Search Results

Search found 33344 results on 1334 pages for 'helper method'.

Page 529/1334 | < Previous Page | 525 526 527 528 529 530 531 532 533 534 535 536  | Next Page >

  • Obfuscating ids in Rails app

    - by fphilipe
    I'm trying to obfuscate all the ids that leave the server, i.e., ids appearing in URLs and in the HTML output. I've written a simple Base62 lib that has the methods encode and decode. Defining—or better—overwriting the id method of an ActiveRecord to return the encoded version of the id and adjusting the controller to load the resource with the decoded params[:id] gives me the desired result. The ids now are base62 encoded in the urls and the response displays the correct resource. Now I started to notice that subresources defined through has_many relationships aren't loading. e.g. I have a record called User that has_many Posts. Now User.find(1).posts is empty although there are posts with user_id = 1. My explanation is that ActiveRecord must be comparing the user_id of Post with the method id of User—which I've overwritten—instead of comparing with self[:id]. So basically this renders my approach useless. What I would like to have is something like defining obfuscates_id in the model and that the rest would be taken care of, i.e., doing all the encoding/decoding at the appropriate locations and preventing ids to be returned by the server. Is there any gem available or does somebody have a hint how to accomplish this? I bet I'm not the first trying this.

    Read the article

  • 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.

    Read the article

  • How can I use TDD to solve a puzzle with an unknown answer?

    - by matthewsteele
    Recently I wrote a Ruby program to determine solutions to a "Scramble Squares" tile puzzle: I used TDD to implement most of it, leading to tests that looked like this: it "has top, bottom, left, right" do c = Cards.new card = c.cards[0] card.top.should == :CT card.bottom.should == :WB card.left.should == :MT card.right.should == :BT end This worked well for the lower-level "helper" methods: identifying the "sides" of a tile, determining if a tile can be validly placed in the grid, etc. But I ran into a problem when coding the actual algorithm to solve the puzzle. Since I didn't know valid possible solutions to the problem, I didn't know how to write a test first. I ended up writing a pretty ugly, untested, algorithm to solve it: def play_game working_states = [] after_1 = step_1 i = 0 after_1.each do |state_1| step_2(state_1).each do |state_2| step_3(state_2).each do |state_3| step_4(state_3).each do |state_4| step_5(state_4).each do |state_5| step_6(state_5).each do |state_6| step_7(state_6).each do |state_7| step_8(state_7).each do |state_8| step_9(state_8).each do |state_9| working_states << state_9[0] end end end end end end end end end So my question is: how do you use TDD to write a method when you don't already know the valid outputs? If you're interested, the code's on GitHub: Tests: https://github.com/mattdsteele/scramblesquares-solver/blob/master/golf-creator-spec.rb Production code: https://github.com/mattdsteele/scramblesquares-solver/blob/master/game.rb

    Read the article

  • Devise password reset issue (new_user?)

    - by rabid_zombie
    When a user's email is inputted into the forgot password form and submitted, I am receiving an error saying login can't be blank. I looked around devise.en.yml for this error message, but can't seem to find it anywhere. Here is my views/devise/passwords/new.html.haml: %div.registration_page %h2 Forgot your password? = form_for(resource, :as => resource_name, :url => user_password_path, :html => { :method => :post, :id => 'forgot_pw_form', :class => 'forgot_pw' }) do |f| %div = f.email_field :email, :placeholder => 'Email', :autofocus => true, :autocomplete => 'off' %div.email_error.error %input.btn.btn-success{:type => 'submit', :value => 'Send Instructions'} = render "devise/shared/links" The form is posting to users/password like it should, but I noticed that my forgot password form attaches class = 'new_user'. Here is what my form displays: <form accept-charset='UTF-8' action='/users/password' class='new_user' id='forgot_pw_form' method='post' novalidate='novalidate'></form> My routes for devise (I have custom sessions and registrations controllers): devise_for :users, :controllers => {:sessions => 'sessions', :registrations => 'registrations'} How can I setup devise's forgot password functionality? Why am I receiving this error message and why is that class being added there? I've tried: Adding my own passwords controller and adding new routes for my custom controller. Same error Adding my own class and id to the form. This successfully changes the id and class of the form, but reverts back to class and id of new_user Thanks.

    Read the article

  • How to convert X/Y position to Canvas Left/Top properties when using ItemsControl

    - by kshahar
    I am trying to use a Canvas to display objects that have "world" location (rather than "screen" location). The canvas is defined like this: <Canvas Background="AliceBlue"> <ItemsControl Name="myItemsControl" ItemsSource="{Binding MyItems}"> <ItemsControl.ItemTemplate> <DataTemplate> <Canvas> <TextBlock Canvas.Left="{Binding WorldX}" Canvas.Top="{Binding WorldY}" Text="{Binding Text}" Width="Auto" Height="Auto" Foreground="Red" /> </Canvas> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> </Canvas> MyItem is defined like this: public class MyItem { public MyItem(double worldX, double worldY, string text) { WorldX = worldX; WorldY = worldY; Text = text; } public double WorldX { get; set; } public double WorldY { get; set; } public string Text { get; set; } } In addition, I have a method to convert between world and screen coordinates: Point worldToScreen(double worldX, double worldY) { // return screen coordinates using the canvas properties and an internal MapData object } With the current implementation, the items are positioned in the wrong location, because their location is not converted to screen coordinates. How can I apply the worldToScreen method on the MyItem objects before they are added to the canvas?

    Read the article

  • Password security; Is this safe?

    - by Camran
    I asked a question yesterday about password safety... I am new at security... I am using a mysql db, and need to store users passwords there. I have been told in answers that hashing and THEN saving the HASHED value of the password is the correct way of doing this. So basically I want to verify with you guys this is correct now. It is a classifieds website, and for each classified the user puts, he has to enter a password so that he/she can remove the classified using that password later on (when product is sold for example). In a file called "put_ad.php" I use the $_POST method to fetch the pass from a form. Then I hash it and put it into a mysql table. Then whenever the users wants to delete the ad, I check the entered password by hashing it and comparing the hashed value of the entered passw against the hashed value in the mysql db, right? BUT, what if I as an admin want to delete a classified, is there a method to "Unhash" the password easily? sha1 is used currently btw. some code is very much appreciated. Thanks

    Read the article

  • Activator.CreateInstance uses a huge amount of memory

    - by Marco
    I have been playing a bit with Silverlight and try to port my Silverlight 3.0 application to Silverlight 4.0. My application loads different XAP files and upon a user request create an instance of a Xaml user control and adds it to the main container, in a sort of MEF approach in order I can have an extensible and pluggable application. The application is pretty huge and to keep acceptable the performances and the initial loading I have built up some helper classes to load in the background all pages and user controls that might be used later on. On Silverlight 3.0 everything was running smoothly without any problem so far. Switching to SL 4.0 I have noticed that when the process approaches to create the instances of the user controls using Activator.CreateInstance, the layout freezes unexpectedly for a minute and sometimes for more. Looking at the task manager the memory usage of IE jumps from 50MB to 400MB and sometimes to 1.5 GB. If the process won't take that much the layout is rendered properly and the memory falls back to 50 MB. Otherwise everything crashes due to out of memory exeption. Does anybody encountered the same problem? Or has anybody a solution about this tricky issue?

    Read the article

  • addField type image and thumbnail path

    - by Christiaan
    Hello, I have a Magento webshop and just created a custom module with the extension (Modulecreator). This module comes with a standard admin interface that can handle file uploads. I found out that if you want to show thumbnails you can use the 'image' field type (addField('myfield', 'image')) instead of the 'file' type field. But now i've got a problem. When I upload files, I save them in a subdirectory called 'slides' in the 'media' directory. But when I edit the item, the image path for the thumbnail next to the uploadfield is set to the 'media' folder. Not my folder as I set it to 'media/slides/'. I use the following code: $fieldset->addField('filename', 'image', array( 'label' => Mage::helper('slideshow')->__('File'), 'required' => true, 'name' => 'filename', )); I tried to set a 'path' key in the array, but this doesn't get picked up by Magento. Hate the lack of support for good and easy to use documentation by Magento... Maybe you can help me out to find a solution?

    Read the article

  • How can I take advantage of IObservable/IObserver to get rid of my "god object"?

    - by Will
    In a system I'm currently working on, I have many components which are defined as interfaces and base classes. Each part of the system has some specific points where they interact with other parts of the system. For example, the data readying component readies some data which eventually needs to go to the data processing portion, the communications component needs to query different components for their status for relaying to the outside, etc. Currently, I glue these parts of the system together using a "god object", or an object with intimate knowledge of different parts of the system. It registers with events over here and shuttles the results to methods over there, creates a callback method here and returns the result of that method over there, and passes many requests through a multi-threaded queue for processing because it "knows" certain actions have to run on STA threads, etc. While its convenient, it concerns me that this one type knows so much about how everybody else in the system is designed. I'd much prefer a more generic hub that can be given instances which can expose events or methods or callbacks or that can consume these. I've been seeing more about the IObservable/IObserver features of the reactive framework and that are being rolled into .NET 4.0 (I believe). Can I leverage this pattern to help replace my "god object"? How should I go about doing this? Are there any resources for using this pattern for this specific purpose?

    Read the article

  • initialise a var in scala

    - by user unknown
    I have a class where I like to initialize my var by reading a configfile, which produces intermediate objects/vals, which I would like to group and hide in a method. Here is the bare minimum of the problem - I call the ctor with a param i, in reality a File to parse, and the init-method generates the String s, in reality more complicated than here, with a lot of intermediate objects being created: class Foo (val i: Int) { var s : String; def init () { s = "" + i } init () } This will produce the error: class Foo needs to be abstract, since variable s is not defined. In this example it is easy to solve by setting the String to "": var s = "";, but in reality the object is more complex than String, without an apropriate Null-implementation. I know, I can use an Option, which works for more complicated things than String too: var s : Option [String] = None def init () { s = Some ("" + i) } or I can dispense with my methodcall. Using an Option will force me to write Some over and over again, without much benefit, since there is no need for a None else than to initialize it that way I thought I could. Is there another way to achieve my goal?

    Read the article

  • I need help solving a rather weird error in a WCF service.

    - by Moulde
    Hi.. I have a solution that contains three projects. A main project with my MVC app, a silverlight application and a (silverlight enabled) WCF service project. In my silverlight project i have made a Service Reference to my WCF service. And i pretty much got that working. In my WCF service i have a method that returns an Book object, which got some random fields like title, date etc. In the book class, i have a ICollection field that contains a list of events. The book class is generated using entity framework 4.0, and Lazy Loading is enabled. If i in my getBook(int id) method return a book with the events field not initialized, it works as a charm. But if i initialize the field, i'm getting this error. The server did not provide a meaningful reply; this might be caused by a contract mismatch, a premature session shutdown or an internal server error. I have a few ideas why that is happening, and while writing this i just got another one. The wcf service somehow threw away the reference to the event class. That would be very weird since i have a reference between my main mvc app (with the models) and my WCF service. Since i have enabled lazy loading in EF 4.0, i suspect that it may be the thing generating the error. But i'm not sure why that would be, because i'm not in any way accessing that field. I could understand that i may not be able to access the events field after i recive the object in my silverlight application since the connection between the book object and the entity framework is like broken. Did i mention that Lazy Loading is enabled on my EF instance? And there is no inner exception in the thrown exception. Thanks in advance. Malte Baden Hansen

    Read the article

  • 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)

    Read the article

  • Redirect in codeigniter after login

    - by edelweiss
    Trying to do a redirect after a successful login. The login info is sent using ajax to the controller. My controller code as below public function login_controller_function() { $this->load->model('login_model'); if ($this->input->is_ajax_request()) { $user_name=$this->input->post('username'); $user_password = $this->input->post('password'); $this->load->helper('url'); $result = $this->login_model->verify_user($user_name,$user_password); // echo 'user_logged_in'; if(strcmp($result,'user_logged_in')==0) { redirect('welcome'); } } } But it is not working at all. Anyone knows whats wrong? Hi my html as requested. i am using twitter bootstrap as well <li class="divider-vertical"></li> <li><a href="#" id="login_btn">Login</a></li> <li><a href="<?php echo base_url('register'); ?>">Register</a></li> for the buttons so when i click the login button, a modal window will appear and ask for login info. so when i click on the login button, my js code will send an ajax request my js code as below /*Attempt register user jquery ajax*/ $('#login').click(function(){ var user_name = $('#loginHere').find('#user_name').val(); var user_password = $('#loginHere').find('#login_pwd').val(); if(user_name==""||user_password=="") return; var login_data = { username:user_name, password:user_password}; $.ajax({ type: "POST", dataType: "json", async: false, url:"login_register/login_controller_function", data: login_data, success: function(data) { if(data.login) { alert(data.redirect); window.location.replace(data.redirect); } else if(!data.login) { alert('data login not true'); } }, error:function(data){ alert('ajax error'); } }); }); });

    Read the article

  • What is an interface in C (COM) is it the same as a interface in C#

    - by numerical25
    Ok, I know what a interface is, but since I got into C and working with COM objects, it seems an interface in COM is a little different from the interface I know of. So what I am trying to do is bridge the gaps here cause since I been learning C, alot of things have been sounding very familiar to me but are not exactly what they seem. The interface I know of are like contracts. They are objects that have only method declarations, with no body. All classes that implement an interface must include the methods of the interface. The interface I hear about in COM seems to be just pointers. They can not retrieve objects directly but only can retrieve objects through the means of a method. Is this what a COM Interface is ?? If so, then why did they give them the same names if they are completely different. Also I just wanted to add that headers in C++ kind of remind me of the C# Interfaces. Not sure if their are any relations. But anyways, I am just trying to clear that up.

    Read the article

  • .net printing multiple reports in one document (architecture question)

    - by LawsonM
    I understand how to print a single document via the PrintDocument class. However, I want to print multiple reports in one document. Each "report" will consist of charts, tables, etc. I want to have two reports per page. I've studied the few examples I can find on how to combine multiple documents into one; however, they always seem to work by creating a collection of objects (e.g. customer or order) that are then iterated over and drawn in the OnPrintPage method. My problem and hence the "architecture" question is that I don't want to cache the objects required to produce the report since they are very large and memory intensive. I'd simply like the resulting "report". One thought I had was to print the report to a metafile, cache that instead in a "MultiplePrintDocument" class and then position those images appropriately two to a page in the OnPrintPage method. I think this would be a lot more efficient and scalable in my case. But I'm not a professional programmer and can't figure out if I'm barking up the wrong tree here. I think the Graphics.BeginContainer and Graphics.Save methods might be relevant, but can't figure out how to implement or if there is a better way. Any pointers would be greatly appreciated.

    Read the article

  • Play! 1.2.5 with mongodb | Model Validation not happening

    - by TGV
    I have a simple User model whose fields are annotated with play validation annotations and morphia annotations like below. import play.data.validation.*; import play.modules.morphia.Model; import com.google.code.morphia.annotations.*; @Entity public class User extends Model{ @Id @Indexed(name="USERID", unique=true) public ObjectId userId; @Required public String userName; @Email @Indexed(name="USEREMAIL", unique=true) @Required public String userEmail; } Now I have a service which has a CreateNewUser method responsible for persisting the data. I have used Morphia plugin for the dao support. But the problem is that User Document gets persisted in mongo-db even if userName or userEmail is NULL. Also @Email validation does not happen // Below code is in app/controllers/Application.java User a = new User(); a.userName = "user1"; // calling bean to create user, userService is in app/service/UserService userService.createNewUser(a); It does not work even after adding @valid and validation.hasErrors() check.Below code is in app/service/UserService public void createNewUser(@Valid User user) { if (Validation.hasErrors()) { System.out.println("has errors"); } else { // TODO Auto-generated method stub userDao.save(user); } }

    Read the article

  • How to best manage multi-frame MovieClips with classes?

    - by Arms
    After switching to AS3, I've been having a hell of a time figuring out the best way to manage MovieClips that have UI elements spread across multiple frames with a single class. An example that I am working on now is a simple email form. I have a MovieClip with two frames: the 1st frame has the form elements (text inputs, submit button) the 2nd frame has a "thank you" message and a button to go back to the first frame (to send another email) In the library I have linked the MovieClip to a custom class (Emailer). My immediate problem is how do I assign a MouseEvent.CLICK event to the button on the 2nd frame? I should note at this point that I am trying to avoid putting code on the timeline (except for stop() calls). This is how I am 'solving' the problem now: Emailer registers an event listener for a frame change ( addEventListener("frame 2", onFrameChange) ) On the 2nd frame of the MovieClip I am calling dispatchEvent(new Event("frame 2")); (I would prefer to not have this code on the frame, but I don't know what else to do) My two complaints with this method are that, first I have calls to addEventListener spread out across different class methods (I would rather have all UI event listeners registered in one method), and second that I have to dispatch those custom "onFrameChange" events. The second complaint grows exponentially for MovieClips that have more than just 2 frames. My so called solution feels makes me feel dirty and makes my brain hurt. I am looking for any advice on what to do differently. Perhaps there's a design pattern I should be looking at? Should I swallow my pride and write timeline code even though the rest of my application is written in class files (and I abhor the Flash IDE code editor)? I absolutely LOVE the event system, and have no problem coding applications with it, but I feel like I'm stuck thinking in terms of AS2 when working with mutl-frame movieclips and code. Any and all help would be greatly appreciated.

    Read the article

  • Trouble with go tour crawler exercise

    - by David Mason
    I'm going through the go tour and I feel like I have a pretty good understanding of the language except for concurrency. On slide 71 there is an exercise that asks the reader to parallelize a web crawler (and to make it not cover repeats but I haven't gotten there yet.) Here is what I have so far: func Crawl(url string, depth int, fetcher Fetcher, ch chan string) { if depth <= 0 { return } body, urls, err := fetcher.Fetch(url) if err != nil { ch <- fmt.Sprintln(err) return } ch <- fmt.Sprintf("found: %s %q\n", url, body) for _, u := range urls { go Crawl(u, depth-1, fetcher, ch) } } func main() { ch := make(chan string, 100) go Crawl("http://golang.org/", 4, fetcher, ch) for i := range ch { fmt.Println(i) } } The issue I have is where to put the close(ch) call. If I put a defer close(ch) somewhere in the Crawl method, then I end up writing to a closed channel in one of the spawned goroutines, since the method will finish execution before the spawned goroutines do. If I omit the call to close(ch), as is shown in my example code, the program deadlocks after all the goroutines finish executing but the main thread is still waiting on the channel in the for loop since the channel was never closed.

    Read the article

  • C++ Dynamic object construction

    - by Rajesh Subramanian
    I have a base class, class Msg { ParseMsg() { ParseMsgData(); ParseTrailer(); } virtual void ParseMsgData() = 0; ParseTrailer(); }; and derived classes, class InitiateMsg { void ParseMsgData() { ... } }; class ReadOperationMsg { void ParseMsgData() { ... } }; class WriteOperationMsg { void ParseMsgData() { ... } }; and the scenario is below, void UsageFunction(string data) { Msg* msg = ParseHeader(data); ParseMsg } Msg* ParseHeader(string data) { Msg *msg = NULL; .... switch() { case 1: msg = new InitiateMsg(); break; case 2: msg = new ReadOperationMsg{(); break; case 3: msg = new WriteOperationMsg{(); break; .... } return msg; } based on the data ParseHeader method will decide which object has to be created, So I have implemented ParseHeader function outside the class where I am using. How can I make the ParseHeader function inside the Msg class and then use it? In C# the same is achieved by defining ParseHeader method as static with in class and use it from outside,

    Read the article

  • Prompting for authentication from a wxPython program and passing it along to IIS?

    - by MetaHyperBolic
    I have a client (written in Python, with a wxPython front end in dead-simple wizard style) which communicates a website running IIS. A python script receives requests and does the usual client-server dance. I would have written this as a browser application, but for the requirement that certain things happen on the local PC that the web can't help with (file manipulation, interfacing with certain USB hardware, etc.) Right now, I am simply using the logon credentials, compounded as a string from os.environ['USERDOMAIN'] and os.environ['USERNAME'], to pass along to the server, which connects to Active Directory and enumerates the members of the group, looking for those logon credentials. It's an ugly hack, but it works. Obviously, I could make people log out of the generic helper accounts and log back into Windows using specific accounts. However, I wondered how feasible it would be to provide some kind of logon prompt wherein the user can type in a name and password, then some kind of authorization token could be passed on to IIS. This seems like something I would not want to do myself, given that amateurs almost always make huge security mistakes. Now you can see why I am wishing this was purely web-based. What's a good way to handle this?

    Read the article

  • Doesn't (didn't) Scala have automatically generated setters?

    - by Malvolio
    Google and my failing memory are both giving me hints that it does, but every attempt is coming up dry. class Y { var y = 0 } var m = new Y() m.y_(3) error: value y_ is not a member of Y Please tell me I am doing something wrong. (Also: please tell me what it is I am doing wrong.) EDIT The thing I am not doing wrong, or at least not the only thing I am doing wrong, is the way I am invoking the setter. The following things also fail, all with the same error message: m.y_ // should be a function valued expression m.y_ = (3) // suggested by Google and by Mchl f(m.y_) // where f takes Int => Unit as an argument f(m.y) // complains that I am passing in Int not a function I am doing this all through SimplyScala, because I'm too lazy and impatient to set up Scala on my tiny home machine. Hope it isn't that... And the winner is ... Fabian, who pointed out that I can't have a space between the _ and the =. I thought out why this should be and then it occurred to me: The name of the setter for y is not y_, it is y_= ! Observe: class Y { var y = 0 } var m = new Y() m.y_=(3) m.y res1: Int = 3 m.y_= error: missing arguments for method y_= in class Y; follow this method with `_` if you want to treat it as a partially applied function m.y_= ^ m.y_=_ res2: (Int) => Unit = def four(f : Int => Unit) = f(4) four(m.y_=) m.y res3: Int = 4 Another successful day on StackExchange.

    Read the article

  • Accessing Instance Variables from NSTimer selector

    - by Timbo
    Firstly newbie question: What's the difference between a selector and a method? Secondly newbie question (who would have thought): I need to loop some code based on instance variables and pause between loops until some condition (of course based on instance variables) is met. I've looked at sleep, I've looked at NSThread. In both discussions working through those options many asked why don't I use NSTimer, so here I am. Ok so it's simple enough to get a method (selector? ) to fire on a schedule. Problem I have is that I don't know how to see instance variables I've set up outside the timer from within the code NSTimer fires. I need to see those variables from the NSTimer selector code as I 1) will be updating their values and 2) will set labels based on those values. Here's some code that shows the concept… eventually I'd invalidate the timers based on myVariable too, however I've excluded that for code clarity. MyClass *aMyClassInstance = [MyClass new]; [aMyClassInstance setMyVariable:0]; [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(doStuff) userInfo:nil repeats:YES]; [NSTimer scheduledTimerWithTimeInterval:5.0 target:self selector:@selector(doSomeOtherStuff) userInfo:nil repeats:YES]; - (void) doStuff { [aMyClassInstance setMyVariable:11]; // don't actually have access to set aMyClassInstance.myVariable [self updateSomeUILabel:[NSNumber numberWithInt:aMyClassInstance.myVariable]]; // don't actually have access to aMyClassInstance.myVariable } - (void) doSomeOtherStuff { [aMyClassInstance setMyVariable:22]; // don't actually have access to set aMyClassInstance.myVariable [self updateSomeUILabel:[NSNumber numberWithInt:aMyClassInstance.myVariable]]; // don't actually have access to aMyClassInstance.myVariable } - (void) updateSomeUILabel:(NSNumber *)arg{ int value = [arg intValue]; someUILabel.text = [NSString stringWithFormat:@"myVariable = %d", value]; // Updates the UI with new instance variable values }

    Read the article

  • C++: inheritance problem

    - by Helltone
    It's quite hard to explain what I'm trying to do, I'll try: Imagine a base class A which contains some variables, and a set of classes deriving from A which all implement some method bool test() that operates on the variables inherited from A. class A { protected: int somevar; // ... }; class B : public A { public: bool test() { return (somevar == 42); } }; class C : public A { public: bool test() { return (somevar > 23); } }; // ... more classes deriving from A Now I have an instance of class A and I have set the value of somevar. int main(int, char* []) { A a; a.somevar = 42; Now, I need some kind of container that allows me to iterate over the elements i of this container, calling i::test() in the context of a... that is: std::vector<...> vec; // push B and C into vec, this is pseudo-code vec.push_back(&B); vec.push_back(&C); bool ret = true; for(i = vec.begin(); i != vec.end(); ++i) { // call B::test(), C::test(), setting *this to a ret &= ( a .* (&(*i)::test) )(); } return ret; } How can I do this? I've tried two methods: forcing a cast from B::* to A::*, adapting a pointer to call a method of a type on an object of a different type (works, but seems to be bad); using std::bind + the solution above, ugly hack; changing the signature of bool test() so that it takes an argument of type const A& instead of inheriting from A, I don't really like this solution because somevar must be public.

    Read the article

  • Array of Arrays - writing to File problem

    - by iFloh
    Hi, and again my array of arrays ... I try to improve my app performance by buffering arrays on file for later reuse. I have an NSMutableArray that contains about 30 NSMutableArrays with NSNumber, NSDate and NSString Objects. I try to write the file using this call: bool result = [myArray writeToFile:[fileMethods getFullPath:[NSString stringWithFormat:@"iEts%@.arr", [aDate shortDateString]]] atomically:NO]; = result = FALSE. The Path method is: + (NSString *) getFullPath:(NSString *)forFileName { NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; return [documentsDirectory stringByAppendingPathComponent:forFileName]; } and the aDate call returns a shortDateString with ddMMyy. The NSLog NSLog(@"%@", [fileMethods getFullPath:[NSString stringWithFormat:@"iEts%@.arr", [aDate shortDateString]]]); on the path generation returns: /Users/me/Library/Application Support/iPhone Simulator/User/Applications/86729620-EC1D-4C10-A799-0C638BB27933/Documents/iEts010510.arr FURTHER: It must have something to do with the Array of Arrays, since I also write 3 further simple arrays (containing NSStrings) that all succeed. The Array of Arrays gets generated using the addObject method Any ideas what could cause the trouble?

    Read the article

  • iPhone SDK: problem managing orientation with multiple view controllers.

    - by Tom
    I'm trying to build an iPhone application that has two subviews in the main window. Each view has its own UIViewController subclass associated with it. Also, within each controller's implementation, I've added the following method: -(BOOL)shouldAutorotateToInterfaceOrientation: (UIInterfaceOrientation)interfaceOrientation { return YES; } Thus, I would expect both of the views to respond to changes in orientation. However, this is not the case. Only the first view added to the app's main window responds to orientation. (If I swap the order the views are added, then only the other view responds. In other words, either will work--but only one at a time.) Why is this? Is it not possible to handle the orientation changes of more than one view? Thanks! EDIT: Someone else had this question, so I'm copying my solution here: I was able to address this issue by providing a root view and a root view controller with the method "shouldAutoRotate..." and adding my other views as subviews to the root view. The subviews inherit the auto-rotating behavior, and their associated view controllers shouldn't need to override "shouldAutoRotate..."

    Read the article

< Previous Page | 525 526 527 528 529 530 531 532 533 534 535 536  | Next Page >