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  • CoreData Model Objects for API

    - by theiOSguy
    I am using CoreData in my application. I want to abstract out all the CoreData related stuff as an API so that the consume can use the API instead of directly using CoreData and its generated model objects. CoreData generates the managed objects model as following @interface Person : NSManagedObject @end I want to define my API for example MyAPI and it has a function called as createPerson:(Person*)p; So the consumer of this createPerson API needs to create a Person data object (like POJO in java world) and invoke this API. But I cannot create Person object using Person *p = [Person alloc] init] because the designated initializer for this Person model created by CoreData does not allow this type of creation. So should I define corresponding user facing data object may be PersonDO and this API should take that instead to carry the data into the API implementation? Is my approach right? Any expert advise if design the API this way is a good design pattern?

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  • SWIG: Throwing exceptions from Python to C++

    - by wheaties
    We've got an interface we've defined in C++ (abstract class, all functions pure virtual) which will be extended in Python. To overcome the cross-language polymorphism issues we're planning on using SWIG directors. I've read how to catch exceptions thrown from C++ code in our Python code here, here, here, and even on SO. It's fairly straight forward and I'm not expecting issues with handling our library's own exceptions. What I'd like to know and can't seem to find in the documentation is how to have our Python implementation of the extended C++ interface throw those C++ exceptions in a way that makes them visible to the C++ code. We could make small functions within the *.i files such that each function throws our exceptions: void throw_myException(){ throw MyException; } but I'm wondering how it will interact with the Python code. Anyone have any experience with throwing C++ exceptions from Python code?

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  • Is base method able to use derived base data members?

    - by iTayb
    Lets assume we have the following code: abstract class Base1 { protected int num; } class Der1:Base1 { protected Color color; protected string name; } class Der2:Base1 { protected DateTime dthen; } and so on. An array of base1 type exists and includes many objects created out of classes that are derived from base1. Is it possible to define the toString() method in the base class only? something like: public override string toString() { if (this is Der1) return "num = " + this.num + "color = " + this.color.toString() + " name = " this.name; if (this is Der2) return "num = " + this.num + "dthen = " + this.dthen.toString(); // and so on ... } Thank you very much :) P.S. This is not an homework question. I've just wondered about.

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  • How to step into the world of J2EE?

    - by Michael Lai
    I am new to J2ee. I have experience in Java core, JSP,Servlet, XML, HTML, What should i learn to step into the world of J2EE? Framework(Spring, Hibernate, Struts)? But the framework is too abstract for me.I saw lots of job post which requires frameworks, some jobs require EJB,JPA. I do not where to start. Any experts can give me hints on that? I found the tutorial of J2EE 5 published by ORACLE is not easy to understand. Too much jargon....

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  • "net use /delete" question

    - by tinmaru
    I want to delete a network connection. When I type net use I get this: Microsoft Windows XP [version 5.1.2600] (C) Copyright 1985-2001 Microsoft Corp. C:\Documents and Settings\totonet use État Local Distant Réseau OK M: \192.168.5.138\share Réseau Microsoft Windows OK R: \192.168.2.18\tools Réseau Microsoft Windows OK \192.168.2.43\data Réseau Microsoft Windows La commande s'est terminée correctement. The syntax for deleting a network map is : net use /delete X: if I want to delete a specific connection net use /delete * * if I want to delete all connections. How can I delete the \192.168.2.43\data connection which, as you can see, is not link to any logical letter?

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  • Any good class diagram editors out there for Java (not UML)

    - by user85116
    I'm looking for an editor that can create class diagrams, similar to the typical UML class diagram, but specifically for java (so using java terminology; instead of terms like "generalization, realization etc", we use the java equivalents "interface, abstract class, extends etc"). I've looked into UML several times, but each time I've been turned off by the shear amount of "stuff" that comes with UML. I just want to be able to model my java classes quickly and intuitively, without getting bogged down by all the cruft that comes with UML. Preferably, it would come with a source reader that can keep the diagram up to date, and with a few nice features like "show only public methods in this class" etc. As well, it would automatically "know" about the classes in the standard java library, and possibly even be able to read classes from jars. Performance is also a big thing for me, I don't like having to wait 2 seconds for a popup menu to appear, or watch the diagram jerk crazily while resizing an element in the model. What do you think, am I asking too much?

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  • Make object by it's name

    - by Ockonal
    Hello, is it possible to return exemplar of object using passed type name (string) in c++? I have some base abstract class Base and a few derivates. Example code: class Base { /* ... */ }; class Der1 : public Base { /* ... */ }; class Der2 : public Base { /* ... */ }; And I need function like: Base *objectByType(const std::string &name); Number of derivates classes are changeable and I don't want to make something like switching of name and returning by hands new object type. Is it possible in c++ to do that automatically anyway? p.s. usage should looks like: dynamic_cast<Der1>(objectByType("Der1")); I need pure c++ code (crossplatform). Using boost is permissible.

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  • C++ enforce conditions on inherited classes

    - by user231536
    I would like to define an abstract base class X and enforce the following: a) every concrete class Y that inherits from X define a constructor Y(int x) b) it should be possible to test whether two Y objects are equal. For a, one not very good solution is to put a pure virtual fromInt method in X which concrete class will have to define. But I cannot enforce construction. For b), I cannot seem to use a pure virtual method in X bool operator == (const X& other) const =0; because in overridden classes this remains undefined. It is not enough to define bool operator == (const Y& other) const { //stuff} because the types don't match. How do I solve these problems?

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  • Dependency Injection. Assign values to IENUMERABLE

    - by Boss
    public interface IFeature { string FeatureName { get; set; } } public interface IFeatureRegistry { IEnumerable<IFeature> Features { get; set; } bool IsEnabled(IEnumerable<string> featurePath); } public interface IApplicationTenant { string ApplicationName { get; } IFeatureRegistry EnabledFeatures { get; } } public abstract class AbstractApplicationTenant : IApplicationTenant { public string ApplicationName { get; protected set; } public IFeatureRegistry EnabledFeatures { get; protected set; } } public class SampleTenant : AbstractApplicationTenant { public SampleTenant() { ApplicationName = "Sample 1"; EnabledFeatures = null; } } I am new to this field. My question is how to assign values to EnabledFeatures? Thanks Jeco

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  • .NET CF 2.0: Stream implements IDisposable ... kind of?

    - by mvanbem
    I've run into something odd in a .NET CF 2.0 project for Pocket PC 2003 (Visual Studio 2005). I was dealing with a System.IO.Stream object and found that the IDE wouldn't auto-complete the Dispose() method. I typed it in manually and received: 'System.IO.Stream.Dispose(bool)' is inaccessible due to its protection level The error is referring to the protected Dispose(bool) method. Dispose() is either private or not present. Question 1: How is this possible? Stream implements IDisposable: public abstract class Stream : MarshalByRefObject, IDisposable ... and IDisposable requires a Dispose() method: public interface IDisposable { void Dispose(); } I know the compiler won't let me get away with that in my code. Question 2: Will I cause problems by working around and disposing my streams directly? IDisposable idisp = someStream; idisp.Dispose(); The implicit cast is accepted by the compiler.

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  • New to threading in C#, can you make thread methods generic and what are the dangers?

    - by ibarczewski
    Hey all, I'm just now starting to get into the idea of threading, and wanted to know if I could make this more abstract. Both foo and bar derive methods from a base class, so I'd like to pass in one or the other and be able to do work using a method that was derived. I'd also like to know how you properly name threads and the methods inside threads. if (ChkFoo.Checked) { Thread fooThread = new Thread(new ThreadStart(this.ThreadedFooMethod)); fooThread.Start(); } if (ChkBar.Checked) { Thread barThread = new Thread(new ThreadStart(this.ThreadedBarMethod)); barThread.Start(); } . . . public void ThreadedFooMethod() { Foo newFoo = new Foo(); //Do work on newFoo } public void ThreadedBarMethod() { Bar newBar = new Bar(); //Do similar work } Thanks all!

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  • Composite pattern in C++ problem

    - by annouk
    Hello! I have to work with an application in C++ similar to a phone book: the class Agenda with an STL list of Contacts.Regarding the contacts hierarchy,there is a base-class named Contact(an abstract one),and the derived classes Friend and Acquaintance(the types of contact). These classes have,for instance, a virtual method called getName,which returns the name of the contact. Now I must implement the Composite pattern by adding another type of contact,Company(being derived from Contact),which also contains a collection of Contacts(an STL list as well),that can be either of the "leaf" type(Friends or Acquaintances),or they can be Companies as well. Therefore,Company is the Compound type. The question is: how and where can I implement an STL find_if to search the contact with a given name(via getName function or suggest me smth else) both among the "leaf"-type Contact and inside the Company collection? In other words,how do I traverse the tree in order to find possible matches there too,using an uniform function definition? I hope I was pretty clear...

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  • How to synchronize between differently structured directories using rsync (or other program)

    - by doetoe
    Does anyone of you know how to perform the following task: Suppose you have two directory trees, which I will call source and target. They may have a very different structure, but could contain many duplicate files. An example would be a structured collection of photographs on one hand (the destination), and just a tmp directory in which you unload everything from your camera on the other (the source). Maybe some of these files are already in the structured directory tree. I would like to rsync from the source to the target, such that only the files from the source that are not in the destination at any location are copied.

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  • Crunchbang asks for URIs to get build dependencies for php5 [closed]

    - by Koen027
    I'm trying to install PHP5, by compiling it myself. I'm doing this on Crunchbang Linux, version 11. Specifically, the version using the 3.2 kernel. Crunchbang 11 is based on Debian. This is a 64-bit Virtual machine, running on a 64-bit Win7 Professional. Using Virtualbox 4.2 This is my sources.list file: http://pastebin.com/rQJNwX7c When I try to do sudo apt-get build-dep php5, I get the following output: Reading package lists... Done Building dependency tree Reading state information... Done E: You must put some 'source' URIs in your sources.list I'm not sure what's going on here. Can anyone point out what's missing in my setup? Also, since I'm under 300 reputation on serverfault, I can't add the "crunchbang" tag.

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  • EF4 (CPT5) ForeignKeyAttribute in base class - Assert Failure entityType != null

    - by Anthony Johnston
    Getting an error when trying to set a ForeignKeyAttribute in a base class class User{} abstract class FruitBase{ [ForeignKey("CreateById")] public User CreateBy{ get; set; } public int CreateById{ get; set; } } class Banana{} class DataContext : DbContext{ DbSet<Banana> Bananas{ get; set; } } If I move the FruitBase code into the banana, all is well, but I don't want to, as there will be many many fruit and I want to remain relatively DRY if I can Is this a know issue that will be fixed by March? Does anyone know a work around?

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  • Why isn't the new() generic constraint satisfied by a class with optional parameters in the construc

    - by Joshua Flanagan
    The following code fails to compile, producing a "Widget must be a non-abstract type with a public parameterless constructor" error. I would think that the compiler has all of the information it needs. Is this a bug? An oversight? Or is there some scenario where this would not be valid? public class Factory<T> where T : new() { public T Build() { return new T(); } } public class Widget { public Widget(string name = "foo") { Name = name; } public string Name { get; set; } } public class Program { public static void Main() { var widget = new Widget(); // this is valid var factory = new Factory<Widget>(); // compiler error } }

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  • Java: ListA.addAll(ListB) fires NullPointerException?

    - by HH
    The err part is Capitalized in the code, it also comes in foreaching. Because of the abstract list, it cannot be initialized, declaration is in a static field. The lists have the same type. import java.util.*; public class Test { public static final List<String> highPrio = Arrays.asList("*","/"); public static List<String> ops; public static void main(String[] args) { //ERROR HERE, why do it throw nullPointer? ops.addAll(highPrio); for(String s : ops) { System.out.println(s); } } }

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  • Create object of unknown class (two inherited classes)

    - by Paul
    I've got the following classes: class A { void commonFunction() = 0; } class Aa: public A { //Some stuff... } class Ab: public A { //Some stuff... } Depending on user input I want to create an object of either Aa or Ab. My imidiate thought was this: A object; if (/*Test*/) { Aa object; } else { Ab object; } But the compiler gives me: error: cannot declare variable ‘object’ to be of abstract type ‘A’ because the following virtual functions are pure within ‘A’: //The functions... Is there a good way to solve this?

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  • Getting all inner classes by reflection

    - by Roman
    I have the following problem. I have this pretty class and now I want to get all the classes that extend that class (inner classes ) and fill 'classList' with it. ( in an automatic way of course ) public abstract class CompoundReference { private static List<Class<? extends CompoundReference>> classList = new ArrayList<Class<? extends CompoundReference>>(); @CompoundKey(gsType = User.class, dbType = UserDetailsMappings.class) public static class CUser extends CompoundReference { } @CompoundKey(gsType = Catalog.class, dbType = CatalogDetailsMappings.class) public static class CCatalog extends CompoundReference { } @CompoundKey(gsType = Product.class, dbType = ProductDetailsMappings.class) public static class CProduct extends CompoundReference { } @CompoundKey(gsType = Category.class) public static class CCategory extends CompoundReference { } @CompoundKey(gsType = Poll.class, dbType = PollDetailsMappings.class) public static class CPoll extends CompoundReference { } // much mroe inner classes Some manual solution would be just to main such a static block , that is something that I dont want to do. static { classList.addAll(Arrays.asList(CUser.class, CCatalog.class, CProduct.class, CCategory.class, CPoll.class, CComment.class, CWebPage.class, CReview.class, CPost.class, CMessage.class, CStory.class,CPicture.class)); }

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  • Just how much do I want to make virtual?

    - by Alex
    I am writing an abstract superclass where literally every method is going to be overridden. There is some default functionality I could implement, but most of the time it's enough to leave the implementation to the subclass writer. Since just about every method is going to be overwritten, how much should I make virtual and how much should I just leave as regular methods? In the current incarnation, everything is virtual, but I still haven't let this loose to anyone to use, so the design is flexible. What advantages/disadvantages are there to virtual functions? Links to good reading material about this would be appreciated.

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  • Working with sets of rows in (My)SQL and comparing values

    - by Pep.
    Hello, I am trying to figure out the SQL for doing some relatively simple operations on sets of records in a table but I am stuck. Consider a table with multiple rows per item, all identified by a common key. For example: serial model color XX1 A blue XX2 A blue XX3 A green XX5 B red XX6 B blue XX1 B blue What I would for example want to do is: Assuming that all model A rows must have the same color, find the rows which dont. (for example, XX3 is green). Assuming that a given serial number can only point to a single type of model, find out the rows which that does not occur (for example XX1 points both to A and B) These are all simple logically things to do. To abstract it, I want to know how to group things by using a single key (or combination of keys) and then compare the values of those records. Should I use a join on the same table? should i use some sort of array or similar? thanks for your help

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  • Core Data: Detecting the type and casting it

    - by Tim Sullivan
    I have set up a Core Data model that includes an entity, Item with a 1-M relationship with the abstract entity Place, so that an item has many places. There are several entities with the parent set to Place. I want to set up several UI elements depending on the descendent place types. I have a loop that looks something like this: for (Place *place in item.places) { } ... but I'm not sure how to detect what type the place is, and how to cast it to the proper type so that I can access its properties. Thanks for any help!

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  • How to filter/sort/rank object model nodes?

    - by BCS
    I have some kind of object model and I need to filter and sort it's nodes for some kind of property. What kinds of automated systems exist to generate and select properties of the object model that correlate to what I want? (I'm intentionally being abstract and non-specific) I'm thinking of a system that works kind of like spam filters or supervised classification systems in that given an example data set it identifies rules that find nodes of interest. However I'm looking for a more general system in that it shouldn't require any design time information about the object model. It should work equality well as a spam filter on e-mail, a bug finder on a code base, an interest filter in a newsgroup or bot accounts finder on a social networking site. As long as it can explore the object model via reflection and be given a set of "interesting" nodes, it should be able to find rules that will find more nodes like them.

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  • Calling inheriting class methods via interface.

    - by Stacey
    Given the scenario... interface IBase{ void Process(int value); } abstract class Base : IBase { public virtual void Process(int value){ throw new NotImplementedException(); } } class Implemented: Base, IBase { public void Process(int value) { // .. some code here.. } } I'm trying to write a loop similar to the following. foreach( Base b in CollectionOfImplemented ) { b.Process( // something will go here // ); } Trying this, it keeps calling Base.Process, instead of Implemented.Process; but the type in the collection is Implemented, not Base. Boxing it seems to work, but I was hoping to see if I could find a more intelligent approach to it, since the Collection will contain other types of objects that also inherit from Base.

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  • How can I remove the numeration of some titles in LaTeX?

    - by Tae
    Hi: I'm writing my degree project report using the article class and I want a structure like this: Abstract Introduction 1. What 2. Where 3. Etc. I was searching and I found that using \setcounter{secnumdepth}{-1} the complete numeration is eliminated. And if I use * these sections don't appear in the table of content. So what can I do? Can this be done without installing packages (like memoir)?

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