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  • Need help understanding the MVC design pattern

    - by Doron Sinai
    Hi, I am trying to find a ood example of MVC design pattern in java. This is what i understood from reading about it, please correct me if I am wrong: I have the Model part which is the logic behind the program, let's say if we have a phonebook, so adding and removing contact from the Array will be the model. The Gui is the view and it contains buttons that upon clicking them, the model is changing. What I am trying to undersand what is the controller part, is it the ActionListeners? how to you seperate those modules in practice. thank you

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  • What effect does static const have on a namespace member

    - by user144182
    namespace MyNamespace { static const double GasConstant = 1.987; Class MyClass { // constructors, methods, etc. }; }; I previously had GasConstant declared within the MyClass declaration (and had a separate definition in the source file since C++ does not support const initialization of non-integral types). I however need to access it from other files and also logically it seems like it should reside at the namespace level. My questions is, what effect does static const have in this case? Clearly const means I can't assign a new value to GasConstant, but what does a static member at the namespace mean. Is this similar to filescope static effect, where the member is not accessible outside of the unit?

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  • How to manually manage Core Data relationships when deleting

    - by Simon
    I have a Core Data entity, which contains a relationship to another entity. Under certain circumstances, I need to delete the managed objects in the relationship, and at other times no action needs to be taken. I have the Delete Rule on the entity is No Action because of this manual management. The problem I have is, where is the best place to enforce these rules? I cannot see any suitable messages to override on NSManagedObject (something that might notify the object it has been deleted and should clear up its relationships). I would rather not do it higher up in the application logic, because the entity objects can get deleted from array controllers and at different points in the applications, making it necessary to stuff relationship update code at all those levels.

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  • Extracting a Rails application into a plugin or engine

    - by Globalkeith
    I have a Rails 2.3 application which I would like to extract into a plugin, or engine. The application has user authentication, and basic cms capabilities supported by ancestry plugin. I want to extract the logic for the application into a plugin/engine so that I can use this code for future projects, with a different "skin" or "theme" if required. I'm not entirely sure I actually understand the difference between plugin and engine concepts, so that would be a good first point. What is the best approach, are there any good starting points, links, explanations, examples that I should follow. Also, with the release of R3 to consider, is there anything that I should be aware of for that, with regards to plugins etc. I am going to start off by watching Ryan's http://railscasts.com/episodes/149-rails-engines but obviously thats over a year old now, so one of the challenges I'm faced with is finding the most up to date and relevant information on this subject. All tips and help gratefully received.

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  • Testing a (big) collection retrieved from a db

    - by Bas
    I'm currently doing integration testing on a live database and I have the following sql statement: var date = DateTime.Parse("01-01-2010 20:30:00"); var result = datacontext.Repository<IObject>().Where(r => r.DateTime > date).First(); Assert.IsFalse(result.Finished); I need to test if the results retrieved from the statement, where the given date is less then the date of the object, have Finished set to False. I do not know how many results I get back and currently I'm getting the first object of the list and check if that object has Finished set to false. I know testing only the first item of the list is not valid testing, as a solution for that I could iterate through the list and check all items on Finished, but putting logic in a Test is kinda going against the concept of writing 'good' tests. So my question is: Does anyone have a good solution of how to properly test the results of this list?

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  • Drag and drop + custom drawing in Android

    - by Rich
    I am working on something that needed custom drag-and-drop functionality, so I have been subclassing View, doing a bunch of math in response to touch events, and then rendering everything manually through code on the canvas in onDraw. Now, the more functionality I add, the more the code is growing out of control and I find myself writing a ton more code than I would expect to write in a high level environment like Android. Is this how it's done, or am I missing something? If I'm not doing anything fancy in the UI, the framework handles the majority of my interactions. Built-in controls handle the touches and drags, and my code is pretty much limited to business logic and data. Is there a way to leverage the power of some of the UI controls and things like animations while also doing some of it manually in the onDraw canvas? Is there an accepted standard of when to use one or the other (if indeed the two approaches can be mixed)?

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  • Strategies for generating Zend Cache Keys

    - by emeraldjava
    ATM i'm manually generating a cache key based on the method name and parameters, then follow to the normal cache pattern. This is all done in the Controller and i'm calling a model class that 'extends Zend_Db_Table_Abstract'. public function indexAction() { $cache = Zend_Registry::get('cache'); $individualleaguekey = sprintf("getIndividualLeague_%d_%s",$leagueid,$division->code); if(!$leaguetable = $cache->load($individualleaguekey)) { $table = new Model_DbTable_Raceresult(); $leaguetable = $table->getIndividualLeague($leagueid,$division,$races); $cache->save($leaguetable, $individualleaguekey); } $this->view->leaguetable = $leaguetable; .... I want to avoid the duplication of parameters to the cache creation method and also to the model method, so i'm thinking of moving the caching logic away from my controller class and into model class packaged in './model/DbTable', but this seems incorrect since the DB model should only handle SQL operations. Any suggestions on how i can implement a clean patterned solution?

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  • signed angle between two 3d vectors with same origin within the same plane? recipe?

    - by Advanced Customer
    Was looking through the web for an answer but it seems like there is no clear recipe for it. What I need is a signed angle of rotation between two vectors Va and Vb lying within the same 3D plane and having the same origin knowing that: the plane contatining both vectors is an arbitrary and is not parallel to XY or any other of cardinal planes Vn - is a plane normal both vectors along with the normal have the same origin O = { 0, 0, 0 } Va - is a reference for measuring the left handed rotation at Vn The angle should be measured in such a way so if the plane would be XY plane the Va would stand for X axis unit vector of it. I guess I should perform a kind of coordinate space transformation by using the Va as the X-axis and the cross product of Vb and Vn as the Y-axis and then just using some 2d method like with atan2() or something. Any ideas? Formulas?

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  • Using Web Flow 2 in JSF application

    - by Tesnep
    Hi, I created a JSF cart application which runs just fine. I am using 'redirect' to fix the problem with refresh. The problem is when there is multiple page flow logic like if you haven't signed up you need to sign up or create an account, and once you do that you need to be redirected back to where you were when you were asked to sign up in the first place. So my goal is to use Web Flow 2 in order to make navigation rules easier to code. I have been working on them separately but I don't know how to merge so that Web Flow can handle navigation instead. Any help is very much appreciated. Thanks.

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  • How to distinguish properties from constants if they both use PascalCasing for naming?

    - by Gishu
    As stated in the framework design guidelines and the WWW in general, the current guideline is to name your constants like this LastTemplateIndex as opposed to LAST_TEMPLATE_INDEX With the PascalCasing approach, how do you differentiate between a Property and a Constant. ErrorCodes.ServerDown is fine. But what about private constants within your class ? I use quite a lot of them for naming magic numbers.. or for expected values in my unit tests and so on. The ALL_CAPS style helps me know that it is a constant . _testApp.SelectTemplate(LAST_TEMPLATE_INDEX); *Disclosure: I have been using the SCREAMING_CAPS style for a while for constants + I find it more readable than squishedTogetherPascalCasedName. It actually STANDS_OUT in a block of text*

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  • Entity Framework 4.1 (Code First) audit column

    - by Ken Pespisa
    I'm using Entity Framework 4.1 with a Code-First approach on an ASP.NET MVC site Say I have an entity named Profile that keeps track of a user's favorite book, and I want to track when the user updates their favorite book. UPDATED: Using the class below as an example, I want to set the FavoriteBookLastUpdated property to the current date whenever the value of the FavoriteBook property changes. public class Profile { public int Id { get; set; } public string Name { get; set; } public string FavoriteBook { get; set; } public DateTime? FavoriteBookLastUpdated { get; set; } } Right now I just update that field, if appropriate, in the controller's Edit action before calling the DBContext's SaveChanges() method. Is there a way I can put that logic in my model somehow? I'd prefer not to use triggers on the database side.

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  • Change Makefile variable value

    - by paulgray
    Is there a way to reassign Makefile variable value inside of the target body? What I am trying to do is to add some extra flags for debug compilation: %.erl: %.beam $(ERLC) $(ERLFLAGS) -o ebin $< test: clean debug_compile_flag compile compile_test debug_compile: $(ERLCFLAGS) += -DTEST So if I invoke test target I would like to clean up my environment, add some new flags (like -DTEST to the existing ones), compile the whole code once again (first sources, then test modules). I do not want to copy/paste the code for compiling with some new flags set since there is a lot of logic put here and there. Is there some easy way to redefine the variable value so I can reuse the existing code?

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  • Using entity framework to detect changes in related table and action appropriate inserts and deletes

    - by Kohan
    Lets say i have a Person table, a Role table with a trel table PersonRoles linking them as many to many. I create a new person and assign them to 2 roles (role 1, role 3). I then want to edit this person; so i retrieve their data and bind their roles to a checkboxes. I change the values (Deselect role 1 and select role 2 instead) I then post this data back through a viewmodel. Can i then get Entity Framework to update these roles for me, as in delete the entry in PersonRoles to role 1 and then add a new entry as role 2? Or do i have to do the logic for this myself? Cheers, Kohan

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  • How can I dispose of an object (say a Bitmap) when it becomes orphaned ?

    - by Jelly Amma
    I have a class A providing Bitmaps to other classes B, C, etc. Now class A holds its bitmaps in a ring queue so after a while it will lose reference to the bitmap. While it's still in the queue, the same Bitmap can be checked out by several classes so that, say, B and C can both hold a reference to this same Bitmap. But it can also happen that only one of them checked out the Bitmap or even none of them. I would like to dispose of the bitmap when it's not being needed any more by either A, B or C. I suppose I have to make B and C responsible for somehow signaling when they're finished using it but I'm not sure about the overall logic. Should it be a call to something like DisposeIfNowOrphan() that would be called : 1 - when the Bitmap gets kicked out of the queue in class A 2 - when B is finished with it 3 - when C is finished with it If that's the best strategy, how can I evaluate the orphan state ? Any advice would be most welcome.

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  • How do I draw an arrow on a histogram drawn using ggplot2?

    - by jon
    Here is dataset: set.seed(123) myd <- data.frame (class = rep(1:4, each = 100), yvar = rnorm(400, 50,30)) require(ggplot2) m <- ggplot(myd, aes(x = yvar)) p <- m + geom_histogram(colour = "grey40", fill = "grey40", binwidth = 10) + facet_wrap(~class) + theme_bw( ) p + opts(panel.margin=unit(0 ,"lines")) I want to add labels to bars which each subject class fall into and produce something like the post-powerpoint processed graph. Is there way to do this within R ? ...... Edit: we can think of different pointer such as dot or error bar, if arrow is not impossible Let's say the following is subjects to be labelled: class name yvar 2 subject4 104.0 3 subject3 8.5 3 subject1 80.0 4 subject2 40.0 4 subject1 115.0 classd <- data.frame (class = c(2,3,3,4,4), name = c ("subject4", "subject3", "subject1", "subject2", "subject1"), yvar = c(104.0, 8.5,80.0,40.0, 115.0))

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  • Non-string role names in ASP.NET MVC?

    - by MikeWyatt
    ASP.NET MVC has good support for role-based security, but the usage of strings as role names is maddening, simply because they cannot be strongly-typed as enumerations. For example, I have an "Admin" role in my app. The "Admin" string will now exist in the Authorize attribute of my action, in my master page (for hiding a tab), in my database (for defining the roles available to each user), and any other place in my code or view files where I need to perform special logic for admin or non-admin users. Is there a better solution, short of writing my own authorization attribute and filter, that would perhaps deal with a collection of enumeration values?

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  • Rails - how do you create a user index page like stack overflows with multiple tabs whilst keeping t

    - by adam
    On stackoverflow in the users profile area there are many tabs which all display differing information such as questions asked and graphs. Its the same view though and im wondering hows its best to achieve this in rails whilst keeping the controller skinny and logic in the view to a minimum. def index @user = current_user case params[:tab_selected] when "questions" @data = @user.questions when "answers" @sentences = @user.answers else @sentences = @user.questions end respond_to do |format| format.html # index.html.erb nd end but how do i process this in the index view without a load of if and else statments. And if questions and answers are presented differently whats the best way to go about this.

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  • DataBind and Postback

    - by Michael La Voie
    This is a general how does DataBind work questions... I have a simple page with a GridView that is bound (in the aspx code) to an ObjectDataSource. I can look in the Select() function called by the ObjectDataSource to see that it is called on the initial load and on every post back. I have some logic that happens on post backs that will affect the GridView's data, and I want to call GridView.DataBind() later on in the post back, after I've made some changes. Is there a way to prevent the automatic rebinding that happens on each post back? Does this mean I can't use an ObjectDataSource for this control?

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  • How to initialize F# list when size is unknown, using while..do loop

    - by James Black
    I have a function that will parse the results of a DataReader, and I don't know how many items are returned, so I want to use a while..do loop to iterate over the reader, and the outcome should be a list of a certain type. (fun(reader) -> [ while reader.Read() do new CityType(Id=(reader.GetInt32 0), Name=(reader.GetString 1), StateName=(reader.GetString 2)) ]) This is what I tried, but the warning I get is: This expression should have type 'unit', but has type 'CityType'. Use 'ignore' to discard the result of the expression, or 'let' to bind the result to a name. So what is the best way to iterate over a DataReader and create a list?

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  • How can I check that I didn't break anything when refactoring?

    - by Nathan Fellman
    I'm about to embark on a bout of refactoring of some functions in my code. I have a nice amount of unit tests that will ensure I didn't break anything, but I'm not sure about the coverage they give me. Are there any tools that can analyze the code and see that the functionality remains the same? I plan to refactor some rather isolated code, so I don't need to check the entire program, just the areas that I'm working on. For context, the code I'm working on is in C/C++, and I work in Linux with GCC and VIM.

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  • Regex for Searching for Text Not Preceeded By a Specific String

    - by James
    Hi, I am working on a web site with several other developers and we have had problems where people commit JavaScript code with AJAX calls that use URL's relative to the site root. An example would be /Home/Index which will not work if the site is hosted in a virtual directory. To get round the problem we use a $.url() method to convert it to a full path, e.g. $("#container").load($.url("/Home/Index")) I am trying to write a unit test that will search each JavaScript file and find places where the $.url method is not being used. The only problem is that I cannot seem to write a regex expression to do this. I have tried the following: (?!\$\.url\()"(/\w*)+" But this does not work. I cannot find a way to say that I don't want the $.url in front. Does anyone know if this is possible? Note that I need regular expressions that are compatible with .NET Thanks.

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  • Accessing every child class of parent class in Java

    - by darkie15
    Hi All, I have to implement a logic whereby given a child class, I need to access its parent class and all other child class of that parent class, if any. I did not find any API in Java Reflection which allows us to access all child classes of a parent class. Is there any way to do it? Ex. class B extends class A class C extends class A Now using class B, I can find the superclass by calling getSuperClass(). But is there any way to find all the child classes once I have the parent class i.e. class B and class C?? Regards, darkie

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  • Invoicing vs Quoting or Estimating

    - by FreshCode
    If invoices can be voided, should they be used as quotations? I have an Invoices tables that is created from inventory associated with a Job or Order. I could have a Quotes table as a halfway-house between inventory and invoices, but it feels like I would have duplicate data structures and logic just to handle an "Is this a quote?" bit. From a business perspective, quotes are different from invoices: a quote is sent prior to an undertaking and an invoice is sent once it is complete and payment is due, but how to represent this in my repository and model. What is an elegant way to store and manage quotes & invoices in a database? Edit: indicated Job === Order for this particular instance.

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  • How to read GPU (graphic card) temperature?

    - by mr.b
    I am interested in a way how to read GPU temperature (graphics processing unit, main chip of graphic card), by using some video card driver API? Everyone knows that there two different chip manufacturers (popular ones, at least) - ATI and nVIDIA - so there are two different kinds of drivers to read temperature from. I'm interested in learning how to do it for each different card driver. Language in question is irrelevant - it could be C/C++, .NET platform, Java, but let's say that .NET is preferred. Anyone been doing this before?

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  • Must a Language that Implements Monads be Statically Typed?

    - by Morgan Cheng
    I am learning functional programming style. From this link http://channel9.msdn.com/shows/Going+Deep/Brian-Beckman-Dont-fear-the-Monads/, Brian Beckman gave a brilliant introduction about Monad. He mentioned that Monad is about composition of functions so as to address complexity. A Monad includes a unit function that transfers type T to an amplified type M(T); and a Bind function that, given function from T to M(U), transforms type M(T) to another type M(U). (U can be T, but is not necessarily). In my understanding, the language implementing monad should be type-checked statically. Otherwise, type errors cannot be found during compilation and "Complexity" is not controlled. Is my understanding correct?

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