Search Results

Search found 13788 results on 552 pages for 'instance'.

Page 127/552 | < Previous Page | 123 124 125 126 127 128 129 130 131 132 133 134  | Next Page >

  • Can I have a type that's both, covariant and contravariant, i.e. fully fungible/changeable with sub

    - by Water Cooler v2
    Just a stupid question. I could try it out in 2 minutes, really. It's just that I have 1 GB RAM and have already got 2 instances of VS 2010 open on my desktop, with an instance of VS 2005, too. Opening another instance of VS 2010 would be an over kill. Can I have a type (for now forgetting its semantics) that can be covariant as well as contravariant? For e.g. public interface Foo<in out T> { void DoFooWith(T arg); } Off to Eric Lippert's blog for the meat and potatoes of variance in C# 4.0 as there's little else anywhere that covers adequate ground on the subject.

    Read the article

  • Reference variable to an object instantiated/initialized in another class in Java

    - by Alex
    The reason I'm asking is because I'm getting NullPointerException. I now this is very easy but I'm pretty new programming and find this a bit confusing. So say I have initialized an object in a class and want to access that same object from another class. Like now for instance I'm working on a small Chess game, in my model Game class I have an instance of Board, an object. Board, in turn, has an array of Squares. Square[][]. Game has board, board has Square[][]. Now if I want to access the Square[][] through the object board (in Game) of type Board. Do I just declare a variable with the same name and type or do I have to initialize it again? Board board OR Board board = new Board(); Note, I have already initialized board in the class Game so if I do it again, won't they be two totally different Board objects?

    Read the article

  • StructureMap singleton behavior not working

    - by user137348
    My code is public static class ContainerBootstrapper { public static void BootstrapStructureMap() { ObjectFactory.Initialize(x => x .ForRequestedType<ValueHolder>() .CacheBy(InstanceScope.Singleton) .TheDefaultIsConcreteType<ValueHolder>()); } } Initialization code (its a windows service) static class Program { static void Main() { ServiceBase[] ServicesToRun; ServicesToRun = new ServiceBase[] { new AppServer() }; ServiceBase.Run(ServicesToRun); ContainerBootstrapper.BootstrapStructureMap(); } } And then I call an instance like this: var valueHolder = ObjectFactory.GetInstance<ValueHolder>(); But I get everytime an new instance not the one used before.

    Read the article

  • Building an array of arrays

    - by iFloh
    I am trying to get the following loop working to fill an array of arrays: while (condition) { [itemsArray fillFromDB]; if (! [checkArray containsObject:checkFlag]) { // Add existing itemsArray to myArray if (itemsArray.count) { // add the itemsArray to myArray and create a new instance of itemsArray [myArray addObject:itemsArray]; [itemsArray release]; NSMutableArray *itemsArray = [[NSMutableArray alloc] init]; } [itemsArray addObject:myObject]; [checkArray addObject:checkFlag]; } else { [itemsArray addObject:tmpEvent]; } } However I try to shape this loop it falls over the release of itemsArray when I use release (as above), the array does not re-initialise as a new instance with alloc. Whilst expecting emptyness, the next Object is added to the old array. when I use removeAllObjects, my Array is emptied and so is the array attached to myArray. Where am I going in the wrong direction?

    Read the article

  • Change list link to foreign key change page

    - by Adam
    When viewing the admin change list for a model, is it possible to make the columns that correspond to foreign keys links to their respective pages? A simple example is I have a Foo object which contains Bar as a foreign key. If I'm viewing the admin change list for Foo (and have it set to include Bar in the display_list columns), the main column would link to the Foo instance's edit page while the Bar column would link to the Boo instance's edit page. I understand I can override the template that's used, but I was curious if there was a solution that didn't require that.

    Read the article

  • Prevent Erroneous Property Assignment

    - by Gordon
    Porting android applications to iphone applications always gives me the following pattern that I accidentally create: - (void) myFunc:(id)prop { self.property = property; } Which instead should be: - (void) myFunc:(id)prop { self.property = prop; } This always causes my program to quietly break because property gets reset to its existing value rather than being set to the new value, 'prop'. I cannot name the parameter 'prop' to 'property' since the compile complains that the parameter masks the instance variables visibility. Is there a good way to avoid this situation? There are no compiler warnings. Is there a way to make xcode prevent this? I cannot see very many situations where you would set a property to the value of its underlying instance variable (maybe to trigger a KVO binding?), but I don't see myself doing that in majority of cases. I understand the above code is synthetic and should be done with @synthesize, but I am just using it as a simplified example to illustrate my point.

    Read the article

  • NSTableview weird error

    - by Matt S.
    I followed the guide here, but for some reason, the table view shows this in the console when I attempt to scroll through it: -[NSCFString objectAtIndex:]: unrecognized selector sent to instance 0x100227710

    Read the article

  • How can one use multi threading in php applications

    - by Steve Obbayi
    Is there a realistic way of implementing a multi-threaded model in php whether truly or just simulating it. Some time back it was suggested that you can force the operating system to load another instance of the php executable and handle other simultaneous processes. The problem with this is that when the php code finished executing the php instance remains in memory because there is no way to kill it from within php. so if you are simulating several threads you can imagine whats going to happen. So am still looking for a way multi-threading can be done or simulated effectively from within php. Any ideas?

    Read the article

  • 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 =/

    Read the article

  • TableView problem with Tab Bar!?!?!

    - by Daniel Granger
    I created a tableView which worked fine in a single view app but as soon as I changed the view controller for a Tab Bar Controller and tapped the tab for the view with the table view in I suddenly get this! What has gone wrong? [Session started at 2010-03-28 15:30:15 +0100.] 2010-03-28 15:30:17.763 LogbookTable[13473:207] *** -[UIViewController tableView:numberOfRowsInSection:]: unrecognized selector sent to instance 0x3b14d10 2010-03-28 15:30:17.765 LogbookTable[13473:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[UIViewController tableView:numberOfRowsInSection:]: unrecognized selector sent to instance 0x3b14d10' 2010-03-28 15:30:17.766 LogbookTable[13473:207] Stack: ( 29303899, 2465178889, 29685819, 29255286, 29107906, 4372518, 4379894, 4378891, 3095430, 3035941, 3077376, 3065931, 55820976, 55820399, 55818438, 55817530, 2739877, 2763572, 2745983, 2773089, 37399897, 29088640, 29084744, 2739733, 2777007, 10496, 10350 )

    Read the article

  • Does every browser open a new HTTPSession

    - by user496934
    I am working on a webbased application which has JSP and servlets. In my application, I am binding some objects to sessions like the following code -- HttpSession session = p_req.getSession(); session.setAttribute(DOWNLOAD_With_WARNINGS, downloadMap); Later I am retrieving them using session.getAttribute. I would like to know if every time I open a new browser does it open a new HTTP session. Because , if I do a setAttribute with some value in one browser instance, that change is visible when I do a getAttribute using the other browser instance.

    Read the article

  • Release variable and assigning it again

    - by David Gonrab
    What is the preferred and/or correct way to release an NSMutableString (or any other class for that matter) instance and assign a new instance to the same variable in Objective-C on the iPhone? Currently I'm using [current release]; current = [NSMutableString new]; but I understand that the following works, too. NSMutableString *new = [NSMutableString new]; [current release]; current = [new retain]; [new release]; The variable current is declared in the interface definition of my class and gets released in dealloc.

    Read the article

  • How to choose programaticaly the column to be querried by Linq using PropertyInfo???

    - by Richard77
    Hello, I would like to control how linq querries my database programaticaly. For instance, I'd like to querry the column X, column Y, or column Z, depending on some conditions. First of all, I've created an array of all the properties inside my class called myPropertyInfo. Type MyType = (typeOf(MyClass)); PropertyInfo[] myPropertyInfo = myType.GetProperties( BindingFlags.Public|BindingFlags.Instance); the myPropertyInfo array allows me to access each property details (Name, propertyType, etc) through the index*[i]* Now, how can I use the above information to control how linq querries my DB? Here's a sample of a querry I'd like to exploit. var myVar = from tp in db.MyClass select tp.{expression}; Expression using myPropertyInfo[i] to choose which property(column) to querry. I'm not sure if that's the way of doing it, but if there's another way to do so, I'll be glad to learn. Thanks for helping.

    Read the article

  • How to instantiate a Singleton multiple times?

    - by Sebi
    I need a singleton in my code. I implemented it in Java and it works well. The reason I did it, is to ensure that in a mulitple environment, there is only one instance of this class. But now I want to test my Singleton object locally with a Unit test. For this reason I need to simulate another instance of this Singleton (the object that would be from another device). So is there a possiblity to instantiate a Singleton a second time for testing purpose or do I have to mock it? I'm not sure, but I think it could be possible by using a different class loader?

    Read the article

  • Making a Wrapper class for ActiveMQ

    - by DarthVader
    I want to make a Wrapper class for ActiveMQ which will have only send and get functions. I want to wrap them in a static class. Users can use this client and send, get messages to the activemq instance. I want this process to be transparent. There are two classes in this link My only handicap is, i need to this in c++ and not sure where to start. I havent used c++ for ages and now not sure how I can create this wrapper class. I m giving it a try as follows: // .h file #include <stdlib.h> #include <iostream> using namespace std; class ActiveMQWrapper { public: static void send(std::string message); static std::string get(); }; // .cpp file #include<string> #include<iostream> #include "ActiveMQWrapper.h" void ActiveMQWrapper::send(std::string message){ std::cout<<message; } std::string ActiveMQWrapper::get(){ return "test"; } // test file #include <string> #include <iostream> #include "ActiveMQWrapper.h" int main() { std::string foo ="test"; ActiveMQWrapper::send(foo); std::cout<<ActiveMQWrapper::get(); return 1; } When I added the following to .h file, hell breaks loose. Do you think I should seperate this impl to a factory and initialize and instance and return to the wrapper above? How do i deal with all the dependencies? private: Connection* connection; Session* session; Destination* destination; MessageProducer* producer; int numMessages; bool useTopic; bool sessionTransacted; std::string brokerURI; and the header files, i get several messages as errors, which complains about the path. How can i get this correct? I eventually want to build a Factory, get an instance and send or get the messages to the queue. is there a code sample i can look into to get this right? essential i want to use the functionality of only this producer and consumer. Edit: I understand there is no such thing as static class in C++ . This is my reference.

    Read the article

  • Messaging in local network with .NET

    - by Richard
    Hi All, I need to implement some form of communication mechanism in my application, to send notifications/messages from one application instance to all the others. This is a normal scenario where someone adds and item or deletes and item and you want to notify other users that this has happened. The application runs on the client and connects to a database on the local network. So its not like all clients access a server instance of the application. So from what I know I could use MessageQueues or some form of Database polling where I have a table that stores all the messages (not ideal). Issue is I need to implement this very quickly, so sadly can't go very complex but need the quickest easiest solution. thanks for the help!

    Read the article

  • Rails attribute alias

    - by Dr1Ku
    Hi, I was just wondering if it's possible to "rename" an association in Rails. Let's assume : # An ActiveRecord Class named SomeModelASubModel (some_model_a_sub_model.rb) class SomeModelASubModel < ActiveRecord::Base has_many :some_model_a_sub_model_items end # An ActiveRecord Class named SomeModelASubModelItem (some_model_a_sub_model_item.rb) class SomeModelASubModelItem < ActiveRecord::Base belongs_to :some_model_a_sub_model end At this point, calling some_model.items, where some_model is an instance of the SomeModelASubModel Class would trigger an undefined method error. What is the best practice for making this happen though, e.g. : # With a method_alias or something, would it be possible to : some_model = SomeModelASubModel.first # for instance items = some_model.items # For the reason stated, this doesn't work, one has to call : items = some_model.some_model_a_sub_model_items Is such a shorthand possible ? Thank you in advance !

    Read the article

  • Is it possible to specify the name of the Index property to use for lists in a fluent nhibernate con

    - by Teevus
    When mapping a HasMany or HasManyToMany in fluent nhibernate, you can specify the column name to use for the list as a parameter to the AsList() method as follows: HasMany(c => c.Customers) .AsList(c => c.Column("PositionIndex")); I would prefer to be able to set this using a Fluent NHibernate convention (either a pre-existing one, or a custom one), especially since the default name appears to be "Index" which is a reserved word in MSSQL. I've tried using a custom convention implementing IHasManyConvention, but the instance parameter does not seem to contain the information about whether its a list, a bag, or a set, and also does not contain the column details for the index column. public void Apply(IOneToManyCollectionInstance instance) { } Any ideas?

    Read the article

  • Regarding C typedef struct

    - by Bruce Duncan
    I have multiple instances of typedef struct box so box box1, box box2 etc. The members of the struct are length, width, height etc. typedef struct { int width; int height; } box; box box1; box box2; How can I create a function that operates on all the width members of each box instance? My confusion is how do I pass a pointer to a typedef struct member that works across all instances of box. I know how to pass a pointer to a specific instance member like box1.width but how to pass .width and then do box1.width=value; box2.width=value; box3.width=value; within the function?

    Read the article

  • C++ Singleton design pattern

    - by Artem Barger
    Recently I've bumped into a realization/implementation of the Singleton design pattern for C++. It has looked like this (I have adopted it from the real life example): // a lot of methods are omitted here class Singleton { public: static Singleton* getInstance( ); ~Singleton( ); private: Singleton( ); static Singleton* instance; }; From this declaration I can deduce that the instance field is initiated on the heap. That means there is a memory allocation. What is completely unclear for me is when exactly the memory is going to be deallocated? Or is there a bug and memory leak? It seems like there is a problem in the implementation. My main question is, how do I implement it in the right way?

    Read the article

  • Shared data in an ASP.NET application

    - by Barguast
    I have a basic ASP.NET application which is used to request data which is stored on disk. This is loaded from files and sent as the response. I want to be able to store the data loaded from these files in memory to reduce the number of reads from disk. All of the requests will be asking for the same data, so it makes sense to have a single cache of in-memory data which is accessible to all requests. What is the best way to create a single accessible object instance which I can use to store and access this cached data? I've looked into HttpApplication, but apparently a new instance of this is created for parallel requests and so it doesn't fit my needs.

    Read the article

  • Java: Superclass to construct a subclass on certain conditions, possible?

    - by ramihope
    I have this condition public class A { public action() { System.out.println("Action done in A"); } } public class B extends A { public action() { System.out.println("Action done in B"); } } when I create an instance of B, the action will do just actions in B, as it overrides the action of the superclass. the problem is that in my project, the super class A is already used too many times, and I am looking for a way that under certain conditions, when i create an instance of A it makes a check and if it is true, replace itself with B. public class A { public A() { if ([condition]) { this = new B(); } } public action() { System.out.println("Action done in A"); } } A a = new A(); a.action(); // expect to see "Action done in B"... is this possible in some way?

    Read the article

  • NSInvalidArgumentException when updating WebView from AppDelegate

    - by H.Protagonist
    I had to do an update in my WebView from the Appdelegate.m I try it like this: [self performSelectorOnMainThread:@selector(loadWebViewWithContent:) withObject:requestObj waitUntilDone:NO]; The loadWebViewWithContent Method works great from ViewController.m, but not from the Appdelegate. I allready wrote this in my Appdelegate.h: -(void)loadWebViewWithContent:(NSURLRequest *)requestObj; Whats wrong? Please help me. I´m still a big Noob in IOS. Error: -[AppDelegate loadWebViewWithContent]: unrecognized selector sent to instance 0x1f86a5e0*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[AppDelegate loadWebViewWithContent]: unrecognized selector sent to instance 0x1f86a5e0'

    Read the article

  • Call function from object instantiated in one class in another

    - by Dk43
    I have two classes, both of which need to be able to call the same instance of entitymanager class Engine { EntityManager::Entitymanager EManager; } And I need to add an object to a vector contained by this particular instance of Engine. What I want to do is be able to add a bullet spawned by the player to the vector that contains all my entities. class Player : Entity { void SpawnBullet() {Engine::EManager.Add(BULLET);} } The above returns this error: error: object missing in reference to ‘Engine::EManager’ How do I resolve this? Any help or pointers in the right direction would be much appreciated!

    Read the article

  • Running script constantly in background: daemon, lock file with crontab, or simply loop?

    - by Mauritz Hansen
    I have a Perl script that queries a database for a list of files to process processes the files and then exits Upon startup this script creates a file (let's say script.lock), and upon exit it removes this file. I have a crontab entry that runs this script every minute. If the lockfile exists then the script exits, assuming that another instance of itself is running. The above process works fine but I am not very happy with the robustness of this approach. Specifically, if for some reason the script exits prematurely and the lockfile is not removed then a new instance will not execute properly. I would appreciate some advice on the following: Is using the lock file a good approach or is there a better/more robust way to do this? Is using crontab for this a good idea or could I better write an endless loop with sleep()? Should I use the GNU 'daemon' program or the Perl Proc::Daemon module (or some other equivalent) for this?

    Read the article

< Previous Page | 123 124 125 126 127 128 129 130 131 132 133 134  | Next Page >