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  • NSArray multiply each argument

    - by seaworthy
    Is the there a way to multiply each NSNumber contained in the array by 10? Here is what I have so far: NSMutableArray *vertex = [NSMutableArray arrayWithCapacity:3]; [vertex addObject:[NSNumber numberWithFloat:1.0]]; [vertex addObject:[NSNumber numberWithFloat:2.0]]; [vertex addObject:[NSNumber numberWithFloat:3.0]]; [vertex makeObjectsPerformSelector:@selector(doSomethingToObject:)]; I am not sure what selector to use to do this, please help!

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  • Is it bad practice to make a setter return "this"?

    - by Ken Liu
    Is it a good or bad idea to make setters in java return "this"? public Employee setName(String name){ this.name = name; return this; } This pattern can be useful because then you can chain setters like this: list.add(new Employee().setName("Jack Sparrow").setId(1).setFoo("bacon!")); instead of this: Employee e = new Employee(); e.setName("Jack Sparrow"); ...and so on... list.add(e); ...but it sort of goes against standard convention. I suppose it might be worthwhile just because it can make that setter do something else useful. I've seen this pattern used some places (e.g. JMock, JPA), but it seems uncommon, and only generally used for very well defined APIs where this pattern is used everywhere. Update: What I've described is obviously valid, but what I am really looking for is some thoughts on whether this is generally acceptable, and if there are any pitfalls or related best practices. I know about the Builder pattern but it is a little more involved then what I am describing - as Josh Bloch describes it there is an associated static Builder class for object creation.

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  • Make is more OOPey - good structure?

    - by Tom
    Hi, I just want advice on whether I could improve structure around a particular class which handles all disk access functions The structure of my program is that I have a class called Disk which gets data from flatfiles and databases on a, you guessed it, hard disk drive. I have functions like LoadTextFileToStringList, WriteStringToTextFile, DeleteLineInTextFile etc which are kind of "generic methods" In the same class I also have some more specific methods such as GetXFromDisk where X might be a particular field in a database table/query. Should I separate out the generic methods from the specialised. Should I make another class which inherits the generic methods. At the moment my class is static as there is no need to have an internal state of the class. I'm not really OOPing am I? Thanks Thomas

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  • Object Oriented Programming in AS3

    - by Jordan
    I'm building a game in as3 that has balls moving and bouncing off the walls. When the user clicks an explosion appears and any ball that hits that explosion explodes too. Any ball that then hits that explosion explodes and so on. My question is what would be the best class structure for the balls. I have a level system to control levels and such and I've already come up with working ways to code the balls. Here's what I've done. My first attempt was to create a class for Movement, Bounce, Explosion and finally Orb. These all extended each other in the order I just named them. I got it working but having Bounce extend Movement and Explosion extend Bounce, it just doesn't seem very object oriented because what if I wanted to add a box class that didn't move, but did explode? I would need a separate class for that explosion. My second attempt was to create Movement, Bounce and Explosion without extending anything. Instead I passed in a reference to the Orb class to each. Then the class stores that reference and does what it needs to do based on events that are dispatched by the Orb such as update, which was broadcast from Orb every enter frame. This would drive the movement and bounce and also the explosion when the time came. This attempt worked as well but it just doesn't seem right. I've also thought about using Interfaces but because they are more of an outline for classes, I feel like code reuse goes out the window as each class would need its own code for a specific task even if that task is exactly the same. I feel as if I'm searching for some form of multiple inheritance for classes that as3 does not support. Can someone explain to me a better way of doing what I'm attempting to do? Am I being to "Object Oriented" by having classed for Movement, Bounce, Explosion and Orb? Are Interfaces the way to go? Any feedback is appreciated!

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  • JAVA Casting error

    - by user1612725
    Im creating a program that uses Dijksrtras algorithm, im using nodes that represent cities on an imported map, and you can create edges between two cities on the map. My problem is every edge has a "weight" where it will represent distance in minutes and i have a function where i want to see the distance between the two edges. But i keep getting the error "Cannot cast from Stad to Edge" at the line Edge<Stad> selectedEdge = (Edge) fvf.visaFörbLista.getSelectedValue(); where "Stad" represents the city and "Edge" an edge. FormVisaförbindelse fvf = new FormVisaförbindelse(); for(;;){ try{ int svar = showConfirmDialog(null, fvf, "Ändra Förbindelser", JOptionPane.OK_CANCEL_OPTION); if (svar != YES_OPTION) return; if (fvf.visaFörbLista.isSelectionEmpty() == true){ showMessageDialog(mainMethod.this, "En Förbindelse måste valjas.","Fel!", ERROR_MESSAGE); return; } Edge<Stad> selectedEdge = (Edge) fvf.visaFörbLista.getSelectedValue(); FormÄndraförbindelse faf = new FormÄndraförbindelse(); faf.setförbNamn(selectedEdge.getNamn()); for(;;){ try{ int svar2 = showConfirmDialog(mainMethod.this, faf, "Ändra Förbindelse", OK_CANCEL_OPTION); if (svar2 != YES_OPTION) return; selectedEdge.setVikt(faf.getförbTid()); List<Edge<Stad>> edges = lg.getEdgesBetween(sB, sA); for (Edge<Stad> edge : edges){ if (edge.getNamn()==selectedEdge.getNamn()){ edge.setVikt(faf.getförbTid()); } } return; } catch(NumberFormatException e){ showMessageDialog(mainMethod.this, "Ogiltig inmatning.","Fel!", ERROR_MESSAGE); }

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  • What is Object Decomposition?

    - by Mustafa
    Hi everyone, I was trying to understand what object decomposition means and read a lot of stuff on internet but every resource talks in terms of lots of keywords that i couldn't understand. So these resources expect you to know a few terms. I need something that lists the basics of decomposition from scratch. Is it anything more than breaking the design into objects? If no, any description will be appreciated. Thanks in advance

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  • about python scripting

    - by kmitnick
    I have this code class HNCS (ThreadingTCPServer): def verify_request(self, request, client_address): for key in connections: if connections[key].client_address[0] == client_address[0]: if client_address[0] != '127.0.0.1': return False return True def welcome(self): return '''______________________________________________________ ------------------------------------------------------ %s ______________________________________________________ ------------------------------------------------------ * Server started %s * Waiting for connections on port %i ''' % (gpl, ctime(), PORT) I only can't figure out the line where it says if connections[key].client_address[0] == client_address[0] how come we used client_address as an attribute after dictionary???

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  • creating a wrapper around a 3rd party assembly - swap out and decouple

    - by mrblah
    I have an email component that I am integrating into my application, looking for some tips on how should build a wrapper around it so I can swap it out with another 3rd party component if needed. My approach right now is it: build an interface will the functionality I need. create a class that implements the interface, using my 3rd party component inside this class. any usage of this component will be via the interface so like: IPop3 pop3 = new AcmeIncePop3Wrapper(); pop3.connect(); and inside AcmeIncePop3Wrapper will be: public void connect() { AcmeIncePop3 pop = new AcmeIncePop3(); pop.connect(); } Is that a good approach? I could probably add another abstraction by using ninject so I could swap out implementations, but really this seems to be all I need as i don't expect to be changing 3rd party assemblies every day, just don't want to make things so tightly coupled.

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  • How can you get a list or traversable tree of bookmarks from within a Firefox Extension?

    - by Nathan
    I am working on a simple Firefox Extension, and I need a list of the user's bookmarks. I have found the nsINavBookmarksService class which appears to be the recommended way of manipulating bookmarks since Firefox 3.0. Strangely I don't see a method that I could use to get a list of all the bookmarks in a folder. I need some way of creating a flat list of all the Bookmark URIs, but without any methods that return information about more than one bookmark I don't see a way to do it.

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  • Javascript static method intheritance

    - by Matteo Pagliazzi
    I want to create a javascript class/object that allow me to have various method: Model class Model.all() » static method Model.find() » static method Model delete() » instance method Model save() » instance method Model.create() » static that returns a new Model instance For static method I can define them using: Model.staticMethod(){ method } while for instance method is better to use: function Model(){ this.instanceMethod = function(){} } and then create a new instance or using prototype? var m = function Model(){ } m.prototype.method() = function(){ } Now let's say that I want to create a new class based on Model, how to inherit not only its prototypes but also its static methods?

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  • "string" != "string"

    - by Misiur
    Hi. I'm doing some kind of own templates system. I want to change <title>{site('title')}</title> Into function "site" execution with parameter "title". Here's private function replaceFunc($subject) { foreach($this->func as $t) { $args = explode(", ", preg_replace('/\{'.$t.'\(\'([a-zA-Z,]+)\'\)\}/', '$1', $subject)); $subject = preg_replace('/\{'.$t.'\([a-zA-Z,\']+\)\}/', call_user_func_array($t, $args), $subject); } return $subject; } Here's site: function site($what) { global $db; $s = $db->askSingle("SELECT * FROM ".DB_PREFIX."config"); switch($what) { case 'title': return 'Title of page'; break; case 'version': return $s->version; break; case 'themeDir': return 'lolmao'; break; default: return false; } } I've tried to compare $what (which is for this case "title") with "title". MD5 are different. strcmp gives -1, "==", and "===" return false. What is wrong? ($what type is string. You can't change call_user_func_array into call_user_func, because later I'll be using multiple arguments)

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  • Class as an Event Observer

    - by emi
    I want to do something like this... var Color = Class.create({ initialize: function() { this._color = "white"; this.observe("evt: colorChanged", this.colorChanged.bind(this)); }, changeColor: function(color) { this._color = color; this.fire("evt: colorChanged"); }, colorChanged: function(event) { alert("You change my color!"); } }); var a = new Color().changeColor("blue"); Why the colorChange custom event will never be dispatched and I need to use, instead of this, a DOM element like document.observe? In my code I'd like to know which class dispatches the event using event.target and I can't if I must use document or some other DOM element. :( I've been working in Actionscript 3 and that's the methodology I learned to work with custom events in classes. What about Javascript?

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  • Transfer data between C++ classes efficiently

    - by David
    Hi, Need help... I have 3 classes, Manager which holds 2 pointers. One to class A another to class B . A does not know about B and vise versa. A does some calculations and at the end it puts 3 floats into the clipboard. Next, B pulls from clipboard the 3 floats, and does it's own calculations. This loop is managed by the Manager and repeats many times (iteration after iteration). My problem: Now class A produces a vector of floats which class B needs. This vector can have more than 1000 values and I don't want to use the clipboard to transfer it to B as it will become time consumer, even bottleneck, since this behavior repeats step by step. Simple solution is that B will know A (set a pointer to A). Other one is to transfer a pointer to the vector via Manager But I'm looking for something different, more object oriented that won't break the existent separation between A and B Any ideas ? Many thanks David

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  • How to return Current Object in a Static function in PHP

    - by streetparade
    I neet access to current object in a static method. Code: protected static $name; public static function name($modulename) { self::$name = $modulename; } public function __call($name, $arguments) { $me = new test(self::$name); return $me->$name($arguments); } I want to be able to call method log in Log class. Like this echo Mods::name("Log")->log("test"); How do i do that?

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  • Call to a member function num_rows() on a non-object

    - by Patrick
    I need to get the number of rows of a query (so I can paginate results). As I'm learning codeigniter (and OO php) I wanted to try and chain a -num_rows() to the query, but it doesn't work: //this works: $data['count'] = count($this->events->findEvents($data['date'], $data['keyword'])); //the following doesn't work and generates // Fatal Error: Call to a member function num_rows() on a non-object $data['count2'] = $this->events->findEvents($data['date'], $data['keyword'])->num_rows(); the model returns an array of objects, and I think this is the reason why I can't use a method on it. function findEvents($date, $keyword, $limit = NULL, $offset = NULL) { $data = array(); $this->db->select('events.*, venues.*, events.venue AS venue_id'); $this->db->join('venues', 'events.venue = venues.id'); if ($date) { $this->db->where('date', $date); } if ($keyword) { $this->db->like('events.description', $keyword); $this->db->or_like('venues.description', $keyword); $this->db->or_like('band', $keyword); $this->db->or_like('venues.venue', $keyword); $this->db->or_like('genre', $keyword); } $this->db->order_by('date', 'DESC'); $this->db->order_by('events.priority', 'DESC'); $this->db->limit($limit, $offset); //for pagination purposes $Q = $this->db->get('events'); if ($Q->num_rows() > 0) { foreach ($Q->result() as $row) { $data[] = $row; } } $Q->free_result(); return $data; } Is there anything that i can do to be able to use it? EG, instead of $data[] = $row; I should use another (OO) syntax?

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  • How to debug PHP?

    - by NutMotion
    Anyone's been trying himself at object oriented programming ? Most probably every developer I guess:D I for one have never studied OO design patterns thoroughly, and trying to put it all together now does prove at times thrilling, and many times frustrating also. Even more so when trying to do it in : PHP! All-in-all, my boss asked me to add some Database persistence functions to her server, but most of all, she asked me to translate her already working procedural code into a working Object Oriented code. Here I am, still standing on my PHP OO project. I'm (already) fed up with this "file logging only" PHP capability. I believe there must be some (free or not too much expansive) PHP debugging utility ? I've heard about Zend Studio and PHPEd so far, which didn't quite do the trick for whatever reasons. WIRCW("Which I don't Remember Correctly Why" lol) What say yé? on debugging PHP ? Is there a tool that provides a good debug mode? what's more, don't forget I'm not speaking about the classical web Request/response model. Talking about a debugging facility which can enable you to trigger a web service (aka client request) and go into debug mode on the SOAP web service side. Thks for any input.

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  • Why is there a constructor method if you can assign the values to variables?

    - by Joel
    I'm just learning PHP, and I'm confused about what the purpose of the __construct() method? If I can do this: class Bear { // define properties public $name = 'Bill'; public $weight = 200; // define methods public function eat($units) { echo $this->name." is eating ".$units." units of food... <br />"; $this->weight += $units; } } Then why do it with a constructor instead? : class Bear { // define properties public $name; public $weight; public function __construct(){ $this->name = 'Bill'; $this->weight = 200; } // define methods public function eat($units) { echo $this->name." is eating ".$units." units of food... <br />"; $this->weight += $units; } }

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  • Single Responsibility Principle vs Anemic Domain Model anti-pattern

    - by Niall Connaughton
    I'm in a project that takes the Single Responsibility Principle pretty seriously. We have a lot of small classes and things are quite simple. However, we have an anemic domain model - there is no behaviour in any of our model classes, they are just property bags. This isn't a complaint about our design - it actually seems to work quite well During design reviews, SRP is brought out whenever new behaviour is added to the system, and so new behaviour typically ends up in a new class. This keeps things very easily unit testable, but I am perplexed sometimes because it feels like pulling behaviour out of the place where it's relevant. I'm trying to improve my understanding of how to apply SRP properly. It seems to me that SRP is in opposition to adding business modelling behaviour that shares the same context to one object, because the object inevitably ends up either doing more than one related thing, or doing one thing but knowing multiple business rules that change the shape of its outputs. If that is so, then it feels like the end result is an Anemic Domain Model, which is certainly the case in our project. Yet the Anemic Domain Model is an anti-pattern. Can these two ideas coexist? EDIT: A couple of context related links: SRP - http://www.objectmentor.com/resources/articles/srp.pdf Anemic Domain Model - http://martinfowler.com/bliki/AnemicDomainModel.html I'm not the kind of developer who just likes to find a prophet and follow what they say as gospel. So I don't provide links to these as a way of stating "these are the rules", just as a source of definition of the two concepts.

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  • Create UML diagrams after or before coding?

    - by ajsie
    I can clearly see the benefits of having UML diagrams showing your infrastructure of the application (class names, their members, how they communicate with each other etc). I'm starting a new project right now and have already structured the database (with visual paradigm). I want to use some design patterns to guide me how to code the classes. I wonder, should I code the classes first before I create UML diagram of it (maybe out of the code... seems possible) or should I first create UML diagram and then code (or generate code from the UML, seems possible that too). What are you experiences telling you is the best way?

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  • How to design a class for managing file path ?

    - by remi bourgarel
    Hi All In my app, I generate some xml file for instance : "/xml/product/123.xml" where 123 is the product's id and 123.xml contains informations about this product. I also have "/xml/customer/123.xml" where 123.xml contains informations about the client ... 123 How can I manage these file paths : 1/ - I create the file path directly in the seralization method ? 2/ I create 2 static class : CustomerSerializationPathManager and ProductSerializationPathManager with 1 method : getPath(int customerID) and getPath(int productID) 3/ I create one static class : SerializationPathManager with 2 method : getCustomerPath(int customerID) and getProductPath(int productID) 4/ something else I'd prefer the solution 3 cause if I think there's only one reason to change this class : I change the root directory. So I'd like to have your thoughts about it... thx

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  • Stuck on Object scope in Java

    - by ivor
    Hello, I'm working my way through an exercise to understand Java, and basically I need to merge the functionality of two classes into one app. I'm stuck on one area though - the referencing of objects across classes. What I have done is set up a gui in one class (test1), and this has a textfield in ie. chatLine = new JTextField(); in another class(test2), I was planning on leaving all the functionality in there and referencing the various gui elements set up in test1 - like this test1.chatLine I understand this level of referencing, I tested this by setting up a test method in the test2 class public static void testpass() { test1.testfield.setText("hello"); } I'm trying to understand how to implement the more complex functionality in test2 class though, specifically this existing code; test1.chatLine.addActionListener(new ActionAdapter() { public void actionPerformed(ActionEvent e) { String s = Game.chatLine.getText(); if (!s.equals("")) { appendToChatBox("OUTGOING: " + s + "\n"); Game.chatLine.selectAll(); // Send the string sendString(s); } } }); This is the bit I'm stuck on, if I should be able to do this - as it's failing on the compile, can I add the actionadapter stuff to the gui element thats sat in test1, but do this from test2 - I'm wondering if I'm trying to do something that's not possible. Hope this makes sense, I'm pretty confused over this - I'm trying to understand how the scope and referencing works. Ideally what i'm trying to achieve is one class that has all the main stuff in, the gui etc, then all the related functionality in the other class, and target the first class's gui elements with the results etc. Any thoughts greatly appreciated.

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  • Overriding an abstract method of base class

    - by jess
    Hi, I have an abstract class with some methods,including an abstract method(Execute()).This method is overridden in child class.Now, an event is raised(somewhere in application),and for this event there is a handler in base class.And,in this handler,I call Execute. Now, the method of chilobject is executed.I am bit confused,how this works under the hood?

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  • Shadows vs Overloads in VB.NET

    - by serhio
    When we have new in C#, that personally I see only as a workaround to override a property that does not have a virtual/overridable declaration, in VB.NET we have two "concepts" Shadows and Overloads. In which case prefer one to another?

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