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  • Should conditional expressions go inside or outside of classes?

    - by Rupert
    It seems that often I will want to execute some methods from a Class when I call it and choosing which function will depend on some condition. This leads me to write classes like in Case 1 because it allows me to rapidly include their functionality. The alternative would be Case 2 which can take a lot of time if there is a lot of code and also means more code being written twice when I drop the Class into different pages. Having said that, Case 1 feels very wrong for some reason that I can't quite put my finger on. I haven't really seen any classes written like this, I suppose. Is there anything wrong with writing classes like in Case 1 or is Case 2 superior? Or is there a better way? What the advantages and disadvantages of each? Case 1 class Foo { public function __construct($bar) { if($bar = 'action1') $this->method1(); else if($bar = 'action2') $this->method2(); else $this->method1(); } public function method1() { } public function method2() { } } $bar = 'action1' $foo = new Foo($bar); Case 2 class Foo { public function __construct() { } public function method1() { } public function method2() { } } $foo = new Foo; $bar = 'action1'; if($bar == 'action1') $foo->method1(); else if($bar == 'action2') $foo->method2(); else $foo->method1();

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  • Java: Tracking a user login session - Session EJBs vs HTTPSession

    - by bguiz
    If I want to keep track of a conversational state with each client using my web application, which is the better alternative - a Session Bean or a HTTP Session - to use? Using HTTP Session: //request is a variable of the class javax.servlet.http.HttpServletRequest //UserState is a POJO HttpSession session = request.getSession(true); UserState state = (UserState)(session.getAttribute("UserState")); if (state == null) { //create default value .. } String uid = state.getUID(); //now do things with the user id Using Session EJB: In the implementation of ServletContextListener registered as a Web Application Listener in WEB-INF/web.xml: //UserState NOT a POJO this this time, it is //the interface of the UserStateBean Stateful Session EJB @EJB private UserState userStateBean; public void contextInitialized(ServletContextEvent sce) { ServletContext servletContext = sce.getServletContext(); servletContext.setAttribute("UserState", userStateBean); ... In a JSP: public void jspInit() { UserState state = (UserState)(getServletContext().getAttribute("UserState")); ... } Elsewhere in the body of the same JSP: String uid = state.getUID(); //now do things with the user id It seems to me that the they are almost the same, with the main difference being that the UserState instance is being transported in the HttpRequest.HttpSession in the former, and in a ServletContext in the case of the latter. Which of the two methods is more robust, and why?

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  • How to unit test generic classes

    - by Rowland Shaw
    I'm trying to set up some unit tests for an existing compact framework class library. However, I've fallen at the first hurdle, where it appears that the test framework is unable to load the types involved (even though they're both in the class library being tested) Test method MyLibrary.Tests.MyGenericClassTest.MyMethodTest threw exception: System.MissingMethodException: Could not load type 'MyLibrary.MyType' from assembly 'MyLibrary, Version=1.0.3778.36113, Culture=neutral, PublicKeyToken=null'.. My code is loosely: public class MyGenericClass<T> : List<T> where T : MyType, new() { public bool MyMethod(T foo) { throw new NotImplementedException(); } } With test methods: public void MyMethodTestHelper<T>() where T : MyType, new() { MyGenericClass<T> target = new MyGenericClass<T>(); foo = new T(); expected = true; actual = target.MyMethod(foo); Assert.AreEqual(expected, actual); } [TestMethod()] public void MyMethodTest() { MyMethodTestHelper<MyType>(); } I'm a bit stumped though, as I can't even get it to break in the debugger to get to the inner exception, so what else do I check? EDIT this does seem to be something specific to the Compact Framework - recompiling the class libraries and the unit tests for the full framework, gives the expected output (i.e. the debugger stops when I'm going to throw a NotImplementedException).

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  • What's the most efficient way to load data from a file to a collection on-demand?

    - by Dan
    I'm working on a java project that will allows users to parse multiple files with potentially thousands of lines. The information parsed will be stored in different objects, which then will be added to a collection. Since the GUI won't require to load ALL these objects at once and keep them in memory, I'm looking for an efficient way to load/unload data from files, so that data is only loaded into the collection when a user requests it. I'm just evaluation options right now. I've also thought of the case where, after loading a subset of the data into the collection, and presenting it on the GUI, the best way to reload the previously observed data. Re-run the parser/Populate collection/Populate GUI? or probably find a way to keep the collection into memory, or serialize/deserialize the collection itself? I know that loading/unloading subsets of data can get tricky if some sort of data filtering is performed. Let's say that I filter on ID, so my new subset will contain data from two previous analyzed subsets. This would be no problem is I keep a master copy of the whole data in memory. I've read that google-collections are good and efficient when handling big amounts of data, and offer methods that simplify lots of things so this might offer an alternative to allow me to keep the collection in memory. This is just general talking. The question on what collection to use is a separate and complex thing. Do you know what's the general recommendation on this type of task? I'd like to hear what you've done with similar scenarios. I can provide more specifics if needed.

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  • Strange behavior while returning csv file from spring controller

    - by Fanooos
    I working in a spring application which have an action method that returns a CSV file. This action works fine but in some cases it throws a predefined exception (MyAppException). I have another method that is annotated @ExceptionHandler(MyAppException.class) In the exception handler method I return another csv file but with different contents. The code that returns the csv file is almost the same in the two methods. List<String[]> list= new ArrayList<String[]>(); list.add(new String[]{ integrationRequestErrorLog.getErrorMessage(), Long.toString(integrationRequestErrorLog.getId()), Integer.toString(integrationRequestErrorLog.getErrorCode()) }); CSVWriter writer = new CSVWriter(response.getWriter(), ','); writer.writeAll(list); writer.close(); the difference between the two method is the list of contents. In the first method the file is returned normally while in the exception handler method I have a strange behavior. The exception handler method works fine with Opera browser while it gives me a 404 with FireFox. Opera browser give me 404 also but it download the file while firefox does not? Really I do not understand what is the difference here.

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  • correct way of initializing variables

    - by OVERTONE
    ok this is just a shot in the dark but it may be the cause of most of the errors ive gotten. when your initializing something. lets say a smal swing program. would it go liek this variables here { private Jlist contactList; String [] contactArray; ArrayList <String> contactArrayList; ResultSet namesList constructor here public whatever() { GridLayout aGrid = new GridLayout(2,2,10,10); contact1 = new String(); contact2 = new String(); contact3 = new String(); contactArrayList = new ArrayList<String>(); // is something supposed too go in the () of this JList? contactList = new JList(); contactArray = new String[5]; from1 =new JLabel ("From: " + contactArray[1]); gridlayout.add(components)// theres too many components to write onto SO. } // methods here public void fillContactsGui() { createConnection(); ArrayList<String> contactsArrayList = new ArrayList<String>(); while (namesList.next()) { contactArrayList.add(namesList.getString(1)); ContactArray[1] = namesList[1]; } } i know this is probably a huge beginner question but this is the code ive gotten used too. im initializing thigns three and fours times without meaning too because im not sure where they gp. can anyone shed some light on this? p.s. sorry for the messy sample code. i done my best.

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  • Pre-formatting text to prevent reflowing

    - by mattjn
    I've written a fairly simple script that will take elements (in this case, <p> elements are the main concern) and type their contents out like a typewriter, one by one. The problem is that as it types, when it reaches the edge of the container mid-word, it reflows the text and jumps to the next line (like word wrap in any text editor). This is, of course, expected behavior; however, I would like to pre-format the text so that this does not happen. I figure that inserting <br> before the word that will wrap would be the best solution, but I'm not quite sure what the best way to go about doing that is that supports all font sizes and container widths, while also keeping any HTML tags intact. I figure something involving a hidden <span> element, adding text to it gradually and checking its width against the container width might be on the right track, but I'm not quite sure how to actually put this together. Any help or suggestions on better methods would be appreciated.

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  • Array passing between classes, gone?

    - by Kenneth
    Hey guys . i have two classes, SelectionScreenTable & GraphView. In the SelectionScreenTable class .h, i declared a NSMutableArray called usagedatas NSMutableArray *usagedatas; } @property (nonatomic, retain) NSMutableArray *usagedatas; In the SelectionScreenTable class.m i remembered to @synthesize. Later on, while processing my methods, i did a NSLog(@"usagedatas count:%i",usagedatas.count); to check whether it has value and it returned 1. so yeah its good up to this point. And in the -(void) dealloc , i remembered to released it . [usagedatas release]; So now comes ME trying to use it in another class. In GraphView.m i imported the "SelectionScreenTable.h". in the -(void)viewDidLoad i did SelectionScreenTable *UD = [SelectionScreenTable alloc]; NSLog(@"GraphView UD.usagedataas.count = :%i",UD.usagedatas.count); it returned 0. Any idea guys?

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  • Flex vs GWT again

    - by CK Lee
    Hi all, I am working on a customized web ontology editor (something like http://webprotege.stanford.edu/ which is built by GWT). My backend will be Java+Spring+Hibernate and domain models are in Java. My frontend will be something like WebProtege which requires extensive RPC call. It is quite clear that I should use GWT as I can refer to the open source code. However, due to company policy, I shall consider Flex as well. I understand Flex can remotely invoke Java backend methods via BlazeDS using AMF (Is there a Flex equivalent of GWT-RPC?). I have read discussion on GWT vs Flex vs ?. If I can make full decision sure I will go with GWT. GWT strengths like support right to left characters, support iPhone/iPad, smaller size, support JSON out of the box, support printing are not important considerations for my project. Besides GWT supports Java generic, enum; domain objects can be shared with both GWT client and server; coding are more seamlessly... anyone can suggest other strong reasons that I should only go with GWT? FYI, I have plenty of Java experience but both GWT and Flex are new to me. Thanks.

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  • Use of unassigned local variable 'xxx'

    - by Tomislav
    I'm writing a database importer from our competitors to ours database:) I have a code generator which create Methods form import to our database like public void Test_Import_Customer_1() // variables string conn; string sqlSelect; string sqlInsert; int extID; string name; string name2; DateTime date_inserted; sqlSelect="select id,name,date_inserted from table_competitors_1"; oledbreader reader = new GetOledbRader(sqlString,conn); while (reader.read()) { name=left((string)myreader["name"],50); //limitation of my field date_inserted=myreader["date_inserted"]; sqlInsert=string.Format("insert into table(name,name2,date_inserted)values '{0}', '{1}', {2})",name,name2,date_inserted); //here is the problem name2 "Use of unassigned local variable" ExecuteSQL(sqlInsert) } As different companies database has different fields i can not set value to each variable and there is a big number of tables to go one variable to next. like sqlSelect_Company_1 = "select name,date_inserted from table_1"; sqlSelect_Company_2 = "select name,name2 from table_2"; is there a way to override the typing of each variable one by one with default values?

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  • How do i integrate paypal in my website? Java

    - by Nitesh Panchal
    Hello, I want to integrate paypal in my java web application. I saw that they offer many methods to accomplish this. But i want my visitors to remain on my site only. My friend told me that Paypal offers webservice. But i can't seem to find any documentation on Paypal site. If anybody could help me with this, i would be really very grateful. Please offer me the relevant links on Paypal where i could read and get my things done. Secondly, my friend also told me that we need to give location to paypal where my visitors would be redirected once paypal payment is complete. But i am confused. I am working on localhost. How would Paypal know about my localhost? I have already created my sandbox testing account. What should be my next step. Please explain me in detail. I don't know anything about Paypal. Once i created a demo application of Express checkout where they give a simple button of Pay Now and on clicking on it shopping cart etc appears. But now i want my visitors to stay on same website. Thanks in advance :)

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  • Rapid taps on an OpenGL ES app introducing input delay

    - by Tim R.
    I am starting out writing a 2D game in OpenGL ES, and I have encountered an odd problem: if I rapidly tap the touchscreen, the input starts lagging behind the display. The more times I tap, the more delay it causes between the input and any indication of that input onscreen. It only happens if I intentionally tap very rapidly, but not from tapping and dragging with any number of fingers. What could be causing this? Excessive details follow: Both accelerometer input and taps are delayed by just tapping. The only events I am responding to are touchesBegan (below) in my EAGLView and accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration in my Game object. There doesn't seem to be any upper limit to the amount of delay: I've gotten up to 12 seconds of delay by tapping rapidly with five fingers. I have not seen any drops in framerate (it stays constantly at 60 fps) in the OpenGL ES tool in Instruments or by taking 1/the time between updates. Possibly relevant code: - (void) drawView:(id) sender { [game update:allTouches]; [renderer render:game]; } -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { allTouches = [event allTouches]; } allTouches is a pointer that gets passed to my Game every update, which passes it to each GameObject in their update methods.

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  • iPhone development - app design patterns

    - by occulus
    There are tons of resources concerning coding on the iPhone. Most of them concern "how do I do X", e.g. "setup a navigation controller", or "download text from a URL". All good and fine. What I'm more interested in now are the questions that follow the simpler stuff - how to best structure your complex UI, or your app, or the common problems that arise. To illustrate: a book like "Beginning iPhone 3 Development" tells you how to set up a multi viewcontroller app with an top 'switcher' viewcontroller that switches between views owned by other view controllers. Fine, but you're only told how to do that, and nothing about the problems that can follow: for example, if I use their paradigm to switch to a UINavigationViewController, the Navigation bar ends up too low on the screen, because UINavigationViewController expects to be the topmost UIViewController (apparently). Also, delegate methods (e.g. relating to orientation changes) go to the top switcher view controller, not the actual controller responsible for the current view. I have fixes for these things but they feel like hacks which makes me unhappy and makes me feel like I'm missing something. One productive thing might be to look at some open source iPhone projects (see this question). But aside from that?

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  • When should EntityManagerFactory instance be created/opened ?

    - by masato-san
    Ok, I read bunch of articles/examples how to write Entity Manager Factory in singleton. One of them easiest for me to understand a bit: http://javanotepad.blogspot.com/2007/05/jpa-entitymanagerfactory-in-web.html I learned that EntityManagerFactory (EMF) should only be created once preferably in application scope. And also make sure to close the EMF once it's used (?) So I wrote EMF helper class for business methods to use: public class EmProvider { private static final String DB_PU = "KogaAlphaPU"; public static final boolean DEBUG = true; private static final EmProvider singleton = new EmProvider(); private EntityManagerFactory emf; private EmProvider() {} public static EmProvider getInstance() { return singleton; } public EntityManagerFactory getEntityManagerFactory() { if(emf == null) { emf = Persistence.createEntityManagerFactory(DB_PU); } if(DEBUG) { System.out.println("factory created on: " + new Date()); } return emf; } public void closeEmf() { if(emf.isOpen() || emf != null) { emf.close(); } emf = null; if(DEBUG) { System.out.println("EMF closed at: " + new Date()); } } }//end class And my method using EmProvider: public String foo() { EntityManager em = null; List<Object[]> out = null; try { em = EmProvider.getInstance().getEntityManagerFactory().createEntityManager(); Query query = em.createNativeQuery(JPQL_JOIN); //just some random query out = query.getResultList(); } catch(Exception e) { //handle error.... } finally { if(em != null) { em.close(); //make sure to close EntityManager } } I made sure to close EntityManager (em) within method level as suggested. But when should EntityManagerFactory be closed then? And why EMF has to be singleton so bad??? I read about concurrency issues but as I am not experienced multi-thread-grammer, I can't really be clear on this idea.

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  • Python: why does this code take forever (infinite loop?)

    - by Rosarch
    I'm developing an app in Google App Engine. One of my methods is taking never completing, which makes me think it's caught in an infinite loop. I've stared at it, but can't figure it out. Disclaimer: I'm using http://code.google.com/p/gaeunitlink text to run my tests. Perhaps it's acting oddly? This is the problematic function: def _traverseForwards(course, c_levels): ''' Looks forwards in the dependency graph ''' result = {'nodes': [], 'arcs': []} if c_levels == 0: return result model_arc_tails_with_course = set(_getListArcTailsWithCourse(course)) q_arc_heads = DependencyArcHead.all() for model_arc_head in q_arc_heads: for model_arc_tail in model_arc_tails_with_course: if model_arc_tail.key() in model_arc_head.tails: result['nodes'].append(model_arc_head.sink) result['arcs'].append(_makeArc(course, model_arc_head.sink)) # rec_result = _traverseForwards(model_arc_head.sink, c_levels - 1) # _extendResult(result, rec_result) return result Originally, I thought it might be a recursion error, but I commented out the recursion and the problem persists. If this function is called with c_levels = 0, it runs fine. The models it references: class Course(db.Model): dept_code = db.StringProperty() number = db.IntegerProperty() title = db.StringProperty() raw_pre_reqs = db.StringProperty(multiline=True) original_description = db.StringProperty() def getPreReqs(self): return pickle.loads(str(self.raw_pre_reqs)) def __repr__(self): return "%s %s: %s" % (self.dept_code, self.number, self.title) class DependencyArcTail(db.Model): ''' A list of courses that is a pre-req for something else ''' courses = db.ListProperty(db.Key) def equals(self, arcTail): for this_course in self.courses: if not (this_course in arcTail.courses): return False for other_course in arcTail.courses: if not (other_course in self.courses): return False return True class DependencyArcHead(db.Model): ''' Maintains a course, and a list of tails with that course as their sink ''' sink = db.ReferenceProperty() tails = db.ListProperty(db.Key) Utility functions it references: def _makeArc(source, sink): return {'source': source, 'sink': sink} def _getListArcTailsWithCourse(course): ''' returns a LIST, not SET there may be duplicate entries ''' q_arc_heads = DependencyArcHead.all() result = [] for arc_head in q_arc_heads: for key_arc_tail in arc_head.tails: model_arc_tail = db.get(key_arc_tail) if course.key() in model_arc_tail.courses: result.append(model_arc_tail) return result Am I missing something pretty obvious here, or is GAEUnit acting up?

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  • Change a finder method w/ parameters to an association

    - by Sai Emrys
    How do I turn this into a has_one association? (Possibly has_one + a named scope for size.) class User < ActiveRecord::Base has_many :assets, :foreign_key => 'creator_id' def avatar_asset size = :thumb # The LIKE is because it might be a .jpg, .png, or .gif. # More efficient methods that can handle that are OK. ;) self.assets.find :first, :conditions => ["thumbnail = '#{size}' and filename LIKE ?", self.login + "_#{size}.%"] end end EDIT: Cuing from AnalogHole on Freenode #rubyonrails, we can do this: has_many :assets, :foreign_key => 'creator_id' do def avatar size = :thumb find :first, :conditions => ["thumbnail = ? and filename LIKE ?", size.to_s, proxy_owner.login + "_#{size}.%"] end end ... which is fairly cool, and makes syntax a bit better at least. However, this still doesn't behave as well as I would like. Particularly, it doesn't allow for further nice find chaining (such that it doesn't execute this find until it's gotten all its conditions). More importantly, it doesn't allow for use in an :include. Ideally I want to do something like this: PostsController def show post = Post.get_cache(params[:id]) { Post.find(params[:id], :include => {:comments => {:users => {:avatar_asset => :thumb}} } ... end ... so that I can cache the assets together with the post. Or cache them at all, really - e.g. get_cache(user_id){User.find(user_id, :include => :avatar_assets)} would be a good first pass. This doesn't actually work (self == User), but is correct in spirit: has_many :avatar_assets, :foreign_key => 'creator_id', :class_name => 'Asset', :conditions => ["filename LIKE ?", self.login + "_%"] (Also posted on Refactor My Code.)

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  • OOP design issue: Polymorphism

    - by Graham Phillips
    I'm trying to solve a design issue using inheritance based polymorphism and dynamic binding. I have an abstract superclass and two subclasses. The superclass contains common behaviour. SubClassA and SubClassB define some different methods: SubClassA defines a method performTransform(), but SubClassB does not. So the following example 1 var v:SuperClass; 2 var b:SubClassB = new SubClassB(); 3 v = b; 4 v.performTransform(); would cause a compile error on line 4 as performTransform() is not defined in the superclass. We can get it to compile by casting... (v as SubClassA).performTransform(); however, this will cause a runtime exception to be thrown as v is actually an instance of SubClassB, which also does not define performTransform() So we can get around that by testing the type of an object before casting it: if( typeof v == SubClassA) { (cast v to SubClassA).performTransform(); } That will ensure that we only call performTransform() on v's that are instances of SubClassA. That's a pretty inelegant solution to my eyes, but at least its safe. I have used interface based polymorphism (interface meaning a type that can't be instantiated and defines the API of classes that implement it) in the past, but that also feels clunky. For the above case, if SubClassA and SubClassB implemented ISuperClass that defined performTransform, then they would both have to implement performTransform(). If SubClassB had no real need for a performTransform() you would have to implement an empty function. There must be a design pattern out there that addresses the issue.

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  • Java Function Analysis

    - by khan
    Okay..I am a total Python guy and have very rarely worked with Java and its methods. The condition is that I have a got a Java function that I have to explain to my instructor and I have got no clue about how to do so..so if one of you can read this properly, kindly help me out in breaking it down and explaining it. Also, i need to find out any flaw in its operation (i.e. usage of loops, etc.) if there is any. Finally, what is the difference between 'string' and 'string[]' types? public static void search(String findfrom, String[] thething){ if(thething.length > 5){ System.err.println("The thing is quite long"); } else{ int[] rescount = new int[thething.length]; for(int i = 0; i < thething.length; i++){ String[] characs = findfrom.split("[ \"\'\t\n\b\f\r]", 0); for(int j = 0; j < characs.length; j++){ if(characs[j].compareTo(thething[i]) == 0){ rescount[i]++; } } } for (int j = 0; j < thething.length; j++) { System.out.println(thething[j] + ": " + rescount[j]); } } }

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  • Questions on Juval Lowy's IDesign C# Coding Standard

    - by Jan
    We are trying to use the IDesign C# Coding standard. Unfortunately, I found no comprehensive document to explain all the rules that it gives, and also his book does not always help. Here are the open questions that remain for me (from chapter 2, Coding Practices): No. 26: Avoid providing explicit values for enums unless they are integer powers of 2 No. 34: Always explicitly initialize an array of reference types using a for loop No. 50: Avoid events as interface members No. 52: Expose interfaces on class hierarchies No. 73: Do not define method-specific constraints in interfaces No. 74: Do not define constraints in delegates Here's what I think about those: I thought that providing explicit values would be especially useful when adding new enum members at a later point in time. If these members are added between other already existing members, I would provide explicit values to make sure the integer representation of existing members does not change. No idea why I would want to do this. I'd say this totally depends on the logic of my program. I see that there is alternative option of providing "Sink interfaces" (simply providing already all "OnXxxHappened" methods), but what is the reason to prefer one over the other? Unsure what he means here: Could this mean "When implementing an interface explicitly in a non-sealed class, consider providing the implementation in a protected virtual method that can be overridden"? (see Programming .NET Components 2nd Edition, end of chapter “Interfaces and Class Hierarchies”). I suppose this is about providing a "where" clause when using generics, but why is this bad on an interface? I suppose this is about providing a "where" clause when using generics, but why is this bad on a delegate?

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  • Contrary to Python 3.1 Docs, hash(obj) != id(obj). So which is correct?

    - by Don O'Donnell
    The following is from the Python v3.1.2 documentation: From The Python Language Reference Section 3.3.1 Basic Customization: object.__hash__(self) ... User-defined classes have __eq__() and __hash__() methods by default; with them, all objects compare unequal (except with themselves) and x.__hash__() returns id(x). From The Glossary: hashable ... Objects which are instances of user-defined classes are hashable by default; they all compare unequal, and their hash value is their id(). This is true up through version 2.6.5: Python 2.6.5 (r265:79096, Mar 19 2010 21:48:26) ... ... >>> class C(object): pass ... >>> c = C() >>> id(c) 11335856 >>> hash(c) 11335856 But in version 3.1.2: Python 3.1.2 (r312:79149, Mar 21 2010, 00:41:52) ... ... >>> class C: pass ... >>> c = C() >>> id(c) 11893680 >>> hash(c) 743355 So which is it? Should I report a documentation bug or a program bug? And if it's a documentation bug, and the default hash() value for a user class instance is no longer the same as the id() value, then it would be interesting to know what it is or how it is calculated, and why it was changed in version 3.

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  • Is there a way to automatically load navigational property using the .NET Entity Framework?

    - by René Wolferink
    Stepping away more and more from writing SQL for my applications, I decided to give the Entity Framework a try. However, I've run into something I believe is causing me to write more code than I think is strictly necessary. When I accessed some navigational properties, I discovered that all many-to-one relations (simple references) were null and all one-to-many and many-to-many relations (EntityCollections) were empty. For example: I have a User with a reference to a Group. When I have retieved a User, by using a simple select-by-id, the Group property is null. If I want to access the Group I have to manually load it (using User.GroupReference.Load()). So I added a GetGroup() method in User which checks whether the Group is loaded already and, if not, does so and then returns the Group. Now this will result in a lot of highly similar methods for all navigational properties. And it all results in the navigational properties not being used, only my custom-made Get"PropertyName"() method's are now being used. I don't want to expand my queries (linq to entities) to immediately load all these properties, because it's not always known at first what is needed. And besides, it would cause a lot of queries to have to be made. Is there a way to configure the Entity Framework to load these objects when they happen to not be present? So when I access User.Group and the group is not loaded yet, it is loaded automatically? Or am I stuck using my own Get"PropertyName"() method's as long as I'm trying to load objects only on demand (or "just-in-time")? Some extra info: I'm using VS2008 SP1 with .NET 3.5 SP1. The Entity Framework I'm using is the one that got shipped with it.

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  • Link compatibility between C++ and D

    - by Caspin
    D easily interfaces with C. D just as easily interfaces with C++, but (and it's a big but) the C++ needs to be extremely trivial. The code cannot use: namespaces templates multiple inheritance mix virtual with non-virtual methods more? I completely understand the inheritance restriction. The rest however, feel like artificial limitations. Now I don't want to be able to use std::vector<T> directly, but I would really like to be able to link with std::vector<int> as an externed template. The C++ interfacing page has this particularly depressing comment. D templates have little in common with C++ templates, and it is very unlikely that any sort of reasonable method could be found to express C++ templates in a link-compatible way with D. This means that the C++ STL, and C++ Boost, likely will never be accessible from D. Admittedly I'll probably never need std::vector while coding in D, but I'd love to use QT or boost. So what's the deal. Why is it so hard to express non-trivial C++ classes in D? Would it not be worth it to add some special annotations or something to express at least namespaces?

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  • C++ destructor problem with boost::scoped_ptr

    - by bb-generation
    I have a question about the following code: #include <iostream> #include <boost/scoped_ptr.hpp> class Interface { }; class A : public Interface { public: A() { std::cout << "A()" << std::endl; } virtual ~A() { std::cout << "~A()" << std::endl; } }; Interface* get_a() { A* a = new A; return a; } int main() { { std::cout << "1" << std::endl; boost::scoped_ptr<Interface> x(get_a()); std::cout << "2" << std::endl; } std::cout << "3" << std::endl; } It creates the following output: 1 A() 2 3 As you can see, it doesn't call the destructor of A. The only way I see to get the destructor of A being called, is to add a destructor for the Interface class like this: virtual ~Interface() { } But I really want to avoid any Implementation in my Interface class and virtual ~Interface() = 0; doesn't work (produces some linker errors complaining about a non existing implementation of ~Interface(). So my question is: What do I have to change in order to make the destructor being called, but (if possible) leave the Interface as an Interface (only abstract methods).

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  • PyGTK: Manually render an existing widget at a given Rectangle? (TextView in a custom CellRenderer)

    - by NicDumZ
    Hello! I am trying to draw a TextView into the cell of a TreeView. (Why? I would like to have custom tags on text, so they can be clickable and trigger different actions/popup menus depending on where user clicks). I have been trying to write a customized CellRenderer for this purpose, but so far I failed because I find it extremely difficult to find generic documentation on rendering design in gtk. More than an answer at the specific question (that might be hard/not doable, and I'm not expecting you to do everything for me), I am first looking for documentation on how a widget is rendered, to understand how one is supposed to implement a CellRenderer. Can you share any link that explains, either for gtk or for pygtk, the rendering mechanism? More specifically: size allocation mechanism (should I say protocol?). I understand that a window has a defined size, and then queries its children, saying "my size is w x h, what would be your ideal size, buddy?", and then sometimes shrinks children when all children cant fit together at their ideal sizes. Any specific documentation on that, and on particular on when this happens during rendering? How are rendered "builtin" widgets? What kind of methods do they call on Widget base class? On the parent Window? When? Do they use pango.Layout? can you manually draw a TextView onto a pango.Layout object? This link gives an interesting example showing how you can draw content in a pango.Layout object and use it in a CellRenderer. I guess that I could adapt it if only I understood how TextView widget are rendered. Or perhaps, to put it more simply: given an existing widget instance, how does one render it at a specific gdk.Rectangle? Thanks a lot.

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  • Why does this threading approach not work?

    - by Tomas Lycken
    I have a wierd problem with threading in an ASP.NET application. For some reason, when I run the code in the request thread, everything works as expected. But when I run it in a separate thread, nothing happens. This is verified by calling the below handler with the three flags "on", "off" and "larma" respectively - in the two first cases everything works, but in the latter nothing happens. What am I doing wrong here? In the web project I have a generic handler with the following code: If task = "on" Then Alarm.StartaLarm(personId) context.Response.Write("Larmet är PÅ") ElseIf task = "off" Then Alarm.StoppaLarm(personId) context.Response.Write("Larmet är AV") ElseIf task = "larma" Then Alarm.Larma(personId) context.Response.Write("Larmar... (stängs av automagiskt)") Else context.Response.Write("inget hände - task: " & task) End If The Alarm class has the following methods: Private Shared Sub Larma_Thread(ByVal personId As Integer) StartaLarm(personId) Thread.Sleep(1000 * 30) StoppaLarm(personId) End Sub Public Shared Sub StartaLarm(ByVal personId As Integer) SandSMS(True, personId) End Sub Public Shared Sub StoppaLarm(ByVal personId As Integer) SandSMS(False, personId) End Sub Public Shared Sub SandSMS(ByVal setOn As Boolean, ByVal personId As Integer) ... End Sub

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