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  • jQuery internals: Organization of the jQuery Object

    - by sonofdelphi
    I was going through the source code of jQuery. I'm having trouble understanding the wrapping strategy for the jQuery object. (function( window, undefined ) { // Define a local copy of jQuery var jQuery = function( selector, context ) { // The jQuery object is actually just the init constructor 'enhanced' return new jQuery.fn.init( selector, context ); }, .... .... .... // Expose jQuery to the global object window.jQuery = window.$ = jQuery; })(window); Specifically, what I'm not able to understand stems from the first line. What is the outermost unnamed container function? Why is it required? Why is the container function anonymous? What is the need for the outermost '(' parantheses ?

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  • Arrays in database tables and normalization

    - by Ivan Petrov
    Hi! Is it smart to keep arrays in table columns? More precisely I am thinking of the following schema which to my understanding violates normalization: create table Permissions( GroupID int not null default(-1), CategoryID int not null default(-1), Permissions varchar(max) not null default(''), constraint PK_GroupCategory primary key clustered(GroupID,CategoryID) ); and this: create table Permissions( GroupID int not null default(-1), CategoryID int not null default(-1), PermissionID int not null default(-1), constraint PK_GroupCategory primary key clustered(GroupID,CategoryID) ); UPD: Forgot to mention, in the scope of this concrete question we will consider that the "fetch rows that have permission X" won't be performed, instead all the lookups will be made by GroupID and CategoryID only Thoughts? Thanks in advance!

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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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  • Building a Monopoly Board with GridBagLayout

    - by Oetzi
    I have been building a Java version of Monopoly in my spare time and am having some trouble understanding layouts etc for Swing. Each one of my spaces on the board is a essentially a custom JButton and I have been trying to lay them around the edge of a frame (like on the monopoly board itself). I can't seem to find a useful explanation of how the layout system works and so am having trouble do so. Could someone please give me an example of how they would lay the buttons around the edge of the frame? Should I be using a different layout?

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  • How does Twitter for iPhone bookmarklet work?

    - by Igor Zevaka
    Twitter client (formerly Tweetie) allows you to define a bookmarklet in Safari that launches the app. I want to know which iPhone API allows you to register the protocol specifier (or whatever it's called) - in this case "tweetie:" - in order for this bookmarklet to work. The instructions can be found here and the bookmarklet itself is below. javascript:window.location='tweetie:'+window.location Clicking the above bookmark is the same as typing in "tweetie:http://google.com" into the address bar. This is obviously supported on the OS/Browser level, much the same as tel: URIs. Am I correct in understanding that developers can add arbitrary URI protocol specifiers as a part of app installation?

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  • How to reduce java concurrent mode failure and excessive gc

    - by jimx
    In Java, the concurrent mode failure means that the concurrent collector failed to free up enough memory space form tenured and permanent gen and has to give up and let the full stop-the-world gc kicks in. The end result could be very expensive. I understand this concept but never had a good comprehensive understanding of A) what could cause a concurrent mode failure and B) what's the solution?. This sort of unclearness leads me to write/debug code without much of hints in mind and often has to shop around those performance flags from Foo to Bar without particular reasons, just have to try. I'd like to learn from developers here how your experience is. If you had previous encountered such performance issue, what was the cause and how you addressed it? If you have coding recommendations, please don't be too general. Thanks!

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  • Why should I reuse XmlHttpRequest objects?

    - by Xavi
    From what I understand, it's a best practice to reuse XmlHttpRequest objects whenever possible. Unfortunately, I'm having a hard time understanding why. It seems like trying to reuse XHR objects can increase code complexity, introduce possible browser incompatibilities, and lead to other subtle bugs. After researching this question for a while, I did come up with a list of possible explanations: Fewer objects created means less garbage collecting Reusing XHR objects reduces the chance of memory leaks The overhead of creating a new XHR object is high The browser is able to perform some sort of network optimization under hood But I'm not sure if any of these reasons are actually valid. Any light you can shed on this question would be much appreciated.

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  • Oracle transaction read-consistency ?

    - by trojanwarrior3000
    I have problem understanding read consistency in db(oracle). Suppose I am manger of a bank . A customer has got lock (which I dont know) and is doing some updation. Now after he has got lock I am viewing account info of the same customer and try to do some thing on it.But because of read consistency I will see data as it existed before customer got the lock. So will not that affect inputs I am getting and the decisions that I am gonna make during that period?

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  • How does Rails find models and controllers? How can I get it to load more models?

    - by David
    I'm trying to create a non-ActiveRecord model in app/models/gamestate.rb. Then inside my controller (PlayController) I should be able to do GameState.new, right? No go: NameError (uninitialized constant PlayController::GameState): app/controllers/play_controller.rb:23:in `play' (at least in the development environment) But! If I do have a model called app/models/play.rb, then it's automatically loaded and I can do Play.new. So my question is: how does Rails know which classes to load? What sort of name mangling does it do to get from play#action to PlayController to app/controllers/play_controller.rb to app/models/play.rb? It seems awfully fragile, but maybe a better understanding of how this works would help. And finally, how can I get it to load app/models/gamestate.rb?

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  • What is the difference between Window.load and document.readyState

    - by prakash
    Hi All, I have one question , In my ASP.NET MVC web application i have to do certain validation once page and all controls got loaded. In javascript i was using belwow line of code for calling a method. window.load = JavascriptFunctionName ; Some one from my team asked me not used above line of code Instead use JQuery to do the same document.attachEvent("onreadystatechange", function() { if (document.readyState === "complete") { CheckThis(); } }); Please help me in understanding what is the difference between two. When i tested by keeping alert in both Jquery check is executing first and calling the CheckThis function where as window.load is taking some time and executing after it. Please suggest

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  • How extensive is an Object in CakePHP model linkage?

    - by Andre
    I was hoping someone with an understanding on CakePHP could shed some light on a question I've been having. Here's my scenario, I have a User this User has a Company which in turn has many Department and many Address. If I were to get a User could I expect to have access to the Company and all models associated with that Company? So would $user['Company']['Department'][0] or $user['Company']['Address'][0] be possible? Which brings me back to the original question, how extensive is the linkage between models?

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  • What simple methods are there to wrap a c++ based object model with a COM interface

    - by Rich
    I have a pre-existing c++ object model which represents the business layer tier of an application. I want to be able to expose the object model to applications written in other languages i.e vbscript, VB, javascript etc. I believe the best way of doing this is to wrap the business objects with a COM layer. What fast and effective methods are there for doing this. Any advice, links to practical "How to" documentation would be very much appreciated. Because I'm starting a bounty on this , here's a few extra guidelines for potential bounty hunters :- 1)I've decided on an ATL approach 2)I'm now specifically looking for links to really good "how to and quickly" documentation on wrapping a pre-existing c++ object model to make it useable by a scripting language like javascript 3) Something with small working examples showing me what code needs to be added to what files, e.g what goes into the cpp , idl and hpp/h etc. It' must include an example I can compile test and change to get a better understanding.

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  • Can someone give me an overview of ASP.net and how it's different from technologies such as php?

    - by DavidR
    I've been doing the html and css for a site, sending it off to a guy to implement in a web server. I get a call from the designer freaking out about the progress, saying the clients aren't happy. He wants me to personally integrate my css with what's on the site. The site is done in ASP.net, time is short, and I'm a little in over my head. I have an understanding of how php works, but have never worked extensively with it. Looking at the stuff on the ftp, I can't even find equivalent of the index.html file (I know that when I go to the site itself, there is nothing after the base url, i.e., www.site.com/ brings me to the homepage.) Can anyone give me a few tips or links as to what I am to do with this, or where to even being navigating this site?

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  • In the following implementation of static_strlen, why are the & and parentheses around str necessary

    - by Ben
    If I change the type to const char str[Len], I get the following error: error: no matching function for call to ‘static_strlen(const char [5])’ Am I correct that static_strlen expects an array of const char references? My understanding is that arrays are passed as pointers anyway, so what need is there for the elements to be references? Or is that interpretation completely off-the-mark? #include <iostream> template <size_t Len> size_t static_strlen(const char (&str)[Len]) { return Len - 1; } int main() { std::cout << static_strlen("oyez") << std::endl; return 0; }

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  • uh-oh windows mobile threading issues!

    - by violet313
    specifically WM6x, winCE5x Now my current understanding from trawling the msdn etal is that the IMAPIAdviseSink::OnNotify callback can be made from any old thread; from (ce)mapi or perhaps even from a third-party service provider. Under WM6x, i cannot seem to coax an in-thread response by invoking HrThisThreadAdviseSink, since while this function is declared in mapiutil.h, a definition appears not to exist (in cemapi.lib or wherever??) ~But i notice that all the OnNotify callbacks i get, derive from windows messages that i am receiving on my thread (=looks to me like an in-thread implementation in any case under cemapi)... So, can anyone confirm that this is infact always the case -or am i just getting lucky right now? ah, i should add that my advise source is IMAPISession::Advise (ActiveSync) erm i should also say that i might have cross-posted this on the msdn forum -but they're mostly numptys over there,,

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  • Can you explain what's going on in this Ruby code?

    - by samoz
    I'm trying to learn Ruby as well as Ruby on Rails right now. I'm following along with Learning Rails, 1st edition, but I'm having a hard time understanding some of the code. I generally do work in C, C++, or Java, so Ruby is a pretty big change for me. I'm currently stumped with the following block of code for a database migrator: def self.up create_table :entries do |t| t.string :name t.timestamps end end Where is the t variable coming from? What does it actually represent? Is it sort of like the 'i' in a for(i=0;i<5;i++) statement? Also, where is the :entries being defined at? (entries is the name of my controller, but how does this function know about that?)

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  • Where to learn about HTTP?

    - by razass
    I am fluent in HTML and PHP and slowly learning JavaScript however I have noticed that there is a huge hole in my knowledge when it comes to understanding how web software communications actually work. I understand the flow of information across the net however I would like to learn about HTTP protocols to better understand how the data is actually sent back and forth through the internet to help me understand things like REST, HTTP Headers, AJAX requests, etc. However, I must be searching the wrong terms because I haven't been able to find a good description of HTTP protocols. Any help is appreciated to point me in the right direction. Thanks!

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  • Authentication from url in Restlet

    - by DutrowLLC
    I've been using Restlets "ChallengeResponse" mechanism to authenticate users so far. ChallengeResponse challengeResponse = getRequest().getChallengeResponse(); if( challengeResponse == null ){ throw new RuntimeException("not authenticated"); } String login = challengeResponse.getIdentifier(); String password = new String(challengeResponse.getSecret()); From my understanding, "ChallengeResponse" requires that the username and password are put into headers. However a client needs to put the credentials into the url like so: https://username:[email protected]/my_secure_document When I looked at what was actually sent, it looks like the password is being hashed. What is the proper way to authenticate in this fashion using Restlet?

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  • car and cdr in Scheme are driving me crazy ...

    - by kristian Roger
    Hi Im facing a problem with the car and cdr functions for example: first I defined a list called it x (define x (a (bc) d ( (ef) g ) )) so x now is equal to (a (bc) d ( (ef) g ) ) now for example I need to get the g from this list using only car and cdr (!! noshortcuts as caddr cddr !!) the correct answer is: (car(cdr(car(cdr(cdr(cdr x)))))) BUT how ? :-( I work according to the rules (the car gives the head of list and cdr gives the tail) and instead of getting the answer above I keep reaching wrong answers. Can any one help me in understanding this ... give me step or a way to solve it step by step Thanks in advance. I'm really sick of Scheme.

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  • iPhone OS: Posting an image + text "story" to a user's news feed through the facebook api

    - by nickthedude
    So what I am trying to do is post an image that has been created by a user on an iphone into that users newsfeed. The functionality I am having a hard time understanding if it is possible: Can I pass a local NSURL (or URL?)(to a png file that lives in the documents folder) through a JSON string and onto Facebook? i want to mimic the action of a user going to his/her facebook page, clicking into the textfield for their newsfeeld, uploading an image by clicking the "photos" icon and selecting an image from a local disk and uploading it. I would also like to add some text into the post optionally. I'm just getting started with the Facebook api and it seems pretty tough right now, any help would be appreciated. code examples appreciated. Thanks, Nick

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  • How do negated patterns work in .gitignore?

    - by chrisperkins
    I am attempting to use a .gitignore file with negated patterns (lines starting with !), but it's not working the way I expect. As a minimal example, I have the folllowing directory structure: C:/gittest -- .gitignore -- aaa/ -- bbb/ -- file.txt -- ccc/ -- otherfile.txt and in my gitignore file, I have this: aaa/ !aaa/ccc/ My understanding (based on this: http://ftp.sunet.se/pub//Linux/kernel.org/software/scm/git/docs/gitignore.html) is that the file aaa/ccc/otherfile.txt should not be ignored, but in fact git is ignoring everything under aaa. Am I misunderstanding this sentence: "An optional prefix ! which negates the pattern; any matching file excluded by a previous pattern will become included again."? BTW, this is on Windows with msysgit 1.7.0.2.

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  • Considering getting into reverse engineering/disassembly

    - by Zombies
    Assuming a decent understanding of assembly on common CPU architectures (eg: x86), how can one explore a potential path (career, fun and profit, etc) into the field of reverse engineering? There is so little educational guides out there so it is difficult to understand what potential uses this has today (eg: is searching for buffer overflow exploits still common, or do stack monitoring programs make this obselete?). I am not looking for any step by step program, just some relevant information such as tips on how to efficiently find a specific area of a program. Basic things in the trade. As well as what it is currently being used for today. So to recap, what current uses does reverse engineering yield today? And how can one find some basic information on how to learn the trade (again it doesn't have to be step-by-step, just anything which can through a clue would be helpful).

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  • dangling pointer, reason for value change after free()?

    - by Aman Jain
    In the following code segment, after free(x), why does y becomes 0? As per my understanding, the memory in the heap that was being pointed to by x, and is still being pointed by y, hasn't been allocated to someone else, so how can it change to 0? And moreover, I don't think it is free(x) that changed it to 0. Any comments? #include <stdio.h> int main ( int argc, char *argv[] ) { int *y = NULL; int *x = NULL; x = malloc(4); *x = 5; y = x; printf("[%d]\n", *y); //prints 5 free(x); printf("[%d]\n", *y); //why doesn't print 5?, prints 0 instead return 0; }

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  • Assigning a MVC Controller property from Asp.Net page

    - by JasonMHirst
    I don't know if I've understanding MVC correctly if my question makes no sense, but I'm trying to understand the following: I have some code on a controller that returns JSON data. The JSON data is populated based on a choice from a dropdown box on an Asp.Net page. I thought (incorrectly) that Session variables would be shared between the Asp.Net project and the MVC Project. What I'd like to do therefore (if this is possible), is to call a Sub on the MVC that sets a variable before the JSON query is run. I have the following: Sub SetCountryID(ByVal CountryID As Integer) Me.pCountrySelectedID = CountryID End Sub Which I can call by the following: Response.Write("http://localhost:7970/Home/SetCountryID/?CountryID=44") But this then results in a blank page - again obviouslly totally incorrect! Am I going about MVC the wrong way or do I still have a hell of a lot more learning to do? Is this even possible to do?

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  • Android 2.1: Muliple Handlers in a Single Activity

    - by Soumya Simanta
    Hi, I've more than one Handlers in an Activity. I create all the handlers in the onCreate() of the main activity. My understanding is the handlerMessage() method of each handler will never be called at the same time because all messages are put in the same queue (the Activity thread MessageQueue). Therefore, they will be executed in the order in which are put into the Queue. They will also be executed in the main activity thread. Is this correct ? public void onCreate() { this.handler1 = new Handler() { @Override public void handleMessage(Message msg) { //operation 1 : some operation with instanceVariable1 super.handleMessage(msg); } }; this.handler2 = new Handler() { @Override public void handleMessage(Message msg) { //Operation 2: some operation with instanceVariable1 super.handleMessage(msg); } }; this.handler3 = new Handler() { @Override public void handleMessage(Message msg) { //Operation 3: some operation with instanceVariable1 super.handleMessage(msg); } }; }

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