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  • Organizing test hierarchy in clojure project

    - by Sergey
    There are two directories in a clojure project - src/ and test/. There's a file my_methods.clj in the src/calc/ directory which starts with (ns calc.my_methods...). I want to create a test file for it in test directory - test/my_methods-test.clj (ns test.my_methods-test (:require [calc.my_methods]) (:use clojure.test)) In the $CLASSPATH there are both project root directory and src/ directory. But the exception is still "Could not locate calc/my_methods__init.class or calc/my_methods.clj on classpath". What is the problem with requiring it in the test file? echo $CLASSPATH gives this: ~/project:~/project/src

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  • Rails - inheritance hierarchy of classes where a subtype can play two roles

    - by Miquel
    I need to model Owners and Rentees in an application, so you have stuff that is always owned by someone and can be rented for someone else. I first approached this problem with Single Table Inheritance because both types of person will share all attributes, so you would have a model called Person associated to a table people with Owner and Rentee inheriting from Person. The problem is that Single type inheritance discerns subtypes using a field type and therefore a record in the table can represent either an Owner or a Rentee but not both at the same time, while in the real context you can have an Owner which is renting something from another Owner and therefore that person is at the same time an Owner and a Rentee. How would you approach this problem? Would you use separated tables for owners and rentees? Is there any other type of table inheritance in Rails?

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  • How the websocket bi-directional concept work?

    - by GMsoF
    I think the main difference between websocket and http streaming (I am not refering to polling and long polling) is websocket allows bi-directional communication which is similar to usual raw socket programming. (above is my understanding, could be wrong, feel free to correct me.) My question is how the web client (browser) continue to send another request in the already-opened websocket? Usual http request will treat another request as new socket connection, but websocket does not, that is why I am confused, how it achieve that? It should be handled in Server side or Client (browser) side?

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  • backbonejs remove anomaly concept

    - by user1537158
    I was building a small app for adding and deleting li from ul using Backbonejs.One of the SO members cymen helped me code it, using that i tailored the code a little.currently if i add one element and delete , it works , but the second time i add an element (to ul) and go to delete it , i get Uncaught TypeError: Cannot call method 'remove' of undefined Pasting my code here , HTML : <input type="text" id="name"> <button id="add">Add</button> <ul id="mylist"></ul> JS: $(function(){ var myCollection = Backbone.Collection.extend(); var myView = Backbone.View.extend({ el:$('body'), tagName:'li', initialize : function(e){ this.collection.bind("add",this.render,this); this.collection.bind("remove",this.render,this); }, events:{ 'click #add' : 'addfoo' }, addfoo : function(){ var myname= $('#name').val(); $('#name').val(''); this.collection.add({name:myname}); }, render : function(){ $('#mylist').empty(); this.collection.each(function(model){ console.log("myView"); var remove = new myRemoveView({model:model}); remove.render(); }); } }); var myRemoveView = Backbone.View.extend({ el:$('body'), events:{ 'click .button':'removeFoo' }, removeFoo : function(){ console.log("here"); this.model.collection.remove(this.model); }, render : function(){ console.log("second view"); $('#mylist').append('<li>'+this.model.get('name') + "<button class='button'>"+"delete"+"</button></li>"); return; } }); var view = new myView({collection: new myCollection()}); }); Two things i did not understand : i) in the removeFoo function , we write this.model.collection.remove(this.model) shouldnt this have been this.collection.model.remove , something of that sort ? ii) i add a li to ul , then i delete it , when i add another li (appending to ul works perfect) but this time when i go to delete it throws me the above error : Uncaught TypeError :cannot call method 'remove' of undefined can you please help me figure out these 2 doubts in my code , btw SO member cymen's code works like a charm only my tailored code (above) is giving me errors. SO member cymen's code : JS Fiddle for his code Thank you

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  • OBJ-C - Getting a class name from a class hierarchy

    - by mmmilo
    Let's say I have the following headers: @interface SuperClass : NSObject @interface SubClass : SuperClass I'm alloc'ing an instance of the class by doing: SubClass *sc = [[SubClass alloc] init]; In my SuperClass.m: - (id) init { self = [super init]; if (self != nil) { NSString *cString = NSStringFromClass([self class]); } return self; } Simple, right? My question is: how can I get cString to return the SuperClass class, rather than the SubClass class? Since the SubClass is alloc'd/init'd, is this not possible? Thanks!

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  • Dont understand the concept of extends in URL.openConnection() in JAVA

    - by user1722361
    Hi I am trying to learn JAVA deeply and so I am digging into the JDK source code in the following lines: URL url = new URL("http://www.google.com"); URLConnection tmpConn = url.openConnection(); I attached the source code and set the breakpoint at the second line and stepped into the code. I can see the code flow is: URL.openConnection() - sun.net.www.protocol.http.Handler.openConnection() I have two questions about this First In URL.openConnection() the code is: public URLConnection openConnection() throws java.io.IOException { return handler.openConnection(this); } handler is an object of URLStreamHandler, define as blow transient URLStreamHandler handler; But URLStreamHandler is a abstract class and method openConnection() is not implement in it so when handler calls this method, it should go to find a subclass who implement this method, right? But there are a lot classes who implement this methods in sun.net.www.protocol (like http.Hanlder, ftp.Handler ) How should the code know which "openConnection" method it should call? In this example, this handler.openConnection() will go into http.Handler and it is correct. (if I set the url as ftp://www.google.com, it will go into ftp.Handler) I cannot understand the mechanism. second. I have attached the source code so I can step into the JDK and see the variables but for many classes like sun.net.www.protocol.http.Handler, there are not source code in src.zip. I googled this class and there is source code online I can get but why they did not put it (and many other classes) in the src.zip? Where can I find a comprehensive version of source code? Thanks!

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  • How to verify the Liskov substitution principle in an inheritance hierarchy?

    - by Songo
    Inspired by this answer: Liskov Substitution Principle requires that Preconditions cannot be strengthened in a subtype. Postconditions cannot be weakened in a subtype. Invariants of the supertype must be preserved in a subtype. History constraint (the "history rule"). Objects are regarded as being modifiable only through their methods (encapsulation). Since subtypes may introduce methods that are not present in the supertype, the introduction of these methods may allow state changes in the subtype that are not permissible in the supertype. The history constraint prohibits this. I was hoping if someone would post a class hierarchy that violates these 4 points and how to solve them accordingly. I'm looking for an elaborate explanation for educational purposes on how to identify each of the 4 points in the hierarchy and the best way to fix it. Note: I was hoping to post a code sample for people to work on, but the question itself is about how to identify the faulty hierarchies :)

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  • How to implement or emulate an "abstract" OCUnit test class?

    - by Quinn Taylor
    I have a number of Objective-C classes organized in an inheritance hierarchy. They all share a common parent which implements all the behaviors shared among the children. Each child class defines a few methods that make it work, and the parent class raises an exception for the methods designed to be implemented/overridden by its children. This effectively makes the parent a pseudo-abstract class (since it's useless on its own) even though Objective-C doesn't explicitly support abstract classes. The crux of this problem is that I'm unit testing this class hierarchy using OCUnit, and the tests are structured similarly: one test class that exercises the common behavior, with a subclass corresponding to each of the child classes under test. However, running the test cases on the (effectively abstract) parent class is problematic, since the unit tests will fail in spectacular fashion without the key methods. (The alternative of repeating the common tests across 5 test classes is not really an acceptable option.) The non-ideal solution I've been using is to check (in each test method) whether the instance is the parent test class, and bail out if it is. This leads to repeated code in every test method, a problem that becomes increasingly annoying if one's unit tests are highly granular. In addition, all such tests are still executed and reported as successes, skewing the number of meaningful tests that were actually run. What I'd prefer is a way to signal to OCUnit "Don't run any tests in this class, only run them in its child classes." To my knowledge, there isn't (yet) a way to do that, something similar to a +(BOOL)isAbstractTest method I can implement/override. Any ideas on a better way to solve this problem with minimal repetition? Does OCUnit have any ability to flag a test class in this way, or is it time to file a Radar? Edit: Here's a link to the test code in question. Notice the frequent repetition of if (...) return; to start a method, including use of the NonConcreteClass() macro for brevity.

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  • How to copy generically superclass instances to subclass instances?

    - by gerry
    Hi @all, I have a class hierarchy / inheritance like this: public class A { private String name; // with getters & setters public void doAWithName(){ ... } } public class B extends A { public void doBWithName(){ // a differnt implementation to what I do in class A } } public class C extends B { public void doCWithName(){ // a differnt implementation to what I do in class A and B } } So at one time there is a instance of class A with the initialized field "name". Later I want this instance of A get wrapped into instance of B or C. So the superclasses should be get wrapped with a subclass! How can I make this most efficent with respect to DRY? I've thought about a constructor that does some copying with the getters/setters. But in this case I have to repeat myself - and this doesn't respect anymore to my initial requirement of DRY! So, how can I warp A to B by just initializing B's new fields (with default values) and delegating the rest to a method in A (which knows more than B about which fields of A should be accessed...). In the same way: If A should be wrapped into C only a method in c should init C's 'new' fields, delegate to B's wrap method (which therefore inits B's 'new' fields in C) and at last B delegates to A which copies it's fields to the fields of C). So in the end I have a new instance of C which has the values of A wrapped (and some default init values to the fields which the inheritance hierarchy has added).

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  • Plus besoin de failles pour exploiter les PDF malicieux, un chercheur publie un "Proof of Concept" q

    Plus besoin de failles pour exploiter les PDF malicieux Un chercheur en sécurité publie un "Proof of Concept" qu'il a communiqué aux éditeurs Didier Stevens est un chercheur en sécurité qui vient de sérieusement ébranler le format PDF. Il a en effet publié un "Proof of Concept" (une démonstration qui, volontairement, ne va pas jusqu'au bout) - ou PoC - qui permet de lancer l'exécution d'un code via une ligne de commande dans un document PDF. Avec cette méthode, Didier Stevens arrive par exemple à lancer et à faire tourner une calculatrice. Le PoC présenté sur son blog a été réalisé avec Adobe Reader 9.3.1 sur Windows XP SP3 et Windows 7. Mais il fonctio...

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  • What would you call the concept of CofeeScript or Sass to be?

    - by MaG3Stican
    There is this rising trend with web development of making new pseudo languages to extend the functionality of JavaScript, CSS and HTML given that those are static and their metamorphosis or evolution is painfully slow due to the variety of browser providers. So I am currently having a concept dilema on how to categorize them for a book I was made to write by my employer as no one seems to have a name for these pseudo languages. A tiny list of them : JavaScript: LiveScript, Metalua, Uberscript, EmberScript. HTML: Razor, Java Scriptlets. CSS : LESS, Sass. I believe the concept of these pseudo languages and a language or an extension of a language is quite different. First these languages do not extend any functionality currently existing on HTML or CSS or JavaScript, they simply work around it. And also they do not "compile" to an intermediate language, they are merely 1-1 translated to something that only then can be compiled. What would you call them?

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  • Ruby Exception or Error?

    - by Ell
    I have noticed that in the Ruby exception hierarchy, there are "errors" such as ArgumentError and there are "exceptions" such as SignalException. Is there a certain practise of naming exceptions? thanks in advance, ell.

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  • Restore deleted default folders

    - by Helena T.
    I was tinkering with my new laptop and, on purpose, deleted those default folders in my "home" directory: "My Music", "Links", "Favorites". This, because, i decided i wanted all my data on another partition, leaving C: only for applications and configs files. But now, some of the explorer functionalities are gone: i cannot use the Favorites tree in the left side pane, also discovered that "My Documents" stores some PowerShell config file. I feel like i misunderstood this folders' purpose and by deleting them, provoked some Explorer instability. Is there any way to restore them? I do not seem to find it. Thank you for taking the time to read this.

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  • How to symlink folders and exclude certain files

    - by Jarrod White
    Hey Guys, I'm not a server guru (unfortunately) but have a decent knowledge of linux & bsd. I'm trying to symlink multiple instances of HLDS (game server) but need to exclude certain folders & config files to achieve this properly. I need to do it this way as HLDS loads many mods automatically, and putting an exception to disable the mods doesnt work for all of them. so basically i want: /home/user/hlds-install (the base install) /home/user/server1 /home/user/server2 etc... and then be able to manually put any configs/mods ive excluded into the server dir's so that each server can be configured individually. Can anyone tell me how to do this, perhaps some sort of bash script so that I can just change the targets to run it each time i want to create a new one. I have quite a number to make so doing the whole thing manually for each one definately isn't an option and im all for working smarter, not harder! Thanks :)

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  • Parallel Class/Interface Hierarchy with the Facade Design Pattern?

    - by Mike G
    About a third of my code is wrapped inside a Facade class. Note that this isn't a "God" class, but actually represents a single thing (called a Line). Naturally, it delegates responsibilities to the subsystem behind it. What ends up happening is that two of the subsystem classes (Output and Timeline) have all of their methods duplicated in the Line class, which effectively makes Line both an Output and a Timeline. It seems to make sense to make Output and Timeline interfaces, so that the Line class can implement them both. At the same time, I'm worried about creating parallel class and interface structures. You see, there are different types of lines AudioLine, VideoLine, which all use the same type of Timeline, but different types of Output (AudioOutput and VideoOutput, respectively). So that would mean that I'd have to create an AudioOutputInterface and VideoOutputInterface as well. So not only would I have to have parallel class hierarchy, but there would be a parallel interface hierarchy as well. Is there any solution to this design flaw? Here's an image of the basic structure (minus the Timeline class, though know that each Line has-a Timeline): NOTE: I just realized that the word 'line' in Timeline might make is sound like is does a similar function as the Line class. They don't, just to clarify.

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  • Counting number of children in hierarchical SQL data

    - by moontear
    Hello, for a simple data structure such as so: ID parentID Text Price 1 Root 2 1 Flowers 3 1 Electro 4 2 Rose 10 5 2 Violet 5 6 4 Red Rose 12 7 3 Television 100 8 3 Radio 70 9 8 Webradio 90 For reference, the hierarchy tree looks like this: ID Text Price 1 Root |2 Flowers |-4 Rose 10 | |-6 Red Rose 12 |-5 Violet 5 |3 Electro |-7 Television 100 |-8 Radio 70 |-9 Webradio 90 I'd like to count the number of children per level. So I would get a new column "NoOfChildren" like so: ID parentID Text Price NoOfChildren 1 Root 8 2 1 Flowers 3 3 1 Electro 3 4 2 Rose 10 1 5 2 Violet 5 0 6 4 Red Rose 12 0 7 3 Television 100 0 8 3 Radio 70 1 9 8 Webradio 90 0 I read a few things about hierarchical data, but I somehow get stuck on the multiple inner joins on the parentIDs. Maybe someone could help me out here. moon

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  • Counting number of children in hierarchical SQL data

    - by moontear
    for a simple data structure such as so: ID parentID Text Price 1 Root 2 1 Flowers 3 1 Electro 4 2 Rose 10 5 2 Violet 5 6 4 Red Rose 12 7 3 Television 100 8 3 Radio 70 9 8 Webradio 90 For reference, the hierarchy tree looks like this: ID Text Price 1 Root |2 Flowers |-4 Rose 10 | |-6 Red Rose 12 |-5 Violet 5 |3 Electro |-7 Television 100 |-8 Radio 70 |-9 Webradio 90 I'd like to count the number of children per level. So I would get a new column "NoOfChildren" like so: ID parentID Text Price NoOfChildren 1 Root 8 2 1 Flowers 3 3 1 Electro 3 4 2 Rose 10 1 5 2 Violet 5 0 6 4 Red Rose 12 0 7 3 Television 100 0 8 3 Radio 70 1 9 8 Webradio 90 0 I read a few things about hierarchical data, but I somehow get stuck on the multiple inner joins on the parentIDs. Maybe someone could help me out here. moon

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  • Finding the order of method calls in Eclipse

    - by Chathuranga Chandrasekara
    Suppose I have a big program that consists of hundreds of methods in it. And according to the nature of input the program flow is getting changed. Think I want to make a change to the original flow. And it is big hassle to find call hierarchy/ references and understand the flow. Do I have any solution for this within Eclipse? Or a plugin? As an example, I just need a Log of method names that is in order of time. Then I don't need to worry about the methods that are not relevant with my "given input" Update : Using debug mode in eclipse or adding print messages are not feasible. The program is sooooo big. :)

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  • iPhone: error: request for member 'table' in something not a structure or union

    - by Jack Griffiths
    Hi there, When it comes to compiling my application, I get the error mentioned in the title. How would I go about remedying this error? Basically, I want to get from one table to the other. Hierarchy, navigation. NextViewController.m #import "RootViewController.h" #import "NextViewController.h" @implementation NextViewController - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Releases the view if it doesn't have a superview // Release anything that's not essential, such as cached data } - (void)dealloc { [super dealloc]; } - (IBAction) changeTable:(NSString *)str{ tblCSS.table = str; } The last line contains the error. If you need any more code, just ask. I'll amend this post with it. Cheers, Jack

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  • Finding the actual runtime call tree of a Java Program

    - by Chathuranga Chandrasekara
    Suppose I have a big program that consists of hundreds of methods in it. And according to the nature of input the program flow is getting changed. Think I want to make a change to the original flow. And it is big hassle to find call hierarchy/ references and understand the flow. Do I have any solution for this within Eclipse? Or a plugin? As an example, I just need a Log of method names that is in order of time. Then I don't need to worry about the methods that are not relevant with my "given input" Update : Using debug mode in eclipse or adding print messages are not feasible. The program is sooooo big. :)

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  • Mimic property/list changes on an object on another object

    - by soundslike
    I need to mimic changes (property/list) changes on an object and then apply it to another object to keep the structure/property the same. In essence it's like cloning etc. the biz rules require certain properties to not be applied to the other object, so I can't just clone the object otherwise this would be easy. I've already walked the source object to get INotifyPropertyChanged and IListChanged events, so I have the "source" and the args (Property or List) changed event notifications. Given that I guess I could build a reflection "hierarchy path" starting from the top level of the source object to get to the Property or List changed "source" (which could be several levels deep). Ignoring for the moment that certain object properties should not propagate to the other object, what's a way to build this "path"? Is a brute force top level down to build the "path" (and discard on the way back up if we don't hit the original changed event "source") the only way to do it? Any clever ideas on how to mimic changes from one object to another object?

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