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• What is a good architecture for a Lift-JPA application?

  - by egervari

  I was wondering what is the best practice for a JPA model in Lift? I noticed that in the jpa demo application, there is just a Model object that is like a super object that does everything. I don't think this can be the most scalable approach, no? Is it is wise to still do the DAO pattern in Lift? For example, there's some code that looks a tad bloated and could be simplified across all model objects: Model.remove(Model.getReference(classOf[Author], someId)) Could be: AuthorDao.remove(someId) I'd appreciate any tips for setting up something that will work with the way Lift wants to work and is also easy to organize and maintain. Preferably from someone who has actually used JPA on a medium to large Lift site rather than just postulating what Spring does (we know how to do that) ;) The first phase of development will be around 30-40 tables, and will eventually get to over 100... we need a scalable, neat approach.

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• How to get the action from the HttpServlet request to dispatch to multiple pages

  - by JFB

  I am using the Page Controller pattern. How could I use the same controller for two different pages by detecting the request action and then dispatching according to the result? Here is my code: account.jsp <form name="input" action="<%=request.getContextPath() %>/edit" method="get"> <input type="submit" value="Modifier" /> </form> Account Servlet public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("received HTTP GET"); String action = request.getParameter("action"); if (action == null) { // the account page dispatch(request, response, "/account"); } else if (action == "/edit") { // the popup edit page dispatch(request, response, "/edit"); } protected void dispatch(HttpServletRequest request, HttpServletResponse response, String page) throws javax.servlet.ServletException, java.io.IOException { RequestDispatcher dispatcher = getServletContext() .getRequestDispatcher(page); dispatcher.forward(request, response); } }

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• Help with regex pulling XML data from response body in PHP

  - by spdaly

  I am working on a project that pulls data from JMS queue using PHP and Zend Framework. The HTTP client response is below. All I need is the XML string. I came up with /(.*)<\/RequestDetails/gs which tests ok on http://gskinner.com/RegExr/ but the preg_match call is returning an empty matches array. I'm going to continue to hunt around for a pattern, but thought I would post here as well. Thanks to all who read, etc... Steve UPDATE: I can't get the code to paste correctly. Here's a link to a pastbin: http://pastebin.com/rQxzcfSg

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• How to imitate the workflow view of Automator?

  - by andyfeind

  I’m starting to develop my first full-blown Cocoa application containing a view which I would like to behave (and look) similar to Automator’s AMWorkflowView. The basic features I’d like to achieve: Positioning of subviews Display of subviews in expanded / collapsed states Multiple selection Drag and drop In order to get accustomed to Cocoa, I started with a custom NSView which mainly served as a container for the custom subviews and handled their positioning and multiple selection. The subviews are also subclasses of NSView, and contain a variable amount of views themselves, like buttons, labels and popup menus, and therefore can have different heights. This worked quite well, but before going on, I want to make sure to have everything neat and tidy according to the MVC pattern. I suspect that there already is a class in Cocoa that facilitates the implementation of a view container, like maybe NSCollectionView. It seems that there is no (easy) way to display differently sized views in an NSCollectionView, though. Should I continue implementing my custom NSView (probably using an NSArrayController for selection and sorting support), or are there better ways to go? Any help is much appreciated

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• Live asynchronous time feed for websites

  - by Maven

  I want to show up the time over my website based over the location of the user, let’s say if user one browsing the website is from USA than the time should be what is in USA currently and same for China etc. and all. I was wondering if there exists a JavaScript plugin for it but I didn’t find any as dynamic as I want, my requirements include: Something that can be fully stylized according to website theme (no iframes) The pattern I want is to be in (HH:MM:SS) It should be asynchronous like the second [SS] keep ticking and the time keep updating Is this possible, a way around to achieve it?

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• What's the right way to handle "One, Both, or None" logic?

  - by Stephen

  I have a logic situation that is best described as two "Teams" trying to win a task. The outcome of this task could be a single winner, a tie (draw), or no winner (stalemate). Currently, I'm using a nested if/else statement like so: // using PHP, but the concept seems language agnostic. if ($team_a->win()) { if ($team_b->win()) { // this is a draw } else { // team_a is the winner } } else { if ($team_b->win()) { // team_b is the winner } else { // This is a stalemate, no winner. } } This seems rather spaghetti-like and repetitive. Is there a more logical, DRY pattern I could use?

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• php regex to split invoice line item description

  - by user1053700

  I am attempting to split strings like the following: An item (Item A) which may contain 89798 numbers and letters @ $550.00 4 of Item B @ $420.00 476584 of Item C, with a larger quantity and different currency symbol @ £420.00 into: array( 0 => 1 1 => "some item which may contain 89798 numbers and letters" 2 => $550.00 ); does that make sense? I am looking for a regex pattern which will split the quantity, description, and price (including symbol). the strings will always be: qty x description @ price+symbol so i assume the regex would be something like: `(match a number and only a number) x (get description letters and numbers before the @ symbol) @ (match the currency symbol and price)` How should I approach this?

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• Should I dive into ASP.NET MVC or start with ASP.NET Webforms?

  - by Sahat

  I plan to pick up Silverlight in the future. Possibility of going into Microsoft WPF. Currently learning Objective-C 2.0 w/ Cocoa. I already know Pros and Cons of ASP.NET MVC vs ASP.NET Webforms. What I want to know is what would be more "efficient" for me to learn given the circumstances above? By efficient I mean learning one design pattern once and then re-using it. Objective-C I believe uses MVC approach? What about Silverlight? WPF? So what do you think? Also as a side question is it true that ASP.NET Webforms is often used by freelancers/small companies and ASP.NET MVC in large enterprises?

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• Which would be better? Storing/access data in a local text file, or in a database?

  - by TerranRich

  Basically, I'm still working on a puzzle-related website (micro-site really), and I'm making a tool that lets you input a word pattern (e.g. "r??n") and get all the matching words (in this case: rain, rein, ruin, etc.). Should I store the words in local text files (such as words5.txt, which would have a return-delimited list of 5-letter words), or in a database (such as the table Words5, which would again store 5-letter words)? I'm looking at the problem in terms of data retrieval speeds and CPU server load. I could definitely try it both ways and record the times taken for several runs with both methods, but I'd rather hear it from people who might have had experience with this. Which method is generally better overall?

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• Injecting a dependancy into a base class

  - by Jamie Dixon

  Hey everyone, I'm on a roll today with questions. I'm starting out with Dependency Injection and am having some trouble injecting a dependency into a base class. I have a BaseController controller which my other controllers inherit from. Inside of this base controller I do a number of checks such as determining if the user has the right privileges to view the current page, checking for the existence of some session variables etc. I have a dependency inside of this base controller that I'd like to inject using Ninject however when I set this up as I would for my other dependencies I'm told by the compiler that: Error 1 'MyProject.Controllers.BaseController' does not contain a constructor that takes 0 argument This makes sense but I'm just not sure how to inject this dependency. Should I be using this pattern of using a base controller at all or should I be doing this in a more efficient/correct way?

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• Force an object to be allocated on the heap

  - by Warren Seine

  A C++ class I'm writing uses shared_from_this() to return a valid boost::shared_ptr<>. Besides, I don't want to manage memory for this kind of object. At the moment, I'm not restricting the way the user allocates the object, which causes an error if shared_from_this() is called on a stack-allocated object. I'd like to force the object to be allocated with new and managed by a smart pointer, no matter how the user declares it. I thought it could be done through a proxy or an overloaded new operator, but I can't find a proper way of doing that. Is there a common design pattern for such usage? If it's not possible, how can I test it at compile time?

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• django-haystack urlpatterns include('haystack.urls') where does it lead to?

  - by Eugene

  I've recently begun to learn/install django/haystack/solr. Following the tutorial given in haystack site, I have urlpatterns = pattern('', r'^search/', include('haystack.urls')) I found haystack installed in /usr/local/lib/python2.6/dist-packages/haystack and located urls.py there. It has urlpatterns=patterns('haystack.views', url(r'^$', SearchView(), name='haystack_search'),) I thought the second argument of url() should be callable object. I looked at the views.py and SearchView is a class. What is going on here? What's get called eventually?

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• Castle Windsor Weak Typed Factory

  - by JeffN825

  In a very very limited number of scenarios, I need to go from an unknown Type (at compile time) to an instance of the object registered for that type. For the most part, I use typed factories and I know the type I want to resolve at compile time...so I inject a Func<IMyType> into a constructor ...but in these limited number of scenarios, in order to avoid a direct call to the container (and thus having to reference Windsor from the library, which is an anti-pattern I'd like to avoid), I need to inject a Func<Type,object>...which I want to internally container.Resolve(type) for the Type parameter of the Func. Does anyone have some suggestions on the easiest/most straightforward way of setting this up? I tried the following, but with this setup, I end up bypassing the regular TypedFactoryFacility altogether which is definitely not what I want: Kernel.Register(Component.For(typeof (Func<Type, object>)).LifeStyle.Singleton.UsingFactoryMethod( (kernel, componentModel, creationContext) => kernel.Resolve(/* not sure what to put here... */))); Thanks in advance for any assistance.

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• ASP.NET MVC Filters: How to set Viewdata for Dropdown based on action parameter

  - by CRice

  Hi, Im loading an entity 'Member' from its id in route data. [ListItemsForMembershipType(true)] public ActionResult Edit(Member someMember) {...} The attribute on the action loads the membership type list items for a dropdown box and sticks it in viewdata. This is fine for add forms, and search forms (it gets all active items) but I need the attribute to execute BASED ON THE VALUE someMember.MembershipTypeId, because its current value must always be present when loading the item (i.e. all active items, plus the one from the loaded record). So the question is, what is the standard pattern for this? How can my attribute accept the value or should I be loading the viewdata for the drop down in a controller supertype or during model binding or something else? It is in an attribute now because the code to set the viewdata would otherwise be duplicated in each usage in each action.

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• What books help one to learn to read code?

  - by Daniel

  Lion's Commentary on Unix Sixth Edition with Source Code is a wonderful book to learn how to read code. Reading code is important -- how does one learn how to write excellent code without having read excellent code? But, sadly, while great writers, of fiction and non-fiction, all spend a great deal of time reading stuff, we, programmers, seem to avoid it like the plague. Worse still, programming books usually go the same way. They might show a pattern or a style, but they often avoid showing good, complex code, and helping one go through it. There are exceptions, of course. I hope. So, with that in mind, what books are to be found which help one learn how to read code?

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• Is it inefficient to access a python class member container in a loop statement?

  - by Dave

  Hi there. I'm trying to adopt some best practices to keep my python code efficient. I've heard that accessing a member variable inside of a loop can incur a dictionary lookup for every iteration of the loop, so I cache these in local variables to use inside the loop. My question is about the loop statement itself... if I have the following class: class A(object): def init(self) self.myList = [ 'a','b','c', 'd', 'e' ] Does the following code in a member function incur one, or one-per-loop-iteration (5) dictionary lookups? for letter in self.myList: print letter IE, should I adopt the following pattern, if I am concerned about efficiency... localList = self.myList for letter in localList: print letter or is that actually LESS efficient due to the local variable assign? Note, I am aware that early optimization is a dangerous pitfall if I'm concerned about the overall efficiency of code development. Here I am specifically asking about the efficiency of the code, not the coding. Thanks in advance! D

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• WPF MVVM: How do ViewModels communicate with each other?

  - by Dev1

  I have a View which has 2 sub views on it and a ViewModel is assigned to each view: ViewA - ViewModelA { ViewB - ViewModelB ViewC - ViewModelC } ViewB has a text box and ViewC has a combobox, both of which i need access from ViewModelA. Not the GUI control itself, but the bound value i.e. .Text of the textbox and .SelectedItem of the ComboBox. Currently i just have ViewModelB and ViewModelC as properties on ViewModelA but it feels wrong. What's the standard way for view models to communicate with each other without breaking the MVVM pattern? I'm completely new to WPF/MVVM.

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• How to handle recursive parent/child problems like this?

  - by lsdude

  In web dev I come across these problems a lot. For example, we have a giant list of URLs that are in this format: /businesses /businesses/food /businesses/food/wendys /businesses/food/wendys/chili /businesses/food/wendys/fries /businesses/food/wendys/chicken-nuggets /businesses/pharmacy/cvs /businesses/pharmacy/cvs/toothpaste /businesses/pharmacy/cvs/toothpaste/brand ... and then we need to output each one, where the parent category is in h1 tags, the child is in h2 tags, and the children of that are in h3 tags. I can handle this but I feel my code is messy. I'm sure there is a design pattern I can use? Langs are ruby/php usually. how would you handle this?

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• MVC - Sanitizing data, where?

  - by dierre

  I'm using CakePHP but it's a question about the MVC pattern. I have in my form the input-text for the tags (separated by commas). To add the tags I've created a Tag model method that basically check if the tag exists and then add the new tag or just a new unit in the tag counter (the Tag model has these fields: id, name, slug, count). In the controller I explode the tags field and pass one tag at a time. The question is: where do I sanitize data? In the controller or in the model method? I think it should be in the controller because that's where I explode but in term of reusability I think I should sanitize data in the model. What do you think?

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• iPhone UIImage number recognition

  - by Skeep

  Hi All, I have a small UIImage (jpg) with a single typed number. I want to be able to read the number with some kind of pattern recognition. I'm really not sure where to start, so any help would be appreciated. my initial idea was to compare this image with other images. For instance compare the image with that of a 1,2,3, etc until a match was found. That just seems slow and cumbersome and wondered if there was a better way to do it? Thanks

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• The ** idiom in C++ for object construction

  - by bobobobo

  In a lot of C++ API'S (COM-based ones spring to mind) that make something for you, the pointer to the object that is constructed is usually required as a ** pointer (and the function will construct and init it for you) You usually see signatures like: HRESULT createAnObject( int howbig, Object **objectYouWantMeToInitialize ) ; -- but you seldom see the new object being passed as a return value. Besides people wanting to see error codes, what is the reason for this? Is it better to use the ** pattern rather than a returned pointer for simpler operations such as: wchar_t* getUnicode( const char* src ) ; Or would this better be written as: void getUnicode( const char* src, wchar_t** dst ) ; The most important thing I can think of is to remember to free it, and the ** way, for some reason, tends to remind me that I have to deallocate it as well.

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• Irregular layout ItemsControl

  - by firoso

  I have a strange layout for an ItemsControl. I have a 4x6 grid with the following pattern: 1 2 3 4 13 14 15 16 5 6 7 8 17 18 19 20 9 10 11 12 21 22 23 24 Is there an easy way to do this? should I be using 6 Items Controls and take "sections" of my list? is there a good way to do this? What about notification? It's important to note that I may, or may not, have all 24 entries present, but the layout needs to be maintained (think of it like filled slots on a bingo card or something)

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• Insert A Line At The Beginnig Of A File

  - by thebourneid

  I'm trying to insert/add a line 'COMMENT DUMMY' at the beginnig of a file as a first row if /PATTERN/ not found. I know how to do this with OPEN CLOSE function. Probably after reading the file it should look something like this: open F, ">", $fn or die "could not open file: $!"; ; print F "COMMENT DUMMY\n", @array; close F; But I have a need to implement this with the use of the Tie::File function and don't know how. use strict; use warnings; use Tie::File; my $fn = 'test.txt'; tie my @lines, 'Tie::File', $fn or die "could not tie file: $!"; untie @lines;

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• Help me understand the code snippet in c#

  - by Benny

  I am reading this blog: Pipes and filters pattern I am confused by this code snippet: public class Pipeline<T> { private readonly List<IOperation<T>> operations = new List<IOperation<T>>(); public Pipeline<T> Register(IOperation<T> operation) { operations.Add(operation); return this; } public void Execute() { IEnumerable<T> current = new List<T>(); foreach (IOperation<T> operation in operations) { current = operation.Execute(current); } IEnumerator<T> enumerator = current.GetEnumerator(); while (enumerator.MoveNext()); } } what is the purpose of this statement: while (enumerator.MoveNext());? seems this code is a noop.

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• When should I use adorners?

  - by Francesco

  Hi all! WPF is great because there are many things to achieve own goals. By example, for what I understand, adorners can add some controls to a UI element, but I think that the same behavior can be achieved through a custom control that contains the additional element. So, my question is: when should I prefer adorners to a more complex (but I think, more flexible) custom control? Please consider that I'm extensively using MVVM pattern and I would like to bind commands to the additional element. Particularly, I'm designing a diagram designer application and I would like to add connection points to my shapes. Thank you

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