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• SQLite dataypes lengths?

  - by XF

  I'm completely new to SQLite (actually 5 minutes ago), but I do know somewhat the Oracle and MySql backends. The question: I'm trying to know the lengths of each of the datatypes supported by SQLite, such as the differences between a bigint and a smallint. I've searched across the SQLite documentation (only talks about affinity, only matters it?), SO threads, google... and found nothing. My guess: I've just slightly revised the SQL92 specifications, which talk about datatypes and its relations but not about its lengths, which is quite obvious I assume. Yet I've come accross the Oracle and MySql datatypes specs, and the specified lengths are mostly identical for integers at least. Should I assume SQLite is using the same lengths? Aside question: Have I missed something about the SQLite docs? Or have I missed something about SQL in general? Asking this because I can't really understand why the SQLite docs don't specify something as basic as the datatypes lengths. It just doesn't make sense to me! Although I'm sure there is a simple command to discover the lengths.. but why not writing them to the docs? Thank you!

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• Concurrent WCF calls via shared channel

  - by Kent Boogaart

  I have a web tier that forwards calls onto an application tier. The web tier uses a shared, cached channel to do so. The application tier services in question are stateless and have concurrency enabled. But they are not being called concurrently. If I alter the web tier to create a new channel on every call, then I do get concurrent calls onto the application tier. But I wanted to avoid that cost since it is functionally unnecessary for my scenario. I have no session state, and nor do I need to re-authenticate the caller each time. I understand that the creation of the channel factory is far more expensive than than the creation of the channels, but it is still a cost I'd like to avoid if possible. I found this article on MSDN that states: While channels and clients created by the channels are thread-safe, they might not support writing more than one message to the wire concurrently. If you are sending large messages, particularly if streaming, the send operation might block waiting for another send to complete. Firstly, I'm not sending large messages (just a lot of small ones since I'm doing load testing) but am still seeing the blocking behavior. Secondly, this is rather open-ended and unhelpful documentation. It says they "might not" support writing more than one message but doesn't explain the scenarios under which they would support concurrent messages. Can anyone shed some light on this?

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• How do you manually set a RadioGroup value in wicket?

  - by Kane

  I'm trying to change the selected radio button in a Wicket RadioGroup during an AjaxEventBehavior but can't figure out how to do so. Specifically when a user types some text in a textbox I want to change the selected radio button to one I specify. How do you do this? Here's what I have so far (it crashes on addComponent): myRadioGroup = new RadioGroup("MyNewGroup", new PropertyModel(getPojo(), "selectedGroup")); Radio internalRadio = new Radio("InternalDirectoryNumber", new Model("Internal")); myRadioGroup .add(internalRadio); Radio externalRadio = new Radio("OtherMobileNumber", new Model("External")); myRadioGroup .add(externalRadio); TextField myTxtField= new TextField("TextBoxPrivateNumber", new PropertyModel(getVoiceItem(), "privateMobilePhone")); myTxtField.add( new AjaxEventBehavior( "onKeyUp" ) { @Override protected void onEvent(AjaxRequestTarget target) { Component component = target.getPage().get("myForm:MyNewGroup").setDefaultModelObject("External"); target.addComponent(component); //this causes an exception } }); myRadioGroup .add(myTxtField); Here is the exception that's thrown. java.lang.IllegalArgumentException: cannot update component that does not have setOutputMarkupId property set to true. Component: [MarkupContainer [Component id = myRadioGroup]] What's the proper way to do this? I'm not finding a whole lot of wicket documentation for this online.

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• openssl crypto library - base64 conversion

  - by Hassan Syed

  I'm using openssl BIO objects to convert a binary string into a base64 string. The code is as follows: void ToBase64(std::string & s_in) { BIO * b_s = BIO_new( BIO_s_mem() ); BIO * b64_f = BIO_new( BIO_f_base64() ); b_s = BIO_push( b64_f , b_s); std::cout << "IN::" << s_in.length(); BIO_write(b_s, s_in.c_str(), s_in.length()); char * pp; int sz = BIO_get_mem_data(b_s, &pp); std::cout << "OUT::" << sz << endl; s_in.assign(pp,sz); //std::cout << sz << " " << std::string(pp,sz) << std::endl; BIO_free (b64_f); // TODO ret error potential BIO_free (b_s); // } The in length is either 64 or 72. However the output is always 65, which is incorrect it should be much larger than that. The documentation isn't the best in the world, AFAIK the bio_s_mem object is supposed to grow dynamically. What am I doing wrong ?

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• JAVASCRIPT ENABLED [closed]

  - by kirchoffs415

  HI, I hope somebody can help, i keep getting the following message when i log on-- Your Javascript is disabled. Limited functionality is available. it will stay for maybe a day sometimes two.I have uninstalled javascript and reinstalled but still the same. Iam using chrome. any help would be gratefull many thanks Dominic p.s. my system spec is as follows System InformationOS Name Microsoft® Windows Vista™ Home Premium Version 6.0.6002 Service Pack 2 Build 6002 Other OS Description Not Available OS Manufacturer Microsoft Corporation System Name DOM-PC System Manufacturer Dell Inc. System Model Inspiron 1545 System Type X86-based PC Processor Pentium(R) Dual-Core CPU T4200 @ 2.00GHz, 2000 Mhz, 2 Core(s), 2 Logical Processor(s) BIOS Version/Date Dell Inc. A05, 25/02/2009 SMBIOS Version 2.4 Windows Directory C:\Windows System Directory C:\Windows\system32 Boot Device \Device\HarddiskVolume3 Locale United Kingdom Hardware Abstraction Layer Version = "6.0.6002.18005" User Name DOM-PC\DOM Time Zone GMT Standard Time Installed Physical Memory (RAM) 3.00 GB Total Physical Memory 2.96 GB Available Physical Memory 1.38 GB Total Virtual Memory 5.89 GB Available Virtual Memory 4.25 GB Page File Space 3.00 GB Page File C:\pagefile.sys My System Specs

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• Alloy MVC Framework Titanium Network (Model)

  - by flyingDuck

  I'm trying to authenticate using the Model in Alloy. I have been trying to figure this problem out since yesterday. If anybody could help me, I'd really appreciate it. So, I have a view login.xml, then a controller login.js. The login.js contains the following function: var user = Alloy.Models.user; //my user.js model function login(e) { if($.username.value !== '' && $.password.value !== ''){ if(user.login($.username.value, $.password.value)){ Alloy.createController('home').getView().open(); $.login.close(); } }else{ alert('Username and/or Password required!'); } } Then in my user.js model, it's like this: extendModel : function(Model) { _.extend(Model.prototype, { login: function(username, password) { var first_name, last_name, email; var _this = this; var url = 'http://myurl.com/test.php'; var auth = Ti.Network.createHTTPClient({ onerror: function(e){ alert(e.error); }, onload: function(){ var json = this.responseText; var response = JSON.parse(json); if(response.logged == true){ first_name = response.f_name; last_name = response.l_name; email = response.email; _this.set({ loggedIn: 1, username: email, realname: first_name + ' ' + last_name, email: email, }); _this.save(); }else{ alert(response.message); } }, }); auth.open('POST', url); var params = { usernames: username, passwords: password, }; auth.send(params); alert(_this.get('email')); //alert email }, }); When I click on login in login.xml it calls the function login in index.js. So, now my problem is that, when I click the button for the first time, I get an empty alert from alert(_this.get('email')), but then when I click the button the second time, everything works fine, it alerts the email. I have no idea what's going on. Thank you for the help.

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• NSIS patching (multiple patches in one file)

  - by Owen

  I'm able to generate patch files from one version to another using NSIS' Vpatch. Let's say I have mydll.dll version 1, and I have a patch to update it to version 2. Then I have a new version again, thus I generate another patch to update it to version 3. What bothers me though is, what if user cancels updating to version 2 and so forth. Then my latest version let's say is version 20. User decides to update to version 20. Is there a way to generate a patch that's like accumulative in nature? whereas user can jump from version any old version to the newest version (i.e ver 3 to ver 20) without passing through the versions in between? I've read this line in vpatch's documentation --- "if you want to be able to upgrade version 1 and 2 to version 3, you can put a 1 3 and 2 3 patch in one file." But how do I that? What if I alread have like 30 versions. Does that mean I have to create a patch whose arguments are old files(versions 1-29) and new file(version20)? Any help would be appreciated. Thanks...

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• How to create a "Shell IDList Array" to support drag-and-drop of virtual files from C# to Windows Ex

  - by JustABill

  I started trying to implement drag-and-drop of virtual files (from a C# 4/WPF app) with this codeplex tutorial. After spending some time trying to figure out a DV_E_FORMATETC error, I figured out I need to support the "Shell IDList Array" data format. But there seems to be next to zero documentation on what this format actually does. After some searching, I found this page on advanced data transfer which said that a Shell IDList Array was a pointer to a CIDA structure. This CIDA structure then contains the number of PIDLs, and a list of offsets to them. So what the hell is a PIDL? After some more searching, this page sort of implies it's a pointer to an ITEMIDLIST, which itself contains a single member that is a list of SHITEMIDs. My next idea was to try dragging a file from another application with virtual files. I just got a MemoryStream back for this format. At least I know what class to provide for the thing, but that doesn't help at all for explaining what to put in it. So now that that's explained, I still have no idea how to create one of these things so that it's valid. There's two real questions here: What is a valid "abID" member for a SHITEMID? These virtual files only exist with my program; will the thing they are dragged to pass the "abID" back later when it executes GetData? Do they have to be system-unique? Why are there two levels of lists; a list of PIDLs and each PIDL has a list of SHITEMIDs? I'm assuming one of them is one for each file, but what's the other one for? Multiple IDs for the same file? Any help or even links that explain what I should be doing would be greatly appreciated.

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• Validating Age field javascript beginner

  - by Marcelo

  Hi people, I'm trying to validate an age field in a form but I'm having some problem. First I tried to make sure that the field will not be send empty. I don't know javascript so I searched some scripts and adapted them to this: function isInteger (s) { var i; if (isEmpty(s)) if (isInteger.arguments.length == 1) return 0; else return (isInteger.arguments[1] == true); for (i = 0; i < s.length; i++) { var c = s.charAt(i); if (!isDigit(c)) return false; } return true; } function isEmpty(s) { return ((s == null) || (s.length == 0)) } function validate_required(field,alerttxt) { with (field) { if (value==null||value=="") { alert(alerttxt);return false; } else { return true; } } } function validate_form(thisform) { with (thisform) { if ((validate_required(age,"Age must be filled out!")==false) || isInteger(age,"Age must be and int number")==false)) {email.focus();return false;} } } //html part <form action="doador.php" onsubmit="return validate_form(this)" method="post"> It's working fine for empty fields, but if I type any letters or characters in age field, it'll be sent and saved a 0 in my database. Can any one help me ? Sorry for any mistake in English, and thanks in andvance for your help.

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• Nested Class member function can't access function of enclosing class. Why?

  - by Rahul

  Please see the example code below: class A { private: class B { public: foobar(); }; public: foo(); bar(); }; Within class A & B implementation: A::foo() { //do something } A::bar() { //some code foo(); //more code } A::B::foobar() { //some code foo(); //<<compiler doesn't like this } The compiler flags the call to foo() within the method foobar(). Earlier, I had foo() as private member function of class A but changed to public assuming that B's function can't see it. Of course, it didn't help. I am trying to re-use the functionality provided by A's method. Why doesn't the compiler allow this function call? As I see it, they are part of same enclosing class (A). I thought the accessibility issue for nested class meebers for enclosing class in C++ standards was resolved. How can I achieve what I am trying to do without re-writing the same method (foo()) for B, which keeping B nested within A? I am using VC++ compiler ver-9 (Visual Studio 2008). Thank you for your help.

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• Is there a good way to execute MySQL statements atomically via JDBC?

  - by javanix

  Suppose I have a table that contains valid data. I would like to modify this data in some way, but I'd like to make sure that if any errors occur with the modification, the table isn't changed and the method returns something to that effect. For instance, (this is kind of a dumb example, but it illustrates the point so bear with me) suppose I want to edit all the entries in a "name" column so that they are properly capitalized. For some reason, I want either ALL of the names to have proper capitalization, or NONE of them to have proper capitalization (and the starting state of the table is that NONE of them do). Is there an already-implemented way to run a batch update on the table and be assured that, if any one of the updates fails, all changes are rolled back and the table remains unchanged? I can think of a few ways to do this by hand (though suggestions are welcomed), but it'd be nice if there was some method I could use that would function this way. I looked at the java.sql.statement.executeBatch() command, but I'm not convinced by the documentation that my table wouldn't be changed if it failed in some manner.

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• Form With Quantity doesn't seem to submit

  - by Karl Entwistle

  Hey guys, I've been trying to understand the documentation and find an example, but I'm at a loss. This is just a submit form within the cart for updating the quantity. However, the updated quantity is not getting saved to the database -- it always makes the quantity 0. Please help. Form <% for line_item in @cart.line_items %> <% form_for :lineitems, :url => {:controller => "line_items", :action => "cart_update", :id => "#{line_item.product_id}"} do |l| %> <%= l.text_field :quantity, :size => '3', :value => line_item.quantity %> <%= l.submit 'cart_update' %> <% end %> Route map.connect 'line_item_update', :controller => 'line_items', :action => 'cart_update' Controller def cart_update @product = Product.find(params[:id]) item = LineItem.find_or_create_by_cart_id(:cart_id => current_cart.id, :product_id => @product.id, :quantity => 0, :unit_price => @product.price) item.quantity = (params[:quantity]).to_i item.save redirect_to :controller => 'products' end

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• Scope of "library" methods

  - by JS

  Hello, I'm apparently laboring under a poor understanding of Python scoping. Perhaps you can help. Background: I'm using the 'if name in "main"' construct to perform "self-tests" in my module(s). Each self test makes calls to the various public methods and prints their results for visual checking as I develop the modules. To keep things "purdy" and manageable, I've created a small method to simplify the testing of method calls: def pprint_vars(var_in): print("%s = '%s'" % (var_in, eval(var_in))) Calling pprint_vars with: pprint_vars('some_variable_name') prints: some_variable_name = 'foo' All fine and good. Problem statement: Not happy to just KISS, I had the brain-drizzle to move my handy-dandy 'pprint_vars' method into a separate file named 'debug_tools.py' and simply import 'debug_tools' whenever I wanted access to 'pprint_vars'. Here's where things fall apart. I would expect import debug_tools foo = bar debug_tools.pprint_vars('foo') to continue working its magic and print: foo = 'bar' Instead, it greets me with: NameError: name 'some_var' is not defined Irrational belief: I believed (apparently mistakenly) that import puts imported methods (more or less) "inline" with the code, and thus the variable scoping rules would remain similar to if the method were defined inline. Plea for help: Can someone please correct my (mis)understanding of scoping regards imports? Thanks, JS

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• Problems with rails and saving to the database.

  - by Grantismo

  I've been having some difficulty in understanding the source of a problem. Below is a listing of the model classes. Essentially the goal is to have the ability to add sentences to the end of the story, or to add stories to an existing sentence_block. Right now, I'm only attempting to allow users to add sentences, and automatically create a new sentence_block for the new sentence. class Story < ActiveRecord::Base has_many :sentence_blocks, :dependent => :destroy has_many :sentences, :through => :sentence_blocks accepts_nested_attributes_for :sentence_blocks end class SentenceBlock < ActiveRecord::Base belongs_to :story has_many :sentences, :dependent => :destroy end class Sentence < ActiveRecord::Base belongs_to :sentence_block def story @sentence_block = SentenceBlock.find(self.sentence_block_id) Story.find(@sentence_block.story_id) end end The problem is occurring when using the show method of the Story. The Story method is as follows, and the associated show method for a sentence is also included. Sentence.show def show @sentence = Sentence.find(params[:id]) respond_to do |format| format.html {redirect_to(@sentence.story)} format.xml { render :xml => @sentence } end end Story.show def show @story = Story.find(params[:id]) @sentence_block = @story.sentence_blocks.build @new_sentence = @sentence_block.sentences.build(params[:sentence]) respond_to do |format| if @new_sentence.content != nil and @new_sentence.sentence_block_id != nil and @sentence_block.save and @new_sentence.save flash[:notice] = 'Sentence was successfully added.' format.html # new.html.erb format.xml { render :xml => @story } else @sentence_block.destroy format.html format.xml { render :xml => @story } end end end I'm getting a "couldn't find Sentence_block without and id" error. So I'm assuming that for some reason the sentence_block isn't getting saved to the database. Can anyone help me with my understanding of the behavior and why I'm getting the error? I'm trying to ensure that every time the view depicts show for a story, an unnecessary sentence_block and sentence isn't created, unless someone submits the form, I'm not really sure how to accomplish this. Any help would be appreciated.

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• Creating A Single Threaded Server with AnyEvent (Perl)

  - by David Williams

  I'm working on creating a local service to listen on localhost and provide a basic call and response type interface. What I'd like to start with is a baby server that you can connect to over telnet and echoes what it receives. I've heard AnyEvent is great for this, but the documentation for AnyEvent::Socket does not give a very good example how to do this. I'd like to build this with AnyEvent, AnyEvent::Socket and AnyEvent::Handle. Right now the little server code looks like this: #!/usr/bin/env perl use AnyEvent; use AnyEvent::Handle; use AnyEvent::Socket; my $cv = AnyEvent->condvar; my $host = '127.0.0.1'; my $port = 44244; tcp_server($host, $port, sub { my($fh) = @_; my $cv = AnyEvent->condvar; my $handle; $handle = AnyEvent::Handle->new( fh => $fh, poll => "r", on_read => sub { my($self) = @_; print "Received: " . $self->rbuf . "\n"; $cv->send; } ); $cv->recv; }); print "Listening on $host\n"; $cv->wait; This doesn't work and also if I telnet to localhost:44244 I get this: EV: error in callback (ignoring): AnyEvent::CondVar: recursive blocking wait attempted at server.pl line 29. I think if I understand how to make a mini, single threaded server that simply prints out whatever its given and then waits for more input, I could take it a lot further from there. Any ideas?

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• How do I implement a listener pattern over RMI using Spring?

  - by predhme

  So here is a generalized version of our application desgin: @Controller public class MyController { @Autowired private MyServiceInterface myServiceInterface; @RequestMapping("/myURL") public @ResponseBody String doSomething() { MyListenerInterface listener = new MyListenerInterfaceImpl(); myServiceInterface.doThenCallListener(listener); // do post stuff } } public interface MyListenerInterface { public void callA(); public void callB(); } public class MyListenerInterfaceImpl implements MyListenerInterface { // ... omitted for clarity } public interface MyServiceInterface { public void doThenCallListener(MyListenerInterface listener); } public class MyServiceImpl { public void doThenCallListener(MyListenerInterface listener) { // do stuff listener.callA(); } } Basically I have a controller that is being called via AJAX in which I am looking to return a response as a string. However, I need to make a call to the backend (MyServiceInterface). That guy is exposed through RMI by using Spring (man that was easy). But the service method as described requires a listener to be registered for invokation completion purposes. So what I assume I need to achieve is transparently to the backend make it so that when the listener methods are called, really the call is going over RMI. I would have thought Spring would have a simple way to wrap a POJO (not a service singleton) with RMI calls. I looked through their documentation but they had nothing besides exposing services via RMI. Could someone point me in the right direction?

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• What are Code Smells? What is the best way to correct them?

  - by Rob Cooper

  OK, so I know what a code smell is, and the Wikipedia Article is pretty clear in its definition: In computer programming, code smell is any symptom in the source code of a computer program that indicates something may be wrong. It generally indicates that the code should be refactored or the overall design should be reexamined. The term appears to have been coined by Kent Beck on WardsWiki. Usage of the term increased after it was featured in Refactoring. Improving the Design of Existing Code. I know it also provides a list of common code smells. But I thought it would be great if we could get clear list of not only what code smells there are, but also how to correct them. Some Rules Now, this is going to be a little subjective in that there are differences to languages, programming style etc. So lets lay down some ground rules: ** ONE SMELL PER ANSWER PLEASE! & ADVISE ON HOW TO CORRECT! ** See this answer for a good display of what this thread should be! DO NOT downmod if a smell doesn't apply to your language or development methodology We are all different. DO NOT just quickly smash in as many as you can think of Think about the smells you want to list and get a good idea down on how to work around. DO downmod answers that just look rushed For example "dupe code - remove dupe code". Let's makes it useful (e.g. Duplicate Code - Refactor into separate methods or even classes, use these links for help on these common.. etc. etc.). DO upmod answers that you would add yourself If you wish to expand, then answer with your thoughts linking to the original answer (if it's detailed) or comment if its a minor point. DO format your answers! Help others to be able to read it, use code snippets, headings and markup to make key points stand out!

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• JFLAP Turing Machine shortcut problem

  - by Robert Lamb

  In JFLAP (http://jflap.org), there are some shortcuts for Turing machine transitions. One of these shortcuts allows you to transition as long as the current tape symbol isn't the indicated symbol. For example, the transition !g,x;R basically says "Take this transition if the current tape symbol is not g". So far, so good. But the transition I want is !?,~;R which basically says "Move right as long as the current symbol is not the end-of-string (empty cell) symbol". The problem is I cannot figure out how to type in "!?". The JFLAP online documentation (http://www.jflap.org/tutorial/turing/one/index.html#syntax) has this to say: The first shortcut is that there exists the option of using the “!” character to convey the meaning of “any character but this character.” For example, concerning the transition (!a; x, R), if the head encounters any character but an “a”, it will replace the character with an “x” and move right. To write the expression “!?”, just type a “1” in when inputting a command. My question is...how do I actually do what that last sentence is trying to explain to me? Thanks for your help! Robert

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• How do I run a universal app on the iPhone 3.1.3 simulator?

  - by bpapa

  I'm working on a new app that I want to be universal for the iPhone and iPad. I started out with the "Create a Window-based app" wizard, and it created separate app delegates in "iPhone" and "iPad" groups. Since I already was quite familiar with iPhone dev, I did that part of my project, and now I'm ready to do some iPad stuff. So... I started out by adding a UISplitViewController to my iPad delegate, switch the Active SDK to 3.2, and it works! But when I switch back to 3.1.3, and try to run it in the simulator, Build and Go fails. For starters, I see: ...path.../iPad/AppDelegate_Pad.h:13: error: expected specifier-qualifier-list before 'UISplitViewController' I've got my Base SDK set to 3.2 and my Deployment Target set to 3.1.3. I thought that was enough. But I also have found in the documentation this method to conditionally compile: #if __IPHONE_OS_VERSION_MAX_ALLOWED >= 30200 MyIPadViewController* vc; // Create the iPad view controller #else MyIPhoneViewController* vc; // Create the iPhone view controller #endif So do I need to do this everywhere? It seems like an awful lot of code to add (that I'll be getting rid of in a short time for 4.0 anyway) so I feel like I must be doing something wrong. And, I don't even have any idea how this works for things like @property or @synthesize declarations. tl;dr version of the question - did I miss a setting somewhere?

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• Creating parallel selenium tests in C# and using Nunit as the runner application

  - by damianmartin

  I am writing a new test suite for the company to test a very complex ASP.NET application which is heavily AJAX driven. We have decided to use Selenium (Grid & Remote Control) and Nunit to run these tests. The actually tests are dynamically created at run time from a spreadsheet. Each Column in an excel spreadsheet relates to a new test and each row relates to a selenium command (but in plain English and the dll converts this into Selenium code). My problem i have at the moment is getting the tests running in parallel. There will be 1000+ tests so it is too time consuming to have 1 test run at a time. Selenium Grid and Selenium Remote Control(s) are setup correctly because I can run there demo. From what i have read I need to use Punit but i can not find any documentation on what a test in punit should look like. Nunit tests are [SetUp] [TearDown] [Test]. Can anyone point me in the right direction. Thanks in advance.

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• embed dll in html <object>

  - by Raynos

  I've come across some old code <object id="foo" classid="/location/bar.dll#ProjectName.ClassName" viewastext></object> It doesn't currently work and used to work in older versions of IE. I've never come across embedding a dll in a web page like this. It appears to be a windows .NET application written in C#. This is used on our intranet. And ClassName is of type System.Windows.Forms.UserControl It also seems I can call the C# methods of the UserControl directly through javascript. Does anyone have any documentation on how this works and whether its possible to hack it into firefox. Rewriting the windows control as a web application would be a nightmare. [Edit] It appears to be some kind of activeX / COM thing where in IE you could just port a windows application directly into a html file. It's supposed to be able to run locally if you set up various correctly. If anyone has an idea of what needs to be set up for this to work, that would be nice.

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• Vehicle License Plate Detection

  - by Ash

  Hey all Basically for my final project at university, I'm developing a vehicle license plate detection application. Now I consider myself an intermediate programmer, however my mathematics knowledge lacks anything above secondary school, therefore producing detection formulae is basically impossible. I've spend a good amount of time looking up academic papers such as: http://www.scribd.com/doc/266575/Detecting-Vehicle-License-Plates-in-Images http://www.cic.unb.br/~mylene/PI_2010_2/ICIP10/pdfs/0003945.pdf http://www.eurasip.org/Proceedings/Eusipco/Eusipco2007/Papers/d3l-b05.pdf When it comes to the maths, I'm lost. Due to this testing various graphic images proved productive, for example: to However this approach is only catered to that particular image, and if the techniques were applied to different images, I'm sure a different, most likely poorer conversion would occur. I've read about a formula called the bottom hat morphology transform, which according to the first does the following: "Basically, the trans- formation keeps all the dark details of the picture, and eliminates everything else (including bigger dark regions and light regions)." Sadly I can't find much information on this, however the image within the documentation near the end of the report shows it's effectiveness. I'm aware this is complicated and vast, I'd just appreciate a little advice, even in terms of what transformation techniques I should focus on developing, or algorithm regarding edge detection or pixel detection. Few things I need to add Developing in C Sharp Confining the project to UK registration plates only I can basically choose the images to convert as a demonstration Thanks

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• Django forms: how to dynamically create ModelChoiceField labels

  - by Henri

  I would like to create dynamic labels for a forms.ModelChoiceField and I'm wondering how to do that. I have the following form class: class ProfileForm(forms.ModelForm): def __init__(self, data=None, ..., language_code='en', family_name_label='Family name', horoscope_label='Horoscope type', *args, **kwargs): super(ProfileForm, self).__init__(data, *args, **kwargs) self.fields['family_name'].label = family_name_label . . self.fields['horoscope'].label = horoscope_label self.fields['horoscope'].queryset = Horoscope.objects.all() class Meta: model = Profile family_name = forms.CharField(widget=forms.TextInput(attrs={'size':'80', 'class': 'contact_form'})) . . horoscope = forms.ModelChoiceField(queryset = Horoscope.objects.none(), widget=forms.RadioSelect(), empty_label=None) The default labels are defined by the unicode function specified in the Profile definition. However the labels for the radio buttons created by the ModelChoiceField need to be created dynamically. First I thought I could simply override ModelChoiceField as described in the Django documentation. But that creates static labels. It allows you to define any label but once the choice is made, that choice is fixed. So I think I need to adapt add something to init like: class ProfileForm(forms.ModelForm): def __init__(self, data=None, ..., language_code='en', family_name_label='Family name', horoscope_label='Horoscope type', *args, **kwargs): super(ProfileForm, self).__init__(data, *args, **kwargs) self.fields['family_name'].label = family_name_label . . self.fields['horoscope'].label = horoscope_label self.fields['horoscope'].queryset = Horoscope.objects.all() self.fields['horoscope'].<WHAT>??? = ??? Anyone having any idea how to handle this? Any help would be appreciated very much.

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• Calling SDL/OpenGL from Assembly code on Linux

  - by Lie Ryan

  I'm write a simple graphic-based program in Assembly for learning purpose; for this, I intended to use either OpenGL or SDL. I'm trying to call OpenGL/SDL's function from assembly. The problem is, unlike many assembly and OpenGL/SDL tutorials I found in the internet, the OpenGL/SDL in my machine apparently doesn't use C calling convention. I wrote a simple program in C, compile it to assembly (using -S switch), and apparently the assembly code that is generated by GCC calls the OpenGL/SDL functions by passing parameters in the registers instead of being pushed to the stack. Now, the question is, how do I determine how to pass arguments to these OpenGL/SDL functions? That is, how do I figure out which argument corresponds to which registers? Obviously since GCC can compile C code to call OpenGL/SDL, so therefore there must be a way to figure out the correspondence between function arguments and registers. In C calling conventions, the rule is easy, push parameters backwards and return value in eax/rax, I can simply read their C documentation and I can easily figure out how to pass the parameters. But how about these? Is there a way to call OpenGL/SDL using C calling convention? btw, I'm using yasm, with gcc/ld as the linker on Gentoo Linux amd64.

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• How do I get save (no exclamation point) semantics in an ActiveRecord transaction?

  - by James A. Rosen

  I have two models: Person and Address which I'd like to create in a transaction. That is, I want to try to create the Person and, if that succeeds, create the related Address. I would like to use save semantics (return true or false) rather than save! semantics (raise an ActiveRecord::StatementInvalid or not). This doesn't work because the user.save doesn't trigger a rollback on the transaction: class Person def save_with_address(address_options = {}) transaction do self.save address = Address.build(address_options) address.person = self address.save end end end (Changing the self.save call to an if self.save block around the rest doesn't help, because the Person save still succeeds even when the Address one fails.) And this doesn't work because it raises the ActiveRecord::StatementInvalid exception out of the transaction block without triggering an ActiveRecord::Rollback: class Person def save_with_address(address_options = {}) transaction do save! address = Address.build(address_options) address.person = self address.save! end end end The Rails documentation specifically warns against catching the ActiveRecord::StatementInvalid inside the transaction block. I guess my first question is: why isn't this transaction block... transacting on both saves?

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