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  • Is it possible to programatically catch JavaScript SyntaxErrors?

    - by Matty
    I don't think that this is doable, but wanted to throw it out to the community to confirm my suspicions. Let's say you're writing a program in another language like Python, PHP, or ASP. This program is intended to build another program written in JavaScript. However, the first program is unfortunately not immune to errors. So, occasionally, the program which builds the JavaScript program does some funky stuff and outputs a syntax error in the JavaScript source. Now some user goes and loads the program and it essentially halts, because the web browser running it can't properly parse the JavaScript. This user is probably not going to be happy. I wouldn't be. This brings me to my question. Is it possible to write an error handler that would catch these kind of syntax problems allowing the application to fail gracefully? Here's an example: <html> <head> <script type="text/javascript" charset="utf-8"> window.onerror = errorHandler; function errorHandler(a,b,c) { alert('horray! No wait, Booo!'); } vara jfs; </script> </head> <body> Can this be done? </body> </html> or <html> <head> <script type="text/javascript" charset="utf-8"> try { vara jfs; } catch (e) { alert('horray! No wait, Booo!'); } </script> </head> <body> Can this be done? </body> </html>

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  • Do you still limit line length in code?

    - by Noldorin
    This is a matter on which I would like to gauge the opinion of the community: Do you still limit the length of lines of code to a fixed maximum? This was certainly a convention of the past for many languages; one would typically cap the number of characters per line to a value such as 80 (and more recnetly 100 or 120 I believe). As far as I understand, the primary reasons for limiting line length are: Readability - You don't have to scroll over horizontally when you want to see the end of some lines. Printing - Admittedly (at least in my experience), most code that you are working on does not get printed out on paper, but by limiting the number of characters you can insure that formatting doesn't get messed up when printed. Past editors (?) - Not sure about this one, but I suspect that at some point in the distant past of programming, (at least some) text editors may have been based on a fixed-width buffer. I'm sure there are points that I am still missing out, so feel free to add to these... Now, when I tend to observe C or C# code nowadays, I often see a number of different styles, the main ones being: Line length capped to 80, 100, or even 120 characters. As far as I understand, 80 is the traditional length, but the longer ones of 100 and 120 have appeared because of the widespread use of high resolutions and widescreen monitors nowadays. No line length capping at all. This tends to be pretty horrible to read, and I don't see it too often, though it's certainly not too rare either. Inconsistent capping of line length. The length of some lines are limited to a fixed maximum (or even a maximum that changes depending on the file/location in code), while others (possibly comments) are not at all. My personal preference here (at least recently) has been to cap the line length to 100 in the Visual Studio editor. This means that in a decently sized window (on a non-widescreen monitor), the ends of lines are still fully visible. I can however see a few disadvantages in this, especially when you end up writing code that's indented 3 or 4 levels and then having to include a long string literal - though I often take this as a sign to refactor my code! In particular, I am curious what the C and C# coders (or anyone who uses Visual Studio for that matter) think about this point, though I would be interested in hearing anyone's thoughts on the subject. Edit Thanks for the all answers - I appreciate the variety of opinions here, all presenting sound reasons. Consensus does seem to be tipping in the direction of always (or almost always) limit the line length. Interestingly, it seems to be in various coding standards to limit the line length. Judging by some of the answers, both the Python and Google CPP guidelines set the limit at 80 chars. I haven't seen anything similar regarding C# or VB.NET, but I would be curious to see if there are ones anywhere.

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  • Suggestions for designing large-scale Java webapp from the group up

    - by Chris Thompson
    Hi all, I'm about to start developing a large-scale system and I'm struggling with which direction to proceed. I've done plenty of Java web apps before and I have plenty of experience with servlet containers and GWT and some experience with Spring. The problem is most of my webapps have been thrown together just to be a proof of concept and what I'm struggling with is what set of frameworks to use. I need to have both a browser based application as well as a web service designed to support access from mobile devices (Android and iPhone for now). Ideally, I'd like to design this system in such a way that I don't end up rewriting all of my servlets for each client (browser and phone) although I don't mind having some small checks in there to properly format the data. In addition, although I'm the only developer now, that won't necessarily be the case down the road and I'd like to design something that scales well both with regards to traffic and number of developers (isn't just a nightmare to maintain). So where I am now is planning on using GWT to design the browser-based interface but I'm struggling with how to reuse that code with to present the interface (most likely xml) for the mobile devices. Using GWT RPC would, I think, make it relatively easy to do all of the AJAX in the browser, but might make generating xml for the mobile phones difficult. In addition, I like the idea of using something like Hibernate for persistence and Spring Security to secure the whole thing. Again, I'm not sure how well those will cooperate with GWT (I think Hibernate should be fine...) There's obviously a lot more to this than I've presented here, but I've tried to give you the 5-minute overview. I'm a bit stumped and was wondering if anybody in the community had any experience starting from this place. Does what I'm trying to do make sense? Is it realistic? I have no doubt I can make all of these frameworks speak the same language, I'm just wondering if it's worth my time to fight with them. Also, am I missing a framework that would be really beneficial? Thanks in advance and sorry for the relatively broad question... Chris

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  • How do I explain this to potential employers?

    - by ReferencelessBob
    Backstory: TL;DR: I've gained a lot of experience working for 5 years at one startup company, but it eventually failed. The company is gone and the owner MIA. When I left sixth-form college I didn't want to start a degree straight away, so when I met this guy who knew a guy who was setting up a publishing company and needed a 'Techie' I thought why not. It was a very small operation, he sent mailings to schools, waited for orders to start arriving, then ordered a short run of the textbooks to be printed, stuck them in an envelope posted them out. I was initially going to help him set up a computerized system for recording orders and payments, printing labels, really basic stuff and I threw it together in Access in a couple of weeks. He also wanted to start taking orders online, so I set up a website and a paypal business account. While I was doing this, I was also helping to do the day-to-day running of things, taking phone orders, posting products, banking cheques, ordering textbooks, designing mailings, filing end of year accounts, hiring extra staff, putting stamps on envelopes. I learned so much about things I didn't even know I needed to learn about. Things were pretty good, when I started we sold about £10,000 worth of textbooks and by my 4th year there we sold £250,000 worth of text books. Things were looking good, but we had a problem. Our best selling product had peaked and sales started to fall sharply, we introduced add on products through the website to boost sales which helped for a while, but we had simply saturated the market. Our plan was to enter the US with our star product and follow the same, slightly modified, plan as before. We setup a 1-866 number and had the calls forwarded to our UK offices. We contracted a fulfillment company, shipped over a few thousand textbooks, had a mailing printed and mailed, then sat by the phones and waited. Needless to say, it didn't work. We tried a few other things, at home and in the US, but nothing helped. We expanded in the good times, moving into bigger offices, taking on staff to do administrative and dispatch work, but now cashflow was becoming a problem and things got tougher. We did the only thing we could and scaled things right back, the offices went, the admin staff went, I stopped taking a wage and started working from home. Nothing helped. The business was wound up about about 2 years ago. In the end it turned out that the owner had built up considerable debt at the start of business and had not paid them off during good years, which left him in a difficult position when cashflow had started to dry up. I haven't been able to contact the owner since I found out. It took me a while to get back on my feet after that, but I'm now at University and doing a Computer Science degree. How do I show the experience I have without having to get into all the gory details of what happened?

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  • Defining where on the page the flowdocument I am printing will 'start' and 'end'

    - by Sagi1981
    Dear community. I am almost done with implementing a printing functionality, but I am having trouble getting the last hurdle done with. My problem is, that I am printing some reports, consisting of a header (with information about the person the report is about), a footer (with a page number) and the content in the middle, which is a FlowDocument. Since the flowdocuments can be fairly long, It is very possible that they will span multiple pages. My approach is to make a custom FlowDocumentPaginator which derives from DocumentPaginator. In there i define my header and my footer. However, when I print my page, the flowdocument and my header and footer are on top of eachother. So my question is plain and simple - how do I define from where and to where the flowdocument part on the pages will be placed? here is the code from my custommade Paginator: public class HeaderedFlowDocumentPaginator : DocumentPaginator { private DocumentPaginator flowDocumentpaginator; public HeaderedFlowDocumentPaginator(FlowDocument document) { flowDocumentpaginator = ((IDocumentPaginatorSource) document).DocumentPaginator; } public override bool IsPageCountValid { get { return flowDocumentpaginator.IsPageCountValid; } } public override int PageCount { get { return flowDocumentpaginator.PageCount; } } public override Size PageSize { get { return flowDocumentpaginator.PageSize; } set { flowDocumentpaginator.PageSize = value; } } public override IDocumentPaginatorSource Source { get { return flowDocumentpaginator.Source; } } public override DocumentPage GetPage(int pageNumber) { DocumentPage page = flowDocumentpaginator.GetPage(pageNumber); ContainerVisual newVisual = new ContainerVisual(); newVisual.Children.Add(page.Visual); DrawingVisual header = new DrawingVisual(); using (DrawingContext dc = header.RenderOpen()) { //Header data } newVisual.Children.Add(header); DrawingVisual footer = new DrawingVisual(); using (DrawingContext dc = footer.RenderOpen()) { Typeface typeface = new Typeface("Trebuchet MS"); FormattedText text = new FormattedText("Page " + (pageNumber + 1).ToString(), CultureInfo.CurrentCulture, FlowDirection.LeftToRight, typeface, 14, Brushes.Black); dc.DrawText(text, new Point(page.Size.Width - 100, page.Size.Height-30)); } newVisual.Children.Add(footer); DocumentPage newPage = new DocumentPage(newVisual); return newPage; } } And here is the printdialogue call: private void btnPrint_Click(object sender, RoutedEventArgs e) { try { PrintDialog printDialog = new PrintDialog(); if (printDialog.ShowDialog() == true) { FlowDocument fd = new FlowDocument(); MemoryStream stream = new MemoryStream(ASCIIEncoding.Default.GetBytes(<My string of text - RTF formatted>)); TextRange tr = new TextRange(fd.ContentStart, fd.ContentEnd); tr.Load(stream, DataFormats.Rtf); stream.Close(); fd.ColumnWidth = printDialog.PrintableAreaWidth; HeaderedFlowDocumentPaginator paginator = new HeaderedFlowDocumentPaginator(fd); printDialog.PrintDocument(paginator, "myReport"); } } catch (Exception ex) { //Handle } }

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  • ASP.NET Client to Server communication

    - by Nelson
    Can you help me make sense of all the different ways to communicate from browser to client in ASP.NET? I have made this a community wiki so feel free to edit my post to improve it. Specifically, I'm trying to understand in which scenario to use each one by listing how each works. I'm a little fuzzy on UpdatePanel vs CallBack (with ViewState): I know UpdatePanel always returns HTML while CallBack can return JSON. Any other major differences? ...and CallBack (without ViewState) vs WebMethod. CallBack goes through most of the Page lifecycle, WebMethod doesn't. Any other major differences? IHttpHandler Custom handler for anything (page, image, etc.) Only does what you tell it to do (light server processing) Page is an implementation of IHttpHandler If you don't need what Page provides, create a custom IHttpHandler If you are using Page but overriding Render() and not generating HTML, you probably can do it with a custom IHttpHandler (e.g. writing binary data such as images) By default can use the .axd or .ashx file extensions -- both are functionally similar .ashx doesn't have any built-in endpoints, so it's preferred by convention Regular PostBack (System.Web.UI.Page : IHttpHandler) Inherits Page Full PostBack, including ViewState and HTML control values (heavy traffic) Full Page lifecycle (heavy server processing) No JavaScript required Webpage flickers/scrolls since everything is reloaded in browser Returns full page HTML (heavy traffic) UpdatePanel (Control) Control inside Page Full PostBack, including ViewState and HTML control values (heavy traffic) Full Page lifecycle (heavy server processing) Controls outside the UpdatePanel do Render(NullTextWriter) Must use ScriptManager If no client-side JavaScript, it can fall back to regular PostBack with no JavaScript (?) No flicker/scroll since it's an async call, unless it falls back to regular postback. Can be used with master pages and user controls Has built-in support for progress bar Returns HTML for controls inside UpdatePanel (medium traffic) Client CallBack (Page, System.Web.UI.ICallbackEventHandler) Inherits Page Most of Page lifecycle (heavy server processing) Takes only data you specify (light traffic) and optionally ViewState (?) (medium traffic) Client must support JavaScript and use ScriptManager No flicker/scroll since it's an async call Can be used with master pages and user controls Returns only data you specify in format you specify (e.g. JSON, XML...) (?) (light traffic) WebMethod Class implements System.Web.Service.WebService HttpContext available through this.Context Takes only data you specify (light traffic) Server only runs the called method (light server processing) Client must support JavaScript No flicker/scroll since it's an async call Can be used with master pages and user controls Returns only data you specify, typically JSON (light traffic) Can create instance of server control to render HTML and sent back as string, but events, paging in GridView, etc. won't work PageMethods Essentially a WebMethod contained in the Page class, so most of WebMethod's bullet's apply Method must be public static, therefore no Page instance accessible HttpContext available through HttpContext.Current Accessed directly by URL Page.aspx/MethodName (e.g. with XMLHttpRequest directly or with library such as jQuery) Setting ScriptManager property EnablePageMethods="True" generates a JavaScript proxy for each WebMethod Cannot be used directly in user controls with master pages and user controls Any others?

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  • Wordpress Iphone App: nsxmlparsererrordomain error 64

    - by iMayne
    Spending hours fixing my function.php page and all seemed well, except Im getting errors on my rss feed at: blog.xternalit.co.uk. I leave that issue to rest and installed wordpress iphone app. The connection to my blog works perfect with wordpress' default theme. Ha! But it keeps making me resetting my password. So hell with that. Switched back to my theme and I cant connect from app to blog. The internet say there's n issue with my function.php. here's a look again at the script: '', 'after_widget' = '', 'before_title' = '', 'after_title' = '', )); function content($num) { $theContent = get_the_content(); $output = preg_replace('/]+./','', $theContent); $limit = $num+1; $content = explode(' ', $output, $limit); array_pop($content); $content = implode(" ",$content)."..."; echo $content; } function post_is_in_descendant_category( $cats, $_post = null ) { foreach ( (array) $cats as $cat ) { // get_term_children() accepts integer ID only $descendants = get_term_children( (int) $cat, 'category'); if ( $descendants && in_category( $descendants, $_post ) ) return true; } return false; } //custom comments function mytheme_comment($comment, $args, $depth) { $GLOBALS['comment'] = $comment; ? id="li-comment-" " %s says:'), get_comment_author_link()) ? comment_approved == '0') : ? $depth, 'max_depth' = $args['max_depth']))) ? </div> 0 && isset($_POST['rockwell_settings']) ) { $options = array ( 'style','logo_img','logo_alt','logo_txt', 'logo_tagline', 'tagline_width', 'contact_email','ads', 'advertise_page', 'twitter_link', 'facebook_link', 'flickr', 'about_tit', 'about_txt', 'analytics'); foreach ( $options as $opt ) { delete_option ( 'rockwell_'.$opt, $_POST[$opt] ); add_option ( 'rockwell_'.$opt, $_POST[$opt] ); } } add_theme_page(__('Rockwell Options'), __('Rockwell Options'), 'edit_themes', basename(__FILE__), 'rockwell_settings'); } function rockwell_settings () {? Rockwell Options Panel General Settings Theme Color Scheme selected="selected"pink.css selected="selected"blue.css selected="selected"orange.css Logo image (full path to image) " class="regular-text" / Logo image ALT text " class="regular-text" / Text logo " class="regular-text" / Leave this empty if you entered an image as logo Logo Tag Line " class="regular-text" / Tag Line Box Width (px)Default width: 300px " class="regular-text" / Email Address for Contact Form " class="regular-text" / Twitter link " class="regular-text" / Facebook link " class="regular-text" / Flickr Photostream selected="selected"Yes selected="selected"No Make sure you have FlickrRSS plugin activated if you choose to enable Flickr Photostream Sidebar About Box Title " class="regular-text" / Text Ads Box Settings Ads Section Enabled: selected="selected"Yes selected="selected"No Make sure you have AdMinister plugin activated and have the position "Sidebar" created within the plugin. Advertise Page Google Analytics code: \'"[\'"].*/i', $post-post_content, $matches); $first_img = $matches [1] [0]; if(empty($first_img)){ //Defines a default image $first_img = "/images/default.jpg"; } return $first_img; } ? Please note, if I add: to the bottome of the page, the blog crashes. Without: I get tons of errors. Any help?

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  • MySQL table organization and optimization (Rails)

    - by aguynamedloren
    I've been learning Ruby on Rails over the past few months with no prior programming experience. Lately, I've been thinking about database optimization and table organization. I know there are great books on the subject, but I typically learn by example / as I go. Here's a hypothetical situation: Let's say I am building a social network for a niche community with 250,000 members (users). The users have the ability to attend events. Let's say there are 50,000 past/present/future events. Much like Facebook events, a user can attend any number of events and an event can have any number of attendees. In the database, there would be a table for users and a table for events. Somehow I would have to create an association between the users and events. I could create an "events" column in the users table such that each user row would contain a hash of event IDs, or I could create an "attendees" column in the events table such that each event row would contain a hash of user IDs. Neither of these solutions seem ideal, however. On a users profile page, I want to display the list of events they are associated with, which would require scanning the 50,000 event rows for the user ID of said user if I include an "attendees" column in the events table. Likewise, on an event page, I want to display a list of attendees for the event, which would require scanning the 250,000 user rows for the event ID of said event if I include an "events" column in the users table. Option 3 would be to create a third table that contains the attendee information for each and every event - but I don't see how this would solve any problems. Are these non-issues? Rails makes accessing all of this information easy, but I guess I'm worried about scale. It is entirely possible that I am under-estimating the speed and processing power of modern databases / servers / etc. How long would it take to scan 250,000 user rows for specific event IDs - 10ms? 100ms? 1,000ms? I guess that's not that bad. Am I just over-thinking this?

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  • Flex - Issues with linkbar dataprovider

    - by BS_C3
    Hello Community! I'm having some issues displaying a linkbar. The data I need to display is in a XML file. However, I couldn't get the linkbar to display a xmllist (I did indeed read that you cannot set a xmlllist as a linkbar dataprovider... ). So, I'm transforming the xmllist in a array of objects. Here is some code. XML file: <data> <languages> <language id="en"> <label>ENGLISH</label> <source></source> </language> <language id="fr"> <label>FRANCAIS</label> <source></source> </language> <language id="es"> <label>ESPAÑOL</label> <source></source> </language> <language id="jp"> <label>JAPANESE</label> <source></source> </language> </languages> </data> AS Code that transforms the xmllist in an array of objects: private function init():void { var list:XMLList = generalData.languages.language; var arr:ArrayCollection = new ArrayCollection; var obj:Object; for(var i:int = 0; i<list.length(); i++) { obj = new Object; obj.id = list[i].@id; obj.label = list[i].label; obj.source = list[i].source; arr.addItemAt(obj, arr.length); } GlobalData.instance.languages = arr.toArray(); } Linkbar code: <mx:HBox horizontalAlign="right" width="100%"> <mx:LinkBar id="language" dataProvider="{GlobalData.instance.languages}" separatorWidth="3" labelField="{label}"/> </mx:HBox> The separator is not displaying, and neither do the label. But the array is populated (I tested it). Thanks for any help you can provide =) Regards, BS_C3

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  • Zend database query result converts column values to null

    - by David Zapata
    Hi again. I am using the next instructions to get some registers from my Database. Create the needed models (from the params module): $obj_paramtype_model = new Params_Model_DbTable_Paramtype(); $obj_param_model = new Params_Model_DbTable_Param(); Getting the available locales from the database // This returns a Zend_Db_Table_Row_Abstract class object $obj_paramtype = $obj_paramtype_model->getParamtypeByValue('available_locales'); // This is a query used to add conditions to the next sentence. This is executed from the Params_Model_DbTable_Param instance class, that depends from Params_Model_DbTable_Paramtype class (reference map and dependentTables arrays are fine in both classes) $obj_select = $this->select()->where('deleted_at IS NULL')->order('name'); // Execute the next query, applying the select restrictions. This returns a Zend_Db_Table_Rowset_Abstract class object. This means "Find Params by Paramtype" $obj_params_rowset = $obj_paramtype->findDependentRowset('Params_Model_DbTable_Param', 'Paramtype', $obj_paramtype); // Here the firebug log displays the queries.... Zend_Registry::get('log')->debug($obj_params_rowset); I have a profiler for all my DB executions from Zend. At this point the log and profiler objects (that includes Firebug writers), shows the executed SQL Queries, and the last line displays the resulting Zend_Db_Table_Rowset_Abstract class object. If I execute the SQL Queries in some MySQL Client, the results are as expected. But the Zend Firebug log writer displays as NULL the column values with latin characters (ñ). In other words, the external SQL client shows es_CO | Español de Colombia and en_US | English of United States but the Query results from Zend displays (and returns) es_CO | null and en_US | English of United States. I've deleted the ñ character from Español de Colombia and the query results are just fine in my Zend Log Firebug screen, and in the final Zend Form element. The MySQL database, tables and columns are in UTF-8 - utf8_unicode_ci collation. All my zend framework pages are in UTF-8 charset. I'm using XAMPP 1.7.1 (PHP 5.2.9, Apache at port 90 and MySQL 5.1.33-community) running on Windows 7 Ultimate; Zend Framework 1.10.1. I'm sorry if there is so much information, but I don't really know why could that happen, so I tryed to provide as much related information as I could to help to find some answer.

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  • How to write specs with MSpec for code that changes Thread.CurrentPrincipal?

    - by Dan Jensen
    I've been converting some old specs to MSpec (were using NUnit/SpecUnit). The specs are for a view model, and the view model in question does some custom security checking. We have a helper method in our specs which will setup fake security credentials for the Thread.CurrentPrincipal. This worked fine in the old unit tests, but fails in MSpec. Specifically, I'm getting this exception: "System.Runtime.Serialization.SerializationException: Type is not resolved for member" It happens when part of the SUT tries to read the app config file. If I comment out the line which sets the CurrentPrincipal (or simply call it after the part that checks the config file), the error goes away, but the tests fail due to lack of credentials. Similarly, if I set the CurrentPrincipal to null, the error goes away, but again the tests fail because the credentials aren't set. I've googled this, and found some posts about making sure the custom principal is serializable when it crosses AppDomain boundaries (usually in reference to web apps). In our case, this is not a web app, and I'm not crossing any AppDomains. Our pincipal object is also serializable. I downloaded the source for MSpec, and found that the ConsoleRunner calls a class named AppDomainRunner. I haven't debugged into it, but it looks like it's running the specs in different app domains. So does anyone have any ideas on how I can overcome this? I really like MSpec, and would love to use it exclusively. But I need to be able to supply fake security credentials while running the tests. Thanks! Update: here's the spec class: [Subject(typeof(CountryPickerViewModel))] public class When_the_user_makes_a_selection : PickerViewModelSpecsBase { protected static CountryPickerViewModel picker; Establish context = () => { SetupFakeSecurityCredentials(); CreateFactoryStubs(); StubLookupServicer<ICountryLookupServicer>() .WithData(BuildActiveItems(new [] { "USA", "UK" })); picker = new CountryPickerViewModel(ViewFactory, ViewModelFactory, BusinessLogicFactory, CacheFactory); }; Because of = () => picker.SelectedItem = picker.Items[0]; Behaves_like<Picker_that_has_a_selected_item> a_picker_with_a_selection; } We have a number of these "picker" view models, all of which exhibit some common behavior. So I'm using the Behaviors feature of MSpec. This particular class is simulating the user selecting something from the (WPF) control which is bound to this VM. The SetupFakeSecurityCredentials() method is simply setting Thread.CurrentPrincipal to an instance of our custom principal, where the prinipal has been populated will full-access rights. Here's a fake CountryPickerViewModel which is enough to cause the error: public class CountryPickerViewModel { public CountryPickerViewModel(IViewFactory viewFactory, IViewModelFactory viewModelFactory, ICoreBusinessLogicFactory businessLogicFactory, ICacheFactory cacheFactory) { Items = new Collection<int>(); var validator = ValidationFactory.CreateValidator<object>(); } public int SelectedItem { get; set; } public Collection<int> Items { get; private set; } } It's the ValidationFactory call which blows up. ValidationFactory is an Enterprise Library object, which tries to access the config.

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  • Suggestions for designing large-scale Java webapp from the ground up

    - by Chris Thompson
    Hi all, I'm about to start developing a large-scale system and I'm struggling with which direction to proceed. I've done plenty of Java web apps before and I have plenty of experience with servlet containers and GWT and some experience with Spring. The problem is most of my webapps have been thrown together just to be a proof of concept and what I'm struggling with is what set of frameworks to use. I need to have both a browser based application as well as a web service designed to support access from mobile devices (Android and iPhone for now). Ideally, I'd like to design this system in such a way that I don't end up rewriting all of my servlets for each client (browser and phone) although I don't mind having some small checks in there to properly format the data. In addition, although I'm the only developer now, that won't necessarily be the case down the road and I'd like to design something that scales well both with regards to traffic and number of developers (isn't just a nightmare to maintain). So where I am now is planning on using GWT to design the browser-based interface but I'm struggling with how to reuse that code with to present the interface (most likely xml) for the mobile devices. Using GWT RPC would, I think, make it relatively easy to do all of the AJAX in the browser, but might make generating xml for the mobile phones difficult. In addition, I like the idea of using something like Hibernate for persistence and Spring Security to secure the whole thing. Again, I'm not sure how well those will cooperate with GWT (I think Hibernate should be fine...) There's obviously a lot more to this than I've presented here, but I've tried to give you the 5-minute overview. I'm a bit stumped and was wondering if anybody in the community had any experience starting from this place. Does what I'm trying to do make sense? Is it realistic? I have no doubt I can make all of these frameworks speak the same language, I'm just wondering if it's worth my time to fight with them. Also, am I missing a framework that would be really beneficial? Thanks in advance and sorry for the relatively broad question... Chris

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  • Keyboard for programming

    - by exhuma
    This may seem a bit a tangential topic. It's not directly related to actual code, but is important for our line of work nevertheless. Over the years, I've switched keyboards a few times. All of them had slightly different key layouts. And I'm not talking about the language/locale layout, but the physical layout! Why not the locale layout? Well, quite frankly, that's easy to change via software. I personally have a German keyboard but have it set to the UK layout. Why? It's quite hard to find different layouts in the shops where I live. Even ordering is not always easy in the shops. So that leaves me with Internet shops. But I prefer to "test" my keyboards before buying. The most notable changes are: Mangled "Home Key Block" I've seen this first on a Logitech keyboard, but it may have originated elsewhere. Shape of the "Enter" key I've seen three different cases so far: Two lines high, wider at the top Two lines high, wider at the bottom One line high Shape of the Backspace button I've seen two types so far: One "character" wide Two "characters" wide OS Keys For Macs, you have the Option and Command buttons, for Windows you have the Windows and Context Menu buttons. Cherry even produced a Linux keyboard once (unfortunately I cannot find many details except news results). I assume a dedicated Linux keyboard would sport a Compose key and had the SysRq always labelled as well (note that some standard layouts do this already). Obviously... .. all these differences entail that some keys have to be moved around the board a lot. Which means, if you are used to one and have to work on another one, you happen to hit the wrong keys quite often. As it happens, this is much more annoying for programmers as it is for people who write texts. Mainly because the keys which are moved around are special character keys, often used in programming. Often these hardware layouts depend also indirectly on where you buy the keyboards. Honestly, I haven't seen a keyboard with a one-line "Enter" key in Germany, nor Luxembourg. I may just have missed it but that's how it looks to me at least. A survey I've seen some attempts at surveys in the style "which keyboard is best for programming". But they all - in my opinion - are not using comparable sets. So I was wondering if it was possible to concoct a survey taking the above criteria into account. But ignoring key dimensions that one would be a bit overkill I guess ;) From what I can see there are the following types of physical layout: Backspace: 2-characters wide Enter: 2-Lines, wider top Backspace: 2-characters wide Enter: 1-Line Backspace: 1-character wide Enter: 2-Lines, wider bottom Then there are the other possible permutations (home-key block, os-keys), which in total makes for quite a large list of categories. Now, I wonder... Would anyone be interested in such a survey? I personally would. Because I am looking for the perfect fit for me. If yes, then I could really use the help of anyone here to propose some models to include in the survey. Once I have some models for each category (I'd say at least 3 per category) I could go ahead and write up a survey, put it on-line and let the it collect data for a while. What do you think?

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  • string categorization strategies

    - by Andrew Heath
    I'm the one-man dev team on a fledgling military history website. One aspect of the site is a catalog of ~1,200 individual battles, including the nations & formations (regiments, divisions, etc) which took part. The formation information (as well as the other battle info) was manually imported from a series of books by a 10-man volunteer team. The formations were listed in groups with varying formatting and abbreviation patterns. At the time I set up the data collection forms I couldn't think of a good way to process that data... and elected to store it all as strings in the MySQL database and sort it out later. Well, "later" - as it tends to happen - has arrived. :-) Each battle has 2+ records in the database - one for each nation that participated. Each record has a formations text string listing the formations present as the volunteer chose to add them. Some real examples: 39th Grenadier Rgmt, 26th Volksgrenadier Division 2nd Luftwaffe Field Division, 246th Infantry Division 247th Rifle Division, 255th Tank Brigade 2nd Luftwaffe Field Division, SS Cavalry Division 28th Tank Brigade, 158th Rifle Division, 135th Rifle Division, 81st Tank Brigade, 242nd Tank Brigade 78th Infantry Division 3rd Kure Special Naval Landing Force, Tulagi Seaplane Base personnel 1st Battalion 505th Infantry Regiment The ultimate goal is for each individual force to have an ID, so that its participation can be traced throughout the battle database. Formation hierarchy, such as the final item above 1st Battalion (of the) 505th Infantry Regiment also needs to be preserved. In that case, 1st Battalion and 505th Infantry Regiment would be split, but 1st Battalion would be flagged as belonging to the 505th. In database terms, I think I want to pull the formation field out of the current battle info table and create three new tables: FORMATION [id] [name] FORMATION_HIERARCHY [id] [parent] [child] FORMATION_BATTLE [f_id] [battle_id] It's simple to explain, but complicated to enact. What I'm looking for from the SO community is just some tips on how best to tackle this problem. Ideally there's some sort of method to solving this that I'm not aware of. However, as a last resort, I could always code a classification framework and call my volunteers back to sort through 2,500+ records...

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  • Square Peg Web: Gets you the traffic to where it matters most: Your Website!

    - by demetriusalwyn
    Have you decided to start your business online or is your business not reaching the targeted audience? Come to Square Peg Web; where you will find what you want to make your business reach new heights. The team at Square Peg Web is professionals who understand what you want and make sure you get it right. Our confidence stems from the fact of thousands of satisfied clients who keep referring friends and business associates to us and we do not let our clients down. Many companies promise the sky but how far is does their work live up to the promises? We do not know about the others however, we are sure that we strive to put together all our ideas and thoughts to make your website rank among the top. Web hosting is something that needs to have a personal touch; Square Peg Web customizes everything to suit your requirements so that you do not have to look further. With Square Peg Web you have a host of features to make your Business go viral. Some of the product details that are offered with Square Peg Web are unlimited product options/ variants/ properties giving you an option on price modifiers. You get unlimited customized input fields for your products and you can also Customer-define the prices. Square Peg Web provides you an option of using multiple product images with zoom features and one can also list a particular product in several categories. There are other aspects which make Square Peg Web the best choice for your website needs; every sale of yours’ is important to you and to us. We make sure that each sale is tracked by the product and also the list of bestsellers that appeal to the audience. Other comprehensive statistics of Square Peg Web includes searchable order data, an interface for shipments and order fulfillments, export sales & customer data for usage in a spreadsheet and the ability to export orders to QuickBooks format. With Square Peg Web; Admin Panel is a lot simpler. Administrative access is completely password protected and any changes done are all in real-time. You can have absolute control on the cart from anywhere around the world using your web browser and the topping on the cake is the unlimited amount of admin accounts that can be created for you. Square Peg Web offers you a world of experience with the options of choosing from marketing websites to e-commerce and from customized applications to community oriented sites. Some of the projects which appear in the portfolio of Square Peg Web are Online Marketing Web Sites, E-Commerce Web Sites, customized web applications, Blog designing and programming, video sharing and the option of downloading web sites, online advertisements, flash animation, customer and product support web sites, web site re-designing and planning and complete information architecture.

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  • java.util.zip - ZipInputStream v.s. ZipFile

    - by lucho
    Hello, community! I have some general questions regarding the java.util.zip library. What we basically do is an import and an export of many small components. Previously these components were imported and exported using a single big file, e.g.: <component-type-a id="1"/> <component-type-a id="2"/> <component-type-a id="N"/> <component-type-b id="1"/> <component-type-b id="2"/> <component-type-b id="N"/> Please note that the order of the components during import is relevant. Now every component should occupy its own file which should be externally versioned, QA-ed, bla, bla. We decided that the output of our export should be a zip file (with all these files in) and the input of our import should be a similar zip file. We do not want to explode the zip in our system. We do not want opening separate streams for each of the small files. My current questions: Q1. May the ZipInputStream guarantee that the zip entries (the little files) will be read in the same order in which they were inserted by our export that uses ZipOutputStream? I assume reading is something like: ZipInputStream zis = new ZipInputStream(new BufferedInputStream(fis)); ZipEntry entry; while((entry = zis.getNextEntry()) != null) { //read from zis until available } I know that the central zip directory is put at the end of the zip file but nevertheless the file entries inside have sequential order. I also know that relying on the order is an ugly idea but I just want to have all the facts in mind. Q2. If I use ZipFile (which I prefer) what is the performance impact of calling getInputStream() hundreds of times? Will it be much slower than the ZipInputStream solution? The zip is opened only once and ZipFile is backed by RandomAccessFile - is this correct? I assume reading is something like: ZipFile zipfile = new ZipFile(argv[0]); Enumeration e = zipfile.entries();//TODO: assure the order of the entries while(e.hasMoreElements()) { entry = (ZipEntry) e.nextElement(); is = zipfile.getInputStream(entry)); } Q3. Are the input streams retrieved from the same ZipFile thread safe (e.g. may I read different entries in different threads simultaneously)? Any performance penalties? Thanks for your answers!

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  • Var null and not an object when using document.getElementById

    - by Dean
    Hi, I'm doing some work in HTML and JQuery. I have a problem of my textarea and submit button not appearing after the radio button is selected. My HTML looks like this: <html> <head><title>Publications Database | Which spotlight for Publications</title> <script type="text/javascript" src="./jquery.js"></script> <script src="./addSpotlight.js" type="text/javascript" charset="utf-8"></script> </head> <body> <div class="wrapper"> <div class="header"> <div class="headerText">Which spotlight for Publications</div> </div> <div class="mainContent"> <p>Please select the publication that you would like to make the spotlight of this month:</p> <form action="addSpotlight" method="POST" id="form" name="form"> <div class="div29" id="div29"><input type="radio" value="29" name="publicationIDs" >A System For Dynamic Server Allocation in Application Server Clusters, IEEE International Symposium on Parallel and Distributed Processsing with Applications, 2008 </div> <div class="div30" id="div30"><input type="radio" value="30" name="publicationIDs" >Analysing BitTorrent's Seeding Strategies, 7th IEEE/IFIP International Conference on Embedded and Ubiquitous Computing (EUC-09), 2009 </div> <div class="div31" id="div31"><input type="radio" value="31" name="publicationIDs" >The Effect of Server Reallocation Time in Dynamic Resource Allocation, UK Performance Engineering Workshop 2009, 2009 </div> <div class="div32" id="div32"><input type="radio" value="32" name="publicationIDs" >idk, hello, 1992 </div> <div class="div33" id="div33"><input type="radio" value="33" name="publicationIDs" >sad, safg, 1992 </div> <div class="abstractWriteup" id="abstractWriteup"><textarea name="abstract"></textarea> <input type="submit" value="Add Spotlight"></div> </form> </div> </div> </body> </html> My javascript looks like this: $(document).ready( function() { $('.abstractWriteup').hide(); addAbstract(); }); function addAbstract() { var abstractWU = document.getElementById('.abstractWriteup'); $("input[name='publicationIDs']").change(function() { var abstractWU = document.getElementById('.abstractWriteup'); var classNameOfSelected = $("input[name='publicationIDs']").val(); var radioSelected = document.getElementById("div"+classNameOfSelected); var parentDiv = radioSelected.parentNode; parentDiv.insertBefore(radioSelected, abstractWU.nextSibling); $('.abstractWriteup').show(); });}; I have developed this by using Node#insertBefore. When I have had it working it has been rearranging the radio buttons. Thanks in Advance Dean

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  • If we don't like it for the presentation layer, then why do we tolerate it for the behavior layer?

    - by greim
    Suppose CSS as we know it had never been invented, and the closest we could get was to do this: <script> // this is the page's stylesheet $(document).ready(function(){ $('.error').css({'color':'red'}); $('a[href]').css({'textDecoration':'none'}); ... }); </script> If this was how we were forced to write code, would we put up with it? Or would every developer on Earth scream at browser vendors until they standardized upon CSS, or at least some kind of declarative style language? Maybe CSS isn't perfect, but hopefully it's obvious how it's better than the find things, do stuff method shown above. So my question is this. We've seen and tasted of the glory of declarative binding with CSS, so why, when it comes to the behavioral/interactive layer, does the entire JavaScript community seem complacent about continuing to use the kludgy procedural method described above? Why for example is this considered by many to be the best possible way to do things: <script> $(document).ready(function(){ $('.widget').append("<a class='button' href='#'>...</div>"); $('a[href]').click(function(){...}); ... }); </script> Why isn't there a massive push to get XBL2.0 or .htc files or some kind of declarative behavior syntax implemented in a standard way across browsers? Is this recognized as a need by other web development professionals? Is there anything on the horizon for HTML5? (Caveats, disclaimers, etc: I realize that it's not a perfect world and that we're playing the hand we've been dealt. My point isn't to criticize the current way of doing things so much as to criticize the complacency that exists about the current way of doing things. Secondly, event delegation, especially at the root level, is a step closer to having a declarative behavior layer. It solves a subset of the problem, but it can't create UI elements, so the overall problem remains.)

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  • Android Alert Dialog Extract User Choice Radio Button?

    - by kel196
    Apologies for any coding ignorance, I am a beginner and am still learning! I am creating a quiz app which reads questions off a SQL database and plots them as points on a google map. As the user clicks each point, an alert dialog appears with radio buttons to answer some question. My radiobuttons are in CustomItemizedOverlay file and when I click submit, I want to be able to send the user choice back to the database, save it and return to the user if their answer is correct. My question is this, how do I pass the user choice out once the submit button has been clicked? I tried making a global variable to read what was selected to no avail. Any suggestions would be appreciated! If I need to post any other code, please ask and I will do so ASAP! package uk.ac.ucl.cege.cegeg077.uceskkw; import java.util.ArrayList; import android.app.AlertDialog; import android.content.Context; import android.content.DialogInterface; import android.graphics.drawable.Drawable; import android.widget.Toast; import com.google.android.maps.ItemizedOverlay; import com.google.android.maps.OverlayItem; public class CustomItemizedOverlay2 extends ItemizedOverlay<OverlayItem> { private ArrayList<OverlayItem> mapOverlays = new ArrayList<OverlayItem>(); private Context context; public CustomItemizedOverlay2(Drawable defaultMarker) { super(boundCenterBottom(defaultMarker)); } public CustomItemizedOverlay2(Drawable defaultMarker, Context context) { this(defaultMarker); this.context = context; } @Override protected OverlayItem createItem(int i) { return mapOverlays.get(i); } @Override public int size() { return mapOverlays.size(); } @Override protected boolean onTap(int index) { OverlayItem item = mapOverlays.get(index); // gets the snippet from ParseKMLAndDisplayOnMap and splits it back into // a string. final CharSequence allanswers[] = item.getSnippet().split("::"); AlertDialog.Builder dialog = new AlertDialog.Builder(context); dialog.setIcon(R.drawable.easterbunnyegg); dialog.setTitle(item.getTitle()); dialog.setSingleChoiceItems(allanswers, -1, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { Toast.makeText(context, "You have selected " + allanswers[whichButton], Toast.LENGTH_SHORT).show(); } }); dialog.setPositiveButton(R.string.button_submit, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { dialog.dismiss(); // int selectedPosition = ((AlertDialog) // dialog).getListView().getCheckedItemPosition(); Toast.makeText(context, "hi!", Toast.LENGTH_SHORT) .show(); } }); dialog.setNegativeButton(R.string.button_close, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { dialog.dismiss(); // on cancel button action } }); AlertDialog question = dialog.create(); question.show(); return true; } public void addOverlay(OverlayItem overlay) { mapOverlays.add(overlay); this.populate(); } }

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  • GoogleTv video using VideoView is clipped, even though its in a separate layout of its own

    - by MYR
    Wrote an application for GoogleTV box to play a video. The video is a separate activity to the main activity. Wired up a button on my main layout/activity to to start the video activity up (using its own video.xml layout), the video activity loads and starts playing, but the video is clipped, only showing a few centimetres of the bottom. The clipped region looks like the views that occupied the previous layout (main.xml) . The intriguing thing is that if I push the back button, before returning to the main activity the full video frame is shown. Not sure what I am doing wrong here. Any suggestions welcome. Code: main.xml <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <TextView android:id="@+id/hello_message" android:layout_width="fill_parent" android:layout_height="200dp" android:gravity="center" android:text="@string/hello_message" android:textSize="78sp" /> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" > <EditText android:id="@+id/edit_message" android:layout_width="0dip" android:layout_height="wrap_content" android:layout_weight="1" android:ems="10" android:hint="@string/edit_message" > <requestFocus /> </EditText> <Button android:id="@+id/button_send" android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="displayMessage" android:text="@string/button_send" /> <Button android:id="@+id/button_send_a" android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="sendMesssage" android:text="@string/button_send_a" /> </LinearLayout> <Button android:id="@+id/videobutton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="startAVideo" android:text="Video Player" /> </LinearLayout> GoogleTVExActivity.java (excerpt): ... public class GoogleTVExActivity extends Activity { public final static String EXTRA_MESSAGE = "uk.co.bbc.googletvex.MESSAGE"; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); } public void displayMessage(View view) { TextView t = (TextView)findViewById(R.id.hello_message); EditText e =(EditText) findViewById(R.id.edit_message); t.setText(e.getText().toString()); e.setText(""); } public void sendMesssage(View view) { Intent intent = new Intent(this, DisplayMessageActivity.class); EditText editText = (EditText) findViewById(R.id.edit_message); String message = editText.getText().toString(); intent.putExtra(EXTRA_MESSAGE, message); startActivity(intent); } public void startAVideo(View view) { Intent intent = new Intent(this, VideoViewActivity.class); startActivity(intent); } } video.xml: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <VideoView android:id="@+id/myvideoview" android:layout_width="fill_parent" android:layout_height="fill_parent" /> </LinearLayout> VideoViewActivity.java (excerpt) ... import android.app.Activity; import android.net.Uri; import android.os.Bundle; import android.widget.MediaController; import android.widget.VideoView; public class VideoViewActivity extends Activity { String SrcPath = "rtsp://v5.cache1.c.youtube.com/CjYLENy73wIaLQnhycnrJQ8qmRMYESARFEIJbXYtZ29vZ2xlSARSBXdhdGNoYPj_hYjnq6uUTQw=/0/0/0/video.3gp"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.video); VideoView myVideoView = (VideoView)findViewById(R.id.myvideoview); myVideoView.setVideoURI(Uri.parse(SrcPath)); myVideoView.setMediaController(new MediaController(this)); myVideoView.requestFocus(); myVideoView.start(); } }

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  • Learn C# now or finish up with Java and then learn C#?

    - by Sahat
    Ok here is my situation. I've studied Java in my college for 2 semesters. But you know they teach you jack in there, just the basics. We skipped half of our textbook and even then our professors don't teach from section to section of each chapter. I don't blame them. It's hard as it is for new students to understand even the basic concepts of programming. Now this is a community college we are talking about and not Stanford, MIT or Berkeley. So like I said I've done 2 semester of Java. I really like our textbook because it has some challenging projects to do at the end of each chapter. This textbook is pretty clear and i have no problem understanding it (although 2-D and 3-D Arrays have given me some trouble). I have tried reading a few C# books such as Pro C# 2008 and .NET 3.5 and C# 4.0 in a Nutshell. I found these books to be dry and overloaded with information that put me to sleep (No offense to the authors of those 2 wonderful, according to amazon ratings, books). Would you suggest I finish my Java textbook, brush up my knowledge of Arrays, Polymorphism, and etc that are universal to most programming languages. And then switch to C#, plus the syntax is very similar so it should be easy to switch. Or should I just start learning C# right now from the very beginning? If it's the latter then could you recommend some free online resources that will keep me engaged and at the same time teach me everything I need to know about C#. Someone has recommended me to learn .NET first, but I found it to be not the brightest idea. .NET is just a big monster full of libraries. How am I going to apply it if I don't even know the C# or VB!? Anyway back to my question: Master Java and switch to C# or just go with C#? DISCLAIMER: I don't want to start .NET vs J2EE or C# vs Java flame war. I am going with C#. I've decided that I want to work in a Microsoft shop in the future. .NET is what I want to learn. Thanks! Will be waiting for the answers.

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  • Migrating from hand-written persistence layer to ORM

    - by Sergey Mikhanov
    Hi community, We are currently evaluating options for migrating from hand-written persistence layer to ORM. We have a bunch of legacy persistent objects (~200), that implement simple interface like this: interface JDBC { public long getId(); public void setId(long id); public void retrieve(); public void setDataSource(DataSource ds); } When retrieve() is called, object populates itself by issuing handwritten SQL queries to the connection provided using the ID it received in the setter (this usually is the only parameter to the query). It manages its statements, result sets, etc itself. Some of the objects have special flavors of retrive() method, like retrieveByName(), in this case a different SQL is issued. Queries could be quite complex, we often join several tables to populate the sets representing relations to other objects, sometimes join queries are issued on-demand in the specific getter (lazy loading). So basically, we have implemented most of the ORM's functionality manually. The reason for that was performance. We have very strong requirements for speed, and back in 2005 (when this code was written) performance tests has shown that none of mainstream ORMs were that fast as hand-written SQL. The problems we are facing now that make us think of ORM are: Most of the paths in this code are well-tested and are stable. However, some rarely-used code is prone to result set and connection leaks that are very hard to detect We are currently squeezing some additional performance by adding caching to our persistence layer and it's a huge pain to maintain the cached objects manually in this setup Support of this code when DB schema changes is a big problem. I am looking for an advice on what could be the best alternative for us. As far as I know, ORMs has advanced in last 5 years, so it might be that now there's one that offers an acceptable performance. As I see this issue, we need to address those points: Find some way to reuse at least some of the written SQL to express mappings Have the possibility to issue native SQL queries without the necessity to manually decompose their results (i.e. avoid manual rs.getInt(42) as they are very sensitive to schema changes) Add a non-intrusive caching layer Keep the performance figures. Is there any ORM framework you could recommend with regards to that?

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  • Patterns: Local Singleton vs. Global Singleton?

    - by Mike Rosenblum
    There is a pattern that I use from time to time, but I'm not quite sure what it is called. I was hoping that the SO community could help me out. The pattern is pretty simple, and consists of two parts: A singleton factory, which creates objects based on the arguments passed to the factory method. Objects created by the factory. So far this is just a standard "singleton" pattern or "factory pattern". The issue that I'm asking about, however, is that the singleton factory in this case maintains a set of references to every object that it ever creates, held within a dictionary. These references can sometimes be strong references and sometimes weak references, but it can always reference any object that it has ever created. When receiving a request for a "new" object, the factory first searches the dictionary to see if an object with the required arguments already exits. If it does, it returns that object, if not, it returns a new object and also stores a reference to the new object within the dictionary. This pattern prevents having duplicative objects representing the same underlying "thing". This is useful where the created objects are relatively expensive. It can also be useful where these objects perform event handling or messaging - having one object per item being represented can prevent multiple messages/events for a single underlying source. There are probably other reasons to use this pattern, but this is where I've found this useful. My question is: what to call this? In a sense, each object is a singleton, at least with respect to the data it contains. Each is unique. But there are multiple instances of this class, however, so it's not at all a true singleton. In my own personal terminology, I tend to call the factory method a "global singleton". I then call the created objects "local singletons". I sometimes also say that the created objects have "reference equality", meaning that if two variables reference the same data (the same underlying item) then the reference they each hold must be to the same exact object, hence "reference equality". But these are my own invented terms, and I am not sure that they are good ones. Is there standard terminology for this concept? And if not, could some naming suggestions be made? Thanks in advance...

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  • Rails learn's confusion

    - by Steve
    This is a beginner's rails learning confusion. When I learn rails, from time to time, I feel frustrated on rails' principle "Convention over Configuration". Rails uses heavily on conventions. A lot of them are just naming conventions. If I forget a convention, I will either use the wrong naming and get unexpected result or get things magically done but don't understand how. Sometimes, I think of configuration. At least configuration lists everything clearly and nothing is in fog. In rails, there seems a hidden, dark contract between you and the machine. If you follow the contract, you communicate well. But a beginner usually forgets items listed on the contract and this usually leads to confusion. That's why when I first pick up rails, I feel like it is somehow difficult to learn. Besides, there are many other things that could be new to a learner, such as using git, using plugins from community, using RESTful routing style, using RSpec. All these are new and come together in learning ruby and rails. This definitely adds up difficulties for a beginner. In contrast, if you learn php, it wouldn't be that bad. You can forget many things and focus on learning php itself. You don't need to learn database handling if you know SQL already(in rails, you need to learn a whole new concept migration), you don't have to learn a new decent unit test(in rails, usually they teach RSpec along the way because rails is agile and you should learn test-driven development in the early learning stage), you don't have to learn a new version control(in rails, you will be taught about git anyway), you don't have to use complicated plugins(in rails, they usually use third-party plugins in textbook examples! what the hell? why not teach how to do a simplified similar thing in rails?), you don't have to worry RESTful style. All in all, when I learn php, I learn it quick and soon I start to write things myself. Learning php is similar to learning C/java. It tastes like those traditional languages. When I learn rails, it is more difficult. And I need to learn ruby as well (I believe many of you learn ruby just because of rails). Does anyone have the similar feeling as I have? How do you overcome it and start to master rails? Hints will be welcomed. Thank you.

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  • iPhone NSCalendar - Incorrect Calendar Drawn for users outside US

    - by xoail
    After trying to work on someone else's code, and so many different iterations, I am unable to understand what am I doing wrong with dates on a calendar month view. I am trying to present a calendar in month view fashion like calendar.app but unfortunately some users in countries like Australia, UK are reporting incorrect alignment of Days to Dates. For instance in Australia it displays 17th March as Friday. Any help is highly appreciated! Here is the code sample I am using: -(void)setCalendar { NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]; NSDateComponents *comps = [gregorian components:units fromDate:[NSDate date]]; self.currentDate = [gregorian dateFromComponents:comps]; NSInteger weekdayInteger=[comps weekday]; currentMonth=[comps month]; currentYear=[comps year]; NSString *dateString=[[NSString stringWithFormat:@"%@",currentDate] substringToIndex:10]; NSArray *array= [dateString componentsSeparatedByString:@"-"]; NSInteger currentDay=[[array objectAtIndex:2] intValue]; currentMonthConstant=currentMonth; currentYearConstant=currentYear; currentDayConstant=currentDay; currentConstantDate=[NSString stringWithFormat:@"%d/%d/%d",currentDayConstant,currentMonthConstant,currentYearConstant]; currentFirstDay=((8+weekdayInteger-(currentDay%7))%7); if(currentFirstDay==0) currentFirstDay=7; [gregorian release]; } And this is how im populating the calendar: -(void)fillCalender:(NSInteger)month weekStarts:(NSInteger)weekday year:(NSInteger)year { currentMonth=month; currentYear=year; currentFirstDay=weekday; UIButton *temp; NSInteger numberOfDays=[self getNumberofDays:month YearVlue:year]; currentLastDay=(currentFirstDay+numberOfDays-1)%7; if(currentLastDay==0) currentLastDay=7; NSString *monthName=[self getMonth:month]; NSInteger grid=(weekday-1); monthLabel.text=[NSString stringWithFormat:@"%@ %d",monthName,year]; for(int i=1;i<=numberOfDays;i++) { if([frontView isEqualToString:@"view1"]) temp=[arr_View2Buttons objectAtIndex:grid]; else temp= [arr_View1Buttons objectAtIndex:grid]; [temp setBackgroundImage:nil forState:UIControlStateNormal]; [temp setUserInteractionEnabled:TRUE]; UILabel *aLbl = (UILabel *)[temp viewWithTag:123]; [aLbl setText:[NSString stringWithFormat:@"%d",i]]; // check for today if(currentDayConstant == i && currentMonthConstant == currentMonth && currentYearConstant == currentYear) { [aLbl setTextColor:[UIColor blueColor]]; } else { [aLbl setTextColor:[UIColor colorWithRed:69/255.0 green:2/255.0 blue:71/255.0 alpha:1.0]]; } [temp setTag:i]; grid++; if(grid==35) grid=0; } } And finally viewdidload: - (void)viewDidLoad { [super viewDidLoad]; [self setCalendar]; // set views [self.view1 setFrame:CGRectMake(0,45,320,232)]; [self.view2 setFrame:CGRectMake(0,277,320,232)]; [self.view addSubview:self.view1]; [self.view addSubview:self.view2]; frontView = @"view2"; [self fillCalender:currentMonth weekStarts:currentFirstDay year:currentYear]; frontView = @"view1"; }

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