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  • NHibernate: discriminator without common base class?

    - by joniba
    Is it possible to map two classes to the same property without them sharing a common base class? For example, a situation like this: class Rule { public virtual int SequenceNumber { get; set; } public virtual ICondition Condition { get; set; } } interface ICondition { } class ExpressionCondition : ICondition { public virtual string Expression { get; set; } } class ThresholdCondition : ICondition { public virtual int Threshold { get; set; } } I also cannot add some empty abstract class that both conditions inherit from because the two ICondition implementations exist in different domains that are not allowed to reference each other. (Please no responses telling me that this situation should not occur in the first place - I'm aware of it and it doesn't help me.)

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  • Advanced queries in HBase

    - by Teflon Ted
    Given the following HBase schema scenario (from the official FAQ)... How would you design an Hbase table for many-to-many association between two entities, for example Student and Course? I would define two tables: Student: student id student data (name, address, ...) courses (use course ids as column qualifiers here) Course: course id course data (name, syllabus, ...) students (use student ids as column qualifiers here) This schema gives you fast access to the queries, show all classes for a student (student table, courses family), or all students for a class (courses table, students family). How would you satisfy the request: "Give me all the students that share at least two courses in common"? Can you build a "query" in HBase that will return that set, or do you have to retrieve all the pertinent data and crunch it yourself in code?

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  • how to import Java class with Python using Eclipse?

    - by JChao
    Hi, I'm trying to write Jython where the Python file imports classes from Java I'm using Eclipse with PyDev. My Python code looks like: from eclipsejavatest import eclipseJavaTest from eclipsejavatest import JavaClass class eclipsePyPrint(eclipseJavaTest): def eclipsepyMain(self): print "python main method" eclipseJavaTest.printerCount(4) print eclipseJavaTest.gotoPython() eclipseJavaTest.printerSentence() samplepyClass = JavaClass("Jython plain") samplepyClass.setName("jython fancy") print samplepyClass.getName() but I'm getting the error ImportError: No module named eclipsejavatest The Python project references the Java project. I've tried exporting the Java project and adding the .jar to the Jython Class Path for the Python project. I'm not sure what to do to get this to work.

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  • After I appendChild() in ie6, do stylesheets apply to that element?

    - by rickharrison
    I am creating some elements in javascript like so: var parent = document.createElement('div'); parent.setAttribute('id', 'parent'); var child = document.createElement('div'); child.setAttribute('class', 'child'); parent.appendChild(child); otherelement.appendChild(parent); I have a stylesheet which has styles for #parent and .child. However, it appears the styles are being applied to the parent but not the child. Does ie6 only support styles on id's and not classes or am I doing something wrong?

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  • Using a backwards relation (i.e FOO_set) for ModelChoiceField in Django

    - by Bwmat
    I have a model called Movie, which has a ManyToManyField called director to a model called Person, and I'm trying to create a form with ModelChoiceField like so: class MovieSearchForm(forms.Form): producer = forms.ModelChoiceField(label='Produced by', queryset=movies.models.Person.producer_set, required=False) but this seems to be failing to compile (I'm getting a ViewDoesNotExist exception for the view that uses the form, but it goes away if I just replace the queryset with all the person objects), I'm guessing because '.producer_set' is being evaluated too 'early'. How can I get this work? here are the relevant parts of the movie/person classes: class Person(models.Model): name = models.CharField(max_length=100) class Movie(models.Model): ... producer = models.ForeignKey(Person, related_name="producers") director = models.ForeignKey(Person, related_name="directors") What I'm trying to do is get ever Person who is used in the producer field of some Movie.

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  • AS3 How to center MC + change background color?

    - by Jennifer Heidelberg
    Hello everyone, I am quite new to AS3 and I have never worked with classes, so I am encountering a couple of problems. I'd like to center a movieclip, have it so that it doesn't scale. And then I'd like to add a background color that stays there no matter how I scale the browser. Can someone please explain me this in babysteps? Since I don't know how to implement a class and make it work with my fla. Thank you so much! J.

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  • How to copy value from class X to class Y with the same property name in c#?

    - by Samnang
    Suppose I have two classes: public class Student { public int Id {get; set;} public string Name {get; set;} public IList<Course> Courses{ get; set;} } public class StudentDTO { public int Id {get; set;} public string Name {get; set;} public IList<CourseDTO> Courses{ get; set;} } I would like to copy value from Student class to StudentDTO class: var student = new Student(); StudentDTO studentDTO = student; How can I do that by reflection or other solution?

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  • Mixing JPA annotations and XML configuration

    - by HDave
    I have a fairly large (new) project in which we have annotated many domain classes with JPA mappings. Now it is time to implement many named queries -- some entities may have as many as 15-20 named queries. I am thinking that writing these named queries in annotations will clutter the source files and therefore am considering putting these in XML mapping files. Is this possible? Mort importantly, is this reasonable? Are there better approaches? How is this done?

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  • Interview question: difference between object and object-oriented languages.

    - by Bar
    My friend was asked the following question: what's the difference between object language and object-oriented language? It's a little unintelligible question. What does term «object language» correspond to? Does that mean «pure» object-oriented language, like the Wikipedia article says: Languages called "pure" OO languages, because everything in them is treated consistently as an object, from primitives such as characters and punctuation, all the way up to whole classes, prototypes, blocks, modules, etc. They were designed specifically to facilitate, even enforce, OO methods. Examples: Smalltalk, Eiffel, Ruby, JADE, VB.NET.

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  • which layout engine for finding coordinates of html elements on the web page?

    - by Mexx
    I am doing some web data classification task and was thinking if I could get the co-ordinates of html elements as they would appear on a web-browser without taking into consideration any css or javascript being referred in the web page. My language of programming is c++ and the need results for a couple million of pages, so it has to be fast. I know there is a Microsoft COM component which renders the page in a web browser control and then can be queried for position of different html tags. But this is not suitable in my case as it first renders the whole page which takes up a lot of time. So as I found out, there are open-source layout engines WebKit, Gecko that can probably be used for this. But that's a huge piece of code and I need someone to direct me to the right classes or right modules to look into or any previous/similar work someone has done previously. Also, please let me know what you guys think is a good choice if I want to customize the existing code for use with multiple threads to make it faster. Thanks

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  • JRI Fatal Error on Ubuntu

    - by Peter Jackson
    I have successfully installed JRI and rJava on Windows 7. I am now trying to get it to work on Ubuntu with 64bit OS. I can make rJava calls from within R but getting JRI to work is more difficult. I am running NetBeans 7.1.2 and I have followed various tricks in setting R_HOME and java.library.path to enable all the classes to be loaded. That is, I am past the error messages such as "jri library not found" and "R_HOME not set". From my java code,I can see that R_HOME = /usr/lib64/R. The error message I get now is Fatal error: you must specify '--save', '--no-save' or '--vanilla' This happens when Rengine is first called: Rengine r = new Rengine(args,false,null); This appears to be an error message from R; it seems to be expecting a command line argument. I haven't seen any posting with this error message. Any ideas? Thanks, Peter

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  • How to go about with real GUI development with Java Swing and MVC.

    - by Myth17
    I am creating a Blackjack Card game emulator. I am a SCJP,familiar with Core Java concepts. I have a very basic understanding of Java swings and awt. Already finished writing the basic game logic,a CLI logic. My design includes several classes like, Dealer,Player,Table,Card,Casino and some others.. Enums for Cards and suite. I have read about MVC as a theoretical concept, familiar with the name 'design patters'(no understanding whatsoever as to how they are implemented) Everywhere I am suggested to learn while writing some real code.So I started off with this... I am stuck now, how should I go about writing code for my project?? Writing the GUI code and organising it within the already existent code.

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  • Parent-Child relation while using object data source

    - by Saba
    Hello guys I am experiencing with a class generator I've written, which generates a class for each table in database with each table field as a property and such. Before that, I used to add a typed dataset to the project and add some tables to it. It automatically detected the relationship between tables and when I added a parent table as data source of a datagrid, I could add another datagrid and use the foreing key data member of it's bindingsource to fill it, and when someone moved the focus on parent datagrid, the data in child datagrid would change accordingly. Now that I have my classes, I add an object as data source for my 2 datagrids, but obviously it doesn't detect a parent child relation. But It'd really help if I could have that foreign key relation in my object datasources. Is there any way to have that relation in object datasource?

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  • Java generics question

    - by user247866
    So I have 3 classes. Abstract class A Class B extends class A independent Class C In class D that contains the main method, I create a list of instances of class B List<B> b = methodCall(); // the method returns a list of instances of class B Now in class C I have one method that is common to both A and B, and hence I don't want to duplicate it. I want to have one method that takes as input an instance of class A, as follows: public void someMethod(List<A> a) However, when I do: C c = new C(); c.someMethod(b); I get an error that some-method is not applicable for the argument List<B>, instead it's expecting to get List<A>. Is there a good way to fix this problem? Many thanks!

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  • In c++ is there any Events/delegates/interfaces/notifications! anything?

    - by Bach
    Say i have these classes ViewA and ViewB In objective C using the delegate pattern I could do @protocol ViewBDelegate{ - (void) doSomething(); } then in ViewB interface: id<ViewBDelegate> delegate; then in ViewA implementation i set the delegate: viewB.delegate = self; and now I can call in doSomething from viewB onto any that unknown type delegate. [delegate doSomething]; "C++ How to Program" has been the worse read an can't find simple examples that demonstrates basic design patterns. What i'm looking for in C++ is: events ActionScript and java either delegates or notifications in Objective C anything that allows class A, Class B and Class C to know that ClassX didSomething()!!! thanks

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  • How do I create a point system in a Rails app that assigns points to users and non-authenticated-use

    - by codyvbrown
    I'm building a question and answer application on top of twitter and I'm hitting some snags because I'm inevitably dealing with two classes of users: authenticated and non-authenticated. The site enable users to give points to other users, who may or may not be authenticated, and I want to create a site-wide point system where the application stores and displays this information on their profile. I want to save this point data to the user because that would be faster and more efficient but non-authenticated users aren't in our system, we only have the twitter handle. So instead we display the points in our system like this: @points = point.all( :select => "tag, count(*) AS count", # Return tag and count :group => 'tag', # Group by the tag :order => "2 desc", :conditions => {:twitter_handle => params[:username]}) Is there a better way to do this? Is there a better way to associate data with non-authenticated users?

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  • Returning a static array without using a class field

    - by Bart Friederichs
    I have the following base and derived (partial, for sake of brevity) classes: class Base { public abstract int[] someArray { get; } } class Derived : Base { private readonly static int[] _someArray = new int[] { 1,2,3,4 }; public override int[] someArray { get { return _someArray; } } } What I would like now, is put the new int[] { 1,2,3,4 } in the return part of the getter. But, that would create a new array every time the getter is called. Is it possible to directly return some kind of object, which stays the same for all objects of class Derived ? Something along the lines of (I know this is invalid C#): get { return (int[]) { 1, 2, 3, 4 }; }

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  • Serialization of an object and its Contained Objects

    - by Amit
    There is a main class having 2 subClasses(each represent separate entity) and all classes needs to be serialized.. how should I proceed ? My requirement is when I serelize MainClass, I should get the xml for each sub class and main class as well. Thanks in advance... and if my approach is incorrect... correct that as well.. Ex given below... class MainClass { SubClass1 objSubclass1 = null; SubClass2 objSubclass2 = null; public MainClass() { objSubclass1 = new SubClass1(); objSubclass2 = new SubClass2(); } [XmlElement("SubClass1")] public SubClass1 SubClass1 {get {return objSubclass1;} } [XmlElement("SubClass2")] public SubClass2 SubClass2 {get {return objSubclass2;} } } Class SubClass1 { Some properties here... } Class SubClass2 { Some properties here... }

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  • Summary count for Python logging

    - by Craig McQueen
    At the end of my Python program, I'd like to be able to get a summary of the number of items logged through the standard logging module. I'd specifically like to be able to get a count for each specified name (and possibly its children). E.g. if I have: input_logger = getLogger('input') input_logger.debug("got input1") input_logger.debug("got input2") input_logger.debug("got input3") network_input_logger = getLogger('input.network') network_input_logger.debug("got network input1") network_input_logger.debug("got network input2") getLogger('output') output_logger.debug("sent output1") Then at the end I'd like to get a summary such as: input: 5 input.network: 2 output: 1 Perhaps by calling a getcount() method for a logger or a handler. What would be a good way to achieve this? I imagine it would involve a sub-class of one of the logging classes, but I'm not sure which one would be best.

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  • avmutablecomposition insertEmptyTimeRange

    - by smartfaceweb
    I have created an avmutablecomposition and tried to use insertEmptyTimeRange to generate 1 minute of silence. This doesn't appear to be working. I have also tried creating an avmutablecompositiontrack using addMutableTrackWithMediaType:preferredTrackID: and then insertEmptyTimeRange on the track and still no success. To give some background on my app, I allow users to add audio samples a timeline and then playback or export and this is working really well using the av classes. The problem is that I need to make sure that the audio is exactly 1 min (for example). Regardless of the info about my specific app above, is it possible to insert an empty time range into a comp or comptrack?

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  • How can I make a core-plot graph on the phone that doesn't auto-expand to fill the whole superview

    - by Robb
    I'm pretty sure I saw an example where the graph wasn't filling the whole iPhone screen, but I can't get that to happen in my app, nor in the Core-Plot Test app from Switch On The Code. I've added a subview to the original CPLayerHostingView in the sample, then changed the classes – original back to UIView, new subview to CPLayerHostingView, and I've reconnected the File's owner's view outlet to the new subview. When I create a graph with: graph = [[CPXYGraph alloc] initWithFrame: theSubviewOutlet.bounds]; … and step through the first stages of building up the layers the bounds are accurate (i.e. the same as in the .xib) however, when all the initialization is done, and the graph shows up, it fills the whole superview. Am I missing something obvious?

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  • What question(s) does an object's behavior answer?

    - by Corwin
    Reading a book I have found the following statement: (Object) Behaviors answer either of two questions: What does this object do (for me)? or What can I do to this object? In the case of an orange, it doesn’t do a whole lot, but we can do things to it. One behavior is that it can be eaten. In my understanding of object behaviour the statement above is correct regarding the first question and is incorrect in case of the second. However, I often see classes with methods like Orange::eat(), and this makes me uncertain about my design skills. So I would like to ask is it a design mistake to give oranges a behaviour eat? (oranges and eat are used just for example)

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  • C++ memory management of reference types

    - by Russel
    Hello, I'm still a fairly novice programmer and I have a question about c++ memory management with refence types. First of all, my understanding of reference types: A pointer is put on the stack and the actual data that the pointer points to is created and placed on the heap. Standard arrays and user defined classes are refence types. Is this correct? Second, my main question is do c and c++'s memory management mechanisms (malloc, free and new, delete) always handle this properly and free the memory that a class or array is pointing to? Does everything still work if those pointers get reassigned somehow to other objects of the same size/type on the heap? What if a class has a pointer member that points to another object? I am assuming that delete/freeing the class object doesn't free what it's member pointer points to, is that correct? Thanks all! -R

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  • Managing Data Prefetching and Dependencies with .NET Typed Datasets

    - by Derek Morrison
    I'm using .NET typed datasets on a project, and I often get into situations where I prefetch data from several tables into a dataset and then pass that dataset to several methods for processing. It seems cleaner to let each method decide exactly which data it needs and then load the data itself. However, several of the methods work with the same data, and I want the performance benefit of loading data in the beginning only once. My problem is that I don't know of a good way or pattern to use for managing dependencies (I want to be sure I load all the data that I'm going to need for each class/method that will use the dataset). Currently, I just end up looking through the code for the various classes that will use the dataset to make sure I'm loading everything appropriately. What are good approaches or patterns to use in this situation? Am I doing something fundamentally wrong? Although I'm using typed datasets, this seems like it would be a common situation where prefetching data is used. Thanks!

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  • Boost singleton and undefined reference

    - by Ockonal
    Hello, I globally use singleton pattern in my project. To make it easier - boost::singleton. Current project uses Ogre3d library for rendering. Here is some class: class GraphicSystem : public singleton<GraphicSystem> { private: Ogre::RenderWindow *mWindow; public: Ogre::RenderWindow *getWindow() const { return mWindow; } }; In GraphicSystem constructor I fill the mWindow value: mWindow = mRoot->createRenderWindow(...); I cheked it, everything makes normally. So, now I have to use handler for the window in input system (to get window handle). Somewhere else in another class: Ogre::RenderWindow *temp = GraphicSystem::get_mutable_instance().getWindow(); GraphicSystem::get_mutable_instance().getWindow()->getCustomAttribute("WINDOW", &mWindowHandle); temp is 0x00, and there is segfault at last line (getting custon attribute). I can't understand, why does singleton returns undefined pointer for the window. All another singleton-based classes work well.

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