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  • iPhone NSTimer OpenGL problem

    - by Toby Wilson
    I've got a problem that only seems to occur on the device, not in the simulator. My app's animation is started and stopped using these methods: NSTimer* animationTimer; -(void)startAnimation { if(animationTimer = nil) animationTimer = [NSTimer scheduledTimerWithTimeInterval:1.0f/60.0f target:self selector:@selector(drawView) userInfo:nil repeats:YES]; } -(void)stopAnimation { [animationTimer invalidate]; animationTimer = nil; } In the simulator this works fine and drawView starts being called at 60fps. On the device (testing on iPod Touch), the scheduleTimerWithTimeInterval method doesn't seem to work. Furthermore, [animationTimer invalidate] causes EXC_BAD_ACCESS. I've spotted an obvious but minor flaw; adding if(animationTimer != nil) to the stopAnimation method will prevent the crash, but doesn't solve the problem of the animation timer not being properly initialised. Edit: The above doesn't prevent a crash. animationTimer != nil yet calling invalidate causes EXC_BAD_ACCESS. Should also add, this problem doesn't occur all the time on the device. Maybe 40% of the time.

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  • How do I initialize attributes when I instantiate objects in Rails?

    - by nfm
    Clients have many Invoices. Invoices have a number attribute that I want to initialize by incrementing the client's previous invoice number. For example: @client = Client.find(1) @client.last_invoice_number > 14 @invoice = @client.invoices.build @invoice.number > 15 I want to get this functionality into my Invoice model, but I'm not sure how to. Here's what I'm imagining the code to be like: class Invoice < ActiveRecord::Base ... def initialize(attributes = {}) client = Client.find(attributes[:client_id]) attributes[:number] = client.last_invoice_number + 1 client.update_attributes(:last_invoice_number => client.last_invoice_number + 1) end end However, attributes[:client_id] isn't set when I call @client.invoices.build. How and when is the invoice's client_id initialized, and when can I use it to initialize the invoice's number? Can I get this logic into the model, or will I have to put it in the controller?

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  • BPEL, initialize variable and repeating onAlarm eventHandler

    - by Michael
    I have a little problem I can't solve so far. In BPEL I want to create an onAlarm eventHandler which fires immediatly (i.e. the "for" element is set to 'PT0S') and repeats every 2 seconds. This eventHandler shall contain a counter which increments every time the alarm fires. The question is: How to initialize the counter? If the variable will be initialized within the onAlarm scope the value would not increment anymore. In the "normal" control flow the value also cannot be initialized, because it is not defined if the process or the onAlarm scope runs first. So I would get every now and then an uninitializedVariable exception. My solution would be to not initialize the variable neither in the process scope nor in the onAlarm scope, but create a faultHandler wherein the variable will be initialized and afterwards the onAlarm flow will be executed. Problem is every uninitializedVariable execution will be caught now by this faultHandler and there may be another too. So is there another possibility to deal with this problem or can I somehow find out which variable wasn't initialized properly so the faultHandler can get two control flows? The solution should work on every BPEL engine. Thanks, Michael

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  • Android AES and init vector

    - by Donald_W
    I have an issue with AES encryptio and decryption: I can change my IV entirely and still I'm able to decode my data. public static final byte[] IV = { 65, 1, 2, 23, 4, 5, 6, 7, 32, 21, 10, 11, 12, 13, 84, 45 }; public static final byte[] IV2 = { 65, 1, 2, 23, 45, 54, 61, 81, 32, 21, 10, 121, 12, 13, 84, 45 }; public static final byte[] KEY = { 0, 42, 2, 54, 4, 45, 6, 7, 65, 9, 54, 11, 12, 13, 60, 15 }; public static final byte[] KEY2 = { 0, 42, 2, 54, 43, 45, 16, 17, 65, 9, 54, 11, 12, 13, 60, 15 }; //public static final int BITS = 256; public static void test() { try { // encryption Cipher c = Cipher.getInstance("AES"); SecretKeySpec keySpec = new SecretKeySpec(KEY, "AES"); c.init(Cipher.ENCRYPT_MODE, keySpec, new IvParameterSpec(IV)); String s = "Secret message"; byte[] data = s.getBytes(); byte[] encrypted = c.doFinal(data); String encryptedStr = ""; for (int i = 0; i < encrypted.length; i++) encryptedStr += (char) encrypted[i]; //decryoption Cipher d_c = Cipher.getInstance("AES"); SecretKeySpec d_keySpec = new SecretKeySpec(KEY, "AES"); d_c.init(Cipher.DECRYPT_MODE, d_keySpec, new IvParameterSpec(IV2)); byte[] decrypted = d_c.doFinal(encrypted); String decryptedStr = ""; for (int i = 0; i < decrypted.length; i++) decryptedStr += (char) decrypted[i]; Log.d("", decryptedStr); } catch (Exception ex) { Log.d("", ex.getMessage()); } } Any ideas what I'm doing wrong? How can I get 256 bit AES encryption (only change key to 32-byte long array?) Encryption is a new topic for me so please for newbie friendly answers.

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  • Initialisation of Objects Syntax question

    - by Brock Woolf
    When I initialise a struct in C (Node is the struct): struct Node { /* Non-Relevant code */ }; This works: Node *rootNode = new Node(); but so does this: Node *rootNode = new Node; Is there a difference, and what is the difference between using () or not using the brackets? Just off memory, I think the same applies above for C++ object initialisations. What is happening here?

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  • Why a variable is seen in the loop and is not seen outside the loop?

    - by Roman
    I have the following code: String serviceType; ServiceBrowser tmpBrowser; for (String playerName: players) { serviceType = "_" + playerName + "._tcp"; tmpBrowser = BrowsersGenerator.getBrowser(serviceType); tmpBrowser.browse(); System.out.println(tmpBrowser.getStatus()); } System.out.println(tmpBrowser.getStatus()); The compiler complains about the last line. It writes "variable tmpBrowser might not been initialized". If I comment the last line the compile does not complain.

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  • Java init method

    - by Johan Sjöberg
    What's a good way to make sure an init method is invoked in java? The alternatives I see are Don't test it, let the method fail by itself, likely by a NullPointerException Test if method was initialized or throw public void foo() { if (!inited) { throw new IllegalArgumentException("not initalized"); } ... } Delagate public void foo() { if (!inited) { throw new IllegalArgumentException("not initalized"); } fooInternal(); } private void fooInternal(){ ... }; Always init, and make init a noop otherwise public void foo() { init(); ... } public void init() { if(!inited) { ... } } Silently init public void foo() { if (!inited) { init(); } ... } Most of these approaches are very verbose and decreases overall readability.

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  • how to init and malloc array to pointer on C

    - by DoronS
    Hi all, looks like a memory leak when i try to initializing an array of pointers, this my code: void initLabelTable(){ register int i; hashNode** hp; labelHashTable = (hashNode**) malloc(HASHSIZE*sizeof(hashNode*)); hp = labelHashTable; for(i=0; i<HASHSIZE; i++) { *(hp+i) = NULL; } } any idea?

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  • How to make an AJAX call immediately on document loading

    - by Ankur
    I want to execute an ajax call as soon as a document is loaded. What I am doing is loading a string that contains data that I will use for an autocomplete feature. This is what I have done, but it is not calling the servlet. I have removed the calls to the various JS scripts to make it clearer. I have done several similar AJAX calls in my code but usually triggered by a click event, I am not sure what the syntax for doing it as soon as the document loads, but I thought this would be it (but it's not): <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <script type="text/javascript"> $(document).ready(function(){ $.ajax({ type: "GET", url: "AutoComplete", dataType: 'json', data: queryString, success: function(data) { var dataArray = data; alert(dataArray); } }); $("#example").autocomplete(dataArray); }); </script> <title></title> </head> <body> API Reference: <form><input id="example"> (try "C" or "E")</form> </body> </html>

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  • Is it safe to call a function to intialize a class in a ctor list?

    - by Michael Dorgan
    I have Angle class that I want initialized to a random value. The Angle constructor can accept an int from a random() function. Is it safe to place this call in the ctor list: foo::foo() : Angle(random(0xFFFF)) {...} or do I have to do it in the body of the constructor? foo::foo() { Angle = Angle(random(0xFFFF)); ...} If it matters, the foo class is derived from another class and does have virtual methods. In addition, no exception handling is allowed in our app.

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  • How are Flash library symbols constructed? Why are width/height already available in constructor?

    - by Triynko
    Suppose I draw a square on the stage, convert it to a symbol, export it for ActionScript with a classname of "MySquare" (and of course a base class of MovieClip). How is it that in the MySquare constructor, the width and height of this MovieClip are already available? In fact, any named instances in the clip are also available. I'm confused about how the Flash player seems to be able to pre-construct my movie clip by populating its properties and child clips before my constructor for the class ever runs. I thought that it would have to first construct the clip, calling my constructor code, and then construct and add any children, but obviously the player is doing something special for clips designed in the Flash authoring environment.

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  • Constructor within a constructor

    - by Chiramisu
    Is this a bad idea? Does calling a generic private constructor within a public constructor create multiple instances, or is this a valid way of initializing class variables? Private Class MyClass Dim _msg As String Sub New(ByVal name As String) Me.New() 'Do stuff End Sub Sub New(ByVal name As String, ByVal age As Integer) Me.New() 'Do stuff End Sub Private Sub New() 'Initializer constructor Me._msg = "Hello StackOverflow" 'Initialize other variables End Sub End Class

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  • Doubt about instance creation by using Spring framework ???

    - by Arthur Ronald F D Garcia
    Here goes a command object which needs to be populated from a Spring form public class Person { private String name; private Integer age; /** * on-demand initialized */ private Address address; // getter's and setter's } And Address public class Address { private String street; // getter's and setter's } Now suppose the following MultiActionController @Component public class PersonController extends MultiActionController { @Autowired @Qualifier("personRepository") private Repository<Person, Integer> personRepository; /** * mapped To /person/add */ public ModelAndView add(HttpServletRequest request, HttpServletResponse response, Person person) throws Exception { personRepository.add(person); return new ModelAndView("redirect:/home.htm"); } } Because Address attribute of Person needs to be initialized on-demand, i need to override newCommandObject to create an instance of Person to initiaze address property. Otherwise, i will get NullPointerException @Component public class PersonController extends MultiActionController { /** * code as shown above */ @Override public Object newCommandObject(Class clazz) thorws Exception { if(clazz.isAssignableFrom(Person.class)) { Person person = new Person(); person.setAddress(new Address()); return person; } } } Ok, Expert Spring MVC and Web Flow says Options for alternate object creation include pulling an instance from a BeanFactory or using method injection to transparently return a new instance. First option pulling an instance from a BeanFactory can be written as @Override public Object newCommandObject(Class clazz) thorws Exception { /** * Will retrieve a prototype instance from ApplicationContext whose name matchs its clazz.getSimpleName() */ getApplicationContext().getBean(clazz.getSimpleName()); } But what does he want to say by using method injection to transparently return a new instance ??? Can you show how i implement what he said ??? ATT: I know this funcionality can be filled by a SimpleFormController instead of MultiActionController. But it is shown just as an example, nothing else

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  • Variable might not have been initialized error

    - by David
    When i try to compile this: public static Rand searchCount (int[] x) { int a ; int b ; ... for (int l= 0; l<x.length; l++) { if (x[l] == 0) a++ ; else if (x[l] == 1) b++ ; } ... } I get these errors: Rand.java:72: variable a might not have been initialized a++ ; ^ Rand.java:74: variable b might not have been initialized b++ ; ^ 2 errors it seems to me that i initialized them at the top of the method. Whats going wrong?

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  • Setting default values for inherited property without using accessor in Objective-C?

    - by Ben Stock
    I always see people debating whether or not to use a property's setter in the -init method. I don't know enough about the Objective-C language yet to have an opinion one way or the other. With that said, lately I've been sticking to ivars exclusively. It seems cleaner in a way. I don't know. I digress. Anyway, here's my problem … Say we have a class called Dude with an interface that looks like this: @interface Dude : NSObject { @private NSUInteger _numberOfGirlfriends; } @property (nonatomic, assign) NSUInteger numberOfGirlfriends; @end And an implementation that looks like this: @implementation Dude - (instancetype)init { self = [super init]; if (self) { _numberOfGirlfriends = 0; } } @end Now let's say I want to extend Dude. My subclass will be called Playa. And since a playa should have mad girlfriends, when Playa gets initialized, I don't want him to start with 0; I want him to have 10. Here's Playa.m: @implementation Playa - (instancetype)init { self = [super init]; if (self) { // Attempting to set the ivar directly will result in the compiler saying, // "Instance variable `_numberOfGirlfriends` is private." // _numberOfGirlfriends = 10; <- Can't do this. // Thus, the only way to set it is with the mutator: self.numberOfGirlfriends = 10; // Or: [self setNumberOfGirlfriends:10]; } } @end So what's a Objective-C newcomer to do? Well, I mean, there's only one thing I can do, and that's set the property. Unless there's something I'm missing. Any ideas, suggestions, tips, or tricks? Sidenote: The other thing that bugs me about setting the ivar directly — and what a lot of ivar-proponents say is a "plus" — is that there are no KVC notifications. A lot of times, I want the KVC magic to happen. 50% of my setters end in [self setNeedsDisplay:YES], so without the notification, my UI doesn't update unless I remember to manually add -setNeedsDisplay. That's a bad example, but the point stands. I utilize KVC all over the place, so without notifications, things can act wonky. Anyway, any info is much appreciated. Thanks!

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  • How to Initialise a static Map in Java

    - by fahdshariff
    How would you initialise a static Map in Java? Method one: Static initialiser Method two: instance initialiser (anonymous subclass) or some other method? What are the pros and cons of each? Here is an example illustrating two methods: import java.util.HashMap; import java.util.Map; public class Test { private static final Map<Integer, String> myMap = new HashMap<Integer, String>(); static { myMap.put(1, "one"); myMap.put(2, "two"); } private static final Map<Integer, String> myMap2 = new HashMap<Integer, String>(){ { put(1, "one"); put(2, "two"); } }; }

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  • Copying pointers in C++

    - by tunnuz
    Hello, I have a class A containing two pointers to objects of another class B. I want to initialize one pointer or the other depending on which one is passed to init(), which also takes other parameters. My situation is thus the following: class A { public: A(); init(int parameter, int otherParameter, B* toBeInitialized); protected: B* myB; B* myOtherB; }; Now my point is that I want to call init() as: init(640, 480, this->myB); or init(640, 480, this->myOtherB); Now, my init is implemented as: void init( int parameter, int otherParameter, B* toBeInitialized ) { toBeInitialized = someConstructorFunction(parameter, otherParameter); } The problem is that the two pointers are not initialized, I suspect that toBeInitialized is overwritten, but the original parameter is not modified. I am doing something wrong? Should I use references to pointers? Thank you Tommaso

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  • C static variables and intialization

    - by yCalleecharan
    Hi, If I have a global static variable x like in this code #include <stdio.h> #include <stdio.h> static int x; int main(void) { DO SOMETHING WITH x HERE x++; } What will be difference if I opted to initialize x to a value first say as in static int x = 0; before entering "main"? In my first case where I didn't assign a value to x, does the compiler implicitly know that x is to be set to zero as it's a static variable? I heard that we can do this with static variables. Thanks a lot...

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  • Initializing Disqus comments in hidden element causes issue in FF 14.0.1

    - by Bazze
    This issue appears only in Firefox 14.0.1 (well I couldn't reproduce it in any other browser). If you put the code for Disqus comments inside an element that is hidden and wait until everything is fully loaded and then display the element using JavaScript, the comment box nor comments will show up. However if you resize the window, it'll show up immediately. It's working fine in latest version of Google Chrome and Safari though. What's causing this and how to fix it? Sample code to reproduce: <div id="test" style="display:none;"> <div id="disqus_thread"></div> <script type="text/javascript"> /* * * CONFIGURATION VARIABLES: EDIT BEFORE PASTING INTO YOUR WEBPAGE * * */ var disqus_shortname = 'onlinefunctions'; // required: replace example with your forum shortname /* * * DON'T EDIT BELOW THIS LINE * * */ (function() { var dsq = document.createElement('script'); dsq.type = 'text/javascript'; dsq.async = true; dsq.src = 'http://' + disqus_shortname + '.disqus.com/embed.js'; (document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(dsq); })(); </script> <noscript>Please enable JavaScript to view the <a href="http://disqus.com/?ref_noscript">comments powered by Disqus.</a></noscript> <a href="http://disqus.com" class="dsq-brlink">comments powered by <span class="logo-disqus">Disqus</span></a> </div> <a href="#" onclick="document.getElementById('test').style.display = 'block'">show</a> I could post a link to a live example but I'm not sure about the policy of posting links here on Stack Overflow.

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