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  • If XmlException.SourceUri is read-only, what good is it?

    - by East of Nowhere
    I have a couple places in my code where it throwing a new System.Xml.XmlException seems appropriate. I could just do throw new XmlException("Your XML sucks go fix it then try again."); But I think it's better to take advantage whenever possible of members particular to the exception class (otherwise ya might as well throw a plain ol' Exception every time). SourceUri and LineNumber would be helpful, but they only have get methods, there's no way I can assign a value to them! There's only 3 constructor overloads and none of them have parameters for those members either; I can only initialize Message, nothing else. There has got to be some way to populate those data members with values, otherwise why does XmlException bother with them? I suppose I could make a new class that inherits XmlException and write a new constructor that initializes SourceUri etc. but still, there must be a way to just use XmlException. Right?

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  • Why is javac failing on @Override annotation

    - by skiphoppy
    Eclipse is adding @Override annotations when I implement methods of an interface. Eclipse seems to have no problem with this. And our automated build process from Cruise Control seems to have no problem with this. But when I build from the command-line, with ant running javac, I get this error: [javac] C:\path\project\src\com\us\MyClass.java:70: method does not override a method from its superclass [javac] @Override [javac] ^ [javac] 1 error Eclipse is running under Java 1.6. Cruise Control is running Java 1.5. My ant build fails regardless of which version of Java I use.

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  • LINQ to SQL Web Application Best Practices

    - by derek
    In my experience building web applications, I've always used a n-tier approach. A DAL that gets data from the db and populates the objects, and BLL that gets objects from the DAL and performs any business logic required on them, and the website that gets it's display data from the BLL. I've recently started learning LINQ, and most of the examples show the queries occurring right from the Web Application code-behinds(it's possible that I've only seen overly simplified examples). In the n-tier architectures, this was always seen as a big no-no. I'm a bit unsure of how to architect a new Web Application. I've been using the Server Explorer and dbml designer in VS2008 to create the dbml and object relationships. It seems a little unclear to me if the dbml would be considered the DAL layer, if the website should call methods within a BLL, which then would do the LINQ queries, etc. What are some general architecture best practices, or approaches to creating a Web Application solution using LINQ to SQL?

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  • python, wrapping class returning the average of the wrapped members

    - by João Portela
    The title isn't very clear but I'll try to explain. Having this class: class Wrapped(object): def method_a(self): # do some operations return n def method_b(self): # also do some operations return n I wan't to have a class that performs the same way as this one: class Wrapper(object): def __init__(self): self.ws = [Wrapped(1),Wrapped(2),Wrapped(3)] def method_a(self): results=[Wrapped.method_a(w) for w in self.ws] sum_ = sum(results,0.0) average = sum_/len(self.ws) return average def method_b(self): results=[Wrapped.method_b(w) for w in self.ws] sum_ = sum(results,0.0) average = sum_/len(self.ws) return average obviously this is not the actual problem at hand (it is not only two methods), and this code is also incomplete (only included the minimum to explain the problem). So, what i am looking for is a way to obtain this behavior. Meaning, whichever method is called in the wrapper class, call that method for all the Wrapped class objects and return the average of their results. Can it be done? how? Thanks in advance. ps-didn't know which tags to include...

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  • Discussion: Working TDD in a Scrum context

    - by Anders Juul
    Hi all, When I work TDD I tend to start out with the big picture and create the tests that should succeed in order for the overall assignment to be completed - it then kicks off a number of supporting classes/methods/tests as I 'dig in'. If my assignment has been planned out in detail, I would then open one task, and in order to solve it, open another and then another. Only when the overall tests are succeeding can I close the original task, which means that at any given time, I would have a number of open tasks. I find that this approach conflict somewhat with the scrum approach where, ideally, I should be able to take and close a task within a day's work - and never have more than one task open at a time. I'm looking for input about how you manage this in your project - references to articles are also very welcome, I'm sure this has been debated thoroughly somewhere... The 'answer tick' will be awarded to best comment/reference. Thanks for any input, Anders, Denmark

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  • Monkeypatch a model in a rake task to use a method provided by a plugin?

    - by gduquesnay.mp
    During some recent refactoring we changed how our user avatars are stored not realizing that once deployed it would affect all the existing users. So now I'm trying to write a rake task to fix this by doing something like this. namespace :fix do desc "Create associated ImageAttachment using data in the Users photo fields" task :user_avatars => :environment do class User # Paperclip has_attached_file :photo ... <paperclip stuff, styles etc> end User.all.each do |user| i = ImageAttachment.new i.photo_url = user.photo.url user.image_attachments << i end end end When I try running that though I'm getting undefined method `has_attached_file' for User:Class I'm able to do this in script/console but it seems like it can't find the paperclip plugin's methods from a rake task.

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  • How to: WCF XML-RPC client?

    - by mr.b
    I have built my own little custom XML-RPC server, and since I'd like to keep things simple, on both server and client side, what I would like to accomplish is to create a simplest possible client (in C# preferably) using WCF. Let's say that Contract for service exposed via XML-RPC is as follows: [ServiceContract] public interface IContract { [OperationContract(Action="Ping")] string Ping(); // server returns back string "Pong" [OperationContract(Action="Echo")] string Echo(string message); // server echoes back whatever message is } So, there are two example methods, one without any arguments, and another with simple string argument, both returning strings (just for sake of example). Service is exposed via http. Aaand, what's next? :) P.S. I have tried googling around for samples and similar, but all that I could come up with are some blog-related samples that use existing (and very big/numerous) classes, which implement appropriate IContract (or IBlogger) interfaces, so that most of what I am interested is hidden below several layers of abstraction...

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  • How is it that the abstract class XmlWriter can be instantiated using XmlWriter.Create(... ?

    - by Cognize
    Hi, Just looking to clarify my understanding of the workings of the XmlWriter and abstract classes in general. My thinking is (was) that an abstract class can not be instantiated, although it can contain base methods that can be used by an inheriting class. So, while investigating XmlWriter, I find that to instantiate the XmlWriter, you call XmlWriter.Create(.... , which returns an instance of... XmlWriter, which can then be used: FileStream fs = new FileStream("XML.xml", FileMode.Create); XmlWriter w = XmlWriter.Create(fs); XmlSerializer xmlSlr = new XmlSerializer(typeof(TestClass)); xmlSlr.Serialize(fs, tsIn); This clearly works, as tested. Can anyone help me understand what is going on here. As far as I can see there is or should be no 'instance' to work with here??

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  • Why would it be a bad idea to have database connection open between client requests?

    - by AspOnMyNet
    1) Book I’m reading argues that connections shouldn’t be opened between client requests, since they are a finite resource. I realize that max pool size can quickly be reached and thus any further attempts to open a connection will be queued until connection becomes available and for that reason it would be imperative that we release connection as soon as possible. But assuming all request will open connection to the same DB, then I’m not sure how having a connection open between two client requests would be any less efficient than having each request first acquiring a connection from connection pool and later returning that object to connection pool? 2) Book also recommends that when database code is encapsulated in a dedicated data access class, then method M opening a database connection should also close that connection. a) I assume one reason why M should also close it, is because if method M opening the connection doesn’t also close it, but instead this connection object is used inside several methods, then it’s more likely that a programmer will forget to close it. b) Are there any other reasons why a method opening the connection should also close it? thanx

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  • Programmatic resource monitoring per process in Linux

    - by tuxx
    Hi, I want to know if there is an efficient solution to monitor a process resource consumption (cpu, memory, network bandwidth) in Linux. I want to write a daemon in C++ that does this monitoring for some given PIDs. From what I know, the classic solution is to periodically read the information from /proc, but this doesn't seem the most efficient way (it involves many system calls). For example to monitor the memory usage every second for 50 processes, I have to open, read and close 50 files (that means 150 system calls) every second from /proc. Not to mention the parsing involved when reading these files. Another problem is the network bandwidth consumption: this cannot be easily computed for each process I want to monitor. The solution adopted by NetHogs involves a pretty high overhead in my opinion: it captures and analyzes every packet using libpcap, then for each packet the local port is determined and searched in /proc to find the corresponding process. Do you know if there are more efficient alternatives to these methods presented or any libraries that deal with this problems?

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  • Cocoa Touch - Display an Activity Indicator while loading a UITabBar View

    - by Aurum Aquila
    I have a UITabBar Application with two views that load large amounts of data from the web in their "viewWillAppear" methods. I want to show a progress bar or an activity indicator while this data is being retrieved, to make sure the user knows the app isn't frozen. I am aware that this has been asked before. I simply need some clarification on what seems to be a rather good solution. I have implimented the code in the example. The question's original asker later solved their problem, by putting the retrieval of data into another "thread". I understand the concept of threads, but I do not know how I would impliment this. With research, I have found that I need to move all of my heavy data retrieval into a background thread, as all of the UI updating occurs in the main thread. If one would be so kind as to provide an example for me, I would be very appreciative. I can provide parts of my existing code as necessary.

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  • How to get window opened/closed/minimized messages from a native app?

    - by Josh Santangelo
    It's tough to write a good title for this one. I'm working on a WPF application which needs to know about the existence of all other open windows on the system. I'm able to do this by calling the native EnumWindows method just fine, and I can call other native methods to filter out just the windows I'm interested in. This works well. The problem I'm having is that I want to know when a window is opened or closed (and, ideally, minimized). I can do this by polling with EnumWindows, but I'm finding that to be pretty slow, even if I push it off to another thread. Is there a better way to get notifications of window opened/closed/minimized? Keep in mind that my knowledge of non-managed code is pretty limited.

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  • ASP.NET MVC authorization & permission to use model classes

    - by Tomek
    Hi, This is my first post here, so hello :) Okey, let's get to the point... I am writing my first app in ASP.NET MVC Framework and i have a problem with checking privileges to use instances of model classes (read, edit). Sample code looks like this: // Controller action [CustomAuthorize(Roles="Editor, Admin")] public ActionResult Stats(int id) { User user = userRepository.GetUser(id); if (user == null || !user.Activated || user.Removed) return View("NotFound"); else if (!user.IsCurrentSessionUserOwned) return View("NotAuthorized"); return View(user); } So far authorize attribute protects only controller actions, so my question is: how to make (custom) authorize attribute to check not only user role, usernames but also did i.e. resources instantiated in action methods (above: User class, but there are other ORM objects like News, Photos etc.) All of these object to check have their unique ID's, so user have own ID, News have their ID and UserID field referecned to Users table (i mean these objects are LINQ2SQL classes). How should i resolve that problem?

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  • lwjgl 101: How can I write applets?

    - by Vuntic
    I have a working app in lwjgl. It doesn't do much yet; I've just started, but it does compile and run like it's supposed to. I want to make it into an applet. I've followed the guide here, and I have an applet that runs nicely and displays text and such in the applet area and can access the functions of lwjgl (like Sys.alert), but I can't figure out how to get opengl to actually render. I've tried extending an AWTGLCanvas and calling this.add(myAWTGLCanvas), where this is the Applet that I'm using, but... nothing. The initGL() and paintGL() methods never get called. I wonder if I'm supposed to be doing something with Display, but that's not for applets, right? Help? Also: This counts as a "beginner" question, right? Edit: Here's a simplified version of what I have.

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  • Most Efficient Way of calling an external webservice in Java?

    - by Sudheer
    In one of our applications we need to call the Yahoo Soap Webservice to Get Weather and other related info. I used the wsdl2java tool from axis1.4 and generated th required stubs and wrote a client. I use jsp's use bean to include the client bean and call methods defined in the client which call the yahoo webservice inturn. Now the problem: When users make calls to the jsp the response time of the webservice differs greatly, like for one user it took less then 10 seconds and the other in the same network took more than a minute. I was just wondering if Axis1.4 queues the requests even though the jsps are multithreaded. And finally is there an efficient way of calling the webservice(Yahoo weather). Typically i get around 200 simultaneous requests from my users.

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  • Java - binary compatibility of abstract class & subclasses

    - by thSoft
    In Java, I define an abstract class with both concrete and abstract methods in it, and it has to be subclassed independently by third-party developers. Just to be sure: are there any changes I could make to the abstract class that are source compatible with their classes but not binary compatible? In other words: after they have compiled their subclasses, could I change the abstract class - apart from e.g. adding an abstract method to it or removing a protected method from it that is called by subclasses, which are of course source incompatible - in a way that could force them to recompile their subclasses?

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  • How to fit page to Silverlight WebBrowser control?

    - by Igor V Savchenko
    Hello. I use WebBrowser Silverlight 4 control to load some page: <WebBrowser Height="350" Name="webBrowser" Width="400" /> ... webBrowser.Navigate(new Uri("http://mail.live.com")); But page loads with horizontal and vertical scroll bars. So I'm trying to find some ways to get actual size of loaded page (then I can change Height/Width of control) OR change scale of loaded page (to fit it to the actual WebControl control). Is it possible to do with standard WebControl methods?

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  • Suggest books/learning path for writing smartphone apps

    - by chibineku
    I have been writing a lot of HTML, CSS, PHP, MySQL and JavaScript lately working on a website, and I would like to move on to 'proper' OOP with an eye to making smartphone apps. I would like to at least cover iPhone and BlackBerry, which means learning Objective C, Cocoa and Java, before learning the specifics of interacting with the devices themselves, such as native bluetooth/GPS/internet API/methods. I would appreciate pointers to books or resources that will get me from a procedural web developer to object oriented app-maker. Most of the reviews of books on Objective C and Java have been mixed. I am about to start working my way through Beginning Java Objects (APress) which I have borrowed from my brother, so even if it's not a good intro at least it was free!

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  • Hibernate - moving annotations from property (method) level to field level

    - by kan
    How do I generate hibernate domain classes from tables with annotations at field level? I used Hibernate Tools project and generated domain classes from the tables in the database. The generated classes have annotations on the getter methods rather than at the field level. Kindly advice a way to generate domain classes that have the fields annotated. Is there any refactoring facility available in eclipse/IDEA etc.. to move the annotations from method level to field level? Appreciate your help and time.

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  • Mapping to a JSON method with url-pattern

    - by Brian
    I'm creating a Spring MVC application that will have a controller with 'RequestMapping'-annotated methods, including a JSON method. It currently has static content that resides in webapps/static, and the app itself resides in webapps/myapp. I assume that Catalina's default servlet is handling the static content, and my *.htm url-pattern in web.xml is returning the request for my JSP page, but I haven't been able to get the JSON method to be called. How do I write the url-pattern in the servlet mapping to do so? Using /* has not worked; it prevents the app from being accessed at all. Is there anything else to be aware of? EDIT: The url-pattern '/' appears to allow the JSON request through, because a 406 error is returned. What then would need to be modified to allow JSON to be returned?

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  • How to monitor and maintain my grails application in live/production environment?

    - by fabien7474
    It is the first time I have ever launched live a website (with Grails web framework under Amazon EC2 platform and Cloud Foundry) and I realized quickly that I am not ready for monitoring and maintening correctly my application in production mode (fortunately the website is accessible to a very limited number of users) . The issues I have faced so far are: Cannot change my views. I need to redeploy my application I have no monitoring. I don't know who is connected, when do they sign in / sign out... Redploying my application (upload WAR + deploy) takes at least 30 minutes. I don't know how to restart my Tomcat server without a redeploy through Cloud Foundry ! ... So, my question is very simple: What tools (including grails plugins) and methods can you recommend me for taking me out from my current blindness?

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  • What exactly is a property in Objective C ? What is the difference between a property ans an instance variable?

    - by tek3
    I am very much confused between instance variables and property. I have read number of posts regarding this but still i am not clear about it. I am from JAVA background and what i infer from objective C documentation is that a property is similar to JAVA BEAN CLASS (one having getter and setter of instance varibles). A property can accessed from other classes through its getter and setter methods while an instance variable is private and cannot be accessed from other classes. Am i right in thinking in this direction ?

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  • Define Instance Variable Outside of Method Defenition (ruby)

    - by Ell
    Hi all, I am developing (well, trying to at least) a Game framework for the Ruby Gosu library. I have made a basic event system wherebye each Blocks::Event has a list of handlers and when the event is fired the methods are called. At the moment the way to implement an event is as follows: class TestClass attr_accessor :on_close def initialize @on_close = Blocks::Event.new end def close @on_close.fire(self, Blocks::OnCloseArgs.new) end end But this method of implementing events seems rather long, my question is, how can I make a way so that when one wants an event in a class, they can just do this class TestClass event :on_close def close @on_close.fire(self, Blocks::OnCloseArgs.new) end end Thanks in advance, ell.

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  • Invoke a subclass method of an anonymous class

    - by arjacsoh
    I am trying right now to dig into anonymous classes and one question was just arised I 'd prefer not to refer to much details and to pose my question straightforward: How can I invoke the method sizzle() in the following anonymous class: public class Popcorn { public void pop() { System.out.println("popcorn"); } } class Food { Popcorn p = new Popcorn() { public void sizzle() { System.out.println("anonymous sizzling popcorn"); } public void pop() { System.out.println("anonymous popcorn"); } }; public void popIt() { p.pop(); // OK, Popcorn has a pop() method p.sizzle(); // Not Legal! Popcorn does not have sizzle() } } It is known and definite in polymorphism rules that a refernce of a superclass cannot invoke methods of subclass without downcasting (even if it refers to an object of the given subclass). However in the above case what is the "key" to invoke the sizzle() method?

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  • Mapping class properties to generic columns in table .NET

    - by Tony_Henrich
    I have have a SQL Server table which has generic names like Text1, Text2.. etc. The table was designed like this because the same structure is used for different projects. I have a class in .NET which has properties. Say a Customer class has a property called FirstName. How can I do the mapping from FirstName to Text1 just once (central place) in the application so that I don't have to remember and hard code the mappings all over the app when I create the different DAL methods? For example, I want the app to know when I want to update, insert a FirstName, the DAL automatically uses Text1. Basically I don't have to remember which property goes to which column. The idea is so the developers do not map the properlies/columns in a wrong way. It's always consistent. Note: Database inserts, updates and deletes are allowed through stored procedures only.

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