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  • JSF getter methods called BEFORE beforePhase fires

    - by Bill Leeper
    I got a recommendation to put all data lookups in the beforePhase for a given page, however, now that I am doing some deeper analysis it appears that some getter methods are being called before the beforePhase is fired. It became very obvious when I added support for a url parameter and I was getting NPEs on objects that are initialized in the beforePhase call. Any thoughts? Something I have set wrong. I have this in my JSP page: <f:view beforePhase="#{someController.beforePhaseSummary}"> That is only the 5th line in the JSP file and is right after the taglibs. Here is the code that is in the beforePhaseSummary method: public void beforePhaseSummary(PhaseEvent event) { logger.debug("Fired Before Phase Summary: " + event.getPhaseId()); if (event.getPhaseId() == PhaseId.RENDER_RESPONSE) { HttpServletRequest request = (HttpServletRequest)FacesContext.getCurrentInstance().getExternalContext().getRequest(); if (request.getParameter("application_id") != null) { loadApplication(Long.parseLong(request.getParameter("application_id"))); } /* Do data fetches here */ } } The logging output above indicates that an event is fired. The servlet request is used to capture the url parameters. The data fetches gather data. However, the logging output is below: 2010-04-23 13:44:46,968 [http-8080-4] DEBUG ...SomeController 61 - Get Permit 2010-04-23 13:44:46,968 [http-8080-4] DEBUG ...SomeController 107 - Getting UnsubmittedCount 2010-04-23 13:44:46,984 [http-8080-4] DEBUG ...SomeController 61 - Get Permit 2010-04-23 13:44:47,031 [http-8080-4] DEBUG ...SomeController 133 - Fired Before Phase Summary: RENDER_RESPONSE(6) The logs indicate 2 calls to the getPermit method and one to getUnsubmittedCount before the beforePhase is fired.

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  • Displaying count for current_user 'likes' on a 'question' in questions/show.html.erb view

    - by bgadoci
    I have an application that allows for users to create questions, create answers to questions, and 'like' answers of others. When a current_user lands on the /views/questions/show.html.erb page I am trying to display the total 'likes' for all answers on that question, for the current_user. In my Likes table I am collecting the question_id, site_id and the user_id and I have the appropriate associations set up between user, question, answers and likes. I think I just need to call this information the right way, which I can't seem to figure out. All of the below is taking place in the /views/questions/show.html.erb page. I have tried the following: <% div_for current_user do %> You have liked this question <%= @question.likes.count %> times <% end %> Which returns all the 'likes' for the question but not filtered by current_user You have liked this question <%= current_user.question.likes.count %> times Which gives an error of 'undefined method `question' You have liked this question <%= @question.current_user.likes.count %> times Which gives an error of 'undefined method `current_user' I have tried a couple of other things but they don't make as much sense as the above to me. What am I missing?

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  • How do I change the application background color at run-time in a Flex 3.5 application?

    - by Adam Tuttle
    I have a Flex 3.5 application that will serve multiple purposes, and as part of the visual changes that I'd like to make to indicate which mode the application is in, I want to change its background color. Currently, the application tag looks like this: <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" xmlns:com="ventures.view.component.*" xmlns:views="ventures.view.*" layout="absolute" preinitialize="onPreInitialize()" creationComplete="onCreationComplete()" applicationComplete="onApplicationComplete()" click="onClick(event)" enabled="{(!chainController.generalLocked)}" backgroundGradientColors="[0xFFFFFF, 0xFFFFFF]" > I've tried using a binding, for both the backgroundColor and backgroundGradientColors attributes: <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" ... backgroundColor="{app_background_color}" > —and— <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" ... backgroundGradientColors="{app_background_color}" > but for the former binding is not allowed, and for the latter there is a warning that: Data binding will not be able to detect assignments to "app_background_color". I also ran across this page which seems to indicate that I could do it with the setStyle() method, but the documentation seems to indicate that this method is only available for components, not the main canvas. I suppose I could wrap everything in a <mx:Canvas></mx:Canvas> specificially for this purpose, but that seems wasteful—like Div-itis in HTML or something. What's the best way to change the main application background color at run-time?

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  • TDD approach for complex function

    - by jamie
    I have a method in a class for which they are a few different outcomes (based upon event responses etc). But this is a single atomic function which is to used by other applications. I have broken down the main blocks of the functionality that comprise this function into different functions and successfully taken a Test Driven Development approach to the functionality of each of these elements. These elements however aren't exposed for other applications would use. And so my question is how can/should i easily approach a TDD style solution to verifying that the single method that should be called does function correctly without a lot of duplication in testing or lots of setup required for each test? I have considered / looked at moving the blocks of functionality into a different class and use Mocking to simulate the responses of the functions used but it doesn't feel right and the individual methods need to write to variables within the main class (it felt really heath robinson). The code roughly looks like this (i have removed a lot of parameters to make things clearer along with a fair bit of irrelevant code). public void MethodToTest(string parameter) { IResponse x = null; if (function1(parameter)) { if (!function2(parameter,out x)) { function3(parameter, out x); } } // ... // more bits of code here // ... if (x != null) { x.Success(); } }

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  • Why does the BackgroundWorker in WPF need Thread.Sleep to update UI controls?

    - by user364060
    namespace WpfApplication1 { /// <summary> /// Interaction logic for Window1.xaml /// </summary> public partial class Window1 : Window { BackgroundWorker bgWorker; Action<int> myProgressReporter; public Window1() { InitializeComponent(); bgWorker = new BackgroundWorker(); bgWorker.DoWork += bgWorker_Task; bgWorker.RunWorkerCompleted += myWorker_RunWorkerCompleted; // hook event to method bgWorker.ProgressChanged += bgWorker_ReportProgress; // hook the delegate to the method myProgressReporter = updateProgress; bgWorker.WorkerReportsProgress = true; } private void myWorker_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e) { object result; result = e.Result; MessageBox.Show(result.ToString()); progressBar1.Value = 0; button1.IsEnabled = true; } private void bgWorker_ReportProgress(object sender, ProgressChangedEventArgs e) { System.Windows.Threading.Dispatcher disp = button1.Dispatcher; disp.BeginInvoke(myProgressReporter,e.ProgressPercentage); //Dispatcher.BeginInvoke(myProgressReporter, DispatcherPriority.Normal, e.ProgressPercentage); } private void updateProgress(int progressPercentage) { progressBar1.Value = progressPercentage; } private void bgWorker_Task(Object sender, DoWorkEventArgs e) { int total = 1000; for (int i = 1; i <= total; i++) { if (bgWorker.WorkerReportsProgress) { int p = (int)(((float)i / (float)total) * 100); bgWorker.ReportProgress(p); } Thread.Sleep(1); // Without Thread.Sleep(x) the main thread freezes or gives stackoverflow exception, } e.Result = "Completed"; } private void button1_Click(object sender, RoutedEventArgs e) { if(!bgWorker.IsBusy) bgWorker.RunWorkerAsync("This is a background process"); button1.IsEnabled = false; } } }

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  • Why can a public class not inherit from a less visible one?

    - by Dan Tao
    I apologize if this question has been asked before. I've searched SO somewhat and wasn't able to find it. I'm just curious what the rationale behind this design was/is. Obviously I understand that private/internal members of a base type cannot, nor should they, be exposed through a derived public type. But it seems to my naive thinking that the "hidden" parts could easily remain hidden while some base functionality is still shared and a new interface is exposed publicly. I'm thinking of something along these lines: Assembly X internal class InternalClass { protected virtual void DoSomethingProtected() { // Let's say this method provides some useful functionality. // Its visibility is quite limited (only to derived types in // the same assembly), but at least it's there. } } public class PublicClass : InternalClass { public void DoSomethingPublic() { // Now let's say this method is useful enough that this type // should be public. What's keeping us from leveraging the // base functionality laid out in InternalClass's implementation, // without exposing anything that shouldn't be exposed? } } Assembly Y public class OtherPublicClass : PublicClass { // It seems (again, to my naive mind) that this could work. This class // simply wouldn't be able to "see" any of the methods of InternalClass // from AssemblyX directly. But it could still access the public and // protected members of PublicClass that weren't inherited from // InternalClass. Does this make sense? What am I missing? }

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  • Refactoring Rspec specs

    - by Steve Weet
    I am trying to cleanup my specs as they are becoming extremely repetitive. I have the following spec describe "Countries API" do it "should render a country list" do co1 = Factory(:country) co2 = Factory(:country) result = invoke :GetCountryList, "empty_auth" result.should be_an_instance_of(Api::GetCountryListReply) result.status.should be_an_instance_of(Api::SoapStatus) result.status.code.should eql 0 result.status.errors.should be_an_instance_of Array result.status.errors.length.should eql 0 result.country_list.should be_an_instance_of Array result.country_list.first.should be_an_instance_of(Api::Country) result.country_list.should have(2).items end it_should_behave_like "All Web Services" it "should render a non-zero status for an invalid request" end The block of code that checks the status will appear in all of my specs for 50-60 APIs. My first thought was to move that to a method and that refactoring certainly makes things much drier as follows :- def status_should_be_valid(status) status.should be_an_instance_of(Api::SoapStatus) status.code.should eql 0 status.errors.should be_an_instance_of Array status.errors.length.should eql 0 end describe "Countries API" do it "should render a country list" do co1 = Factory(:country) co2 = Factory(:country) result = invoke :GetCountryList, "empty_auth" result.should be_an_instance_of(Api::GetCountryListReply) status_should_be_valid(result.status) result.country_list.should be_an_instance_of Array result.country_list.first.should be_an_instance_of(Api::Country) result.country_list.should have(2).items end end This works however I can not help feeling that this is not the "right" way to do it and I should be using shared specs, however looking at the method for defining shared specs I can not easily see how I would refactor this example to use a shared spec. How would I do this with shared specs and without having to re-run the relatively costly block at the beginning namely co1 = Factory(:country) co2 = Factory(:country) result = invoke :GetCountryList, "empty_auth"

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  • Why can't we just use a hash of passphrase as the encryption key (and IV) with symmetric encryption algorithms?

    - by TX_
    Inspired by my previous question, now I have a very interesting idea: Do you really ever need to use Rfc2898DeriveBytes or similar classes to "securely derive" the encryption key and initialization vector from the passphrase string, or will just a simple hash of that string work equally well as a key/IV, when encrypting the data with symmetric algorithm (e.g. AES, DES, etc.)? I see tons of AES encryption code snippets, where Rfc2898DeriveBytes class is used to derive the encryption key and initialization vector (IV) from the password string. It is assumed that one should use a random salt and a shitload of iterations to derive secure enough key/IV for the encryption. While deriving bytes from password string using this method is quite useful in some scenarios, I think that's not applicable when encrypting data with symmetric algorithms! Here is why: using salt makes sense when there is a possibility to build precalculated rainbow tables, and when attacker gets his hands on hash he looks up the original password as a result. But... with symmetric data encryption, I think this is not required, as the hash of password string, or the encryption key, is never stored anywhere. So, if we just get the SHA1 hash of password, and use it as the encryption key/IV, isn't that going to be equally secure? What is the purpose of using Rfc2898DeriveBytes class to generate key/IV from password string (which is a very very performance-intensive operation), when we could just use a SHA1 (or any other) hash of that password? Hash would result in random bit distribution in a key (as opposed to using string bytes directly). And attacker would have to brute-force the whole range of key (e.g. if key length is 256bit he would have to try 2^256 combinations) anyway. So either I'm wrong in a dangerous way, or all those samples of AES encryption (including many upvoted answers here at SO), etc. that use Rfc2898DeriveBytes method to generate encryption key and IV are just wrong.

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  • ApplicationDispatcher exception

    - by JFB
    Whenever I try to redirect to a certain page using this dispatch method that is called from my doGet method, I get the following exception. I have no idea why! account controller servlet protected void dispatch(HttpServletRequest request, HttpServletResponse response, String page) throws javax.servlet.ServletException, java.io.IOException { RequestDispatcher dispatcher = getServletContext() .getRequestDispatcher(page); try { dispatcher.forward(request, response); } catch (java.lang.NullPointerException e) { System.out.println("NullPointerException: attribute expected in view"); } } Error msg java.lang.NullPointerException org.apache.jasper.JasperException: java.lang.NullPointerException org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:502) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:430) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260) javax.servlet.http.HttpServlet.service(HttpServlet.java:717) controller.AccountController.dispatch(AccountController.java:91) controller.AccountController.doExecute(AccountController.java:72) controller.AccountController.doGet(AccountController.java:34) javax.servlet.http.HttpServlet.service(HttpServlet.java:617) javax.servlet.http.HttpServlet.service(HttpServlet.java:717) java.lang.NullPointerException org.apache.jsp.content.edit_jsp._jspService(edit_jsp.java:109) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) javax.servlet.http.HttpServlet.service(HttpServlet.java:717) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260) javax.servlet.http.HttpServlet.service(HttpServlet.java:717) controller.AccountController.dispatch(AccountController.java:91) controller.AccountController.doExecute(AccountController.java:72) controller.AccountController.doGet(AccountController.java:34) javax.servlet.http.HttpServlet.service(HttpServlet.java:617) javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

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  • Threading in client-server socket program - proxy sever

    - by crazyTechie
    I am trying to write a program that acts as a proxy server. Proxy server basically listens to a given port (7575) and sends the request to the server. As of now, I did not implement caching the response. The code looks like ServerSocket socket = new ServerSocket(7575); Socket clientSocket = socket.accept(); clientRequestHandler(clientSocket); I changed the above code as below: //calling the same clientRequestHandler method from inside another method. Socket clientSocket = socket.accept(); Thread serverThread = new Thread(new ConnectionHandler(client)); serverThread.start(); class ConnectionHandler implements Runnable { Socket clientSocket = null; ConnectionHandler(Socket client){ this.clientSocket = client; } @Override public void run () { try { PrxyServer.clientRequestHandler(clientSocket); } catch (Exception ex) { ex.printStackTrace(); } } } Using the code, I am able to open a webpage like google. However, if I open another web page even I completely receive the first response, I get connection reset by peer expection. 1. How can I handle this issue Can i use threading to handle different requests. Can someone give a reference where I look for example code that implements threading. Thanks. Thanks.

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  • how are association, aggregation and composition written?

    - by ajsie
    i have read some posts about the differences between these 3 relationships and i think i get the point. i just wonder, are all these written the same when coding? question 1: all 3 are just a value of the object type in a instance variable? class A { public $b = '' public function __construct($object) { $this->b = $object // <-- could be a association, aggregation or a composition relation? } } question 2: does it have to be an instance variable or can it be a static one? class A { public static $b = '' // <-- nothing changed? public function __construct($object) { $this->b = $object } } question 3: is there a difference in where the object is created? i tend to think that composition object is created inside the object: class A { public $b = '' public function __construct() { $this->b = new Object // is created inside the object } } and aggregation/association is passed through a constructor or another method: class A { public $b = '' public function __construct($object) { // passed through a method $this->b = $object } } question 4: why/when is this important to know. do i have to comment an object inside another what relation its about or do you do it in an UML diagram? could someone shed a light on these questions. thanks!

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  • Why does my SQL database not work in Android?

    - by user1426967
    In my app a click on an image button brings you to the gallery. After clicking on an image I want to call onActivityResult to store the image path. But it does not work. In my LogCat it always tells me that it crashes when it tries to save the image path. Can you find the problem? My onActivityResult method: mImageRowId = savedInstanceState != null ? savedInstanceState.getLong(ImageAdapter.KEY_ROWID) : null; @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if(requestCode == PICK_FROM_FILE && data != null && data.getData() != null) { Uri uri = data.getData(); if(uri != null) { Cursor cursor = getContentResolver().query(uri, new String[] { android.provider.MediaStore.Images.ImageColumns.DATA}, null, null, null); cursor.moveToFirst(); String image = cursor.getString(0); cursor.close(); if(image != null) { // HERE IS WHERE I WANT TO SAVE THE IMAGE. HERE MUST BE THE ERROR! if (mImageRowId == null) { long id = mImageHelper.createImage(image); if (id > 0) { mImageRowId = id; } } // Set the image and display it in the edit activity Bitmap bitmap = BitmapFactory.decodeFile(image); mImageButton.setImageBitmap(bitmap); } } } } This is my onSaveInstanceState method: private static final Long DEF_ROW_ID = 0L; @Override protected void onSaveInstanceState(Bundle outState) { outState.putLong(ImageAdapter.KEY_ROWID, mImageRowId != null ? mImageRowId : DEF_ROW_ID); super.onSaveInstanceState(outState); } This is a part from my DbAdapter: public long createImage(String image) { ContentValues cv = new ContentValues(); cv.put(KEY_IMAGE, image); return mImageDb.insert(DATABASE_TABLE, null, cv); }

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  • Is it possible to cancel function override in parent class and use function from top level parent

    - by Anatoliy Gusarov
    class TopParent { protected function foo() { $this->bar(); } private function bar() { echo 'Bar'; } } class MidParent extends TopParent { protected function foo() { $this->midMethod(); parent::foo(); } public function midMethod() { echo 'Mid'; } public function generalMethod() { echo 'General'; } } Now the question is if I have a class, that extends MidParent because I need to call class Target extends MidParent { //How to override this method to return TopParent::foo(); ? protected function foo() { } } So I need to do this: $mid = new MidParent(); $mid->foo(); // MidBar $taget = new Target(); $target->generalMethod(); // General $target->foo(); // Bar UPDATE Top parent is ActiveRecord class, mid is my model object. I want to use model in yii ConsoleApplication. I use 'user' module in this model, and console app doesn't support this module. So I need to override method afterFind, where user module is called. So the Target class is the class that overrides some methods from model which uses some modules that console application doesn't support.

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  • Better way to catch trouble points

    - by mac
    User submits a CSV file which is consumed by a program. Values which are used throughout the program come from the CSV, natually if values are missed it is a problem. Below is my solution. Ip on top private List<String> currentFieldName = new ArrayList<String>(); As part of the method: try { setCurrentFieldName("Trim Space"); p.setTrimSpace(currentLineArray[dc.getTRIM_POSITION()].equals("yes") ? true : false); setCurrentFieldName("Ignore Case"); p.setIgnoreCase(currentLineArray[dc.getIGNORE_CASE_POSITION()].equals("yes") ? true : false); } catch (NullPointerException e) { throw new InputSpreadsheetValueUnassignedException("\"Type\" field not set: " + currentFieldName); } And the method which keeps track of a current field being looked at: private void setCurrentFieldName(String fieldName) { currentFieldName.clear(); currentFieldName.add(fieldName); } The idea there is that if user fails to submit value and i will end up getting null, before throwing an exception, i will know what value was not assigned. So, this being said, specific questions: Is what i have shown below an acceptable solution? Can you suggest something more elegant?

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  • Django Save Incomplete Progress on Form

    - by jimbob
    I have a django webapp with multiple users logging in and fill in a form. Some users may start filling in a form and lack some required data (e.g., a grant #) needed to validate the form (and before we can start working on it). I want them to be able to fill out the form and have an option to save the partial info (so another day they can log back in and complete it) or submit the full info undergoing validation. Currently I'm using ModelForm for all the forms I use, and the Model has constraints to ensure valid data (e.g., the grant # has to be unique). However, I want them to be able to save this intermediary data without undergoing any validation. The solution I've thought of seems rather inelegant and un-django-ey: create a "Save Partial Form" button that saves the POST dictionary converts it to a shelf file and create a "SavedPartialForm" model connecting the user to partial forms saved in the shelf. Does this seem sensible? Is there a better way to save the POST dict directly into the db? Or is an add-on module that does this partial-save of a form (which seems to be a fairly common activity with webforms)? My biggest concern with my method is I want to eventually be able to do this form-autosave automatically (say every 10 minutes) in some ajax/jquery method without actually pressing a button and sending the POST request (e.g., so the user isn't redirected off the page when autosave is triggered). I'm not that familiar with jquery and am wondering if it would be possible to do this.

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  • Accessing my own datalayer using RIA & Silverlight

    - by Norsten
    Is it possible for me to connect to my own data provide via WCF RIA services? I've created a small datalayer that connnects to DynamicAX datasource. I would like to use Silverlight 4 & RIA service to access that datalayer. At it's most basic -I've done the following... 1) I've added an empty domainclass to the webproject and in that class I created a simple method to return a string... [EnableClientAccess()] public class ProjectService : DomainService { public string TestViaRIA() { return "Hello!"; } } 2) I then added reference to the web project in my silvelight class and created a bit of code to try and invoke the method... using ProjectApp.Web; namespace ProjectApp.Views { public partial class ProjectControl : UserControl { public ProjectControl() { InitializeComponent(); ProjectContext ctx = new ProjectContext(); var x = ctx.TestViaRIA(); testTextBox.Text = x.ToString(); } } } the returned value is "{System.ServiceModel.DomainServices.Client.InvokeOperation}". I'm obviously doing something wrong here and I would appreciate some guidance on how I can achive this. Thanks in advance

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  • NSManagedObject How To Reload

    - by crissag
    I have a view that consists of a table of existing objects and an Add button, which allows the user to create a new object. When the user presses Add, the object is created in the list view controller, so that the object will be part of that managed object context (via the NSEntityDescription insertNewObjectForEntityForName: method). The Add view has a property for the managed object. In the list view controller, I create an Add view controller, set the property to the managed object I created, and then push the Add view on to the navigation stack. In the Add view, I have two buttons for save and cancel. In the save, I save the managed object and pass the managed object back to the list view controller via a delegate method. If the user cancels, then I delete the object and pass nil back to the list view controller. The complication I am having in the add view is related to a UIImagePickerController. In the Add view, I have a button which allows the user to take a photo of the object (or use an existing photo from the photo library). However, the process of transferring to the UIImagePickerController and having the user use the camera, is resulting in a didReceiveMemoryWarning in the add view controller. Further, the view was unloaded, which also caused my NSManagedObject to get clobbered. My question is, how to you go about reloading the NSManagedObject in the case where it was released because of the low memory situation?

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  • Ways to make (relatively) safe assumptions about the type of concrete subclasses?

    - by Kylotan
    I have an interface (defined as a abstract base class) that looks like this: class AbstractInterface { public: bool IsRelatedTo(const AbstractInterface& other) const = 0; } And I have an implementation of this (constructors etc omitted): class ConcreteThing { public: bool IsRelatedTo(const AbstractInterface& other) const { return m_ImplObject.has_relationship_to(other.m_ImplObject); } private: ImplementationObject m_ImplObject; } The AbstractInterface forms an interface in Project A, and the ConcreteThing lives in Project B as an implementation of that interface. This is so that code in Project A can access data from Project B without having a direct dependency on it - Project B just has to implement the correct interface. Obviously the line in the body of the IsRelatedTo function cannot compile - that instance of ConcreteThing has an m_ImplObject member, but it can't assume that all AbstractInterfaces do, including the other argument. In my system, I can actually assume that all implementations of AbstractInterface are instances of ConcreteThing (or subclasses thereof), but I'd prefer not to be casting the object to the concrete type in order to get at the private member, or encoding that assumption in a way that will crash without a diagnostic later if this assumption ceases to hold true. I cannot modify ImplementationObject, but I can modify AbstractInterface and ConcreteThing. I also cannot use the standard RTTI mechanism for checking a type prior to casting, or use dynamic_cast for a similar purpose. I have a feeling that I might be able to overload IsRelatedTo with a ConcreteThing argument, but I'm not sure how to call it via the base IsRelatedTo(AbstractInterface) method. It wouldn't get called automatically as it's not a strict reimplementation of that method. Is there a pattern for doing what I want here, allowing me to implement the IsRelatedTo function via ImplementationObject::has_relationship_to(ImplementationObject), without risky casts? (Also, I couldn't think of a good question title - please change it if you have a better one.)

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  • Adding fields to Django form dynamically (and cleanly)

    - by scott
    Hey guys, I know this question has been brought up numerous times, but I'm not quite getting the full implementation. As you can see below, I've got a form that I can dynamically tell how many rows to create. How can I create an "Add Row" link that tells the view how many rows to create? I would really like to do it without augmenting the url... # views.py def myView(request): if request.method == "POST": form = MyForm(request.POST, num_rows=1) if form.is_valid(): return render_to_response('myform_result.html', context_instance=RequestContext(request)) else: form = MyForm(num_rows=1) return render_to_response('myform.html', {'form':form}, context_instance=RequestContext(request)) # forms.py class MyForm(forms.Form): def __init__(self, *args, **kwargs): num_rows = kwargs.pop('num_rows',1) super(MyForm, self).__init__(*args, **kwargs) for row in range(0, num_rows): field = forms.CharField(label="Row") self.fields[str(row)] = field # myform.html http://example.com/myform <form action="." method="POST" accept-charset="utf-8"> <ul> {% for field in form %} <li style="margin-top:.25em"> <span class="normal">{{ field.label }}</span> {{ field }} <span class="formError">{{ field.errors }}</span> </li> {% endfor %} </ul> <input type="submit" value="Save"> </form> <a href="ADD_ANOTHER_ROW?">+ Add Row</a>

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  • How to structure code with 2 methods, one after another, which throw the same two exceptions?

    - by dotnetdev
    Hi, I have two methods, one called straight after another, which both throw the exact same 2 exceptions (IF an erroneous condition occurs, not stating that I'm getting exceptions). For this, should I write seperate try and catch blocks with the one statement in each try block and catch both exceptions (Both of which I can handle as I checked MSDN class library reference and there is something I can do, eg, re-open SqlConnection or run a query and not a stored proc which does not exist). So code like this: try { obj.Open(); } catch (SqlException) { // Take action here. } catch (InvalidOperationException) { // Take action here. } And likewise for the other method I call straight after. This seems like a very messy way of coding. The other way is to code with the exception variable (that is ommited as I am using AOP to log the exception details, using a class-level attribute). Doing this, this could aid me in finding out which method caused an exception and then taking action accordingly. Is this the best approach or is there another best practise altogether? I also assume that, as only these two methods are thrown, I do not need to catch Exception as that would be for an exception I cannot handle (causes way out of my control). Thanks

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  • Can you explain this generics behavior and if I have a workaround?

    - by insta
    Sample program below: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace GenericsTest { class Program { static void Main(string[] args) { IRetrievable<int, User> repo = new FakeRepository(); Console.WriteLine(repo.Retrieve(35)); } } class User { public int Id { get; set; } public string Name { get; set; } } class FakeRepository : BaseRepository<User>, ICreatable<User>, IDeletable<User>, IRetrievable<int, User> { // why do I have to implement this here, instead of letting the // TKey generics implementation in the baseclass handle it? //public User Retrieve(int input) //{ // throw new NotImplementedException(); //} } class BaseRepository<TPoco> where TPoco : class,new() { public virtual TPoco Create() { return new TPoco(); } public virtual bool Delete(TPoco item) { return true; } public virtual TPoco Retrieve<TKey>(TKey input) { return null; } } interface ICreatable<TPoco> { TPoco Create(); } interface IDeletable<TPoco> { bool Delete(TPoco item); } interface IRetrievable<TKey, TPoco> { TPoco Retrieve(TKey input); } } This sample program represents the interfaces my actual program uses, and demonstrates the problem I'm having (commented out in FakeRepository). I would like for this method call to be generically handled by the base class (which in my real example is able to handle 95% of the cases given to it), allowing for overrides in the child classes by specifying the type of TKey explicitly. It doesn't seem to matter what parameter constraints I use for the IRetrievable, I can never get the method call to fall through to the base class. Also, if anyone can see an alternate way to implement this kind of behavior and get the result I'm ultimately looking for, I would be very interested to see it. Thoughts?

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  • Is this a good way to generically deserialize objects?

    - by Damien Wildfire
    I have a stream onto which serialized objects representing messages are dumped periodically. The objects are one of a very limited number of types, and other than the actual sequence of bytes that arrives, I have no way of knowing what type of message it is. I would like to simply try to deserialize it as an object of a particular type, and if an exception is thrown, try again with the next type. I have an interface that looks like this: public interface IMessageHandler<T> where T : class, IMessage { T Handle(string message); } // elsewhere: // (These are all xsd.exe-generated classes from an XML schema.) public class AppleMessage : IMessage { ... } public class BananaMessage : IMessage { ... } public class CoconutMessage : IMessage { ... } Then I wrote a GenericHandler<T> that looks like this: public class GenericHandler<T> : IMessageHandler<T> where T: class, IMessage { public class MessageHandler : IMessageHandler { T IMessageHandler.Handle(string message) { T result = default(T); try { // This utility method tries to deserialize the object with an // XmlSerializer as if it were an object of type T. result = Utils.SerializationHelper.Deserialize<T>(message); } catch (InvalidCastException e) { result = default(T); } return result; } } } Two questions: Using my GenericHandler<T> (or something similar to it), I'd now like to populate a collection with handlers that each handle a different type. Then I want to invoke each handler's Handle method on a particular message to see if it can be deserialized. If I get a null result, move onto the next handler; otherwise, the message has been deserialized. Can this be done? Is there a better way to deserialize data of unknown (but restricted) type?

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  • declare decision structure inside of a System.out.println

    - by user2899249
    So I am working on an assignment where I have to have a print method in a constructor that displays a distance. I also have to have three separate get methods depending on what the input is in the demo class. My question is that I am trying to write the print method to contain a decision structure based on which get is used. public void prt() { DecimalFormat formatter = new DecimalFormat("#,##0.00"); System.out.println("The time it takes the sound to travel " + distance + " feet through air is " + if (getSpeedInAir() > 0) { formatter.format(getSpeedInAir()); } else if (getSpeedInWater() > 0) { formatter.format(getSpeedInWater()); } else if (getSpeedInSteel() > 0) { formatter.format(getSpeedInSteel()); } else "error";) } After trying to compile I am getting the following errors. Microsoft Windows [Version 6.1.7601] Copyright (c) 2009 Microsoft Corporation. All rights reserved. C:\Users\GlaDOS\Desktop\JavaStuffj Speed C:\Users\GlaDOS\Desktop\JavaStuffdel *.class C:\Users\GlaDOS\Desktop\JavaStuffjavac Speed.java Speed.java:43: error: illegal start of expression " feet through air is " + if (getSpeedInAir() 0) ^ Speed.java:43: error: ';' expected " feet through air is " + if (getSpeedInAir() 0) ^ Speed.java:43: error: not a statement " feet through air is " + if (getSpeedInAir() 0) ^ Speed.java:43: error: ';' expected " feet through air is " + if (getSpeedInAir() 0) ^ Speed.java:47: error: 'else' without 'if' else if (getSpeedInWater() > 0) ^ Speed.java:56: error: not a statement "error";) ^ Speed.java:56: error: illegal start of expression "error";) ^ 7 errors C:\Users\GlaDOS\Desktop\JavaStuffjava Speed Error: Could not find or load main class Speed Any help on why this is happening would be greatly appreciated.

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  • Is there an alias for 'this' in TypeScript?

    - by Todd
    I've attempted to write a class in TypeScript that has a method defined which acts as an event handler callback to a jQuery event. class Editor { textarea: JQuery; constructor(public id: string) { this.textarea = $(id); this.textarea.focusin(onFocusIn); } onFocusIn(e: JQueryEventObject) { var height = this.textarea.css('height'); // <-- This is not good. } } Within the onFocusIn event handler, TypeScript sees 'this' as being the 'this' of the class. However, jQuery overrides the this reference and sets it to the DOM object associated with the event. One alternative is to define a lambda within the constructor as the event handler, in which case TypeScript creates a sort of closure with a hidden _this alias. class Editor { textarea: JQuery; constructor(public id: string) { this.textarea = $(id); this.textarea.focusin((e) => { var height = this.textarea.css('height'); // <-- This is good. }); } } My question is, is there another way to access the this reference within the method-based event handler using TypeScript, to overcome this jQuery behavior?

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  • Why can't I pass a form field of type file to a CFFUNCTION using structure syntax?

    - by Eric Belair
    I'm trying to pass a form field of type "file" to a CFFUNCTION. The argument type is "any". Here is the syntax I am trying to use (pseudocode): <cfloop from="1" to="5" index="i"> <cfset fieldname = "attachment" & i /> <cfinvoke component="myComponent" method="attachFile"> <cfinvokeargument name="attachment" value="#FORM[fieldname]#" /> </cfinvoke> </cfloop> The loop is being done because there are five form fields named "attachment1", "attachment2", et al. This throws an exception in the function: coldfusion.tagext.io.FileTag$FormFileNotFoundException: The form field C:\ColdFusion8\...\neotmp25080.tmp did not contain a file. However, this syntax DOES work: <cfloop from="1" to="5" index="i"> <cfinvoke component="myComponent" method="attachFile"> <cfinvokeargument name="attachment" value="FORM.attachment#i#" /> </cfinvoke> </cfloop> I don't like writing code like that in the second example. It just seems like bad practice to me. So, can anyone tell me how to use structure syntax to properly pass a file type form field to a CFFUNCTION??

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