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• MCV/MVP Patterns and Applications that interface with Hardware (DAQ/PLC/etc)

  - by Ryan

  I've been reading a lot about the MCV and MVP patterns for use with UI and it seems like a really nice powerful way to handle user interfaces. I am - however - having a difficult time deciding how this could integrate into a system where data in the model is created from a Data Acquisition System or Serial/Ethernet devices. There is also the added step that 70% of application interaction is performed by a PLC instead of a live user. It seems that for apps that just read/write & manipulate information from a database this works great, but how does does hardware and automation fit into these patterns? Is it as simple as another controller (for lack of a better term) that interacts with hardware that manipulates data and writes to a model? Maybe I am over thinking this or thinking too simply, so any advice would be great. I'm not quite sure where I'm going with this, so if something doesn't make sense or I was too vague leave me a comment. Thanks!

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• Breakdown of this Ruby code?

  - by randombits

  Would anyone be kind enough to dissect the merge! method? Its usage of conditions and variable assignment looks rather terse, and I'm having a difficult time following it. Would love to hear a Ruby-savvy developer break this apart. module ActiveRecord class Errors def merge!(errors, options={}) fields_to_merge = if only=options[:only] only elsif except=options[:except] except = [except] unless except.is_a?(Array) except.map!(&:to_sym) errors.entries.map(&:first).select do |field| !except.include?(field.to_sym) end else errors.entries.map(&:first) end fields_to_merge = [fields_to_merge] unless fields_to_merge.is_a?(Array) fields_to_merge.map!(&:to_sym) errors.entries.each do |field, msg| add field, msg if fields_to_merge.include?(field.to_sym) end end end end

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• Time Complexities of recursive algorithms

  - by Peter

  Whenever I see a recursive solution, or I write recursive code for a problem, it is really difficult for me to figure out the time complexity, in most of the cases I just say its exponential? How is it exponential actually? How people say it is 2^n, when it is n!, when it is n^n or n^k. I have some questions in mind, let say find all permutations of a string (O(n!)) find all sequences which sum up to k in an array (exponential, how exactly do I calculate). Find all subsets of size k whose sum is 0 (will k come somewhere in complexity , it should come right?). Can any1 help me how to calculate the exact complexity of such questions, I am able to wrote code for them , but its hard understanding the exact time complexity.

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• Group SQL tables in Microsoft SQL Server Management Studio object explorer

  - by MainMa

  I have a table which has approximately sixty tables, and other tables are added constantly. Each table is a part of a schema. A such quantity of tables makes it difficult to use Microsoft SQL Server Management Studio 2008. For example, I must scroll up in object explorer to access database related functions, or scroll down each time I need to access Views or Security features. Is it possible to group several tables to be able to expand or collapse them in Object Explorer? Maybe a folder may be displayed for each schema, letting collapse the folders I don't need to use?

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• Performance implications of finalizers on JVM

  - by Alexey Romanov

  According to this post, in .Net, Finalizers are actually even worse than that. Besides that they run late (which is indeed a serious problem for many kinds of resources), they are also less powerful because they can only perform a subset of the operations allowed in a destructor (e.g., a finalizer cannot reliably use other objects, whereas a destructor can), and even when writing in that subset finalizers are extremely difficult to write correctly. And collecting finalizable objects is expensive: Each finalizable object, and the potentially huge graph of objects reachable from it, is promoted to the next GC generation, which makes it more expensive to collect by some large multiple. Does this also apply to JVMs in general and to HotSpot in particular?

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• Working effectively unit tests / Anyone tried the in-assembly approach?

  - by CodingCrapper

  I'm trying to re-introduce unit testing into my team as our current coverage is very poor. Our system is quite large 40+ projects/assemblies. We current use a project named [SystemName].Test.csproj were all the test code is dumped and organised to represent the namespaces using folders. This approach is not very scalable and makes it difficult to find tests. I've been thinking about added a Tests folder to each project, this would put the unit tests "in the developers face" and make them easy to find. The downside is the Production release code would contain references to nunit, nmocks as well as the test code and test data.... Has anyone tried this approach? How is everyone else working with unit tests on large projects? Having a Tests project per "real" project/assembly would introduce too many new projs. Thanks in advance

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• stop script debug error dialogs occur in ie8 ?

  - by Haroldo

  I get this, clicking 'no' means the page displays flawlessly. it's refering to this part of jquery1.4.2.js: // Get the Nth element in the matched element set OR // Get the whole matched element set as a clean array get: function( num ) { return num == null ? // Return a 'clean' array this.toArray() : // Return just the object ( num < 0 ? this.slice(num)[ 0 ] : this[ num ] ); }, I assume i'm calling something in the wrong context somewhere in one of my js files (which would be a real mission to find). Will standard IE8 users get this error? (i imagine ms make it pretty difficult to reinstall ie!)

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• uitextfield delegate must be file's owner?

  - by deafgreatdane

  I've seen a few references (eg here) in response to folks having trouble getting the keyboard to dismiss in iPhone that say "double check that the delegate is attached to file's owner. Is this necessarily true? Or just standard practice? Can't I have other objects in my nib, such as a subclass of UIViewController, and make connections to those as I like? I'd hate to have to route everything into the object that happens to be file owner. That said, I'm having a difficult time getting the keyboard to disappear. I know it's connected to the delegate, because I can set break points and step through the code. I can see the [theTextField resignFirstResponder] get called (and return true), but the keyboard still won't go away. Any other suggestions?

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• What are real-world examples of Gradle's dependency graph?

  - by Michael Easter

  As noted in the documentation, Gradle uses a directed acyclic graph (DAG) to build a dependency graph. From my understanding, having separate cycles for evaluation and execution is a major feature for a build tool. e.g. The Gradle doc states that this enables some features that would otherwise be impossible. I'm interested in real-world examples that illustrate the power of this feature. What are some use-cases for which a dependency graph is important? I'm especially interested in personal stories from the field, whether with Gradle or a similarly equipped tool. I am making this 'community wiki' from the outset, as it will be difficult to assess a 'correct' answer.

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• Why Aren't Programs Written In Assembly More Often?

  - by mudge

  It seems to be a mainstream opinion that assembly programming takes longer and is more difficult to program in than a higher level language such as C. Therefore it seems to be recommend or assumed that it is better to write in a higher level language for these reasons and for the reason of better portability. Recently I've been writing in x86 assembly and it has dawned on me that perhaps these reasons are not really true, except perhaps portability. Perhaps it is more of a matter of familiarity and knowing how to write assembly well. I also noticed that programming in assembly is quite different than programming in an HLL. Perhaps a good and experienced assembly programmer could write programs just as easily and as quickly as an experienced C programmer writing in C. Perhaps it is because assembly programming is quite different than HLLs, and so requires different thinking, methods and ways, which makes it seem very awkward to program in for the unfamiliar, and so gives it its bad name for writing programs in. If portability isn't an issue, then really, what would C have over a good assembler such as NASM?

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• Clever "add tag" javascript help needed

  - by Camran

  I have this function for adding options to a Select list: function addOption(selectbox, value, text, cl ) { var optn = document.createElement("OPTION"); optn.text = text; optn.value = value; if (cl==1){ optn.className = "nav_option_main"; } selectbox.options.add(optn); } I have just discovered the "optgroup" tag, but I don't know how to implement it to the drop list. The function above is called on another selectboxes "OnChange" event, to fill sub-select-box with the desired options. I don't think it should be too difficult to add the "optgroup" tag into this, or is it? Thanks and if you need more input let me know...

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• MVVM and division of amongst multiple developers

  - by nlawalker

  Can anyone speak to the ease of dividing work amongst multiple developers when designing and building a medium- to large-complexity Silverlight or WPF application? My team is finding it difficult to cleanly split work when you've got, for example, a number of controls that provide different visualizations of a Model/ViewModel that's fairly complex and has a lot of properties and methods for interacting with data. It seems like a very big portion of the work ends up being the design and build of the Model/ViewModel, and much less inside each of the controls, which are naturally what are easy to ration out to multiple people.

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• How useful are design patterns when it comes to web programming?

  - by Raja

  Background: My organization uses Microsoft .Net (3.5) with SQL Server 2005 as back end. With RAD being the norm and Agile being the widely used process. I have always found using design patterns difficult since it involves a bit more understanding and bit more training. Can you give me some examples where design patterns have solved real time problems in Web programming? What is the criteria for using any design pattern? What is the benefit reaped from it. I know it is a general question but this would help me a bunch.

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• Beautifying a SWT application on Mac

  - by Mark

  SWT is designed to be cross-platform, so it can run on a Mac. The problem is it commits the cardinal sin of Macland - it's UGLY. Toolbars don't look like Mac toolbars, status bars don't look like Mac status bars, etc. Does anyone have any experience in making an SWT application look more like a Mac application? For example, by making platform-specific JNI calls via the 'OS' class in SWT? If so, how difficult was it? (This question arises because we are looking at porting an existing SWT app designed to run on Windows) Thanks

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• Load external swf from a button in external swf and unload self?

  - by ChristinaR

  Hello, I am an uber n00b to flash AS3. And it is not my intention to sound like a complete moron, but honestly, I have had a hard enough time figuring out just how to load an external .swf into my main file! And now my friend is asking me if I could please add a button within the external .swf which will unload itself and load a new on in its place... I have looked around in the forums for an answer for a while now and I believe it is time for me to break down, admit defeat, and ask for help. Can someone please tell me it's not that difficult..? Surely it is possible... Thank you in advance for any advice at all! I am looking forward to the time when I can post a response here!

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• How to implement thread timeout in J2ME?

  - by lilo

  I am using Connector in J2ME and found that sometimes it take a very long time to send a request, and sometime it may halt the whole process. So I try to put code related to Connector in a thread and try to set timeout to the thread. But I found out that it's very difficult to do this in J2ME because there's no join(long) in J2ME. Is there any way to do this? Or any better way to deal with network connection in J2ME? Thanks a lot in advance.

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• Minifying CSS, JS, and HTML - together

  - by Radu

  Minifying JS and CSS is quite common. The benefits of minifying JS are much greater that those seen with CSS because with CSS you can't rename elements - and same goes for HTML. But what if all 3 were minified together so that the benefits of using shorter names can be brought to CSS and HTML? That is, instead of minifying without any regard to the relationships between the 3, these could be preserved and made simpler. I imagine that the implementation could be quite difficult but if it were possible, do you think it would provide a significant advantage over traditional minification?

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• Get local network interface addresses using only proc?

  - by Matt Joiner

  How can I obtain the (IPv4) addresses for all network interfaces using only proc? After some extensive investigation I've discovered the following: ifconfig makes use of SIOCGIFADDR, which requires open sockets and advance knowledge of all the interface names. It also isn't documented in any manual pages on Linux. proc contains /proc/net/dev, but this is a list of interface statistics. proc contains /proc/net/if_inet6, which is exactly what I need but for IPv6. Generally interfaces are easy to find in proc, but actual addresses are very rarely used except where explicitly part of some connection. There's a system call called getifaddrs, which is very much a "magical" function you'd expect to see in Windows. It's also implemented on BSD. However it's not very text-oriented, which makes it difficult to use from non-C languages.

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• How can I retrieve the values of controls in the form that posted?

  - by Mike at KBS

  I know this has got to be the simplest-sounding question ever asked about ASP.Net but I'm baffled. I have a form wherein my visitor will enter name, address, etc. Then I am POSTing that form via the PostBackUrl property of my Submit button to another page, where the fields are supposed to be all re-formed into new hidden fields, then POSTed again to Paypal. My problem is I cannot get at the values entered by the visitor in the original page. Any time I put in "runat='server'", ASP.Net completely changes the ID of the control, making it impossible to figure out how to access. In the POSTed form I tried Request.Form["_txtFirstName"] and that turned up null. Then I tried ((TextBox)PreviousPage.FindControl("_txtFirstName")).Text and that was null, too. I've tried variations on those. I cannot figure out how I'm supposed to get at these controls. Why does this stuff need to be so difficult?

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• Can't access my files in ASP.NET web site

  - by jumbojs

  I'm having a very difficult time. I am running windows 2008 server, I have an Able Commerce site using ASP.NET with C#. I'm writing an automated task that will ftp some xml files down into a local directory on our web server and then the program parses the xml file and saves information to our database. The problem, once I save the files to our local directory, my program has no access to the files. The NETWORK SERVICE user permissions isn't being inherited by the xml files so my program can't do anything with them. I can manually change the permissions, but this wouldn't be automated and won't work. How can I get this to work? help please, it's very frustrating.

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• ASP.NET Controls with Highly Customizable GUI

  - by micha12

  We are developing an ASP.NET web application where some of the features that we will need to implement are quite standard: for example, a chat between users, a forum, etc. There are ASP.NET chats and forums components available. However, they all have a predetermined GUI and html markup that is almost impossible to change and very difficult to customize. And this is a very common situation for most controls like grids, etc.: you have very low control over the html markup that is being generated by the control. In our case, our web app will have its own web design created by a professional web designer in PhotoShop, and then it will but transformed into html markup that will then be transformed in aspx pages. We would ideally like to create the html markup for the forum and chat by ourselves, and use only the non-GUI part of the ASP.NET components. Is this approach feasible? Has anyone dealt with such approach in practice?

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• Why people do not like OOP? [closed]

  - by Gabriel Šcerbák

  I do not understand why people choose C++ over Smalltalk in past and why Java over Python or Ruby. What is it that ties people so much to the procedural programming and makes it so difficult to go "all the way" to object oriented programming? What makes OOP hard? Should not objects be an abstraction which is easier to grasp for people, i.e. a more natural one than procedures? Is education the problem (because people tend to learn procedural programming before object oriented)?

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• How do I override methods of nested types?

  - by Mason Wheeler

  I've got a custom TObjectList descendant in Delphi 2009, and I'd like to play with its enumerator a bit and add some filtering functionality to the MoveNext method, to cause it to skip certain objects. MoveNext is called by DoMoveNext, which is a virtual method, so this shouldn't be difficult to override... except for one thing. The TEnumerator for TObjectList isn't its own class; it's declared as a nested type within the TObjectList declaration. Is there any simple way to override TEnumerator.DoMoveNext in my descendant class, or do I have to reimplement the whole TEnumerator? It's not a very big class, but I'd prefer to keep redundancies to a minimum if I can...

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• Overcoming Inertia - How to Just Get Going on Stuff

  - by kronoz

  I wondered whether you guys could help me - I have a big problem with overcoming inertia, i.e. how to just get started on a project/work when you simply feel the inertia of not being in the right 'zone' to do work such that it really becomes pretty damn tough to actually get on with what you want to do. Forgive me quoting my blog post where I try to express the problem as best I can:- The problem is that it feels so damned difficult to exert the force required to shift from one mode to another, so much so that you find it almost inconceivable to do so at the time. You need to force yourself somehow, or at least find some sort of hack to trick yourself into it. Do you guys have any ideas/hacks as to how to overcome this? Thanks in advance, and hopefully the community feel this question is valid for stack overflow (I have set it community wiki due to its fairly subjective nature.)

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• How is the "click to view more" function implemented?

  - by bobo

  We often see websites that display first few lines of an article and then append ... [More] so that people who are interested in can click on it to view the full article. To implement this functionality, we first need to find out where the article text should be cut to append the ... [More]. Since there must be some HTML/ CSS coupled with the article text, we must remember to ignore them when calculating the length of the text. But there is something I just can't figure it out, if more than one language is mixed in the first few lines of the article text, the length of the text will be very difficult to calculate since the characters can be of variable length. How should we solve this problem?

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