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  • refactor LINQ TO SQL custom properties that instantiate datacontext

    - by Thiago Silva
    I am working on an existing ASP.NET MVC app that started small and has grown with time to require a good re-architecture and refactoring. One thing that I am struggling with is that we've got partial classes of the L2S entities so we could add some extra properties, but these props create a new data context and query the DB for a subset of data. This would be the equivalent to doing the following in SQL, which is not a very good way to write this query as oppsed to joins: SELECT tbl1.stuff, (SELECT nestedValue FROM tbl2 WHERE tbl2.Foo = tbl1.Bar), tbl1.moreStuff FROM tbl1 so in short here's what we've got in some of our partial entity classes: public partial class Ticket { public StatusUpdate LastStatusUpdate { get { //this static method call returns a new DataContext but needs to be refactored var ctx = OurDataContext.GetContext(); var su = Compiled_Query_GetLastUpdate(ctx, this.TicketId); return su; } } } We've got some functions that create a compiled query, but the issue is that we also have some DataLoadOptions defined in the DataContext, and because we instantiate a new datacontext for getting these nested property, we get an exception "Compiled Queries across DataContexts with different LoadOptions not supported" . The first DataContext is coming from a DataContextFactory that we implemented with the refactorings, but this second one is just hanging off the entity property getter. We're implementing the Repository pattern in the refactoring process, so we must stop doing stuff like the above. Does anyone know of a good way to address this issue?

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  • RMI no such object in table, Server communication error

    - by ben-casey
    My goal is to create a Distributed computing program that launches a server and client at the same time. I need it to be able to install on a couple of machines and have all the machines communicating with each other, i.e. Master node and 5 slave nodes all from one application. My problem is that I cannot properly use unicastRef, I'm thinking that it is a problem with launching everything on the same port, is there a better way I am overlooking? this is part of my code (the part that matters) try { RMIServer obj = new RMIServer(); obj.start(5225); } catch (Exception e) { e.printStackTrace(); } try { System.out.println("We are slave's "); Registry rr = LocateRegistry.getRegistry("127.0.0.1", Store.PORT, new RClient()); Call ss = (Call) rr.lookup("FILLER"); System.out.println(ss.getHello()); } catch (Exception e) { e.printStackTrace(); } } this is my main class (above) this is the server class (below) public RMIServer() { } public void start(int port) throws Exception { try { Registry registry = LocateRegistry.createRegistry(port, new RClient(), new RServer()); Call stuff = new Call(); registry.bind("FILLER", stuff); System.out.println("Server ready"); } catch (Exception e) { System.err.println("Server exception: " + e.toString()); e.printStackTrace(); } } I don't know what I am missing or what I am overlooking but the output looks like this. Listen on 5225 Listen on 8776 Server ready We are slave's Listen on 8776 java.rmi.NoSuchObjectException: no such object in table at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:255) at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:233) at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:359) at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source) at Main.main(Main.java:62) line 62 is this ::: Call ss = (Call) rr.lookup("FILLER");

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  • Passing string with (accidental) escape character loses character even though it's a raw string

    - by Steen
    I have a function with a python doctest that fails because one of the test input strings has a backslash that's treated like an escape character even though I've encoded the string as a raw string. My doctest looks like this: >>> infile = [ "Todo: fix me", "/** todo: fix", "* me", "*/", r"""//\todo stuff to fix""", "TODO fix me too", "toDo bug 4663" ] >>> find_todos( infile ) ['fix me', 'fix', 'stuff to fix', 'fix me too', 'bug 4663'] And the function, which is intended to extract the todo texts from a single line following some variation over a todo specification, looks like this: todos = list() for line in infile: print line if todo_match_obj.search( line ): todos.append( todo_match_obj.search( line ).group( 'todo' ) ) And the regular expression called todo_match_obj is: r"""(?:/{0,2}\**\s?todo):?\s*(?P<todo>.+)""" A quick conversation with my ipython shell gives me: In [35]: print "//\todo" // odo In [36]: print r"""//\todo""" //\todo And, just in case the doctest implementation uses stdout (I haven't checked, sorry): In [37]: sys.stdout.write( r"""//\todo""" ) //\todo My regex-foo is not high by any standards, and I realize that I could be missing something here. EDIT: Following Alex Martellis answer, I would like suggestions on what regular expression would actually match the blasted r"""//\todo fix me""". I know that I did not originally ask for someone to do my homework, and I will accept Alex's answer as it really did answer my question (or confirm my fears). But I promise to upvote any good solutions to my problem here :) I'm using Python 2.6.4 (r264:75706, Dec 7 2009, 18:45:15) Thank you for reading this far (If you skipped directly down here, I understand)

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  • Invalidating Memcached Keys on save() in Django

    - by Zack
    I've got a view in Django that uses memcached to cache data for the more highly trafficked views that rely on a relatively static set of data. The key word is relatively: I need invalidate the memcached key for that particular URL's data when it's changed in the database. To be as clear as possible, here's the meat an' potatoes of the view (Person is a model, cache is django.core.cache.cache): def person_detail(request, slug): if request.is_ajax(): cache_key = "%s_ABOUT_%s" % settings.SITE_PREFIX, slug # Check the cache to see if we've already got this result made. json_dict = cache.get(cache_key) # Was it a cache hit? if json_dict is None: # That's a negative Ghost Rider person = get_object_or_404(Person, display = True, slug = slug) json_dict = { 'name' : person.name, 'bio' : person.bio_html, 'image' : person.image.extra_thumbnails['large'].absolute_url, } cache.set(cache_key) # json_dict will now exist, whether it's from the cache or not response = HttpResponse() response['Content-Type'] = 'text/javascript' response.write(simpljson.dumps(json_dict)) # Make sure it's all properly formatted for JS by using simplejson return response else: # This is where the fully templated response is generated What I want to do is get at that cache_key variable in it's "unformatted" form, but I'm not sure how to do this--if it can be done at all. Just in case there's already something to do this, here's what I want to do with it (this is from the Person model's hypothetical save method) def save(self): # If this is an update, the key will be cached, otherwise it won't, let's see if we can't find me try: old_self = Person.objects.get(pk=self.id) cache_key = # Voodoo magic to get that variable old_key = cache_key.format(settings.SITE_PREFIX, old_self.slug) # Generate the key currently cached cache.delete(old_key) # Hit it with both barrels of rock salt # Turns out this doesn't already exist, let's make that first request even faster by making this cache right now except DoesNotExist: # I haven't gotten to this yet. super(Person, self).save() I'm thinking about making a view class for this sorta stuff, and having functions in it like remove_cache or generate_cache since I do this sorta stuff a lot. Would that be a better idea? If so, how would I call the views in the URLconf if they're in a class?

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  • How to debug anomalous C memory/stack problems

    - by EBM
    Hello, Sorry I can't be specific with code, but the problems I am seeing are anomalous. Character string values seem to be getting changed depending on other, unrelated code. For example, the value of the argument that is passed around below will change merely depending on if I comment out one or two of the fprintf() calls! By the last fprintf() the value is typically completely empty (and no, I have checked to make sure I am not modifying the argument directly... all I have to do is comment out a fprintf() or add another fprintf() and the value of the string will change at certain points!): static process_args(char *arg) { /* debug */ fprintf(stderr, "Function arg is %s\n", arg); ...do a bunch of stuff including call another function that uses alloc()... /* debug */ fprintf(stderr, "Function arg is now %s\n", arg); } int main(int argc, char *argv[]) { char *my_arg; ... do a bunch of stuff ... /* just to show you it's nothing to do with the argv array */ my_string = strdup(argv[1]); /* debug */ fprintf(stderr, "Argument 1 is %s\n", my_string); process_args(my_string); } There's more code all around, so I can't ask for someone to debug my program -- what I want to know is HOW can I debug why character strings like this are getting their memory changed or overwritten based on unrelated code. Is my memory limited? My stack too small? How do I tell? What else can I do to track down the issue? My program isn't huge, it's like a thousand lines of code give or take and a couple dynamically linked external libs, but nothing out of the ordinary. HELP! TIA!

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  • OpenCMS - Search field of custom bean

    - by Luigi 1982
    Hi at all... I make some beans with information from VFS of OpenCMS. I want to make searchable the data of my beans. I follow this step but without success: 1) Extends my bean class with CmsSearch and ovverride init method. After I make some stuff for the constructor of my bean: /* Some stuff for CMSSearch */ /** Constant for the fields we will search */ static final String[] DOC_QRY_FIELDS = new String[] {"oggettoDocumento","dataPubblicazione", "societa"}; /** The names of our search index files */ static final String OFFLINE_INDEX = "all_bacheca"; static final String ONLINE_INDEX = "all_bacheca"; public DocumentBean(){ super(); m_parameters.setSort(CmsSearchParameters.SORT_DEFAULT); m_parameters.setFields(Arrays.asList(DocumentBean.DOC_QRY_FIELDS)); m_parameters.setIndex(ONLINE_INDEX); m_parameters.setMatchesPerPage(20); } public void init(CmsObject cms) { super.init(cms); // set search index to offline or online based on current //user project if (cms.getRequestContext().currentProject().isOnlineProject()) { m_parameters.setIndex(ONLINE_INDEX); } else { m_parameters.setIndex(OFFLINE_INDEX); } } // getters and setters.. 2) Configure a new DocumentField with the new field 3) Adding code to my jsp: <input type="hidden" name="field" value="oggettoDocumento"/> But nothing... How can I perform the custom bean search? I can't find any document.. If anyone know some info, basic.. is good for me.. Thanks!

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  • How can I make this work with deep properties

    - by Martin Robins
    Given the following code... class Program { static void Main(string[] args) { Foo foo = new Foo { Bar = new Bar { Name = "Martin" }, Name = "Martin" }; DoLambdaStuff(foo, f => f.Name); DoLambdaStuff(foo, f => f.Bar.Name); } static void DoLambdaStuff<TObject, TValue>(TObject obj, Expression<Func<TObject, TValue>> expression) { // Set up and test "getter"... Func<TObject, TValue> getValue = expression.Compile(); TValue stuff = getValue(obj); // Set up and test "setter"... ParameterExpression objectParameterExpression = Expression.Parameter(typeof(TObject)), valueParameterExpression = Expression.Parameter(typeof(TValue)); Expression<Action<TObject, TValue>> setValueExpression = Expression.Lambda<Action<TObject, TValue>>( Expression.Block( Expression.Assign(Expression.Property(objectParameterExpression, ((MemberExpression)expression.Body).Member.Name), valueParameterExpression) ), objectParameterExpression, valueParameterExpression ); Action<TObject, TValue> setValue = setValueExpression.Compile(); setValue(obj, stuff); } } class Foo { public Bar Bar { get; set; } public string Name { get; set; } } class Bar { public string Name { get; set; } } The call to DoLambdaStuff(foo, f => f.Name) works ok because I am accessing a shallow property, however the call to DoLambdaStuff(foo, f => f.Bar.Name) fails - although the creation of the getValue function works fine, the creation of the setValueExpression fails because I am attempting to access a deep property of the object. Can anybody please help me to modify this so that I can create the setValueExpression for deep properties as well as shallow? Thanks.

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  • html5 vs flash - full comparison chart anywhere?

    - by iddqd
    So since Steve Jobs said Flash sucks and implied that HTML5 can do everything Flash can without the need for a Plugin, I keep hearing those exact words from a lot of People. I would really like to have a Chart somewhere (similar to http://en.wikipedia.org/wiki/Comparison_of_layout_engines_%28HTML5%29#Form_elements_and_attributes ) that I can just show to those people. Showing all the little things that Flash can do right now, that HTML5/Ajax/CSS is not yet even thinking about. But of course also the things that HTML5 does better. I would like to see details compared like audio playback, realtime audio processing, byte level access, bitmap data manipulation, webcam access, binary sockets, stuff in the works such as P2P technology (adobe stratus) and all the stuff I don't know about myself. Ideally with examples of what can be accomplished with, lets say Binary Sockets (such as a POP3 client) because otherwise it won't mean a lot to non-programmers since they will just say "well we can do without Binary Sockets". And ideally with some current benchmarks and some examples of websites that use this technology. I've searched the web and am surprised not to find anything. So is there such a comparison somewhere? Or does anybody want to create this and post it to Wikipedia? ;-)

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  • xml declaration not being omitted from page

    - by Mark Schultheiss
    I have an XSLT transform I am using to process an XML file, inserting it into the body of my aspx page. Reference the following for background information: background on xml/xslt I have the following in my xml file: <?xml version="1.0" encoding="utf-8"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:msxsl="urn:schemas-microsoft-com:xslt" exclude-result-prefixes="msxsl" xmlns:myCustomStrings="urn:customStrings"> <xsl:output method="xml" version="2.0" media-type="text/html" omit-xml-declaration="yes" indent="yes" />...unrelated stuff left out here Here is the output that is relevent: <div id="example" /> <?xml version="1.0" encoding="utf-8"?><div xmlns:myCustomStrings="urn:customStrings"><div id="imFormBody" class="imFormBody"> My question relates to the output, specifically to the <?xml version="1.0" encoding="utf-8"?> which is getting included in the output anyway. Is the issue related to the custom method I have used? If so, I don't really see the need to include the xml part as the namespace is in the div tag. Is there a way to ensure that this extra stuff gets left out as I asked it to?

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  • How to write C++ audio processing applications?

    - by cesko82
    Hi everyone, I'm an Electronics and Telecommunications student, next to my graduation. I'm gonna work on a project that involves my knowledge about DSP, music and audio in general. I allready know all the basic mathematic instruments and all the stuff I need to manage it, such as FFT, circular convolution ecc ecc. I want to learn C++ programming basically for one reason: it's very important in the professional world!!! And I think it's one of the most used to write applications working with audio, especially when it's about real time processing. Ok, after this small introduction I would like to know first, which are the most used libraries to work with audio processing in c++?? I was longer looking on the web but i couldn't find a lo of working stuff. (I work under linux with eclipse CDT enviroment). Then I would like to know if there are good sources to learn how to write some working code, such as for example how to write a simple low pass filter. Basically now i will not write real time applications, I would like to start from the processing of a WAV file, or even better an MP3 file, so basically on vectors of samples. Let's say that basically for now I would like to extract the waveform from an audio file, and save it to a thumbnail or to a PNG image. Ok, for now I think it's all I would need. Any ideas, advices, libraries, books, interesting sources about that? Thanks a lot in advance for any kind of answer. Giovanni.

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  • How do I get a UIView to appear instantly?

    - by matsgrip
    I'm trying to create an activity indicator in iPhone app. The problem is that I cannot get it to appear before the actual task i want it to diplay during is already done. Is there something funky about the order in which the iPhone does stuff? Here is my problematic code (in my app delegate): -(BOOL)showProgressView: (NSString *) message { self.progress = [[UIView alloc] initWithFrame:window.frame]; UIImageView *img = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"squircle.png"]]; [img setAlpha:0.5]; [img setFrame:CGRectMake(94, 173, 133, 133)]; UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(51.5, 51.5, 30, 30)]; spinner.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhiteLarge; [img addSubview:spinner]; [self.progress addSubview:img]; [spinner startAnimating]; [img release]; [spinner release]; [window addSubview:self.progress]; return YES; } I then call this code like this: if ([appDelegate showProgressView:@"Loading..:"]) { //My actual code loads data and stuff here but that is not important //drawCtrl is a UIViewController subclass that is instantiated here UINavigationController *navController = [appDelegate navigationController]; [navController pushViewController:drawCtrl animated:YES]; [drawCtrl release]; } The problem is that my activity indicator does not appear until the new view controller is pushed onto the navController's stack. Can I control this in some way? Thanks in advance! -Mats

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  • Is there a PHP library that performs MySQL Data Validation and Sanitization According to Column Type

    - by JW
    Do you know of any open source library or framework that can perform some basic validation and escaping functionality for a MySQL Db. i envisage something along the lines of: //give it something to perform the quote() quoteInto() methods $lib->setSanitizor($MyZend_DBAdaptor); //tell it structure of the table - colnames/coltypes/ etc $lib->setTableDescription($tableDescArray); //use it to validate and escape according to coltype foreach ($prospectiveData as $colName => $rawValue) if ( $lib->isValid($colName, $rawValue)) { //add it to the set clause $setValuesArray[$lib->escapeIdentifier($colName);] = $lib->getEscapedValue($colName,$rawValue); } else { throw new Exception($colName->getErrorMessage()); } etc... I have looked into - Zend_Db_Table (which knows about a table's description), and - Zend_Db_Adaptor (which knows how to escape/sanitize values depending on TYPE) but they do not automatically do any clever stuff during updates/inserts Anyone know of a good PHP library to preform this kind of validation that I could use rather than writing my own? i envisage alot of this kind of stuff: ... elseif (eregi('^INT|^INTEGER',$dataset_element_arr[col_type])) { $datatype='int'; if (eregi('unsigned',$dataset_element_arr[col_type])) { $int_max_val=4294967296; $int_min_val=0; } else { $int_max_val=2147483647; $int_min_val=-2147483648; } } (p.s I know eregi is deprecated - its just an example of laborious code)

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  • Static variable not initialized

    - by Simon Linder
    Hi all, I've got a strange problem with a static variable that is obviously not initialized as it should be. I have a huge project that runs with Windows and Linux. As the Linux developer doesn't have this problem I would suggest that this is some kind of wired Visual Studio stuff. Header file class MyClass { // some other stuff here ... private: static AnotherClass* const Default_; }; CPP file AnotherClass* const Default_(new AnotherClass("")); MyClass(AnotherClass* const var) { assert(Default_); ... } Problem is that Default_is always NULL. I also tried a breakpoint at the initialization of that variable but I cannot catch it. There is a similar problem in another class. CPP file std::string const MyClass::MyString_ ("someText"); MyClass::MyClass() { assert(MyString_ != ""); ... } In this case MyString_is always empty. So again not initialized. Does anyone have an idea about that? Is this a Visual Studio settings problem? Cheers Simon

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  • How Can I Generate Equivalent Output Using the CryptoAPI and the .NET Encryption (TripleDESCryptoSer

    - by S. Butts
    I have some C#/.NET code that encrypts and decrypts data using TripleDES encryption. It sticks to the sample code provided at MSDN pretty closely. The encryption piece looks like the following: TripleDESCryptoServiceProvider _desProvider = new TripleDESCryptoServiceProvider(); //bytes for key and initialization vector //keyBytes is 24 bytes of stuff, vectorBytes is 8 bytes of stuff byte[] keyBytes; byte[] vectorBytes; FileStream fStream = File.Open(locationOfFile, FileMode.Create, FileAccess.Write); CryptoStream cStream = new CryptoStream(fStream, _desProvider.CreateEncryptor(keyBytes, vectorBytes), CryptoStreamMode.Write); BinaryWriter bWriter = new BinaryWriter(cStream); //write out encrypted data //raw data is a few bytes of binary information byte[] rawData; bWriter.Write(rawData); With encrypting and decrypting in C#, this all works like a charm. The problem is I need to write a small Win32 utility that will duplicate the encryption above. I have tried several methods using the CryptoAPI, and I simply do not get output that the .NET piece can decrypt, no matter what I do. Can someone please tell me what the equivalent C++ code is that will produce the same output? I am not certain just what methods of the CryptoAPI the .NET functions use to encrypt the data. What options are used, and what method of generating the key is used? Before someone suggests that I just write it in C# anyway, or create some common library bridge for them, those options are unfortunately off the table. It really has to work in Win32 with .NET and without using a DLL. I have some leeway in changing the C# code. I apologize in advance if this is bone-headed, as I am new to encryption.

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  • Flex: embedded fonts not being applied correctly in Label and DataGrid

    - by lje
    Folks, I am observing a problem with how an embedded font is applied to certain Flex components, namely mx:Label and mx:DataGrid. I have a CSS that declares three variations on an embedded font as follows: @font-face { src:url("buttons.swf"); font-family: "Arial"; } @font-face { src:url("buttons.swf"); font-family: "Arial"; font-weight: bold; } @font-face { src:url("buttons.swf"); font-family: "Arial"; font-style: italic; } And in the style declaration for Label and DataGrid, I have: Label { fontFamily: "Arial"; fontSize: 11; fontFamily: LucidaSans; } and DataGrid { fontFamily: "Arial"; height: 16; } (I've snipped some stuff from both style rules, so if you think there's something that may be causing a conflict I can certainly post the entire definition. It's mostly color, line and padding stuff for the DataGrid.) The problem that is for both Label and cells in the DataGrid the text is being rendered as sort of a times new roman font. The headers in the DataGrid are fine, just the text in the cells is wonky. All other components use the correct font as defined in the CSS/SWF. Any ideas why this is happening?

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  • How to avoid loading a LINQ to SQL object twice when editting it on a website.

    - by emzero
    Hi guys I know you are all tired of this Linq-to-Sql questions, but I'm barely starting to use it (never used an ORM before) and I've already find some "ugly" things. I'm pretty used to ASP.NET Webforms old school developing, but I want to leave that behind and learn the new stuff (I've just started to read a ASP.NET MVC book and a .NET 3.5/4.0 one). So here's is one thing I didn't like and I couldn't find a good alternative to it. In most examples of editing a LINQ object I've seen the object is loaded (hitting the db) at first to fill the current values on the form page. Then, the user modify some fields and when the "Save" button is clicked, the object is loaded for second time and then updated. Here's a simplified example of ScottGu NerdDinner site. // // GET: /Dinners/Edit/5 [Authorize] public ActionResult Edit(int id) { Dinner dinner = dinnerRepository.GetDinner(id); return View(new DinnerFormViewModel(dinner)); } // // POST: /Dinners/Edit/5 [AcceptVerbs(HttpVerbs.Post), Authorize] public ActionResult Edit(int id, FormCollection collection) { Dinner dinner = dinnerRepository.GetDinner(id); UpdateModel(dinner); dinnerRepository.Save(); return RedirectToAction("Details", new { id=dinner.DinnerID }); } As you can see the dinner object is loaded two times for every modification. Unless I'm missing something about LINQ to SQL caching the last queried objects or something like that I don't like getting it twice when it should be retrieved only one time, modified and then comitted back to the database. So again, am I really missing something? Or is it really hitting the database twice (in the example above it won't harm, but there could be cases that getting an object or set of objects could be heavy stuff). If so, what alternative do you think is the best to avoid double-loading the object? Thank you so much, Greetings!

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  • making my player sprite land on top of my platform sprite

    - by Stone
    Hi, in my XNA game(im fairly new to XNA by the way) i would like to have my player sprite land on top of a platform. i have a player sprite class that inherits from my regular sprite class, and the regular sprite class for basic non playable sprite stuff such as boxes, background stuff, and platforms. However, i am unsure how to implement a way to make my player sprite land on a platform. My player Sprite can jump and move around, but i dont know where and how to check to see if it is on top of my platform sprite. My player sprites jump method is here private void Jump() { if (mCurrentState != State.Jumping) { mCurrentState = State.Jumping; mStartingPosition = Position; mDirection.Y = MOVE_UP; mSpeed = new Vector2(jumpSpeed, jumpSpeed); } } mStartingPosition is player sprites starting position of the jump, and Position is the player sprites current position. I would think that my code for checking to see whether my player sprite is on top of my platform sprite. I am unsure how to reference my platform sprite inside of the playersprite class and inside of the jump method. i think it should be something like this //platformSprite.CollisonBox would be the rectangle around the platform, but im not //sure how to check to see if player.Position is touching any point //on platformSprite.CollisionBox if(player.Position == platformSprite.CollisionBox) { player.mDirection = 0; } Again im pretty new to programming and XNA, and some of this logic i dont quite understand so any help on any of it would be greatly appreciated:D Thanks

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  • notify listener inside or outside inner synchronization

    - by Jary Zeels
    Hello all, I am struggling with a decision. I am writing a thread-safe library/API. Listeners can be registered, so the client is notified when something interesting happens. Which of the two implementations is most common? class MyModule { protected Listener listener; protected void somethingHappens() { synchronized(this) { ... do useful stuff ... listener.notify(); } } } or class MyModule { protected Listener listener; protected void somethingHappens() { Listener l = null; synchronized(this) { ... do useful stuff ... l = listener; } l.notify(); } } In the first implementation, the listener is notified inside the synchronization. In the second implementation, this is done outside the synchronization. I feel that the second one is advised, as it makes less room for potential deadlocks. But I am having trouble to convince myself. A downside of the second imlementation is that the client might receive 'incorrect' notifications, which happens if it accessed the module prior to the l.notify() statement. thanks a lot

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  • Should I use a collection here?

    - by Eva
    So I have code set up like this: public interface IInterface { public void setField(Object field); } public abstract class AbstractClass extends JPanel implements IInterface { private Object field_; public void setField(Object field) { field_ = field; } } public class ClassA extends AbstractClass { public ClassA() { // unique ClassA constructor stuff } public Dimension getPreferredSize() { return new Dimension(1, 1); } } public class ClassB extends AbstractClass { public ClassB() { // unique ClassB constructor stuff } public Dimension getPreferredSize() { return new Dimension(42, 42); } } public class ConsumerA { public ConsumerA(Collection<AbstractClass> collection) { for (AbstractClass abstractClass : collection) { abstractClass.setField(this); abstractClass.repaint(); } } } All hunky-dory so far, until public class ConsumerB { // Option 1 public ConsumerB(ClassA a, ClassB b) { methodThatOnlyTakesA(a); methodThatOnlyTakesB(b); } // Option 2 public ConsumerB(Collection<AbstractClass> collection) { for (IInterface i : collection) { if (i instanceof ClassA) { methodThatOnlyTakesA((ClassA) i); else if (i instanceof ClassB) { methodThatOnlyTakesB((ClassB) i); } } } } public class UsingOption1 { public static void main(String[] args) { ClassA a = new ClassA(); ClassB b = new ClassB(); Collection<AbstractClass> collection = Arrays.asList(a, b); ConsumerA consumerA = new ConsumerA(collection); ConsumerB consumerB = new ConsumerB(a, b); } } public class UsingOption2 { public static void main(String[] args) { Collection<AbstractClass> collection = Arrays.asList(new ClassA(), new ClassB()); ConsumerA = new ConsumerA(collection); ConsumerB = new ConsumerB(collection); } } With a lot more classes extending AbstractClass, both options get unwieldly. Option1 would make the constructor of ConsumerB really long. Also UsingOption1 would get long too. Option2 would have way more if statements than I feel comfortable with. Is there a viable Option3? If it helps, ClassA and ClassB have all the same methods, they're just implemented differently. Thanks for slogging through my code!

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  • cannot override a concrete member without a third member that's overridden by both

    - by huynhjl
    What does the following error message mean? cannot override a concrete member without a third member that's overridden by both (this rule is designed to prevent ``accidental overrides''); I was trying to do stackable trait modifications. It's a little bit after the fact since I already have a hierarchy in place and I'm trying to modify the behavior without having to rewrite a lot of code. I have a base class called AbstractProcessor that defines an abstract method sort of like this: class AbstractProcessor { def onPush(i:Info): Unit } I have a couple existing traits, to implement different onPush behaviors. trait Pass1 { def onPush(i:Info): Unit = { ... } } trait Pass2 { def onPush(i:Info): Unit = { ... } } So that allows me to use new AbstractProcessor with Pass1 or new AbstractProcessor with Pass2. Now I would like to do some processing before and after the onPush call in Pass1 and Pass2 while minimizing code changes to AbstractProcessor and Pass1 and Pass2. I thought of creating a trait that does something like this: trait Custom extends AbstractProcessor { abstract override def onPush(i:Info): Unit = { // do stuff before super.onPush(i) // do stuff after } And using it with new AbstractProcessor with Pass1 with Custom and I got that error message.

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  • Properly declare delegation in Objective C (iPhone)

    - by Gordon Fontenot
    Ok, This has been explained a few times (I got most of the way there using this post on SO), but I am missing something. I am able to compile cleanly, and able to set the delegate as well as call methods from the delegate, but I'm getting a warning on build: No definition of protocol 'DetailViewControllerDelegate' is found I have a DetailViewController and a RootViewController only. I am calling a method in RootViewController from DetailViewController. I have the delegate set up as so: In RootViewController.h: #import "DetailViewController.h" @interface RootViewController : UITableViewController <NSFetchedResultsControllerDelegate, DetailViewControllerDelegate> //Error shows up here { //Some Stuff Here } //Some other stuff here @end In RootViewController.m I define the delegate when I create the view using detailViewController.delegate = self In DetailViewController.h: @protocol DetailViewControllerDelegate; #import "RootViewController.h" @interface DetailViewController : UITableViewController <UITextFieldDelegate> { id <DetailViewControllerDelegate> delegate; } @property (nonatomic, assign) id <DetailViewControllerDelegate> delegate; @end @protocol DetailViewControllerDelegate //some methods that reside in RootViewController.m @end I feel weird about declaring the protocol above the import in DetailViewController.h, but if I don't it doesn't build. Like I said, the methods are called fine, and there are no other errors going on. What am I missing here?

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  • Test multiple domains using ASP.NET development server

    - by Pete Lunenfeld
    I am developing a single web application that will dynamically change its content depending on which domain name is used to reach the site. Multiple domains will point to the same application. I wish to use the following code (or something close) to detect the domain name and perform the customizations: string theDomainName = Request.Url.Host; switch (theDomainName) { case "www.clientone.com": // do stuff break; case "www.clienttwo.com": // do other stuff break; } I would like to test the functionality of the above using the ASP.NET development server. I created mappings in the local HOSTS file to map www.clientone.com to 127.0.0.1, and www.clienttwo.com to 127.0.0.1. I then browse to the application with the browser using www.clinetone.com (etc). When I try to test this code using the ASP.net development server the URL always says localhost. It does NOT capture the host entered in the browser, only localhost. Is there a way to test the URL detection functionality using the development server? Thanks.

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  • need primitive public key signature with out of band key distribution

    - by Mike D
    I pretty much a complete neophyte at this signature business so I don't know if what I'm asking is nonsense or not. Anyway, here goes... I want to send an out of band message (don't worry about how it gets there) to a program I've written on a distant machine. I want the program to have some confidence the message is legit by attaching a digital signature to the message. The message will be small less than 200 characters. It seems a public key based signature is what I want to use. I could embed the public key in the program. I understand that the program would be vulnerable to attack by anyone who modifies it BUT I'm not too worried about that. The consequences are not dire. I've looked through the MSDN and around the web but the prospect of diving in is daunting. I'm writing in straight c++, no NET framework or other fancy stuff. I've had no experience including NET framework stuff and little luck during previous attempts. Can anyone point me at some very basic resources to get me started? I need to know 1)how to generate the public and private keys 2)how to sign the message 3)how to verify the signature Any help much appreciated. TIA, Mike

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  • jQuery - Callback failing if there is no options parameter

    - by user249950
    Hi, I'm attempting to build a simple plugin like this (function($) { $.fn.gpSlideOut = function(options, callback) { // default options - these are used when no others are specified $.fn.gpSlideOut.defaults = { fadeToColour: "#ffffb3", fadeToColourSpeed: 500, slideUpSpeed: 400 }; // build main options before element iteration var o = $.extend({}, $.fn.gpSlideOut.defaults, options); this.each(function() { $(this) .animate({backgroundColor: o.fadeToColour},o.fadeToColourSpeed) .slideUp(o.SlideUpSpeed, function(){ if (typeof callback == 'function') { // make sure the callback is a function callback.call(this); // brings the scope to the callback } }); }); return this; }; // invoke the function we just created passing it the jQuery object })(jQuery); The confusion I'm having is that normally on jQuery plugins you can call something like this: $(this_moveable_item).gpSlideOut(function() { // Do stuff }); Without the options parameter, but it misses the callback if I do it like that so I have to always have var options = {} $(this_moveable_item).gpSlideOut(options, function() { // Do stuff }); Even if I only want to use the defaults. Is there anyway to make sure the callback function is called whether or not the options parameter is there? Cheers.

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  • Haskell math performance

    - by Travis Brown
    I'm in the middle of porting David Blei's original C implementation of Latent Dirichlet Allocation to Haskell, and I'm trying to decide whether to leave some of the low-level stuff in C. The following function is one example—it's an approximation of the second derivative of lgamma: double trigamma(double x) { double p; int i; x=x+6; p=1/(x*x); p=(((((0.075757575757576*p-0.033333333333333)*p+0.0238095238095238) *p-0.033333333333333)*p+0.166666666666667)*p+1)/x+0.5*p; for (i=0; i<6 ;i++) { x=x-1; p=1/(x*x)+p; } return(p); } I've translated this into more or less idiomatic Haskell as follows: trigamma :: Double -> Double trigamma x = snd $ last $ take 7 $ iterate next (x' - 1, p') where x' = x + 6 p = 1 / x' ^ 2 p' = p / 2 + c / x' c = foldr1 (\a b -> (a + b * p)) [1, 1/6, -1/30, 1/42, -1/30, 5/66] next (x, p) = (x - 1, 1 / x ^ 2 + p) The problem is that when I run both through Criterion, my Haskell version is six or seven times slower (I'm compiling with -O2 on GHC 6.12.1). Some similar functions are even worse. I know practically nothing about Haskell performance, and I'm not terribly interested in digging through Core or anything like that, since I can always just call the handful of math-intensive C functions through FFI. But I'm curious about whether there's low-hanging fruit that I'm missing—some kind of extension or library or annotation that I could use to speed up this numeric stuff without making it too ugly.

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