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• Can I have fixed typed ArrayList in C#, just like C++?

  - by Kazoom

  I have an ArrayList which contains fixed type of objects. However everytime I need to extract an object a particular index, I need to typecast it to my user defined type from object type. Is there a way in C# to declare ArrayList of fixed types just like Java and C++, or is there a work around to avoid the typecasting everytime? Edit: I apologize I forgot mentioning that I require the datastructure to be thread-safe, which List is not. Otherwise I would have just used a normal Array. But I want to save myself from the effort of explicitly locking and unlocking while writing the array. So I thought of using ArrayList, synchronize it, but it requires typecasting every time.

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• Creating and releasing objects in the same method, while using self as delegate

  - by user200341

  In objective-c you are responsible for releasing objects you allocate, but what happens when you allocate an object in a method, assign self as the objects delegate, and then release the object. The callbacks from the newly created (and released) object fails at this point, or rather, doesn't happen. - (void)doSomething { MyObj *myObj = [[MyObj alloc] init]; myObj.delegate = self; [myObj performOperation]; [myObj release]; } - (void)callbackMethodFromMyObj:(NSString *)message { NSLog(message); } I can't release the object until the callback has occurred, and I can't avoid releasing the object in the same method that creates it (because it exists outside the scope). One way of doing it would be to pass the object along in the call-back and release it in the callback, but is this the right way to go about this?

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• Enterprise Library Validation Block - Should validation be placed on class or interface?

  - by Robert MacLean

  I am not sure where the best place to put validation (using the Enterprise Library Validation Block) is? Should it be on the class or on the interface? Things that may effect it Validation rules would not be changed in classes which inherit from the interface. Validation rules would not be changed in classes which inherit from the class. Inheritance will occur from the class in most cases - I suspect some fringe cases to inherit from the interface (but I would try and avoid it). The interface main use is for DI which will be done with the Unity block.

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• Hashing a python function to regenerate output when the function is modified

  - by Seth Johnson

  I have a python function that has a deterministic result. It takes a long time to run and generates a large output: def time_consuming_function(): # lots_of_computing_time to come up with the_result return the_result I modify time_consuming_function from time to time, but I would like to avoid having it run again while it's unchanged. [time_consuming_function only depends on functions that are immutable for the purposes considered here; i.e. it might have functions from Python libraries but not from other pieces of my code that I'd change.] The solution that suggests itself to me is to cache the output and also cache some "hash" of the function. If the hash changes, the function will have been modified, and we have to re-generate the output. Is this possible or ridiculous? Updated: based on the answers, it looks like what I want to do is to "memoize" time_consuming_function, except instead of (or in addition to) arguments passed into an invariant function, I want to account for a function that itself will change.

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• Cakephp ajax Autocomplete not working

  - by Vijay Kumbhar

  Hello All, I am using ajax autocomplete in my application, but it is not giving the output. Ajax request to the desired function goes but it is not giving back any response, it is blank. I am also using jquery but it is used for other effects. i added jquery no conflict to avoid the prototype & jquery conflicts. I have tried other ajax helper methods like obeserverfield, it is working fine & returning the proper response, but when i use autocomplete it fails Can anybody help me ..........

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• Rails Variable across all controller actions

  - by bob

  Hello, This should be a very simple rails question. I have a variable like the following. @administration = Administration.first I want this variable to be accessible through every controller action across all my controllers so for example if I have a Product controller and inside of it I have the usual CRUD actions, I want the @administration variable as defined above to be put into all the CRUD actions. (It would not be needed in destroy or create or update). I have many controllers throughout my project and I was wondering if there is an easier way than adding it manually through all of the actions that I want it in. I tried a global variable $administration = Administration.first but I run into an issue where it is not updated when I update the actual content of the Administration.first table. Also, I would like to avoid global variables. Any help would be much appreciated. Thanks! :)

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• website is very slow on IE

  - by Bhupi

  Hi, I need to know what can be the main reasons (apart from the basics like grouping CSS selectors, reducing image size, using image sprite etc.) which makes a website slow on Internet Explorer, because my website works fine on the others like FF, chrome etc. Is it the huge use of Javascript framework (ie. jQuery, extjs, prototype)? Is it because of the use of plugins based on JS framework? Should I use core javascript and remove the use of any js framework? Should I try to avoid using jQuery(document).ready()? in case of jQuery framework? Above some of the questions which I know and please answer the questions which I couldn't ask because of lesser knowledge about these. I need to make my website perform well on IE (6,7,8) also please suggest. Thanks

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• Is there a way to cause a new C++ class instance to fail, if certain conditions in the contructor ar

  - by Jim Fell

  As I understand it, when a new class is instantiated in C++, a pointer to the new class is returned, or NULL, if there is insufficient memory. I am writing a class that initializes a linked list in the constructor. If there is an error while initializing the list, I would like the class instantiator to return NULL. For example: MyClass * pRags = new MyClass; If the linked list in the MyClass constructor fails to initialize properly, I would like pRags to equal NULL. I know that I can use flags and additional checks to do this, but I would like to avoid that, if possible. Does anyone know of a way to do this? Thanks.

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• Is shortening properties names worth it?

  - by raam86

  in how to node Blog rolling with node.js and mongoDB the author mentions it's a good idea to shorten proprieties names: ....oft-reported issue with mongoDB is the size of the data on the disk... each and every record stores all the field-names .... This means that it can often be more space-efficient to have properties such as 't', or 'b' rather than 'title' or 'body', however for fear of confusion I would avoid this unless truly required! I am aware of solutions of how to do it I am more intrested in when is it truly required?

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• mysql reference result from subquery

  - by iamrohitbanga

  this is what i am doing update t1 set x=a,y=b where a and b are obtained from (select query here) i know the select query the select query returns multiple results which are the same when i use group by or distinct query execution slows down considerably a and b are forward references so mysql reports an error i want to set a equal to the value obtained in the first row and b equal to the value obtained in the first row for the respective columns, to avoid group by. i don't know how to refer to the first result from the select query. how can i achieve all this?

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• Raphael how to get last path and last circle, if i have 2 elements in the paper?

  - by 3gwebtrain

  I need to find the last path or circle in a paper, in order to perform further calculations to draw more elements, and calling 'paper.bottom' only gets the last element. Is there any way to get shapes of specific types, e.g. bottom.path, bottom.circle or traverse for the n'th child? I want to avoid using jQuery selectors, as i can't retrieve any properties from those. An example of a paper populated with shapes: var paper = Raphael('paper',500,500); var c1 = paper.circle(100,100,50) var p1 = paper.path("M10 20l70 0") var c2 = paper.circle(200,100,50)

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• Java: Reflection against casting when you know superclass

  - by Ema

  I don't know exactly how to define my doubt so please be patient if the question has already been asked. Let's say I have to dinamically instantiate an object. This object will surely be instance of a subclass of a known, immutable class A. I can obtain dinamically the specific implementation class. Would it be better to use reflection exactly as if I didn't know anything about the target class, or would it be preferrable/possible to do something like: A obj = (Class.forName("com.package.Sub-A")) new A(); where Sub-A extends A ? The purpose would be to avoid reflection overhead times... Thank you in advance.

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• How to solve this Java type safety warning? (Struts2)

  - by Nicolas Raoul

  Map session = ActionContext.getContext().getSession(); session.put("user", user); This code generates a warning: Type safety: The method put(Object, Object) belongs to the raw type Map. References to generic type Map should be parameterized. Map<String, Serializable> session = (Map<String, Serializable>)ActionContext.getContext().getSession(); session.put("user", user); This code generates a warning: Type safety: Unchecked cast from Map to Map. The getSession method belongs to Struts2 so I can't modify it. I would like to avoid using @SuppressWarnings because other warnings can be useful. I guess all Struts2 users in the world faced the same problem... is there an elegant solution?

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• C# - Why can't I enforce derived classes to have parameterless constructors?

  - by FrisbeeBen

  I am trying to do the following: public class foo<T> where T : bar, new { _t = new T(); private T _t; } public abstract class bar { public abstract void someMethod(); // Some implementation } public class baz : bar { public overide someMethod(){//Implementation} } And I am attempting to use it as follows: foo<baz> fooObject = new foo<baz>(); And I get an error explaining that 'T' must be a non-abstract type with a public parameterless constructor in order to use it as parameter 'T' in the generic type or method. I fully understand why this must be, and also understand that I could pass a pre-initialized object of type 'T' in as a constructor argument to avoid having to 'new' it, but is there any way around this? any way to enforce classes that derive from 'bar' to supply parameterless constructors?

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• Unreachable, existing variable

  - by Oden

  I'm new at as3, maybe thats the reason why i don't understand, why the setInterval causes an error. <mx:Script> <![CDATA[ import flash.utils.setInterval; import mx.controls.Alert; [Bindable] public var MyInt:int = 500; setInterval(function():void{ ++MyInt; },1000); ]]> </mx:Script> I have a label where the value of MyInt gets visible, the bind works perfect, i've tested it several ways, and i i create a button it grows the number, but if i use the setInterval function i get an error: Access of undefined property myInt. Why? What does cause this? Please explain it, so I can avoid errors like this. Thanks

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• Missing something with Entity Framework for .NET 3.5?

  - by AC

  Is it not possible to have EF create the necessary entities when I have two related tables linked with a FK in .NET3.5SP1? I see where the checkbox to support this is disabled but it is available in .NET4. I've got a DB that has only tables with relationships in it. I need to build a Silverlight app (SL4) that allows management of the data within this app. I can't use .NET4 on the server... only .NET3.5SP1 so FK relationship bit in EF4 isn't available to me. Looking to avoid building as much of the plumbing to get back to the DB from the SL4 app as possible...

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• Can a function defined in a bookmarklet be called from a page-level script?

  - by Soviut

  I have a bookmarklet that needs to open a new window/tab. In order to avoid the popup blocker, I need to call the window.open() method directly in the bookmarklet ie: at the browser-level. However, I want to keep the bookmarklet updatable by loading external Javascript files. To do this, the bookmarklet needs to append script nodes to the DOM. If i were to put window.open() code in one of these externally loaded scripts, the popup blocker would block it since its page-level. What I want to know is if I can create a wrapper function around window.open() in my bookmarklet, then call it from the externally loaded script? What is the scope and what are the permissions on a wrap such as this?

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• JPA 2.0 Eclipse Link ... Composite primary keys

  - by Parhs

  I have two entities(actually more but it doenst matter) Exam and Exam_Normals Its a oneToMany relationship... The problem is that i need a primary key for Exams_Normals PK (Exam_ID Item) Item should be 1 2 3 4 5 etc.... But cant achieve it getting errors An alternative would be to: I cound use an IDENTITY and a ManyToOne relationship at Exam_Normals but that should be like PK(Exam_Normals_ID) and a reference to Exam and an extra collumn Item to keep an order.. SO 3 collumns But to avoid the alternative tried I tried with @IdClass and got errors Tried @EmbeddedID everything nothing works Any idea??

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• How to handle dependency files in a cross-platform manner?

  - by Brian Knoblauch

  I'm working on updating an old app. It has some dependency files that live in the same directory as the app. Obviously this broke when Windows Vista came out (since it violates the API and Vista/7 now enforce that (XP didn't)). Ideally, I'd like to avoid hardcoding anything into the app for just Windows. I can live with that if I have to though. I've already been down that path with pulling the APPDATA and LOCALAPPDATA environment variables, but that doesn't help any since they just give you the current user area... I need these to live somewhere accessible for all users, and I'd like to obey the Windows API expectations that they go into the all user appdata area. Suggestions?

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• Android how do I wait until a service is actually connected?

  - by Ryan

  I have an Activity calling a Service defined in IDownloaderService.aidl: public class Downloader extends Activity { IDownloaderService downloader = null; // ... In Downloader.onCreate(Bundle) I tried to bindService Intent serviceIntent = new Intent(this, DownloaderService.class); if (bindService(serviceIntent, sc, BIND_AUTO_CREATE)) { // ... and within the ServiceConnection object sc I did this public void onServiceConnected(ComponentName name, IBinder service) { Log.w("XXX", "onServiceConnected"); downloader = IDownloaderService.Stub.asInterface(service); // ... By adding all kinds of Log.xx I found that the code after if(bindService(...)) actually goes BEFORE ServiceConnection.onServiceConnected is being called - that is, when downloader is still null - which gets me into trouble. All the samples in ApiDemos avoid this timing problem by only calling services when triggered by user actions. But what should I do to right use this service after bindService succeeds? How can I wait for ServiceConnection.onServiceConnected being called reliably?

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• Preprocessor directive to test if this is C or C++

  - by Collin

  I'm trying to find a standard macro which will test whether a header file is being compiled as C or as C++. The purpose of this is that the header may be included by either C or C++ code, and must behave slightly differently depending on which. Specifically: In C, I need this to be the code: extern size_t insert (const char*); In C++, I need this to be the code: extern "C" size_t insert (const char*); Additionally, is there a way to avoid putting #ifdef's around every declaration in the header?

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• The underlying connection was closed when using a WSDL web service

  - by joshlrogers

  I am trying to consume this WSDL service: Transit Time Service I successfully connect and get a response the first time but on subsequent calls I receive the exception: The underlying connection was closed: A connection that was expected to be kept alive was closed by the server. I overrode the GetWebRequest in the reference.cs file as such: protected override System.Net.WebRequest GetWebRequest(Uri uri) { HttpWebRequest webRequest = (HttpWebRequest)base.GetWebRequest(uri); webRequest.KeepAlive = false; return webRequest; } This hasn't yielded any improvement. I am at a loss as to what options I have now, does anyone have any other ideas that I could try so that I may avoid this error? Thanks in advance! Josh

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• Online payment service recommendation?

  - by Shadowman

  We're currently in the process of looking for an online payment service that will allow us to accept credit cards, etc. However, our business model also involves revenue sharing in a model similar to that of iTunes. That is, content creators will be able to sell content through our site and we take a small percentage of the revenue. Can anyone recommend an online payment service that supports this model? We're also interested in: Accept all major credit cards Being able to do international transactions in the appropriate local currency Recurring transactions (monthly, yearly, etc.) Additionally, if the service provided a Java API for integration or the ability to broker PayPal transactions that would be an added bonus. I know Amazon provides a hosted payment service, but I'd prefer not to require all of our customers to have an Amazon account. That provides an additional barrier to entry that we'd prefer to avoid. I'd appreciate any recommendations you can provide!

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• How to Execute Base Class's Method Before Implementors's Method?

  - by DaveDev

  I have the following page public partial class GenericOfflineCommentary : OfflineFactsheetBase { } where OfflineFactsheetBase is defined as public class OfflineFactsheetBase : System.Web.UI.Page { public OfflineFactsheetBase() { this.Load += new EventHandler(this.Page_Load); this.PreInit += new EventHandler(this.Page_PreInit); } protected void Page_PreInit(object sender, EventArgs e) { if (Request.QueryString["data"] != null) { this.PageData = StringCompressor.DecompressString(Request.QueryString["data"]); this.ExtractPageData(); } } } OfflineFactsheetBase has the following virtual method: public virtual void ExtractPageData() { // get stuff relevant to all pages that impmement OfflineFactsheetBase } which is implemented in all pages that impmement OfflineFactsheetBase as follows: public partial class GenericOfflineCommentary : OfflineFactsheetBase { public override void ExtractPageData() { // get stuff relevant to an OfflineCommentary page. } } Currently, only GenericOfflineCommentary's ExtractPageData() is firing. How can I modify this to first run OfflineFactsheetBase's ExtractPageData() and then GenericOfflineCommentary's? edit: I'm trying to avoid having to call base.ExtractPageData() in every implementor. Is this possible?

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• Get previous element in IObservable without re-evaluating the sequence

  - by dcstraw

  In an IObservable sequence (in Reactive Extensions for .NET), I'd like to get the value of the previous and current elements so that I can compare them. I found an example online similar to below which accomplishes the task: sequence.Zip(sequence.Skip(1), (prev, cur) => new { Previous = prev, Current = cur }) It works fine except that it evaluates the sequence twice, which I would like to avoid. You can see that it is being evaluated twice with this code: var debugSequence = sequence.Do(item => Debug.WriteLine("Retrieved an element from sequence")); debugSequence.Zip(debugSequence.Skip(1), (prev, cur) => new { Previous = prev, Current = cur }).Subscribe(); The output shows twice as many of the debug lines as there are elements in the sequence. I understand why this happens, but so far I haven't found an alternative that doesn't evaluate the sequence twice. How can I combine the previous and current with only one sequence evaluation?

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