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  • Spring MessageSource not being used during validation

    - by Jeremy
    I can't get my messages in messages.properties to be used during Spring validation of my form backing objects. app-config.xml: <bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource"> <property name="basename" value="messages" /> </bean> WEB-INF/classes/messages.properties: NotEmpty=This field should not be empty. Form Backing Object: ... @NotEmpty @Size(min=6, max=25) private String password; ... When I loop through all errors in the BindingResult and output the ObjectError's toString I get this: Field error in object 'settingsForm' on field 'password': rejected value []; codes [NotEmpty.settingsForm.password,NotEmpty.password,NotEmpty.java.lang.String,NotEmpty]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [settingsForm.password,password]; arguments []; default message [password]]; default message [may not be empty] As you can see the default message is "may not be empty" instead of my message "This field should not be empty". I do get my correct message if I inject the messageSource into a controller and output this: messageSource.getMessage("NotEmpty", new Object [] {"password"}, "default empty message", null); So why isn't the validation using my messages.properties? I'm running Spring 3.1.1. Thanks!

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  • Checking instance of non-class constrained type parameter for null in generic method

    - by casperOne
    I currently have a generic method where I want to do some validation on the parameters before working on them. Specifically, if the instance of the type parameter T is a reference type, I want to check to see if it's null and throw an ArgumentNullException if it's null. Something along the lines of: // This can be a method on a generic class, it does not matter. public void DoSomething<T>(T instance) { if (instance == null) throw new ArgumentNullException("instance"); Note, I do not wish to constrain my type parameter using the class constraint. I thought I could use Marc Gravell's answer on "How do I compare a generic type to its default value?", and use the EqualityComparer<T> class like so: static void DoSomething<T>(T instance) { if (EqualityComparer<T>.Default.Equals(instance, null)) throw new ArgumentNullException("instance"); But it gives a very ambiguous error on the call to Equals: Member 'object.Equals(object, object)' cannot be accessed with an instance reference; qualify it with a type name instead How can I check an instance of T against null when T is not constrained on being a value or reference type?

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  • Searching with a UISearchbar is slow and blocking the main thread.

    - by Robert
    I have a Table with over 3000 entries and searching is very slow. At the moment I am doing just like in the 'TableSearch' example code (but without scopes) - (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString { [self filterContentForSearchText: searchString]; // Return YES to cause the search result table view to be reloaded. return YES; } And the filterContentForSearchText method is as follows: - (void) filterContentForSearchText:(NSString*)searchText { // Update the filtered array based on the search text // First clear the filtered array. [filteredListContent removeAllObjects]; // Search the main list whose name matches searchText // add items that match to the filtered array. if (fetchedResultsController.fetchedObjects) { for (id object in fetchedResultsController.fetchedObjects) { NSString* searchTarget = [tableTypeDelegate getStringForSearchFilteringFromObject:object]; if ([searchTarget rangeOfString:searchText options:(NSCaseInsensitiveSearch|NSDiacriticInsensitiveSearch)].location != NSNotFound) { [filteredListContent addObject:object]; } } } } My question is twofold: How do can I make the searching process faster? How can I stop the search from blocking the main thread? i.e. stop it preventing the user from typing more characters. For the second part, I tried "performSelector:withObject:afterDelay:" and "cancelPreviousPerformRequests..." without much success. I suspect that I will need to use threading instead, but I do not have much experience with it.

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  • I can not use Session In Page_Load and I got error bellow

    - by LostLord
    hi my dear friends .... why i got this error : Object reference not set to an instance of an object. when i put this code in my page_load.: protected void Page_Load(object sender, EventArgs e) { BackEndUtils.OverallLoader(); string Teststr = Session["Co_ID"].ToString(); } ========================================================================== this session is made when user logins to my web site and this session works in other areas... thanks for your attention ========================================================================== thanks for your answers i removed BackEndUtils.OverallLoader(); but error still exists i tried Teststr = Convert.ToString(Session["Co_ID"]); and error disappeared - but i don't know why that session is null in other areas that session works perfectly = such as a button in that form what is the matter? my web page markup is like this : <%@ Page Title="" Language="C#" MasterPageFile="~/Admin/AdminBackend.Master" AutoEventWireup="true" CodeBehind="Personel.aspx.cs" Inherits="Darman.Admin.Personel" Theme="DefaultTheme" %> ================================================================================= i put this code in a button like this : string Teststr = Convert.ToString(Session["Co_ID"]); when i press that button THIS code in page Load(POSTBACK) + IN Button_Click works perfectly and shows me 23 (my Co_ID) But when i run my page in browser (first time) this code in page load shows me null. why? thanks a lot

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  • How to fetch populated associated models in CakePHP when calling read()

    - by Code Commander
    I have the following Models: class Site extends AppModel { public $name = "Site"; public $useTable = "site"; public $primaryKey = "id"; public $displayField = 'name'; public $hasMany = array('Item' => array('foreignKey' => 'siteId')); public function canView($userId, $isAdmin = false) { if($isAdmin) { return true; } return array_key_exists($this->id, $allowedSites); } } and class Item extends AppModel { public $name = "Item"; public $useTable = "item"; public $primaryKey = "id"; public $displayField = 'name'; public $belongsTo = array('Site' => array('foreignKey' => 'siteId')); public function canView($userId, $isAdmin = false) { // My problem appears to be the next line: return $this->Site->canView($userId, $isAdmin); } } In my controller I am doing something like this: $result = $this->Item->read(null, $this->request->id); // Verify permissions if(!$this->Item->canView($this->Session->read('userId'), $this->Session->read('isAdmin'))) { $this->httpCodes(403); die('Permission denied.'); } I notice that in Item->canView() $this->data['Site'] is populated with the column data from the site table. But it merely an array and not an object. On the other hand $this->Site is a Site object, but it has not been populated with the column data from the site table like $this->data. What is the proper way to have CakePHP get the associated model as the object and containing the data? Or am I going about this all wrong? Thanks!

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  • Get a button in itemscontrol and add eventhandler to its click event

    - by rockdale
    I have a custom control shows a customer info with an itemscontrol shows this customer's invoices. within the itemscontrol, I have button, in my code behind I want to wire the button's click event to my host window, but do now know how. //public event RoutedEventHandler ViewDetailClick; public static readonly RoutedEvent ButtonViewClickEvent = EventManager.RegisterRoutedEvent( "ButtonViewClick", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(custitem)); public event RoutedEventHandler ButtonViewClick { add { AddHandler(ButtonViewClickEvent, value); } remove {RemoveHandler(ButtonViewClickEvent, value);} } public override void OnApplyTemplate() { base.OnApplyTemplate(); this.lstInv = GetTemplateChild("lstInv") as ItemsControl; lstInv.ItemContainerGenerator.StatusChanged += new EventHandler(ItemContainerGenerator_StatusChanged); } private void ItemContainerGenerator_StatusChanged(object sender, EventArgs e) { if (lstInv.ItemContainerGenerator.Status == System.Windows.Controls.Primitives.GeneratorStatus.ContainersGenerated) { lstInv.ItemContainerGenerator.StatusChanged -= ItemContainerGenerator_StatusChanged; for (int i = 0; i < this.lstInv.Items.Count; i++) { ContentPresenter c = lstInv.ItemContainerGenerator.ContainerFromItem(lstInv.Items[i]) as ContentPresenter; DataTemplate dt = c.ContentTemplate; Grid grd = dt.LoadContent() as Grid; Button btnView = grd.FindName("btnView") as Button; if (btnView != null) { btnView.Click += new RoutedEventHandler(ButtonView_Click); //btnView.Click+= delegate(object senderObj, RoutedEventArgs eArg) //{ // if (this.ViewDetailClick != null) // { // this.ViewDetailClick(this, eArg); // } //}; } } private void ButtonView_Click(object sender, RoutedEventArgs e) { MessageBox.Show("clicked"); //e.RoutedEvent = ButtonViewClickEvent; //e.Source = sender; //RaiseEvent(e); } I succeed getting the btnView, then attach the click event, but the click event never get fired. Thanks in advance -rockdale

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  • why is OOP hard for me?

    - by netrox
    I have trouble writing OOP in PHP... I understand the concept but I never create classes for my projects... mainly because it's often a small project and nothing complex. But when I read OOP, it seems more difficult to code than writing simple procedural statements. It also seems to take a lot of room as well with so many empty abstract classes and that can be easily lost in the land of objects... it's becoming like a junkyard to me. Also, I noticed that virtually all instructions on how to use OOP use "car" or "cat" or "dog" analogies. Hello... we're not dealing with animals or cars... we're dealing with windows or consoles. You can talk about analogies to death and I will never learn. What I want is see a code that's written to show how objects are created - not, "aCow-moo!" For example, I want to see a browser window object displaying say... three inputs. I want to see an "object" created to output a window with three inputs then I want to see how overriding works, like change the window object to display only two inputs instead of three inputs. I think that would make learning more easy, wouldn't it? Any recommended tutorials of that nature instead of quacks, moos, and woofs.

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  • How do I link one listview to another to create a football league table?

    - by Richard Nixon
    Hi I am creating a football system in windows forms c#. I have one listview where data is entered. I have 4 columns, 2 with team names linked to combo boxes and 2 with the scores linked to numericupdown controls. There are 3 buttons to add the results, Remove and clear. the code is below: private void addButton_Click(object sender, EventArgs e) { { ListViewItem item = new ListViewItem(comboBox1.SelectedItem.ToString()); item.SubItems.Add(numericUpDown1.Value.ToString()); item.SubItems.Add(numericUpDown2.Value.ToString()); item.SubItems.Add(comboBox2.SelectedItem.ToString()); listView1.Items.Add(item); } } private void clearButton_Click(object sender, EventArgs e) { listView1.Items.Clear(); } private void removeButton_Click(object sender, EventArgs e) { foreach (ListViewItem itemSelected in listView1.SelectedItems) { listView1.Items.Remove(itemSelected); } } I have another listview that i want to link the first one to. The second one is a usual english football league table and i want to use maths to add up the games played and the points etc. please help. cheers

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  • C# 4.0 'dynamic' doesn't set ref/out arguments

    - by Buu Nguyen
    I'm experimenting with DynamicObject. One of the things I try to do is setting the values of ref/out arguments, as shown in the code below. However, I am not able to have the values of i and j in Main() set properly (even though they are set correctly in TryInvokeMember()). Does anyone know how to call a DynamicObject object with ref/out arguments and be able to retrieve the values set inside the method? class Program { static void Main(string[] args) { dynamic proxy = new Proxy(new Target()); int i = 10; int j = 20; proxy.Wrap(ref i, ref j); Console.WriteLine(i + ":" + j); // Print "10:20" while expect "20:10" } } class Proxy : DynamicObject { private readonly Target target; public Proxy(Target target) { this.target = target; } public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) { int i = (int) args[0]; int j = (int) args[1]; target.Swap(ref i, ref j); args[0] = i; args[1] = j; result = null; return true; } } class Target { public void Swap(ref int i, ref int j) { int tmp = i; i = j; j = tmp; } }

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  • c++ - strange problem with polymorphism - cellular automaton

    - by Green
    Hello, I am making "game of life" implementation that, when cell has: two live neighbours I make object of class CCellB two live neighbours I make object of class CCellA when has 3 or <2 I make object of class CCellX (dead) Class CCell is base of CCellA, CCellB, CCellX My problem is: That works fine, until I change new CCell(); to new CCellB();: CCell ***temp = allocateArray(); for(int i = 0; i < n; i++) { for(int j = 0; j < m; j++) { c = arr[i][j]->countAliveNeighbor(); if(c == 3) { temp[i][j] = new CCellA(); temp[i][j]->alive = 1; }else if(c == 2) { temp[i][j] = new CCell(); // HERE, WHEN I CHANGE IT TO CCELLB IT DON'T WORKS temp[i][j]->alive = tab[i][j]->alive; }else if((c >= 4)||(c < 2)) { temp[i][j] = new CCellX(); } } } Then it seems don't work properly... Seems like neighbours are not count properly, Cell with 4,5 neighbours still alive alive var is member of base class - CCell, all is public, please help!

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  • Test MVC using moq

    - by Raminder
    I am new to moq and I was trying to test a controller (MVC) behaviour that when the view raises a certain event, controller calls a certain function on model, here are the classes - public class Model { public void CalculateAverage() { ... } ... } public class View { public event EventHandler CalculateAverage; private void RaiseCalculateAverage() { if (CalculateAverage != null) { CalculateAverage(this, EventArgs.Empty); } } ... } public class Controller { private Model model; private View view; public Controller(Model model, View view) { this.model = model this.view = view; view.CalculaeAverage += view_CalculateAverage; } priavate void view_CalculateAverage(object sender, EventArgs args) { model.CalculateAverage(); } } and the test - [Test] public void ModelCalculateAverageCalled() { Mock<Model> modelMock = new Mock<Model>(); Mock<View> viewMock = new Mock<View>(); Controller controller = new Controller(modelMock.Object, viewMock.Object); viewMock.Raise(x => x.CalculateAverage += null, new EventArgs.Empty); modelMock.Verify(x => x.CalculateAverage()); //never comes here, test fails in above line and exits Assert.True(true); } The issue is that the test is failing in the second last line with "Invocation was not performed on the mock: x = x.CalculateAverage()". Another thing I noticed is that the test terminates on this second last line and the last line is never executed. Am I doing everything correct?

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  • WPF BackGroundWorker ProgressChanged not updating textblock

    - by user354469
    I have the method below that seems to behaving strangely. The ProgressChanged and RunWorkerCompleted seem to be updating themselves at the same time. If I comment out the RunWorkerCompleted code which updates the Textblock I see the ProgressChanged taking effect after the data is transferred. What am i doing wrong here? I obviously want the textblock to show I'm getting data, then change when I have finished getting the data. public void GetAppointmentsBackground() { System.Windows.Threading.Dispatcher webServiceDispatcher = this.Dispatcher; worker = new BackgroundWorker(); worker.WorkerReportsProgress = true; worker.DoWork += delegate(object sender, DoWorkEventArgs args) { GetAppointmentsForDayDelegate getAppt = new GetAppointmentsForDayDelegate(GetAppointmentsForDay); webServiceDispatcher.BeginInvoke(getAppt); (sender as BackgroundWorker).ReportProgress(25); }; worker.ProgressChanged += delegate(object s, ProgressChangedEventArgs args) { txtMessages.Text = "Contacting Server"; }; worker.RunWorkerCompleted += delegate(object s, RunWorkerCompletedEventArgs args) { txtMessages.Text = "Completed Successfully"; }; worker.RunWorkerAsync(); }

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  • Rails rake test returns an error message

    - by eakkas
    I am a rails newbie and receive the following message when I run rake test. This is a an application based on rails community engine. I tried creating a test application just to make sure that my gems etc. are fine and I am able to run rake test successfully in that application. It would be great if someone could shed a light on what is going wrong... /usr/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/whiny_nil.rb:52:in `method_missing': undefined method `merge' for nil:NilClass (NoMethodError) from /home/eakkas/NetBeansProjects/hello_ce/vendor/plugins/community_engine/app/controllers/users_controller.rb:17 from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `require' from /usr/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:158:in `require_without_desert' from /usr/lib/ruby/gems/1.8/gems/desert-0.5.3/lib/desert/ruby/object.rb:8:in `require' from /usr/lib/ruby/gems/1.8/gems/desert-0.5.3/lib/desert/ruby/object.rb:32:in `__each_matching_file' from /usr/lib/ruby/gems/1.8/gems/desert-0.5.3/lib/desert/ruby/object.rb:7:in `require' from /usr/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:265:in `require_or_load' from /usr/lib/ruby/gems/1.8/gems/desert-0.5.3/lib/desert/rails/dependencies.rb:27:in `depend_on' from /usr/lib/ruby/gems/1.8/gems/desert-0.5.3/lib/desert/rails/dependencies.rb:26:in `each' from /usr/lib/ruby/gems/1.8/gems/desert-0.5.3/lib/desert/rails/dependencies.rb:26:in `depend_on' from /usr/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:136:in `require_dependency' from /usr/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/initializer.rb:414:in `load_application_classes' from /usr/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/initializer.rb:413:in `each' from /usr/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/initializer.rb:413:in `load_application_classes' from /usr/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/initializer.rb:411:in `each' from /usr/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/initializer.rb:411:in `load_application_classes' from /usr/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/initializer.rb:197:in `process' from /usr/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/initializer.rb:113:in `send' from /usr/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/initializer.rb:113:in `run'

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  • Looking for a fast, compact, streamable, multi-language, strongly typed serialization format

    - by sanity
    I'm currently using JSON (compressed via gzip) in my Java project, in which I need to store a large number of objects (hundreds of millions) on disk. I have one JSON object per line, and disallow linebreaks within the JSON object. This way I can stream the data off disk line-by-line without having to read the entire file at once. It turns out that parsing the JSON code (using http://www.json.org/java/) is a bigger overhead than either pulling the raw data off disk, or decompressing it (which I do on the fly). Ideally what I'd like is a strongly-typed serialization format, where I can specify "this object field is a list of strings" (for example), and because the system knows what to expect, it can deserialize it quickly. I can also specify the format just by giving someone else its "type". It would also need to be cross-platform. I use Java, but work with people using PHP, Python, and other languages. So, to recap, it should be: Strongly typed Streamable (ie. read a file bit by bit without having to load it all into RAM at once) Cross platform (including Java and PHP) Fast Free (as in speech) Any pointers?

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  • Constructor and Destructors in C++ [Not a question] [closed]

    - by Jack
    I am using gcc. Please tell me if I am wrong - Lets say I have two classes A & B class A { public: A(){cout<<"A constructor"<<endl;} ~A(){cout<<"A destructor"<<endl;} }; class B:public A { public: B(){cout<<"B constructor"<<endl;} ~B(){cout<<"B destructor"<<endl;} }; 1) The first line in B's constructor should be a call to A's constructor ( I assume compiler automatically inserts it). Also the last line in B's destructor will be a call to A's destructor (compiler does it again). Why was it built this way? 2) When I say A * a = new B(); compiler creates a new B object and checks to see if A is a base class of B and if it is it allows 'a' to point to the newly created object. I guess that is why we don't need any virtual constructors. ( with help from @Tyler McHenry , @Konrad Rudolph) 3) When I write delete a compiler sees that a is an object of type A so it calls A's destructor leading to a problem which is solved by making A's destructor virtual. As user - Little Bobby Tables pointed out to me all destructors have the same name destroy() in memory so we can implement virtual destructors and now the call is made to B's destructor and all is well in C++ land. Please comment.

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  • Java downcasting dilemma

    - by Shades88
    please have a look at this code here. class Vehicle { public void printSound() { System.out.print("vehicle"); } } class Car extends Vehicle { public void printSound() { System.out.print("car"); } } class Bike extends Vehicle{ public void printSound() { System.out.print("bike"); } } public class Test { public static void main(String[] args) { Vehicle v = new Car(); Bike b = (Bike)v; v.printSound(); b.printSound(); Object myObj = new String[]{"one", "two", "three"}; for (String s : (String[])myObj) System.out.print(s + "."); } } Executing this code will give ClassCastException saying inheritance.Car cannot be cast to inheritance.Bike. Now look at the line Object myObj = new String[]{"one", "two", "three"};. This line is same as Vehicle v = new Car(); right? In both lines we are assigning sub class object to super class reference variable. But downcasting String[]myObj is allowed but (Bike)v is not. Please help me understand what is going on around here.

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  • How to get a Class literal from a generically specific Class

    - by h2g2java
    There are methods like these which require Class literals as argument. Collection<EmpInfo> emps = SomeSqlUtil.select( EmpInfo.class, "select * from emps"); or GWT.create(Razmataz.class); The problem presents itself when I need to supply generic specific classes like EmpInfo<String> Razmataz<Integer> The following would be wrong syntax Collection<EmpInfo<String>> emps = SomeSqlUtil.select( EmpInfo<String>.class, "select * from emps"); or GWT.create(Razmataz<Integer>.class); Because you cannot do syntax like Razmataz<Integer>.class So, how would I be able to squeeze a class literal out of EmpInfo<String> Razmataz<Integer> so that I could feed them as arguments to methods requiring Class literals? Further info Okay, I confess that I am asking this primarily for GWT. I have a pair of GWT RPC interface Razmataz. (FYI, GWT RPC interface has to be defined in server-client pairs). I plan to use the same interface pair for communicating whether it be String, Integer, Boolean, etc. GWT.create(Razmataz) for Razmataz<T> complains that, since I did not specify T, GWT compiler treated it as Object. Then GWT compiler would not accept Object class. It needs to be more specific than being an Object. So, it seems there is no way for me to tell GWT.create what T is because a Class literal is a runtime concept while generics is a compile time concept, Right?

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  • Is NSManagedObjectContext autosaved or am I looking at NSFetchedResultsController's cache?

    - by Andreas
    I'm developing an iPhone app where I use a NSFetchedResultsController in the main table view controller. I create it like this in the viewDidload of the main table view controller: NSSortDescriptor *sortDescriptorDate = [[NSSortDescriptor alloc] initWithKey:@"date" ascending:YES]; NSSortDescriptor *sortDescriptorTime = [[NSSortDescriptor alloc] initWithKey:@"start" ascending:YES]; NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptorDate,sortDescriptorTime, nil]; [fetchRequest setSortDescriptors:sortDescriptors]; [sortDescriptorDate release]; [sortDescriptorTime release]; [sortDescriptors release]; controller = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:context sectionNameKeyPath:@"date" cacheName:nil]; [fetchRequest release]; NSError *error; BOOL success = [controller performFetch:&error]; Then, in a subsequent view, I create a new object on the context: TestObject *testObject = [NSEntityDescription insertNewObjectForEntityForName:@"TestObject" inManagedObjectContext:context]; The TestObject has several related object which I create in the same way and add to the testObject using the provided add...Objects methods. Then, if before saving the context, I press cancel and go back to the main table view, nothing is shown as expected. However, if I restart the app, the object I created on the context shows in the main table view. How come? At first, I thought it was because the NSFetchedResultsController was reading from the cache, but as you can see I set this to nil just to test. Also, [context hasChanges] returns true after I restart. What am I missing here?

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  • getting a "default" concrete class that implements an interface

    - by Roger Joys
    I am implementing a custom (and generic) Json.net serializer and hit a bump in the road that I could use some help on. When the deserializer is mapping to a property that is an interface, how can I best determine what sort of object to construct to deserialize to to place into the interface property. I have the following: [JsonConverter(typeof(MyCustomSerializer<foo>))] class foo { int Int1 { get; set; } IList<string> StringList {get; set; } } My serializer properly serializes this object, and but when it comes back in, and I try to map the json parts to to object, I have a JArray and an interface. I am currently instantiating anything enumerable like List as theList = Activator.CreateInstance(property.PropertyType); This works create to work with in the deserialization process, but when the property is IList, I get runtime complaints (obviously) about not being able to instantiate an interface. So how would I know what type of concrete class to create in a case like this? Thank you

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  • Implementing list position locator in C++?

    - by jfrazier
    I am writing a basic Graph API in C++ (I know libraries already exist, but I am doing it for the practice/experience). The structure is basically that of an adjacency list representation. So there are Vertex objects and Edge objects, and the Graph class contains: list<Vertex *> vertexList list<Edge *> edgeList Each Edge object has two Vertex* members representing its endpoints, and each Vertex object has a list of Edge* members representing the edges incident to the Vertex. All this is quite standard, but here is my problem. I want to be able to implement deletion of Edges and Vertices in constant time, so for example each Vertex object should have a Locator member that points to the position of its Vertex* in the vertexList. The way I first implemented this was by saving a list::iterator, as follows: vertexList.push_back(v); v->locator = --vertexList.end(); Then if I need to delete this vertex later, then rather than searching the whole vertexList for its pointer, I can call: vertexList.erase(v->locator); This works fine at first, but it seems that if enough changes (deletions) are made to the list, the iterators will become out-of-date and I get all sorts of iterator errors at runtime. This seems strange for a linked list, because it doesn't seem like you should ever need to re-allocate the remaining members of the list after deletions, but maybe the STL does this to optimize by keeping memory somewhat contiguous? In any case, I would appreciate it if anyone has any insight as to why this happens. Is there a standard way in C++ to implement a locator that will keep track of an element's position in a list without becoming obsolete? Much thanks, Jeff

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  • Adding defaults and indexes to a script/generate command in a Rails Template?

    - by charliepark
    I'm trying to set up a Rails Template that would allow for comprehensive set-up of a specific Rails app. Using Pratik Naik's overview (http://m.onkey.org/2008/12/4/rails-templates), I was able to set up a couple of scaffolds and models, with a line that looks something like this ... generate("scaffold", "post", "title:string", "body:string") I'm now trying to add in Delayed Jobs, which normally has a migration file that looks like this: create_table :delayed_jobs, :force => true do |table| table.integer :priority, :default => 0 # Allows some jobs to jump to the front of the queue table.integer :attempts, :default => 0 # Provides for retries, but still fail eventually. table.text :handler # YAML-encoded string of the object that will do work table.text :last_error # reason for last failure (See Note below) table.datetime :run_at # When to run. Could be Time.now for immediately, or sometime in the future. table.datetime :locked_at # Set when a client is working on this object table.datetime :failed_at # Set when all retries have failed (actually, by default, the record is deleted instead) table.string :locked_by # Who is working on this object (if locked) table.timestamps end So, what I'm trying to do with the Rails template, is to add in that :default = 0 into the master template file. I know that the rest of the template's command should look like this: generate("migration", "createDelayedJobs", "priority:integer", "attempts:integer", "handler:text", "last_error:text", "run_at:datetime", "locked_at:datetime", "failed_at:datetime", "locked_by:string") Where would I put (or, rather, what is the syntax to add) the :default values in that? And if I wanted to add an index, what's the best way to do that?

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  • Android ArrayList<Location> passing between activities

    - by squixy
    I have simple class Track, which stores information about route: import java.io.Serializable; import java.util.ArrayList; import java.util.Date; import android.location.Location; public class Track implements Serializable { private static final long serialVersionUID = -5317697499269650204L; private Date date; private String name; private int time; private double distance, speed; private ArrayList<Location> route; public Track(String name, int time, double distance, ArrayList<Location> route) { this.date = new Date(); this.name = name; this.time = time; this.distance = distance; this.speed = distance / (time / 3600.); this.route = route; } public String getDate() { return String.format("Date: %1$td-%1$tb-%1$tY%nTime: %1$tH:%1$tM:%1$tS", date); } public String getName() { return name; } public int getTime() { return time; } public double getDistance() { return distance; } public float getSpeed() { return (float) speed; } public ArrayList<Location> getRoute() { return route; } @Override public String toString() { return String.format("Name: %s%nDate: %2$td-%2$tb-%2$tY%nTime: %2$tH:%2$tM:%2$tS", name, date); } } And I'm passing it from one activity to another: Intent showTrackIntent = new Intent(TabSavedActivity.this, ShowTrackActivity.class); showTrackIntent.putExtra("track", adapter.getItem(position)); startActivity(showTrackIntent); Where (Track object is element on ListView). I get error during passing Track object: java.lang.RuntimeException: Parcelable encountered IOException writing serializable object (name = classes.Track) What is happening?

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  • Read specific line from text file, according to Checked Listbox selection number.

    - by Manolis
    Heya, i want to create an application which will read a specific line from a text file and show it in a textbox. The line will be chosen according to the number of the listbox selection i will make. Here's the code: Public Class Form1 Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load End Sub Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim i As Integer For i = 0 To Me.CheckedListBox1.CheckedIndices.Count - 1 Me.CheckedListBox1.SetItemChecked(Me.CheckedListBox1.CheckedIndices(0),False) Next i End Sub Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click If CheckedListBox1.CheckedItems.Count <> 0 Then Dim reader As New System.IO.StreamReader(CurDir() & "\" & "READ.txt") Dim x As Integer Dim s As String = "" For x = 0 To CheckedListBox1.CheckedItems.Count - 1 s = s & "Answer " & (x + 1).ToString & ") " & CheckedListBox1.CheckedItems(x).ToString & ControlChars.CrLf & reader.ReadLine() & ControlChars.CrLf & ControlChars.CrLf Next x Answer.Text = (s) Else MessageBox.Show("Please select questions.", "Error", _ MessageBoxButtons.OK, _ MessageBoxIcon.Information) Return End If End Sub End Class So lets say i 'check' the first, second, and fifth items from the checked listbox, i want it to read from the text file the first, second, and fifth lines of text and show them in the textbox. The current code just reads line 1, 2, 3 (...) in order, no matter what item i have 'checked'. Thanks in advance!

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  • Getting around IBActions limited scope

    - by Septih
    Hello, I have an NSCollectionView and the view is an NSBox with a label and an NSButton. I want a double click or a click of the NSButton to tell the controller to perform an action with the represented object of the NSCollectionViewItem. The Item View is has been subclassed, the code is as follows: #import <Cocoa/Cocoa.h> #import "WizardItem.h" @interface WizardItemView : NSBox { id delegate; IBOutlet NSCollectionViewItem * viewItem; WizardItem * wizardItem; } @property(readwrite,retain) WizardItem * wizardItem; @property(readwrite,retain) id delegate; -(IBAction)start:(id)sender; @end #import "WizardItemView.h" @implementation WizardItemView @synthesize wizardItem, delegate; -(void)awakeFromNib { [self bind:@"wizardItem" toObject:viewItem withKeyPath:@"representedObject" options:nil]; } -(void)mouseDown:(NSEvent *)event { [super mouseDown:event]; if([event clickCount] > 1) { [delegate performAction:[wizardItem action]]; } } -(IBAction)start:(id)sender { [delegate performAction:[wizardItem action]]; } @end The problem I've run into is that as an IBAction, the only things in the scope of -start are the things that have been bound in IB, so delegate and viewItem. This means that I cannot get at the represented object to send it to the delegate. Is there a way around this limited scope or a better way or getting hold of the represented object? Thanks.

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  • Rails Tableless Model

    - by mplacona
    I'm creating a tableless Rails model, and am a bit stuck on how I should use it. Basically I'm trying to create a little application using Feedzirra that scans a RSS feed every X seconds, and then sends me an email with only the updates. I'm actually trying to use it as an activerecord model, and although I can get it to work, it doesn't seem to "hold" data as expected. As an example, I have an initializer method that parses the feed for the first time. On the next requests, I would like to simply call the get_updates method, which according to feedzirra, is the existing object (created during the initialize) that gets updated with only the differences. I'm finding it really hard to understand how this all works, as the object created on the initialize method doesn't seem to persist across all the methods on the model. My code looks something like: def initialize feed parse here end def get_updates feedzirra update passing the feed object here end Not sure if this is the right way of doing it, but it all seems a bit confusing and not very clear. I could be over or under-doing here, but I'd like your opinion about this approach. Thanks in advance

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