyMethod() { try { int x = 20; SomethingThatThrowsException(x); } catch (Exception) { throw; } } static void SomethingThatThrowsException(int x) { int y = x / (x - x); } But not in this one: static void Main(string[] args) { try { LongFaultyMethod(); } catch (System.Exception ex) { Console.WriteLine(ex.StackTrace); } } static void LongFaultyMethod() { try { int x = 20; int y = x / (x - 20); } catch (Exception) { throw; } } The second scenario is producing the same output as throw ex would? In both cases, one expects to see the line number where y is initialized.

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• Backup AWS Dynamodb to S3

  - by Ali

  It has been suggested on Amazon docs http://aws.amazon.com/dynamodb/ among other places, that you can backup your dynamodb tables using Elastic Map Reduce, I have a general understanding of how this could work but I couldn't find any guides or tutorials on this, So my question is how can I automate dynamodb backups (using EMR)? So far, I think I need to create a "streaming" job with a map function that reads the data from dynamodb and a reduce that writes it to S3 and I believe these could be written in Python (or java or a few other languages). Any comments, clarifications, code samples, corrections are appreciated.

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• JPanel: both implementing my own paintComponent() and rendering children doesn't work

  - by Paul Marshall

  I'm extending a JPanel to display a game board, and adding a JEditorPane at the bottom to hold some status text. Unfortunately, the game board renders just fine, but the JEditorPane is just a blank gray area until I highlight the text in it, when it will render whatever text is highlighted (but not the rest). If I'm understanding Swing right, it should work, because super.paintComponent(g) should render the other children (i.e., the JEditorPane). Tell me, o great stackoverflow, what bonehead mistake am I making? public GameMap extends JPanel { public GameMap() { JEditorPane statusLines = new JEditorPane("text/plain","Stuff"); this.setLayout(new BoxLayout(this,BoxLayout.PAGE_AXIS)); this.add(new Box.Filler(/*enough room to draw my game board*/)); this.add(statusLines); } public void paintComponent(Graphics g){ super.paintComponent(g); for ( all rows ){ for (all columns){ //paint one tile } } } }

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• The Definition of Regular Languages

  - by AraK

  Good Day, I have tried, and burned my brain to understand the definition of Regular Languages in Discrete Mathematics and its Applications(Rosen) without reaching the goal of understanding why the definition is like that in this book. On page(789), I am rephrasing the definition: Type 3 grammars are defined as: w1 --> w2 Where w1 is a non-terminal, and w2 is of the form: w2 = aB w2 = a Where B is a non-terminal, and a is a terminal. A special case is when w1 is the starting symbol and w2 is lambda(the empty string): w1 = S S --> lambda Two questions I couldn't find an answer for. First, Why can't w2 be of the form Ba. Second, Why lambda is only allowed for the starting symbol only. The book states that, regular languages are equivalent to Finite State Automaton, and we can easily see that a we can build FSA for both cases. I took a look at other resources, and these restrictions don't exist in these resources. Thanks,

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• Is there an easy way to convert C# classes to PHP?

  - by John

  I am used to writing C# Windows application. However I have some free hosted PHP web space that I would like to make use of. I have a basic understanding of PHP but have never used it's object oriented capabilities. Is there an easy way to convert C# classes to PHP classes or is it just not possible to write a fully object oriented application in PHP? Update: There are no reliance on the .NET framework beyond the basics. The main aim would be to restructure the class properties, variable enums, etc. The PHP will be hosted on a Linux server.

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• What exactly is a Monad?

  - by WeNeedAnswers

  Can someone please explain to me what a Monad is. I think I grasp Monoids and I grasp that they basically control the input of state into a system. I just look at the text in Haskell and glaze over. A simple example in python would be great. My current understanding is that a Monoid is a procedural piece of code that needs to be read from top to bottom in sequence with the output being the input for the function. I think that I may even got that wrong, but hey I am here to learn.

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• How do I create queries to SQL Server tables via Visual Studio when no knowledge about SQL nor Linq?

  - by Kent S. Clarkson

  Let´s be frank, my knowledge regarding SQL language is very low. Nevertheless, my boss gave me the task to build a database application using the following tools: SQL Server and Visual Studio 2008; C#. I use the VS DataSet as a local mirror of the SQL Server. And let´s be frank again, my understanding of the VS Query builder is also very small, I´m finding it quite confusing, actually. So no help to find from Query builder. And my knowledge of Linq is even lower... Perhaps I should mention that the deadline for the project is "aggressively" set, so I have no chance to learn enough about these things during the project. And I´m a bit stupid too, which is no help when it comes to challenges like this (on other occations it might be quite useful though) With these permissions, what should I do (except for killing myself or retire) to be able to query my tables in a sufficient way?

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• how to compare between Doctrine & Propel in symfony

  - by Patrick

  I am in the early stages of rearchitecting my company's application. The app is currently running on symfony 1.2, and I used the default ORM at the time, Propel. Symfony has since updated to 1.4 and switched default ORM to Doctrine. From my understanding, each ORM excels at particular types of database structures. Is this true or is one far and away better than the other? Are there any good methods to test which ORM would be best in my situation in a test environment using my schema (i.e.- set up dual, identical sites and run tests)?

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• strategies for learning complex software packages

  - by Tom

  I am a fairly novice Java programmer and I am currently working on a project to extend a piece of software that has been developed over a few years. So it has pretty big code base and the previous developers knew it well, so extending it is not going to be easy without a thorough understanding of the structure and function. 1) I had begun by trying to tackle small parts of the system and document them with mindmap. (particularly I am trying to document the interactions with external systems) 2) I have the book "code complete", which I am working through. 3) I have pointed some tools like "tattletale" at the code to get some diagrams of dependency relationships. What other strategies should I employ, should I focus on one particular aspect?

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• MySQL - Sort on a calculated value based on two dates

  - by Petter Magnusson

  I have the following problem that needs to be solved in a MySQL query: Fields info - textfield date1 - a date field date2 - a date field offset1 - a text field with a number in the first two positions, example "10-High" offset2 - a text field with a number in the first two positions, example "10-High" I need to sort the records by the calculated "sortvalue" based on the current date (today): If today=date2 then sortvalue=offset1*10+offset2*5+1000 else sortvalue=offset1*10+offset2*5 I have quite good understanding of basic SQL with joins etc, but this I am not even sure if its possible...if it helps I could perhaps live with a single formula giving the same sort of effect as the IFs do....ie. before date1 = low value, after date2 = high value... Rgds PM

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• Good learning resources for JNDI implementation (JBoss 5)

  - by iandisme

  I have been working with JavaEE/EJB3 web apps for about half a year now. Until recently, I haven't had to touch a lot of the behind-the-scenes stuff, just the meat of the code. I have been wrestling with JNDI problems, and though I've solved a couple of them, I'm pretty much just doing the whole cargo cult copy-paste routine. It would really help me to better understand JNDI; my understanding of it right now can be summarized as "it's that thing these classes sometimes do to find other classes." My question is, has anyone had success learning JNDI/EJB3/related topics from a book or online content? I've googled for it but the stuff that comes up is old or specific to a certain framework I'm not using. I'm looking for something that's either JBoss-specific or generic enough to be useful anyway.

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• setting url in yaml file for google app engin (page not found) problem

  - by mswallace

  I am new to python and I am super excited to learn. I am building my first app on app engin and I am not totally understanding why my yaml file is not resolving to the url that I set up. here is the code handlers: - url: .* script: main.py - url: /letmein/.* script: letmein.py so if I go to http://localhost:8080/letmein/ I get a link is brooken or page not found error. here is the python code that I have in letmein.py from google.appengine.ext import webapp from google.appengine.ext.webapp import util class LetMeInHandler(webapp.RequestHandler): def get(self): self.response.out.write('letmein!') def main(): application = webapp.WSGIApplication([('/letmein/', LetMeInHandler)], debug=True) util.run_wsgi_app(application) if __name__ == '__main__': main() thanks in advance for the help!

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• help me understand JS execution on onclick event of button

  - by Anil Namde

  <input type="button" name="reset" onclick="return ValidateValue(); __doPostBack('ApplyBtn','')" /> The above is the code generated for asp server button button control on browser. Now my query is that irrespective of ValidateValue() returning true/false __doPostBack('ApplyBtn','') function is not showing any effect for me. My understanding is that string passed to onclick acts like function body, and return will from first function will return control preventing second function from execution. Is that correct ? Please provide helpful inputs.

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• What is the JavaScript variable scope in a switch / case statment?

  - by Todd Moses

  While creating JavaScript with ASP.NET MVC I noticed several scope warnings and realized that I am missing something with understanding the variable scope inside the switch / case statement. Warning: 'i' is already defined referring to case b and case c My code looks similar to this: switch(element) { case 'a': for(var i=0; i < count; i++){ do something } break; case 'b': for(var i=0; i < count; i++){ do something } break; case 'c': for(var i=0; i < count; i++){ do something } break; } I thought scope ended with each break statement but it seems that scope does not end until the end of the switch/case. Is scope for the entire switch/case?

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• What is the difference between MVC model 1 and model 2?

  - by Alex Ciminian

  I've recently discovered that MVC is supposed to have two different flavors, model one and model two. I'm supposed to give a presentation on MVC1 and I was instructed that "it's not the web based version, that is refered to as MVC2". As the presentations are about design patterns in general, I doubt that this separation is related to Java (I found some info on Sun's site, but it seemed far off) or ASP. I have a pretty good understanding of what MVC is and I've used several (web) frameworks that enforce it, but this terminology is new to me. How is the web-based version different from other MVC (I'm guessing GUI) implementations? Does it have something to do with the stateless nature of HTTP? Thanks, Alex

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• how to pass in dynamic data to decorators

  - by steve

  Hi, I am trying to write a base crud controller class that does the following: class BaseCrudController: model = "" field_validation = {} template_dir = "" @expose(self.template_dir) def new(self, *args, **kwargs) .... @validate(self.field_validation, error_handler=new) @expose() def post(self, *args, **kwargs): ... My intent is to have my controllers extend this base class, set the model, field_validation, and template locations, and am ready to go. Unfortunately, decorators (to my understanding), are interpreted when the function is defined. Hence it won't have access to instance's value. Is there a way to pass in dynamic data or values from the sub class? If not, I guess I could use override_template as a workaround to expose and set the template within the controller action. How would I go about validating the form within the controller action? Thanks, Steve

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• Identifying iPhone OS's on a Network and Sending Push Notifications

  - by portalservices

  tldr; Can you identify devices on your network as an iPhone OS device easily? Can you send push notifications to devices identified as using the iPhone OS on your network without a a target app? Is is possible to identify which devices on a network are using the iPhone OS? With this information, is it possible to send push notifications to these devices? From my understanding, your application server will contact APNs, which will contact the users. So, the above would be impossible. Can someone confirm this for me? Thanks, P.S.

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• LAMP Stack with APC installed - WordPress Site - Is WP opcode being cached with APC?

  - by Christopher Altman

  I have a LAMP stack with APC installed. I have a WordPress site on this server. Is WP taking advantage of the opcode caching? I have done no WP configurations. My understanding is that simply having APC installed means that all PHP code is being cached. If that is untrue, please point me to the direction where I can configure WP to take advantage of APC. Note: I thought about this as a ServerFault question, but since the solution to is code related I posted on Stackoverflow.

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• EXC_BAD_ACCESS when not using self.

  - by chris

  I got nabbed by the following bug again and would like some clarification to exactly why it is a bug. I have a simple UITableView that loads some data: // myclass.h @property (nonatomic, retain) NSArray *myData // myclass.m @synthesize myData; - (void) viewDidLoad { ... myData = someDataSource // note the lack of self } - (UITableViewCell *) cellForRowAtIndexPath ... { ... cell.textLabel.text = [self.myData objectAtIndex:indexPath.row]; // EXC_BAD_ACCESS } The table first loads fine, but when scrolling up enough that one of the cells is totally out of the view I then get the EXC_BAD_ACCESS error. Am I missing something in regards to @property retain. My understanding is that it releases anything that the pointer was previously pointing to before the reassignment. If I am correct then why would not using self. cause any problems? Thanks for the help.

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• is there a downside to putting N in front of strings in scripts? Is it considered a "best practice"?

  - by jcollum

  Let's say I have a table that has a varchar field. If I do an insert like this: INSERT MyTable SELECT N'the string goes here' Is there any fundamental difference between that and: INSERT MyTable SELECT 'the string goes here' My understanding was that you'd only have a problem if the string contained a Unicode character and the target column wasn't unicode. Other than that, SQL deals with it just fine and converts the string with the N'' into a varchar field (basically ignores the N). I was under the impression that N in front of strings was a good practice, but I'm unable to find any discussion of it that I'd consider definitive. Title may need improvement, feel free.

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• Are Scala "continuations" just a funky syntax for defining and using Callback Functions?

  - by Alex R

  And I mean that in the same sense that a C/Java for is just a funky syntax for a while loop. I still remember when first learning about the for loop in C, the mental effort that had to go into understanding the execution sequence of the three control expressions relative to the loop statement. Seems to me the same sort of effort has to be applied to understand Continuations (in Scala and I guess probably other languages). And then there's the obvious follow-up question... if so, then what's the point? It seems like a lot of pain (language complexity, programmer errors, unreadable programs, etc) for no gain.

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