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• Books on data-intensive enterprise integration patterns

  - by Tristan

  I'm trying to understand design patterns used by data-intensive enterprise applications. A classic example is the financial industry, where system must consume, analyze, and execute on real-time financial data while providing information and configuration options to a broad set of traders and analysts. One can imagine similar system in airlines, major supply chain operations, and utility providers. Are there good books that provide and inside view of how these systems work? Enterprise Integration Patterns is one example, but I'm looking for something with more real-world applications, particularly in finance.

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• How to handle images folder with many images

  - by Billy

  I'm developing a new aspnet website with 200k images in a /Images/ -folder. Many operations in Visual Studio is slow because it access the folder, adding a web service takes 10 minutes. The images is not checked into scm (svn). How should I structure the tree of code, to improve performance in VS? It would also be neat if not all developers needed to copy 200k images to their local disk to be able to develop on the site. Images as DB blobs is not an option.

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• c++11 atomic ordering: extended total order memory_order_seq_cst for locks

  - by itaj

  There's this note in c++11 29.3-p3: [ Note: Although it is not explicitly required that S include locks, it can always be extended to an order that does include lock and unlock operations, since the ordering between those is already included in the "happens before" ordering. - end note ] What does it mean by "always"? I can understand that any certain implementation can be designed to support such an extended S. But in some general implementation that wasn't designed for it, I don't see that S can be extended so. I had sent this question to comp.std.c++ but got no answers there. http://groups.google.com/group/comp.std.c++/browse_frm/thread/5242fa70d0594d1b#

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• Appropriate data structure for a buffer of the packets

  - by psihodelia

  How to implement a buffer of the packets where each packet is of the form: typedef struct{ int32 IP; //4-byte IP-address int16 ID; //unique sequence id }t_Packet; What should be the most appropriate data structure which: (1) allows to collect at least 8000 such packets (fast Insert and Delete operations) (2) allows very fast filtering using IP address, so that only packets with given IP will be selected (3) allows very fast find operation using ID as a key (4) allows very fast (2), then (3) within filtered results ? RAM size does matter, e.g. no huge lookup table is possible to use.

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• Javascript: Access the right scope "under" apply(...)

  - by Chau

  This is a very old problem, but I cannot seem to get my head around the other solutions presented here. I have an object function ObjA() { var a = 1; this.methodA = function() { alert(a); } } which is instantiated like var myObjA = new ObjA(); Later on, I assign my methodA as a handler function in an external Javascript Framework, which invokes it using the apply(...) method. When the external framework executes my methodA, this belongs to the framework function invoking my method. Since I cannot change how my method is called, how do I regain access to the private variable a? My research tells me, that closures might be what I'm looking for.

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• Pattern for iPhone background loading during init?

  - by Rob S.

  Hi everyone, I'm currently kicking off a background thread to do some REST queries in my app delegate's didFinishLaunchingWithOptions. This thread creates some objects and populates the model as the rest of the app continues to load (because I don't block, and didFinishLaunchingWithOptions returns YES). I also put up a loading UIViewController 'on top' of the main view that I tear down after the background initialization is complete. My problem is that I need to notify the first view (call it the Home view) that the model is ready, and that it should populate itself. The trick is that the background download could have finished before Home.viewDidAppear is called, or any of the other Home.initX methods. I'm having difficulty synchronizing all of this and I've thought about it long enough that it feels like I'm barking up the wrong tree. Are there any patterns here for this sort of thing? I'm sure other apps start by performing lengthy operations with loading screens :) Thanks!

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• MS SQL 2005 - Understanding ouput of DBCC SHOWCONTIG

  - by user169743

  I'm seeing some slow performance on a MS SQL 2005 database. I've been doing some research regarding MS SQL performance but I'm having difficulty fully understanding the output of SHOWCONTIG and would be very grateful if someone could have a look and offer some suggestions to improve performance. TABLE level scan performed. Pages Scanned................................: 19348 Extents Scanned..............................: 2427 Extent Switches..............................: 3829 Avg. Pages per Extent........................: 8.0 Scan Density [Best Count:Actual Count].......: 63.16% [2419:3830] Logical Scan Fragmentation ..................: 8.40% Extent Scan Fragmentation ...................: 35.15% Avg. Bytes Free per Page.....................: 938.1 Avg. Page Density (full).....................: 88.41%

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• How should I think about perspectives and rotation in OpenGL ES?

  - by Omega

  As I start to write rendering code, how do I want to consider my drawing operations? Will they always be relative to a fixed coordinate system on the screen, or does this change based on the camera perspective? The best example I can try to come up with is say I'm at (0,0,0) and I draw a line to (3,3,3). If I change the perspective +1 on the X axis and conduct the same operation, does it happen at (4,3,3), or am I just getting a new view of the line still being made at (3,3,3)? When doing rotation, am I moving the point from which a frustum emanates, or am I moving the rendering underneath?

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• Benefits of arrays

  - by Vitalii Fedorenko

  As I see it, the advantages of List over array are pretty obvious: Generics provide more precise typing: List<Integer>, List<? extends Number>, List<? super Integer>. List interface has a bunch useful methods: addAll, remove etc. While for arrays all standard operations except get/set must be performed in a procedure manner by passing it to a static method. Collections offer different implementations like ArrayList, LinkedList, unmodifieable and synchronized lists, which can be hidden under common List interface. OOB length control. As disadvantages I can only mention absence of syntactic sugar and runtime type check. At the same time supporting of both structures requires frequent using of asList and toArray methods, which makes code less readable. So I am curious if there are any important benefits of using arrays that I miss.

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• Best Ruby ORM for Wrapping around Legacy MSSQL Database?

  - by Technocrat

  Hi. I found this answer and it sounds like almost exactly what I'm doing. I have heard mixed answers about whether or not datamapper can support mssql through dataobjects. Basically, we have an app that uses a consistently structured database, consistently named tables, etc in MSSQL. We're making all kinds of tools and stuff that have to interact with it, some of them remotely and so I decided that we need to create some common, simple access point to do read/write operations on the MSSQL app since it's API is all C# and other things I despise. Now my question is if anyone has any examples or projects they know of where a ruby ORM can essentially create models for another application's legacy database by defining the conventions of each model's pkeys, fkeys, table names, etc. Sequel is the only ORM I've used with MSSQL but never to do anything quite like this. Any suggestions?

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• Windows Phone: Updating backend datastore (via web service) while keeping UI very responsive

  - by will

  I am developing a Windows Phone app where users can update a list. Each update, delete, add etc need to be stored in a database that sits behind a web service. As well as ensuring all the operations made on the phone end up in the cloud, I need to make sure the app is really responsive and the user doesn’t feel any lag time whatsoever. What’s the best design to use here? Each check box change, each text box edit fires a new thread to contact the web service? Locally store a list of things that need to be updated then send to the server in batch every so often (what about the back button)? Am I missing another even easier implementation? Thanks in advance,

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• jQuery way to handle select lists, radio buttons and checkboxes

  - by Álvaro G. Vicario

  When I handle HTML form elements with jQuery, I always end up with an ugly mix of jQuery syntax and plain JavaScript like, e.g.: function doStuff($combo){ if( $combo.get(0).options[$combo.get(0).selectedIndex].value=="" ){ var txt = ""; }else{ var txt = $combo.get(0).options[$combo.get(0).selectedIndex].text; } var $description = $combo.closest("div.item").find("input[name$=\[description\]]"); $description.val(txt); } Are there standard jQuery methods to handle typical operations on elements like <select>, <input type="radio"> and <input type="checkbox">? With typical, I mean stuff like reading the value of the selected radio button in a group or replacing elements in a selection list. I haven't found them in the documentation but I admit that method overloading can make doc browser kind of tricky.

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• Compiler reordering around mutex boundaries?

  - by shojtsy

  Suppose I have my own non-inline functions LockMutex and UnlockMutex, which are using some proper mutex - such as boost - inside. How will the compiler know not to reorder other operations with regard to calls to the LockMutex and UnlockMutex? It can not possibly know how will I implement these functions in some other compilation unit. void SomeClass::store(int i) { LockMutex(_m); _field = i; // could the compiler move this around? UnlockMutex(_m); } ps: One is supposed to use instances of classes for holding locks to guarantee unlocking. I have left this out to simplify the example.

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• Firing a Keyboard Event at the Body - JavaScript (?)

  - by user317985

  I've done a lot of research on this but have come up empty handed. What I would like to do is invoke or create an event for the right arrow key (Key Code 39). I was planning on using an onclick event inside an tag to go to a function where this event could be 'fired'. Any help would be appreciated. If anyone needs context, I have a jQuery content slider that's functionality is very hard to alter and currently the functionality I need to emulate only occurs when a user hits the right arrow on their keyboard. What I would like to do is tie an onclick() event to a image that when clicked on fires the right keyboard event and the content will slide. Please let me know if I can provide further details or explanation. My working demo for this is: http://greenplanet3d.com

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• How to use SQL trigger to record the affected column's row number

  - by Freeman

  I want to have an 'updateinfo' table in order to record every update/insert/delete operations on another table. In oracle I've written this: CREATE TABLE updateinfo ( rnumber NUMBER(10), tablename VARCHAR2(100 BYTE), action VARCHAR2(100 BYTE), UPDATE_DATE date ) DROP TRIGGER TRI_TABLE; CREATE OR REPLACE TRIGGER TRI_TABLE AFTER DELETE OR INSERT OR UPDATE ON demo REFERENCING NEW AS NEW OLD AS OLD FOR EACH ROW BEGIN if inserting then insert into updateinfo(rnumber,tablename,action,update_date ) values(rownum,'demo', 'insert',sysdate); elsif updating then insert into updateinfo(rnumber,tablename,action,update_date ) values(rownum,'demo', 'update',sysdate); elsif deleting then insert into updateinfo(rnumber,tablename,action,update_date ) values(rownum,'demo', 'delete',sysdate); end if; -- EXCEPTION -- WHEN OTHERS THEN -- Consider logging the error and then re-raise -- RAISE; END TRI_TABLE; but when checking updateinfo, all rnumber column is zero. is there anyway to retrieve the correct row number?

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• Can I use Blender to create 3D wall image viewer application under Linux?

  - by sgon00

  Hi, Is that possible to use Blender to create Cooliris-like 3D wall image viewer application under Linux? I don't see many people use Blender (BGE) to create desktop application, so I am wondering if this is possible. People normally use Blender for modeling/movie and game engine. I can not find a good way to create 3D application in Linux so far. I was thinking about pyQT+opengl. But I feel that is hard to do. No robust and easy-to-use qt+opengl toolkit available from my research. I know a little bit of Blender, that's why I am asking if Blender is an alternative solution. (python is preferred) The image viewer doesn't have to be windowed. It can be full screen, like a game?. I would like to add many cool effects into this application. Hopefully cooler than Cooliris which is written in flash. Thanks a lot.

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• Send and receive data trough the power network

  - by luvieere

  I'm not interested in a hardware solution, I want to know about software that may "read" modulated signal received trough the power supply - some sort of a low-level driver that would access the power signal in a convenient place and demodulate it. Is there a way to receive signal from the computer's power supply? I'm interested in an API or library that would allow the computer to be seen as a node in a Power Line Communication network and receive data directly through the power cable, without the need for a converter. Is there any active research in this field? Edit: There is software that reads monitors and displays internal component voltages - DC voltage after being converted and filtered by the power supply - now I need is a method of data encoding that would be invariant to conversion and filtering, the original signal embedded in AC being present in some form within the converted DC signal.

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• Strategy for desugaring Haskell

  - by luqui

  I'm developing a virtual machine for purely functional programs, and I would like to be able to test and use the the wide variety of Haskell modules already available. The VM takes as input essentially terms in the untyped lambda calculus. I'm wondering what would be a good way to extract such a representation from modern Haskell modules (eg. with MPTC's, pattern guards, etc.). I did a little research and there doesn't seem to be a tool that does this already (I would be delighted to be mistaken), and that's okay. I'm looking for an approach. GHC Core seems too operationally focused, especially since one of the things the VM does is to change the evaluation order significantly. Are there any accessible intermediate representations that correspond more closely to the lambda calculus?

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• iPhone: How do I override the back button in a Navigation Controller?

  - by Angelo Stracquatanio

  Hello, In my app I have a basic Navigation Controller. For all of my views, except one, the controller works as it should. However, for one view in particular, I would like the 'back' button to not go back to the previous view, but to go to one I set. In particular it is going to go back 2 views and skip over one. After doing some research I found that I can intercept the view when it disappears, so I tried to put in code to have it navigate to the page I would like: - (void)viewWillDisappear:(BOOL)animated { [super viewWillDisappear:animated]; //i set a flag to know that the back button was pressed if (viewPushed) { viewPushed = NO; } else { // Here, you know that back button was pressed mainMenu *mainViewController = [[mainMenu alloc] initWithNibName:@"mainMenu" bundle:nil]; [self.navigationController pushViewController:mainViewController animated:YES]; [mainViewController release]; } } That didn't work, so does anyone have any ideas? Thanks!!

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• JavaScript QR Code Reader - can it be done? Or, Remote Service?

  - by Myk

  I'm doing a bit of preliminary research on an upcoming project and I have a quick question that I figure I'll throw up here while I look elsewhere, in case anyone has any experience with this. The question is simple: is it possible to read a QR code using JavaScript? Is there a remote service to which I can pass a bitmap object from a camera and do it that way? Are there currently any libraries that allow this? The project is going to be deployed to various mobile devices and we'd like to try to use Appcelerator to make it work. I know Appcelerator does expose the Camera API on its host devices, but whatever we do with it has to be able to parse QR codes. Is this something that can be done? Thanks in advance! myk

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• Counting bits set in a .Net BitArray Class

  - by Sam

  I am implementing a library where I am extensively using the .Net BitArray class and need an equivalent to the Java BitSet.Cardinality() method, i.e. a method which returns the number of bits set. I was thinking of implementing it as an extension method for the BitArray class. The trivial implementation is to iterate and count the bits set (like below), but I wanted a faster implementation as I would be performing thousands of set operations and counting the answer. Is there a faster way than the example below? count = 0; for (int i = 0; i < mybitarray.Length; i++) { if (mybitarray [i]) count++; }

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• Would you make this method Static or not?

  - by Adam Drummond

  During a code review I presented a method quickly to the team that I had made static and one person agreed that there was no reason for it to not be static and a person disagreed saying that he would not make it static because it wasn't necessary and just to be on the safe side for future modifications and testing. So I did quite a bit of research and obviously it's a specialized case but I would like to know what you would do in this situation and why? (Its basically a helper method I call from a few different methods, a very low traffic page. More for my knowledge and learning on Static.) private IEnumerable<Category> GetCategoryByID(int id, Context context) { var categoryQuery = from selectAllProc in context.SelectAll_sp() where selectAllProc.CategoryID == id select selectAllProc; return categoryQuery; }

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• FOR loop performance in Javascript

  - by AndrewMcLagan

  As my research leads me to believe that for loops are the fastest iteration construct in javascript language. I was thinking that also declaring a conditional length value for the for loop would be faster... to make it clearer, which of the following do you think would be faster? Example ONE for(var i = 0; i < myLargeArray.length; i++ ) { console.log(myLargeArray[i]); } Example TWO var count = myLargeArray.length; for(var i = 0; i < count; i++ ) { console.log(myLargeArray[i]); } my logic follows that on each iteration in example one accessing the length of myLargeArray on each iteration is more computationally expensive then accessing a simple integer value as in example two?

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• Why is forwarding variadic parameters invalid?

  - by awesomeyi

  Consider the variadic function parameter: func foo(bar:Int...) -> () { } Here foo can accept multiple arguments, eg foo(5,4). I am curious about the type of Int... and its supported operations. For example, why is this invalid? func foo2(bar2:Int...) -> () { foo(bar2); } Gives a error: Could not find an overload for '_conversion' that accepts the supplied arguments Why is forwarding variadic parameters invalid? What is the "conversion" the compiler is complaining about?

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• javascript window.close, once again

  - by John Kjøller

  Im sorry if I havent done my research properly, - but couldnt find the answer I needed, so here goes: From my main page I open a new window using mainPlayer = window.open(); This window stays open until user clicks on a mainPlayer.close(); event. (or simply x closes the window) However, the idea is to make it possible to let the player keep playing, while browsing around the rest of the pages. But as soon as the user leaves the page that opened the mainPlayer window, the reference to the mainPlayer window seem to be lost. How do I, from the site's other pages, check if the mainPlayer window is open and close it on a click event? Thx John

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