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  • What is the the relation between programming and mathematics?

    - by Math Grad
    Programmers seem to think that their work is quite mathematical. I understand this when you try to optimize something in performance, find the most efficient alogithm, etc.. But it patently seems false when you look at a billing application for a shop, or a systems software riddled with I/O calls. So what is it exactly? Is computation and associated programming really mathematical? Here I have in mind particularly the words of the philosopher Schopenhauer in mind: That arithmetic is the basest of all mental activities is proved by the fact that it is the only one that can be accomplished by means of a machine. Take, for instance, the reckoning machines that are so commonly used in England at the present time, and solely for the sake of convenience. But all analysis finitorum et infinitorum is fundamentally based on calculation. Therefore we may gauge the “profound sense of the mathematician,” of whom Lichtenberg has made fun, in that he says: “These so-called professors of mathematics have taken advantage of the ingenuousness of other people, have attained the credit of possessing profound sense, which strongly resembles the theologians’ profound sense of their own holiness.” I lifted the above quote from here. It seems that programmers are doing precisely the sort of mechanized base mental activity the grand old man is contemptuous about. So what exactly is the deal? Is programming really the "good" kind of mathematics, or just the baser type, or altogether something else just meant for business not to be confused with a pure discipline?

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  • Switching textstorage of NSTextViews back and forth

    - by Jakob Dam Jensen
    I'm trying to make a feature in a product which gives the user the ability to split a textview into two. The way this is done is by removing the textview from it's superview, making a NSSplitView and adding the textview as well as a new NSTextView instance to this splitview. Lastly I make these two textviews share the same textstorage in order to make them share the same content. It works great. But the problem is when I want to make one of the two textviews change textstorage. The replaceTextStorage method in NSLayoutManager causes both NSTextView to change textStorage. The API documentation states: replaceTextStorage: All NSLayoutManager objects sharing the original NSTextStorage object then share the new one. This method makes all the adjustments necessary to keep these relationships intact, unlike setTextStorage:. So it makes sense that it would do this. But the question is how do I make it possible to have two (or more) textviews first share the same storage and after that having them using their own? I've tried replacing the layoutManager and even making new instances of NSTextViews but no luck... Any suggestions?

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  • Swimlane Diagram Softwares with Expand/Collapse Features

    - by louis xie
    I've been searching real hard for a software which can fulfill my needs, but to no avail. I have a swimlane diagram which is extremely huge, and almost impossible to model using Visio or any traditional swimlane software. I would need to model both the operational process, as well as the interactions within an application and between different applications. Therefore, without wasting additional effort modelling these separately, I am looking for a solution which I can combine both views together. That is, possibly one which I can expand/collapse/group/ungroup processes/subprocesses together. Take a typical credit card process for instance, a hypothetical description of the swimlane could be as such: Customer submits application form to the bank Bank Officer A receives the application form and validates that it was correctly filled Bank Officer A submits application form to Bank Officer B for processing. Bank Officer B checks credit quality of the customer through Application X. Application X submits query to Application Y to retrieve Credit Report. Application X retrieves credit report and submits to Application Z for computation of credit scores Bank Officer B validates that customer is credit worthy, and submits application to Bank Officer C for processing. The above is an over-simplified credit card request process, and a purely hypothetical one. What I'm trying to drive at is, each of the above processes have sub-processes, and I want to be able to switch between a "detailed" view and "aggregated" view. If possible, add in time dependency of the different tasks, as well. I haven't been able to find one such software which could do this.

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  • Printing to different printers using mozilla.

    - by Nick-ACNB
    I am currently creating a web application that will be deployed in an intranet environment. I chose firefox to be the browser that will run it. However, in the application I am building, I need to be able to print to different printers quickly since they use different paper size depending on what client is coming. To avoid many time-wasting mistakes that could occur, for instance someone choosing the wrong printer and wasting paper. Also, the time used to find the right printer for the job and then pressing print is considered too long in the current context. Is there any solution to this problem? I understand the potential security flaw behind this, but please be aware that this is solely an intranet project and that I can reduce the browser's security to the lowest since they don't access internet. I know there could be something doable behind IE (ActiveX or VBScript) but I am using firefox. Also, I guess there could also be something rather tricky that when you press print on the browser, it saves what needs to be printed to a DB and then there is an exe app that runs and fetch that DB every set ammount of time and print to the right printer. Any suggestion would be greatly appreciated. I doubt I am the only one to ever face this issue! :) Thank you very much.

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  • How to Make a DVCS Completely Interoperable with Subversion?

    - by David M
    What architectural changes would a DVCS need to be completely interoperable with Subversion? Many DVCSs have some kind of bidirectional interface with Subversion, but there are limitations and caveats. For instance, git-svn can create a repository that mirrors Subversion, and changes to that repo can be sent back to Subversion via 'dcommit'. But the git-svn manpage explicitly cautions against making clones of that repository, so essentially, it's a Subversion working copy that you can use git commands on. Bazaar has a bidirectional Subversion capability too, but its documentation notes that Subversion properties aren't supported at all. Here's the end that I'm pursuing. I want a Subversion repository and a DVCS repository that, in the steady state, have identical content. When something is changed on one, it's automatically mirrored to the other. Subversion users interact with the Subversion repository normally. DVCS users clone the DVCS repository, pull changes from it, and push changes back to it. Most importantly, they don't need to know that this special DVCS repository is associated with a Subversion repository. It would probably be nifty if any clone of the special repository is itself a special repository and could commit directly to Subversion, but it might be sufficient if only the special repository directly interacts with Subversion. I think that's what mostly needed is to improve the bidirectional capability so that changes to Subversion properties are translated to changes in the DVCS repository. Some changes in the DVCS repository would be translated to changes to Subversion properties. Or is the answer to create a new capability in Subversion that interacts with a DVCS repository, using the DVCS repository as just a special storage layer such as fsfs or bdb? If there's not a direct mapping between the things that Subversion and a DVCS regard as having versions, does that imply that there's always going to be some activity that cannot be recorded properly on one or the other?

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  • PHP & cUrl - POST problems in while loop.

    - by Max Hoff
    I have a while loop, with cUrl inside. (I can't use curl_multi for various reasons.) The problem is that cUrl seems to save the data it POSTS after each loop traversal. For instance, if parameter X is One the first loop through, and if it's Two the second loop through, cUrl posts: "One,Two". It should just POST "Two".(This is despite closing and unsetting the curl handle.) Here's a simplified version of the code (with unecessary info stripped out): while(true){ // code to form the $url. this code is local to the loop. so the variables should be "erased" and made new for each loop through. $ch = curl_init(); $userAgent = 'Googlebot/2.1 (http://www.googlebot.com/bot.html)'; curl_setopt($ch,CURLOPT_USERAGENT, $userAgent); curl_setopt($ch,CURLOPT_URL,$url); curl_setopt($ch,CURLOPT_POST,count($fields)); curl_setopt($ch,CURLOPT_POSTFIELDS,$fields_string); curl_setopt($ch, CURLOPT_FAILONERROR, true); curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true); curl_setopt($ch, CURLOPT_AUTOREFERER, true); curl_setopt($ch, CURLOPT_RETURNTRANSFER,true); curl_setopt($ch, CURLOPT_TIMEOUT, 10); $html = curl_exec($ch); curl_close($ch); unset($ch); $dom = new DOMDocument(); @$dom->loadHTML($html); $xpath = new DOMXPath($dom); $resultTable = $xpath->evaluate("/html/body//table"); // $resultTable is 20 the first time through the loop, and 0 everytime thereafter becauset he POSTing doesn't work right with the "saved" parameters. What am I doing wrong here?

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  • Use of Syntactic Sugar / Built in Functionality

    - by Kyle Rozendo
    I was busy looking deeper into things like multi-threading and deadlocking etc. The book is aimed at both pseudo-code and C code and I was busy looking at implementations for things such as Mutex locks and Monitors. This brought to mind the following; in C# and in fact .NET we have a lot of syntactic sugar for doing things. For instance (.NET 3.5): lock(obj) { body } Is identical to: var temp = obj; Monitor.Enter(temp); try { body } finally { Monitor.Exit(temp); } There are other examples of course, such as the using() {} construct etc. My question is when is it more applicable to "go it alone" and literally code things oneself than to use the "syntactic sugar" in the language? Should one ever use their own ways rather than those of people who are more experienced in the language you're coding in? I recall having to not use a Process object in a using block to help with some multi-threaded issues and infinite looping before. I still feel dirty for not having the using construct in there. Thanks, Kyle

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  • C# connect to domain SQL Server 2005 from non-domain machine

    - by user304582
    Hi, I asked a question a few days ago (http://stackoverflow.com/questions/2795723/access-to-sql-server-2005-from-a-non-domain-machine-using-windows-authentication) which got some interesting, but not usable suggestions. I'd like to ask the question again, but make clear what my constraints are: I have a Windows domain within which a machine is running SQL Server 2005 and which is configured to support only Windows authentication. I would like to run a C# client application on a machine on the same network, but which is NOT on the domain, and access a database on the SQL Server 2005 instance. I CANNOT create or modify OS or SQL Server users on either machine, and I CANNOT make any changes to permissions or impersonation, and I CANNOT make use of runas. I know that I can write Perl and Java applications that can connect to the SQL Server database using only these four parameters: server name, database name, username (in the form domain\user), and password. In C# I have tried various things around: string connectionString = "Data Source=server;Initial Catalog=database;User Id=domain\user;Password=password"; SqlConnection connection = new SqlConnection(connectionString); connection.Open(); and tried setting integrated security to true and false, but nothing seems to work. Is what I am trying to do simply impossible in C#? Thanks for any help, Martin

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  • problem writing xml to file with .net mvc - timeout?

    - by Mark
    Hey, so having an issue with writing out to an xml file. Works fine for single requests via the browser, but when I use something like Charles to perform 5-10 repeated requests concurrently several of them will fail. The trace simply shows a 500 error with no content inside, basically I think they start timing out waiting for write access or something... This method is inside my repository class, have also attempted to have repository instance as a singleton but doesn't appear to make any difference.. Any help would be much appreciated. Cheers public void Add(Request request) { try { XDocument requests; XmlReader xmlReader; using (xmlReader = XmlReader.Create(_requestsFilePath)) { requests = XDocument.Load(xmlReader); XElement xmlRequest = new XElement("request", new XElement("code", request.code), new XElement("date", request.date), new XElement("email", new XCData(request.email)), new XElement("name", new XCData(request.name)), new XElement("recieveOffers", request.recieveOffers) ); requests.Root.Element("requests").Add(xmlRequest); xmlReader.Close(); } requests.Save(_requestsFilePath); } catch (Exception ex) { HttpContext.Current.Trace.Warn("Error writing to file: "+ex); } }

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  • BWToolkit inclusion crashing

    - by Schroedinger
    Hey guys I'm using the latest version of XCode (3.2.2) and I've linked the framework using the tutorial. I was building my app and tested it and I get a BWToolkit exception on decoding. I've included the Framework in the frameworks and added it to the copy files stage. I even created a new dummy app including the framework and adding it to the copy files stage and it still crashes when I try to run. Any ideas? Do I need to include it somewhere in the app? I'm worried I've overlooked something really simple. 2010-04-13 14:14:24.540 BWTestFramework[7504:a0f] An uncaught exception was raised 2010-04-13 14:14:24.543 BWTestFramework[7504:a0f] *** -[NSKeyedUnarchiver decodeObjectForKey:]: cannot decode object of class (BWSplitView) 2010-04-13 14:14:24.545 BWTestFramework[7504:a0f] *** Terminating app due to uncaught exception 'NSInvalidUnarchiveOperationException', reason: '*** -[NSKeyedUnarchiver decodeObjectForKey:]: cannot decode object of class (BWSplitView)' *** Call stack at first throw: ( 0 CoreFoundation 0x00007fff84a77d24 __exceptionPreprocess + 180 1 libobjc.A.dylib 0x00007fff82ba00f3 objc_exception_throw + 45 2 CoreFoundation 0x00007fff84a77b47 +[NSException raise:format:arguments:] + 103 3 CoreFoundation 0x00007fff84a77ad4 +[NSException raise:format:] + 148 4 Foundation 0x00007fff83804aa6 _decodeObjectBinary + 2427 5 Foundation 0x00007fff83805825 -[NSKeyedUnarchiver _decodeArrayOfObjectsForKey:] + 1229 6 Foundation 0x00007fff83805d65 -[NSArray(NSArray) initWithCoder:] + 462 7 Foundation 0x00007fff83804b1f _decodeObjectBinary + 2548 8 Foundation 0x00007fff83803f99 _decodeObject + 208 9 AppKit 0x00007fff8069fbfb -[NSView initWithCoder:] + 362 10 Foundation 0x00007fff83804b1f _decodeObjectBinary + 2548 11 Foundation 0x00007fff83803f99 _decodeObject + 208 12 AppKit 0x00007fff806adfbb -[NSWindowTemplate initWithCoder:] + 3824 13 Foundation 0x00007fff83804b1f _decodeObjectBinary + 2548 14 Foundation 0x00007fff83805825 -[NSKeyedUnarchiver _decodeArrayOfObjectsForKey:] + 1229 15 Foundation 0x00007fff83805268 -[NSSet(NSSet) initWithCoder:] + 447 16 Foundation 0x00007fff83804b1f _decodeObjectBinary + 2548 17 Foundation 0x00007fff83803f99 _decodeObject + 208 18 AppKit 0x00007fff8062fcde -[NSIBObjectData initWithCoder:] + 1983 19 Foundation 0x00007fff83804b1f _decodeObjectBinary + 2548 20 Foundation 0x00007fff83803f99 _decodeObject + 208 21 AppKit 0x00007fff8062f40d loadNib + 146 22 AppKit 0x00007fff8062e96d +[NSBundle(NSNibLoading) _loadNibFile:nameTable:withZone:ownerBundle:] + 248 23 AppKit 0x00007fff8062e7a5 +[NSBundle(NSNibLoading) loadNibNamed:owner:] + 326 24 AppKit 0x00007fff8062bd27 NSApplicationMain + 279 25 BWTestFramework 0x0000000100001891 main + 33 26 BWTestFramework 0x0000000100001868 start + 52 ) terminate called after throwing an instance of 'NSException' That's the crash report

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  • Returning true or error message in Ruby

    - by seaneshbaugh
    I'm wondering if writing functions like this is considered good or bad form. def test(x) if x == 1 return true else return "Error: x is not equal to one." end end And then to use it we do something like this: result = test(1) if result != true puts result end result = test(2) if result != true puts result end Which just displays the error message for the second call to test. I'm considering doing this because in a rails project I'm working on inside my controller code I make calls to a model's instance methods and if something goes wrong I want the model to return the error message to the controller and the controller takes that error message and puts it in the flash and redirects. Kinda like this def create @item = Item.new(params[:item]) if [email protected]? result = @item.save_image(params[:attachment][:file]) if result != true flash[:notice] = result redirect_to(new_item_url) and return end #and so on... That way I'm not constructing the error messages in the controller, merely passing them along, because I really don't want the controller to be concerned with what the save_image method itself does just whether or not it worked. It makes sense to me, but I'm curious as to whether or not this is considered a good or bad way of writing methods. Keep in mind I'm asking this in the most general sense pertaining mostly to ruby, it just happens that I'm doing this in a rails project, the actual logic of the controller really isn't my concern.

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  • Deploy GWT Application to Google App Engine using NetBeans

    - by Yan Cheng CHEOK
    Hello, I try to deploy a GWT application, to Google App Engine using NetBeans. I had successful run GWT sample http://code.google.com/webtoolkit/doc/latest/tutorial/create.html using Personal GlassFish v3 Prelude Domain, by 1) Copy generated source code from StockWatcher to C:\Projects\StockWatcherNetbeans\src\java\com\google\ 2) Modify C:\Projects\StockWatcherNetbeans\nbproject\gwt.properties gwt.module=com.google.gwt.stockwatcher.StockWatcher 3) Select Personal GlassFish v3 Prelude Domain, and run. All works fine! Now, I try to select Google App Engine server, and run. However, I get the error "There is no appengine web project opened!" I check... There is file called C:\Projects\StockWatcherNetbeans\war\WEB-INF\appengine-web.xml with content <?xml version="1.0" encoding="UTF-8"?> <appengine-web-app xmlns="http://appengine.google.com/ns/1.0" xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://kenai.com/projects/nbappengine/downloads/download/schema/appengine-web.xsd appengine-web.xsd'> <application>StockWatcherNetbeans</application> <version>1</version> </appengine-web-app> I am using NetBeans 6.7.1 GWT4NB (GWT Plugin for NetBeans) 2.6.12 Google App Engine plugin for NetBeans from http://kenai.com/downloads/nbappengine/1.0_NetBeans671/updates.xml Anything I had missed out? Even when I right click to the project, the Deploy to Google App Engine options is disabled. And yes, please do not ask me why not use Eclipse.

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  • how can I parse and group/do stats on user agent strings?

    - by user151841
    I have a database that has the various user-agent strings of visitors to our site. I'd like to do a 'survey' of them to see what browsers our users are using, so that I can know what features I can use in future development. Is there a tool to parse and run statistics on user-agent strings, or a bunch of strings like this? Ideally, I'd like to see a hierarchical grouping of the stats. For instance: Opera/9.80 (Windows Mobile; WCE; Opera Mobi/WMD-50301; U; en) Presto/2.4.13 Version/10.00 Opera/9.80 (J2ME/MIDP; Opera Mini/4.2.14912/1280; U; en) Presto/2.2.0 Opera/9.80 (J2ME/MIDP; Opera Mini/4.2.13918/812; U; en) Presto/2.2.0 Opera/9.64 (Macintosh; Intel Mac OS X; U; en) Presto/2.1.1 Opera/9.60 (J2ME/MIDP; Opera Mini/4.2.13918/786; U; en) Presto/2.2.0 Opera/9.60 (J2ME/MIDP; Opera Mini/4.0.10992/432; U; en) Presto/2.2.0 I'd like to see 6 entries for Opera, broken down into 3 for 9.80, 1 for 9.64 and 2 for 9.60, and so forth for all browsers. Other dimensions, such as OS, would cross the boundaries of the browser version hierarchy, but it might be nice to see also.

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  • Do I have to allocate and free records when using TList<T> in Delphi?

    - by afrazier
    The question more or less says it all. Given the following record structure: type TPerson = record Name: string; Age: Integer; end; PPerson = ^TPerson; TPersonList = TList<TPerson>; Is the following code valid? procedure ReadPeople(DataSet: TDataSet; PersonList: TPersonList); begin PersonList.Count := DataSet.RecordCount; if DataSet.RecordCount = 0 then Exit; DataSet.First; while not DataSet.Eof do begin PersonList[DataSet.RecNo].Name := DataSet.FieldByName('Name').AsString; PersonList[DataSet.RecNo].Age := DataSet.FieldByName('Age').AsInteger; DataSet.Next; end; end; Do I have to use GetMem/FreeMem to allocate and free records an instance of TPersonList, or am I free to directly access the TPersonList entries directly? My gut says that the code should be valid, though I'm not sure if there's any wrinkles related to record initialization or finalization.

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  • Create PDF from HTML page with formatting retained in PDF in ASP.Net

    - by Vishal Avhad
    I am trying to convert an HTML page to a PDF using iTextSharp.dll in ASP.Net. I am able to convert the contents to my PDF , but the problem is that the Formatting of HTML page (which is inline) get removed from my PDF created. For instance I have the following code block to be formatted from my HTML page to PDF. <table style="width:90%; float:left; background:#dddddd; padding:15px; border:1px solid #000; color:#000;"><tr><td style="text-transform:uppercase; font-size:14px;font-weight:bold;">SPECIAL DELIVERY FOR:</td></tr><tr><td style="padding-left:40px; font-size:12px; color:#4e4e4e;">Name: #CustomerName# <br /><br /><label> <b>Date: #CreatedOn# </b></label><br /> </td></tr> </table> I have to format my PDF with much more HTML codes like this. I have used the Stylesheet class also, but that was not much of help.

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  • Google Maps in Drupal: reference to gmap object from JavaScript

    - by user280817
    Is there a way to obtain JavaScript references to the Google maps that are embedded into Drupal pages by the GMap module? I want to be able to manipulate the maps in these pages. I want to pan and zoom them. But I cannot find a reference to an embedded map object. I've dissected the relevant JavaScript objects Drupal.gmap and Drupal.settings.gmap with no success--unless I've overlooked something. The Drupal GMap module doesn't seem to explicitly provide references (within its API) to the GMap objects that it embeds into pages. It just generates themed text which is interpolated into the page. The technique of passing the HTML ID of the map container to either the GMap2 object constructor or the similar Drupal.gmap.getMap() function in order to obtain a map reference doesn't appear to work: Both simply return an instance to a new map, one having the same dimensions and basic characteristics of the original map, but apparently sans all of its overlays (which could contain markers). And I have to call setCenter() on it before I can use it, which initializes the structure, so I know it has no overlays.

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  • problem when cloning jQuery UI datepicker

    - by h3
    I have a div in which there is a datepicker. I use something like this to clone it: mydiv = $('#someDiv'); // works fine so far mydiv.find('input.datefield').datepicker(); // clone without the events and insert newDiv = myDiv.clone(false).insertAfter(myDiv); // datepicker won't re-init if this class is present newDiv.find('.hadDatepicker').removeClass('hadDatepicker'); // reinitialize datepicker newDiv.find('input.datefield').datepicker(); This is a stripped down version of my code. It works and the calendar shows up as expected where it is expected .. but when a date is clicked, the previous datepicker's value gets updated.. (the one from which it was cloned). I've tried to destroy the (inexisting) instance before like this: newDiv.find('input.datefield').datepicker('destroy').datepicker(); No luck .. I've checked how it keeps track of instances and manually cleared the data like this: newDiv.find('input.datefield').data('datepicker', false).datepicker('destroy').datepicker(); Still no luck. What I don't understand is that only the date selection behavior is buggy, everything else works as expected. I really don't know what else to check now ..

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  • What is the way to go to fake my database layer in a unit test?

    - by Michel
    Hi, i have a question about unit testing. say i have a controller with one create method which puts a new customer in the database: //code a bit shortened public actionresult Create(Formcollection formcollection){ client c = nwe client(); c.Name = formcollection["name"]; ClientService.Save(c); { Clientservice would call a datalayer object and save it in the database. What i do now is create a database testscript and set my database in a know condition before testing. So when i test this method in the unit test, i know that there must be one more client in the database, and what it's name is. In short: ClientController cc = new ClientController(); cc.Create(new FormCollection (){name="John"}); //i know i had 10 clients before assert.areEqual(11, ClientService.GetNumberOfClients()); //the last inserted one is John assert.areEqual("John", ClientService.GetAllClients()[10].Name); So i've read that unit testing should not be hitting the database, i've setup an IOC for the database classes, but then what? I can create a fake database class, and make it do nothing. But then ofcourse my assertions will not work because if i say GetNumberOfClients() it will alwasy return X because it has no interaction with the fake database class used in the Create Method. I can also create a List of Clients in the fake database class, but as there will be two different instance created (one in the controller action and one in the unit test), they will have no interaction. What is the way to make this unit test work without a database?

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  • Ruby ROXML - how to get an array to render its xml?

    - by Brian D.
    I'm trying to create a Messages object that inherits Array. The messages will gather a group of Message objects. I'm trying to create an xml output with ROXML that looks like this: <messages> <message> <type></type> <code></code> <body></body> </message> ... </messages> However, I can't figure out how to get the message objects in the Messages object to display in the xml. Here is the code I've been working with: require 'roxml' class Message include ROXML xml_accessor :type xml_accessor :code xml_accessor :body end class Messages < Array include ROXML # I think this is the problem - but how do I tell ROXML that # the messages are in this instance of array? xml_accessor :messages, :as => [Message] def add(message) self << message end end message = Message.new message.type = "error" message.code = "1234" message.body = "This is a test message." messages = Messages.new messages.add message puts messages.length puts messages.to_xml This outputs: 1 <messages/> So, the message object I added to messages isn't getting displayed. Anyone have any ideas? Or am I going about this the wrong way? Thanks for any help.

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  • Why are virtual methods considered early bound?

    - by AspOnMyNet
    One definition of binding is that it is the act of replacing function names with memory addresses. a) Thus I assume early binding means function calls are replaced with memory addresses during compilation process, while with late binding this replacement happens during runtime? b) Why are virtual methods also considered early bound (thus the target method is found at compile time, and code is created that will call this method)? As far as I know, with virtual methods the call to actual method is resolved only during runtime and not compile time?! thanx EDIT: 1) A a=new A(); a.M(); As far as I know, it is not known at compile time where on the heap (thus at which memory address ) will instance a be created during runtime. Now, with early binding the function calls are replaced with memory addresses during compilation process. But how can compiler replace function call with memory address, if it doesn’t know where on the heap will object a be created during runtime ( here I’m assuming the address of method a.M will also be at same memory location as a )? 2) v-table calls are neither early nor late bound. Instead there's an offset into a table of function pointers. The offset is fixed at compile time, but which table the function pointer is chosen from depends on the runtime type of the object (the object contains a hidden pointer to its v-table), so the final function address is found at runtime. But assuming the object of type T is created via reflection ( thus app doesn’t even know of existence of type T ), then how can at compile time exist an entry point for that type of object?

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  • In app purchase on iphone.: How to receive your available products *before* someone may be able to b

    - by Thorsten S.
    Currently I am loading my supported products from a plist and after that I send a SKProductsRequest to guarantee that my SKProducts are still valid. So I set up the request, start it and get the response in: (void)productsRequest:(SKProductsRequest *)request didReceiveResponse:(SKProductsResponse *)response Now, so far all functions correctly. Problem: From calling the request until receiving the response it may last several seconds. Until that my app is already loaded and the user may be able to choose and buy a product. But because no products have been received, the available products are not in sync with the validated products - unlikely, but possible error. So my idea is to wait until the data is loaded and only continue when the list is validated. (Just a few seconds waiting...). I have a singleton instance managing all products. + (MyClass *) sharedInstance { if (!sharedInstance) sharedInstance = [MyClass new]; // Now wait until we have our data [condition lock]; while (noEntriesYet) // is yes at begin [condition wait]; [condition unlock]; return sharedInstance; } - productsRequest: didReceiveResponse: { [condition lock]; // I have my data noEntriesYet = false; [condition signal]; [condition unlock]; } Problem: The app freezes. Everything works fine if didReceiveResponse is completed before the sharedInstance is queried. There are different threads, the lock is working if wait is reached during didReceiveResponse, everything fine. But if not, didReceiveResponse is never called even if the request was sent. The lock is released, everything looks ok. I have tried to send the product request in a separate NSThread, with NSOperationQueue...without avail. Why ? What is happening ? How to solve the problem ?

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  • How to update a property using Type.GetProperties() method?

    - by Richard77
    Hello, I've a collection of a class' properties and would like to update each one's value by iterating over the collection through the index. 1) I create the collection of properties this way private PropertyInfo[] GetPropertiesOfMyClass() { Type myType = (typeof(myClass)); PropertyInfo[] PropertyInfoArray = myType.GetProperties( BindingFlags.Public | BindingFlags.Instance); return PropertyInfoArray; } 2)Now, I'd like to set up the value of each one depending on the index this way public void UpdateProperty(MyClass instanceOfMyClass, string valueToUpdate, int index) { //TODO: //1. Get an individual property from the GetPropertyOfMyClass() using index //2. Update the value of an individual property of the instanceOfMyClass } I'd like to be able to call UpdateProperty from a Controller like this: UpdateProperty(instanceOfMyClass, valueToUpdate, indexOfTheProperty); Honestly, I do not know how to involve the instanceOfMyClass in the game as GetProperty only plays with myClass. Since I saw that I can use Name, PropertyType, ... to get information on the property. So, I've tried also GetPropertyOfMyClass()[index].SetValue(...), but I was lost in the arguments of its constructor, so I abandoned. What I want is to be able to update the value of a property in my collection just by using the index. Thanks for helping

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  • iPhone: Leak with UIWebView loading Office documents. Any ideas how to avoid it?

    - by Thomas Tempelmann
    While there are already quite a few posts about leaks around UIWebView, mine is a bit more special, I believe, and thus deserves its own post here. I see a reproducible large leak every time I load a Office document such as a Word or Excel file. For instance, every time I display a 180KB .doc file, I get a 100KB leak. And that happens with both the simulator and an actual device, running OS 3.1.3. The leak is not visible with the Leaks instrument but only by looking at the malloc instances via the ObjectAlloc instrument. Here's a picture from the instruments trace: I've also made a demo project, UIWebView-Leak.zip, so you can verify this yourself. To see the leak, use the ObjectAlloc instrument, switch to the view where you see individual allocation objects, and sort by size so that you see the large ones in a group, just like in my picture above. Then view a Office document a few times and find the Malloc objects that keep staying "Live" even after the actual UIWebView has been freed. Is this a known bug? Or is there any way I can avoid these leaks? I.e, have you successfully shown Office documents on an iPhone withing getting such leaks? Note: I've reported this as a bug to Apple now, too (ID 7950594) I am still waiting for someone (including Apple) to confirm this as a true leak or show why it isn't (i.e. that I do something wrong or make wrong assumptions)

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  • FindControl() from UserControl inside a for loop

    - by Kyle
    I'm creating a usercontrol that will have a series of LinkButtons. I've declared all of my link buttons at the top of my class LinkButton LB1 = new LinkButton(); LinkButton LB2 = new LinkButton(); //... LinkButton LB9 = new LinkButton(); now I'd like to be able to create a loop to access all of those link buttons so I don't have to write them all out every time. I tried something like this within my overridden CreateChildControls() method: for (int i = 1; i < 10; i++) { LinkButton lb = (LinkButton)FindControl("LB" + i.ToString()); lb.Text = i.ToString() + "-Button"; } I keep getting an exception saying that lb.Text... is not set to an instance of an object. I also tried giving all of my LB1, LB2 etc valid Ids. ie: LB1.ID = "LB1"; still not dice. how can I do this?

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  • Ubuntu server or Debian server (to run C++ apps developed on Ubuntu)

    - by skyeagle
    I have written a number of C++ server side daemons for my website, using my Ubuntu 9.10 dev machine. I am now about to venture out to look for a hosting provider etc. This is my problem: I have read on many posts (admittedly old posts) that Debian server is much more robust than Ubuntu server - is this till the case?. In particular, I am constantly "raising elephants" with my Ubuntu 9.10 - this is "ok" for home use, but for a website server, I would not be so forgiving. Also, there seems to be a new "patch" every few weeks - which I would not like on a server (I want to leave the server well alone, and let it get on with its business of serving pages). So in this instance Debian looks a more attractive proposition. I am worried that the C++ apps I have developed on Ubuntu may not be binary compatable with Debian (or I may need to install additional libraries/packages etc to get things to work), and I have zero experience with Debian. Additionally, I dont want to be grappling with the learning curve associated with a new OS, whilst trying to launch a new web site (I am assuming Debian UI is quite different from Ubuntu). In this case, the maxim "the devil you know is better than the one you dont", seems appropriate - and I find Ubuntu a more attractive proposition (atleast I know my apps will run without any probs etc). Can anyone provide some rational advice (based on actual experience), to help me decide which route to take - given the two (conflicting) trains of thought outlined above?

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