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  • How do I dynamically define an instance variable?

    - by Moses
    Hi everyone, I have two classes (class1 and class2) that just store data, no methods. I have a third class that has an instance variable that, depending on some user input, will be set to one of the two classes. So, in the third class I declare the variable generically as NSObject *aClass; and during runtime set it to whatever it should be. aClass = [[Class1 alloc] init]; // or aClass = [[Class2 alloc] init]; However, when I try to access fields from aClass NSString *str = aClass.field1; It gives me the error: request for member 'field1' in something not a structure or a union. Field1 is declared in both class1 and class2. When I try to cast aClass aClass = (Class1 *) aClass; it gives the same error. What am I doing wrong, is there a better way to do this?

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  • Java: how to represent graphs?

    - by Rosarch
    I'm implementing some algorithms to teach myself about graphs and how to work with them. What would you recommend is the best way to do that in Java? I was thinking something like this: public class Vertex { private ArrayList<Vertex> outnodes; //Adjacency list. if I wanted to support edge weight, this would be a hash map. //methods to manipulate outnodes } public class Graph { private ArrayList<Vertex> nodes; //algorithms on graphs } But I basically just made this up. Is there a better way? Also, I want it to be able to support variations on vanilla graphs like digraphs, weighted edges, multigraphs, etc.

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  • API verbs for an interruptible operation

    - by 280Z28
    I have a long running task as part of my application. The task can be started, paused, resumed, and cancelled. I'm trying to find the best interface for these operations. Two seem clear: Pause and Cancel. This leaves the start and resume operations. I could include both Start and Resume. This has the downside of either requiring the API consumer to check the state before starting/resuming the operation to call the right method, or making the methods aliases of each other. I'm thinking I should include either Start or Resume, but I don't know which one is the most appropriate. Does anyone have any examples in the .NET Framework of such behavior? I prefer to follow established patterns whenever they are available.

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  • iPhone: Custom UITableViewCell with multiple areas that respond to taps?

    - by Nick
    I've been asked to create a custom UITableViewCell with multiple areas that can be tapped. These areas won't have buttons or any graphics - they'll be invisible. 3 different methods will be called depending on which third of the cell the user taps i.e. || decrementFooCount || viewFooDetails || incrementFooCount || The cell has a few labels on it that need to be visible at all times - the fooName and fooCount. I'm thinking perhaps three hidden UIButtons over the cell? I also need to maintain the swipe to delete default behavior.

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  • What is a good way of coding a file processing program, which accepts multisource data in Java

    - by jjepsuomi
    I'm making a data prosessing system, which currently is using csv-data as input and output form. In the future I might want to add support for example database-, xml-, etc. typed input and output forms. How should I desing my program so that it would be easy to add support for new type of data sources? Should simply make for example an abstract data class (which would contain the basic file prosessing methods) and then inherit this class for database, xml, etc. cases? Hope my question is clear =) In other words my question is: "How to desing a file prosessing system, which can be easily updated to accept input data from different sources (database, XML, Excel, etc.)".

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  • How to use intent between tabs in java/Android?

    - by Praveen Chandrasekaran
    I would need to know how to handle the intent between tabs. For example, I have a tab activity with two tabs. First on content is a text view. another one is a map view. When i click that text view it redirects to the tab2. it can be easily achieved by setCurrentTab(1) or setCurrentTabByTag("tab2") methods. But i want to pass lat and long values to that Map Activity to drop pin. What is the better way to use intents or getter/setter in java? What do you prefer? if your answer is "Intents". How?

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  • Using scanf() in C++ programs is faster than using cin ?

    - by zeroDivisible
    Hello, I don't know if this is true, but when I was reading FAQ on one of the problem providing sites, I found something, that poke my attention: Check your input/output methods. In C++, using cin and cout is too slow. Use these, and you will guarantee not being able to solve any problem with a decent amount of input or output. Use printf and scanf instead. Can someone please clarify this? Is really using scanf() in C++ programs faster than using cin something ? If yes, that is it a good practice to use it in C++ programs? I thought that it was C specific, though I am just learning C++...

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  • Instantiation vs. Typed reference

    - by Farstucker
    Just when I think Im starting to understand the basics, I find something that brings me right back to reality. In this case, typed reference. I found an example similar to this: class Worker { Boss boss; public void Advise(Boss pBoss) { this.boss = pBoss; } How can you reference methods within the Boss class if its not static and not instantiated? I guess my real question is whats the difference between: Boss boss; and Boss boss = new Boss(); Thank you, FS

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  • C# - How to convert 10 bytes to unsigned long

    - by Justin
    Hey, I have 10 bytes - 4 bytes of low order, 4 bytes of high order, 2 bytes of highest order - that I need to convert to an unsigned long. I've tried a couple different methods but neither of them worked: Try #1: var id = BitConverter.ToUInt64(buffer, 0); Try #2: var id = GetID(buffer, 0); long GetID(byte[] buffer, int startIndex) { var lowOrderUnitId = BitConverter.ToUInt32(buffer, startIndex); var highOrderUnitId = BitConverter.ToUInt32(buffer, startIndex + 4); var highestOrderUnitId = BitConverter.ToUInt16(buffer, startIndex + 8); return lowOrderUnitId + (highOrderUnitId * 100000000) + (highestOrderUnitId * 10000000000000000); } Any help would be appreciated, thanks!

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  • WSAT Security tab error for Custom Role provider

    - by shesb
    I have created custome Membership Role and Profile provider using INGRES db. Now I can see my IngresMembership and IngresRole provider in the Provider tab(Select a different provider for each feature (advanced) ) of WSAT but when I clik on security tab I get this error: "There is a problem with your selected data store. This can be caused by an invalid server name or credentials, or by insufficient permission. It can also be caused by the role manager feature not being enabled. Click the button below to be redirected to a page where you can choose a new data store. The following message may help in diagnosing the problem: Object reference not set to an instance of an object." What am I missing? Do I need to add code for all override methods for Role provider? I have just written code for the Initialize and GetRolesForUser functions. Thanks

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  • Javascript data parsing in IE vs other browsers... It seems kinda screwed up. What's the deal?

    - by Carter
    Firstly, when I say other browsers I really only mean Firefox because that's all I tested in. Internet Explorer can parse a date followed by a single character as a proper date. Whereas Firefox behaves as I'd expect. For example... var dateString = new Date("1/1/2010f"); alert(dateString); In IE it will alert... Thu Dec 31 21:00:00 UTC-0900 2009 Whereas in FF is will spit out... "Invalid Date" I first noticed this using the jquery validation plug in. http://docs.jquery.com/Plugins/Validation/Methods/date It seems like it just subtracts some amount of hours off the actual date in IE when a character is appended. I've tested in IE6 and IE8. Am I missing something?

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  • What is the time taken by java to call a method in another package?

    - by satish
    I have an assignment where i need to do feasibility study on two of my approaches and find optimized one. There are two packages A and B User input is gathered in A and then sent to B for execution. Now my approaches are 1. Call B methods from package A one by one. 2. Create a common method in B and send all the input as parameters. Which is feasible and best one, I know 2 is good in terms of code optimization and less number of calls. But, I want to understand what will be the execution time difference in above approaches How much time does java take to call method in another package? Is there any default value like x nano seconds or y milli seconds. Based on the time taken I can choose the appropiate one. Thanks

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  • response.sendRedirect - check redirect is up

    - by Trick
    From JSP I just want a redirect to another page... <% response.sendRedirect("http://www.google.com/"); %> Can I check if google.com is up and then redirect (or write a msg else)... Something like that: <% if(ping("www.google.com")) { response.sendRedirect("http://www.google.com/"); } else { // write a message }%> Or <% try { response.sendRedirect("http://www.google.com/"); } catch(SomeException e) { // write a message }%> It is just an JSP page, I don't have any libraires available (like ApacheCommons for http GET methods).

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  • Rails + simple role system through associative table

    - by user202411
    So I have the Ninja model which has many Hovercrafts through ninja_hovercrafts (which stores the ninja_id and the hovercraft_id). It is of my understanding that this kind of arrangement should be set in a way that the associative table stores only enough information to bind two different classes. But I'd like to use the associative table to work as a very streamlined authorization hub on my application. So i'd also like this table to inform my system if this binding makes the ninja the pilot or co-pilot of a given hovercraft, through a "role" field in the table. My questions are: Is this ugly? Is this normal? Are there methods built into rails that would help me to automagically create Ninjas and Hovercrafts associations WITH the role? For exemple, could I have a nested form to create both ninjas and hcs in a way that the role field in ninjas_hovercrafts would be also filled? If managing my application roles this way isn't a good idea, whats the non-resource heavy alternative (my app is being designed trying to avoid scalability problems such as excessive joins, includes, etc) thank you

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  • Creating an interface and swappable implementations in python

    - by Blankman
    Hi, Would it be possible to create a class interface in python and various implementations of the interface. Example: I want to create a class for pop3 access (and all methods etc.). If I go with a commercial component, I want to wrap it to adhere to a contract. In the future, if I want to use another component or code my own, I want to be able to swap things out and not have things very tightly coupled. Possible? I'm new to python.

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  • What is the MVC version of this code?

    - by Ian Boyd
    i'm trying to wrap my head around how to enterprise up my code: taking a simple routine and splitting it up into 5 or 6 methods in 3 or 4 classes. i quickly came up three simple examples of code how i currently write it. Could someone please convert these into an MVC/MVP obfuscated version? Example 1: The last name is mandatory. Color the text box red if nothing is entered. Color it green if stuff is entered: private void txtLastname_TextChanged(object sender, EventArgs e) { //Lastname mandatory. //Color pinkish if nothing entered. Greenish if entered. if (txtLastname.Text.Trim() == "") { //Lastname is required, color pinkish txtLastname.BackColor = ControlBad; } else { //Lastname entered, remove the coloring txtLastname.BackColor = ControlGood; } } Example 2: The first name is optional, but try to get it. We'll add a bluish tint to this "try to get" field: private void txtFirstname_TextChanged(object sender, EventArgs e) { //Firstname can be blank. //Hint them that they should *try* to get it with a bluish color. //If they do enter stuff: it better be not all spaces. if (txtFirstname.Text == "") { //Nothing there, hint it blue txtFirstname.BackColor = ControlRequired; } else if (txtFirstname.Text.Trim() == "") { //They entered spaces - bad user! txtFirstname.BackColor = ControlBad; } else { //Entered stuff, remove coloring txtFirstname.BackColor = SystemColors.Window; } } Example 3 The age is totally optional. If an age is entered, it better be valid: private void txtAge_TextChanged(object sender, EventArgs e) { //Age is optional, but if entered it better be valid int nAge = 0; if (Int32.TryParse(txtAge.Text, out nAge)) { //Valid integer entered if (nAge < 0) { //Negative age? i don't think so txtAge.BackColor = ControlBad; } else { //Valid age entered, remove coloring txtAge.BackColor = SystemColors.Window; } } else { //Whatever is in there: it's *not* a valid integer, if (txtAge.Text == "") { //Blank is okay txtAge.BackColor = SystemColors.Window; } else { //Not a valid age, bad user txtAge.BackColor = ControlBad; } } } Every time i see MVC code, it looks almost like random splitting of code into different methods, classes, and files. i've not been able to determine a reason or pattern to their madness. Without any understanding of they why it's being one some way, it makes no sense. And using the words model, view, controller and presenter, like i'm supposed to know what that means, doesn't help. The model is your data. The view shows data on screen. The controller is used to carry out the users actions And oranges taste orangy. Here's my attempt at splitting things up in order to make the code more difficult to follow. Is this anywhere close to MVC? private void txtFirstname_TextChanged(object sender, EventArgs e) { FirstnameTextChangedHandler(sender, e); } private void FirstnameTextChangedHandler(sender, e) { string firstname = GetFirstname(); Color firstnameTextBoxColor = GetFirstnameTextBoxColor(firstname); SetFirstNameTextBoxColor(firstnameTextBoxColor); } private string GetFirstname() { return txtFirstname.Text; } private Color GetFirstnameTextBoxColor(string firstname) { //Firstname can be blank. //Hint them that they should *try* to get it with a bluish color. //If they do enter stuff: it better be not all spaces. if (firstname == "") { //Nothing there, hint it blue return GetControlRequiredColor(); } else if (firstname.Trim() == "") { //They entered spaces - bad user! return GetControlBadColor(); } else { //Entered stuff, remove coloring return GetControlDefaultColor(); } } private Color GetControlRequiredColor() { return ControlRequired; } private Color GetControlBadColor() { return ControlBad; } private Color GetControlGoodColor() { return ControlGood; } //am i doin it rite i've obfuscated the code, but it's still altogether. The next step in the MVC obfuscation, i gather, is to hide the code in 3 or 4 different files. It's that next step that i don't understand. What is the logical separation of which functions are moved into what other classes? Can someone translate my 3 simple examples above into full fledged MVC obfuscation? Edit: Not ASP/ASP.NET/Online. Pretend it's on a desktop, handheld, surface, kiosk. And pretend it's language agnostic.

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  • Jquery/CSS help needed to make fallback for IE and older browsers

    - by matt_50
    Wondering if any of you can help me: I've made a signup modal that uses a CSS transform to switch between two methods of signing up. I've decided to try a 'card flip' type effect. Have a look at this JSfiddle in any browser that supports CSS 3D transforms - click the 'old fashioned way' text to 'flip' the modal (simplified for demo purposes): http://jsfiddle.net/voodoo6/cnTMz/8/ Then take a look in IE8/9 - as the 'back' is taller than the front and IE does;t support 'backface-visibility: hidden;' the reverse can be seen below the front. I've been trying to use JQuery and conditional CSS to 'display:none' the 'back' on load in IE (and older browsers), then add a 'display:block;' class to show it on click, problem is, I'm a JQuery beginner and have been struggling to get it to work! Not even sure if this is the best approach? Can anybody suggest an approach that would get this working in less-capable browsers? Thanks for any advice..

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  • Is select() Ok to implement single socket read/write timeout ?

    - by chmike
    I have an application processing network communication with blocking calls. Each thread manages a single connection. I've added a timeout on the read and write operation by using select prior to read or write on the socket. Select is known to be inefficient when dealing with large number of sockets. But is it ok, in term of performance to use it with a single socket or are there more efficient methods to add timeout support on single sockets calls ? The benefit of select is to be portable.

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  • Re-ordering a collection of UIView's based on their CGPoint

    - by Chris
    Hi all, I have a NSMutableArray that holds a collection of UIViewControllers Amongst other properties and methods an instance of each of the viewControllers are placed in a parent view The user will place these objects individually when desired to. So essentially I use - (void)addSubview:(UIView *)view when a new view is added to the parent view controller. Because the UI is isometric it's made things a tad more complicated What I am trying to do is re-order the views based on their co-ordinate position, so items higher up the parent UIView frame is indexed lower then views lower in the parent UIview frame. And items that are on the left side of the view are positioned at a higher index to those on the right I think the solution may have to do with re-ordering the NSMutableArray but how can I compare the CGpoints? Do I need to compare the x and y separately?

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  • How to modify posted form data within controller action before sending to view?

    - by Gary
    I want to render the same view after a successful action (rather than use RedirectToAction), but I need to modify the model data that is rendered to that view. The following is a contrived example that demonstrates two methods that that do not work: [AcceptVerbs("POST")] public ActionResult EditProduct(int id, [Bind(Include="UnitPrice, ProductName")]Product product) { NORTHWNDEntities entities = new NORTHWNDEntities(); if (ModelState.IsValid) { var dbProduct = entities.ProductSet.First(p => p.ProductID == id); dbProduct.ProductName = product.ProductName; dbProduct.UnitPrice = product.UnitPrice; entities.SaveChanges(); } /* Neither of these work */ product.ProductName = "This has no effect"; ViewData["ProductName"] = "This has no effect either"; return View(product); } Does anyone know what the correct method is for accomplishing this?

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  • Method params match signature, but still getting error

    - by Jason
    I am in the midst of converting a VB library to C#. One of my methods has the following signature in VB: Private Shared Sub FillOrder(ByVal row As DataRowView, ByRef o As Order) In C# I converted it to: private static void FillOrder(DataRowView row, ref Order o) From my constructor inside my Order class, I am calling the FillOrder() method like so: DataView dv = //[get the data] if (dv.Count > 0) { FillOrder(dv[0], this); } In VB, this works: Dim dv As DataView = '[get data]' If dv.Count > 0 Then FillOrder(dv.Item(0), Me) End If However, in VS10 in the C# file I am getting a red squiggle under this call with the following error: The best overloaded method match for [the method] has some invalid arguments This was working code in VB. What am I doing wrong?

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  • Access the camera of a Smartphone using libGDX

    - by PH-zero
    I searched the web, browsed through the libGDX wiki, but without success. My Question: Is there a way, to access the camera of smartphones, let the user take a photo, and then store the image in a Texture-instance? I could imagin something like this: @Override public void onCamTrigger(){ ApplicationType appType = Gdx.app.getType(); switch (appType) { case Android: case iOS: Texture someTexture = new Texture(Gdx.input.getCamera().getImage()); //do something with the Texture instance... someTexture.dispose(); break; default: break; } } Of course this is pure fiction! I know that there's a lot more to this like opening the camera, displaying it, then take a photo etc. . But is there a convenience method like this? If so, how does it work? On Android, i think i could implement it without using any convenience methods offered by libGDX, but i have no idea on how this works on iOS =/

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  • Migrating Data to MSSQL 2008

    - by Fred Clown
    I am trying to migrate data from an Informix database to MSSQL 2008. I've got quite a lot of data to move. I've been try multiple methods to get the data over, and so far SQLBulkCopy in multiple chunks seems to be the fastest that I can find. Does anyone know of a faster means of getting the data over? I'm trying to cut down on the transfer time so that on my cut-over date I don't run out of time to do the full cut-over. Thanks.

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  • How to bind to current riacontext user in xaml

    - by Jakob
    Hi. I Have a datacontext that has a "getuserbyguid" method, i want to pass in the current logged in user.userid as a parameter, but I don't know how to bind to the current logged in user through xaml. I've tried {Binding Path=User.UserId} but without any luck. I'm using the built in riaservices authentication methods, so the userinfo should be exposed in the riacontext, or am I wrong about this? I have this for instance <riaControls:DomainDataSource x:Name="FollowingGridData" AutoLoad="True" QueryName="GetUsersFollowedByIDQuery" LoadSize="20"> <riaControls:DomainDataSource.DomainContext> <my:NotesDomainContext /> </riaControls:DomainDataSource.DomainContext> <riaControls:DomainDataSource.QueryParameters> <riaControls:Parameter ParameterName="userguid" Value="{Binding Path=User.UserId}" /> </riaControls:DomainDataSource.QueryParameters> </riaControls:DomainDataSource> But it gives me an error saying that it's not a guid, meaning that it must not be binding correctly

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  • Basic QT Event handling / Threading questions ?

    - by umanga
    Greetings , I am new to QT (4.6) and have some basic questions regarding its event mechanism.I come from Swing background so I am trying to compare it with QT. 1) Does Event-processing-loop run in seperate thread? (like EventDispatch thread in Swing) ? 2) If we open several 'QMainWindow' do they run in several threads? 3) Whats the best way to run an intensive process in a seperate thread? (like SwingWorker in Swing ? ) 4) If intesive-process runs in a seperate thread ,is it possible to call UI methods like update(),repaint() from that process? thanks in advance.

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