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• ASP.NET design not SOLID

  - by w0051977

  SOLID principles are described here: http://en.wikipedia.org/wiki/SOLID_%28object-oriented_design%29 I am developing a large ASP.NET app. The previous developer created a few very large classes each with lots of different purposes. It is very difficult to maintain and extend. The classes are deployed to the web server along with the code behind files etc. I want to share a small amount of the app with another application. I am considering moving all of the classes of the ASP.NET web app to a DLL, so the small subset of functionality can be shared. I realise it would be better to only share the classes which contain code to be shared but because of the dependencies this is proving to be very difficult e.g. class A contains code that should be shared, however class A contains references to classes B, C, D, E, F, G etc, so class A cannot be shared on its own. I am planning to refactor the code in the future. As a temporary solution I am planning to convert all the classes into a single class library. Is this a bad idea and if so, is there an alternative? as I don't have time to refactor at the moment.

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• Layout Columns - Equal Height

  - by Kyle

  I remember first starting out using tables for layouts and learned that I should not be doing that. I am working on a new site and can not seem to do equal height columns without using tables. Here is an example of the attempt with div tags. <div class="row"> <div class="column">column1</div> <div class="column">column2</div> <div class="column">column3</div> <div style="clear:both"></div> </div> Now what I tried with that was doing making columns float left and setting their widths to 33% which works fine, I use the clear:both div so that the row would be the size of the biggest column, but the columns will be different sizes based on how much content they have. I have found many fixes which mostly involve css hacks and just making it look like its right but that's not what I want. I thought of just doing it in javascript but then it would look different for those who choose to disable their javascript. The only true way of doing it that I can think of is using tables since the cells all have equal heights in the same row. But I know its bad to use tables. After searching forever I than came across this: http://intangiblestyle.com/lab/equal-height-columns-with-css/ What it seems to do is exactly the same as tables since its just setting its display exactly like tables. Would using that be just as bad as using tables? I honestly can't find anything else that I could do. edit @Su' I have looked into "faux columns" and do not think that is what I want. I think I would be able to implement better designs for my site using the display:table method. I posted this question because I just wasn't sure if I should since I have always heard its bad using tables in website layouts.

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• OpenGL Application displays only 1 frame

  - by Avi

  EDIT: I have verified that the problem is not the VBO class or the vertex array class, but rather something else. I have a problem where my vertex buffer class works the first time its called, but displays nothing any other time its called. I don't know why this is, and it's also the same in my vertex array class. I'm calling the functions in this order to set up the buffers: enable client states bind buffers set buffer / array data unbind buffers disable client states Then in the draw function, that's called every frame: enable client states bind buffers set pointers unbind buffers bind index buffer draw elements unbind index buffer disable client states Is there something wrong with the order in which I'm calling the functions, or is it a more specific code error? EDIT: here's some of the code Code for setting pointers: //element is the vertex attribute being drawn (e.g. normals, colors, etc.) static void makeElementPointer(VertexBufferElements::VBOElement element, Shader *shade, void *elementLocation) { //elementLocation is BUFFER_OFFSET(n) if a buffer is bound switch (element) { .... glVertexPointer(3, GL_FLOAT, 0, elementLocation); //changes based on element .... //but I'm only dealing with } //vertices for now } And that's basically all the code that isn't just a straight OpenGL function call.

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• Bluetooth mouse no longer paired after resuming from suspend since upgrading to 13.10

  - by Korakys

  Since upgrading to 13.10 from 13.04 my mouse no longer connects via bluetooth. In settings it states that the mouse is not paired. Restarting bluetooth with sudo /etc/init.d/bluetooth restart does not help. Restarting the computer does fix the problem if bluetooth is restarted also with the previously mentioned command, but this is not ideal. The mouse worked fine prior to updating to 13.10. The computer is a ThinkPad X230 with a Broadcom 'BCM20702A0' bluetooth module (I think). When it is not working hciconfig hci0 -a returns: hci0: Type: BR/EDR Bus: USB BD Address: C0:18:85:DB:F3:D1 ACL MTU: 1021:8 SCO MTU: 64:1 UP RUNNING PSCAN RX bytes:766129 acl:49888 sco:0 events:2233 errors:0 TX bytes:5953 acl:240 sco:0 commands:274 errors:0 Features: 0xbf 0xfe 0xcf 0xfe 0xdb 0xff 0x7b 0x87 Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 Link policy: RSWITCH SNIFF Link mode: SLAVE ACCEPT Name: 'BCM20702A' Class: 0x6e0100 Service Classes: Networking, Rendering, Capturing, Audio, Telephony Device Class: Computer, Uncategorized HCI Version: 4.0 (0x6) Revision: 0x1000 LMP Version: 4.0 (0x6) Subversion: 0x220e Manufacturer: Broadcom Corporation (15) When it is working hciconfig hci0 -a returns: hci0: Type: BR/EDR Bus: USB BD Address: C0:18:85:DB:F3:D1 ACL MTU: 1021:8 SCO MTU: 64:1 UP RUNNING PSCAN RX bytes:253334 acl:16391 sco:0 events:842 errors:0 TX bytes:2519 acl:65 sco:0 commands:84 errors:0 Features: 0xbf 0xfe 0xcf 0xfe 0xdb 0xff 0x7b 0x87 Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 Link policy: RSWITCH SNIFF Link mode: SLAVE ACCEPT Name: 'ubuntu-0' Class: 0x6e0100 Service Classes: Networking, Rendering, Capturing, Audio, Telephony Device Class: Computer, Uncategorized HCI Version: 4.0 (0x6) Revision: 0x1000 LMP Version: 4.0 (0x6) Subversion: 0x220e Manufacturer: Broadcom Corporation (15) I am a relative novice with linux so don't ask me compile anything please, but I can use google.

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• How to store a list of Objects that might change in future?

  - by Amogh Talpallikar

  I have set of Objects of the same class which have different values of their attributes. and I need to find the best match from a function under given scenarios out of these objects. In future these objects might increase as well. Quite similar to the way we have Color class in awt. we have some static color objects in the class with diff rgb values. But in my case say, I need to chose the suitable color out of these static ones based on certain criteria. So should I keep them in an arrayList or enum or keep them as static vars as in case of Colors. because I will need to parse through all of them and decide upon the best match. so I need them in some sort of collection. But in future if I need to add another type I will have to modify the class and add another list.add(object) call for this one and then it will violate the open-close principle. How should I go about it ?

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• How can I design my classes to include calendar events stored in a database?

  - by Gianluca78

  I'm developing a web calendar in php (using Symfony2) inspired by iCal for a project of mine. At this moment, I have two classes: a class "Calendar" and a class "CalendarCell". Here you are the two classes properties and method declarations. class Calendar { private $month; private $monthName; private $year; private $calendarCellList = array(); private $translator; public function __construct($month, $year, $translator) {} public function getCalendarCellList() {} public function getMonth() {} public function getMonthName() {} public function getNextMonth() {} public function getNextYear() {} public function getPreviousMonth() {} public function getPreviousYear() {} public function getYear() {} private function calculateDaysPreviousMonth() {} private function calculateNumericDayOfTheFirstDayOfTheWeek() {} private function isCurrentDay(\DateTime $dateTime) {} private function isDifferentMonth(\DateTime $dateTime) {} } class CalendarCell { private $day; private $month; private $dayNameAbbreviation; private $numericDayOfTheWeek; private $isCurrentDay; private $isDifferentMonth; private $translator; public function __construct(array $parameters) {} public function getDay() {} public function getMonth() {} public function getDayNameAbbreviation() {} public function isCurrentDay() {} public function isDifferentMonth() {} } Each calendar day can includes many calendar events (such as appointments or schedules) stored in a database. My question is: which is the best way to manage these calendar events in my classes? I think to add a eventList property in CalendarCell and populate it with an array of CalendarEvent objects fetched by the database. This kind of solution doesn't allow other coders to reuse the classes without db (because I should inject at least a repository services also) just to create and visualize a calendar... so maybe it could be better to extend CalendarCell (for instance in CalendarCellEvent) and add the database features? I feel like I'm missing some crucial design pattern! Any suggestion will be very appreciated!

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• How to visualize code?

  - by gablin

  I've mostly only had to read my own code. As such, I've had no need to visualize the code as I already know how each and every class and module communicate with one another. But the few times I've had to read someone else's code - let us now assume we are talking about at least one larger module which contains several internal classes - I've almost always found myself wishing "This would have been so much easier to understand if I could just visualize it!" So what are the common methods or tools for enabling this? Which do you use, and why do you prefer them over the others? I've heard stuff like UML, module and class diagrams, but I imagine there are more. Furthermore, any of these is most likely better than anything I can devise on my own. EDIT: For those who answer with "Use pen and paper and just draw it": This isn't very helpful unless you explain this further. What exactly am I supposed to draw? A box for each class? Should I include the public methods? What about its fields? How should I draw connections that explain how one class uses another? What about modules? What if the language isn't object-oriented but functional or logical, or even just imperative (C, for instance)? What about global variables and functions? Is there an already-standardized way of drawing this, or do I need to think up of a method of my own? You get the drift.

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• Dental adventures ...

  - by nospam(at)example.com (Joerg Moellenkamp)

  Today my dentist pulled all the stops. Really. Just to explain ... half a year ago or so, i got the base part of an dental implant in my jaw. Today i got the teeth ... beside other things. At first i made the acquaintance of a really weird instrument to remove a temporary tooth crown ... it's called "Hirtenstab" in german ... or "crown remover" in english ... i would call it tool of torture. After the fourth time using it, the temporary flew through the room and the final crowns were set on two teeth left and right of the implant. But the strangest instrument i saw was the instrument to fix the abatement (the thing between the crown and the screw thread implanted in the jaw). They really use a torque wrench (albeit a really small one) to screw the abatement into the jaw. Well .. at least i have a zirconium dioxide smile now ...

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• Java game design question (graphical objects)

  - by vemalsar

  Hello Guys, I'm beginner in game development, in Java and here on this site too and I have a game design question. Please comment my idea: I have a main loop which call update and draw method. I want to use an ArrayList which store graphical objects, they have coordinate and image or text to draw and my game objects extends this class. In update, I can choose which objects should be put in the array and in draw method I'll display the elements of array on the screen. I'm using a buffer and draw first there, but it is not important now I guess...Here is a simple (not full) code, only the logic: public class GamePanel extends JPanel implements KeyListener { ArrayList<graphicalObjects> graphArray = new ArrayList<graphicalObjects>(); public void update() { //change the game scene, update the graphArray, process input etc. } public void draw() { //draws every element of graphArray to a JPanel } public static main(String[] args) { while(true) { update(); draw(); } } } My questions: Should have I use interface or abstract class for graphicalObjects? graphicalObjects class and the ArrayList really needs or there is some better solution? How to draw objects? They draw themself with their own method or in the draw method I have to draw manually based on graphicalObjects variables (x,y coordinates, image etc.)? If this conception is wrong, please suggest another one! All comments are welcome and sorry if this is dumb question, thanks!

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• Resource Acquisition is Initialization in C#

  - by codeWithoutFear

  Resource Acquisition Is Initialization (RAII) is a pattern I grew to love when working in C++.  It is perfectly suited for resource management such as matching all those pesky new's and delete's.  One of my goals was to limit the explicit deallocation statements I had to write.  Often these statements became victims of run-time control flow changes (i.e. exceptions, unhappy path) or development-time code refactoring. The beauty of RAII is realized by tying your resource creation (acquisition) to the construction (initialization) of a class instance.  Then bind the resource deallocation to the destruction of that instance.  That is well and good in a language with strong destructor semantics like C++, but languages like C# that run on garbage-collecting runtimes don't provide the same instance lifetime guarantees. Here is a class and sample that combines a few features of C# to provide an RAII-like solution: using System; namespace RAII { public class DisposableDelegate : IDisposable { private Action dispose; public DisposableDelegate(Action dispose) { if (dispose == null) { throw new ArgumentNullException("dispose"); } this.dispose = dispose; } public void Dispose() { if (this.dispose != null) { Action d = this.dispose; this.dispose = null; d(); } } } class Program { static void Main(string[] args) { Console.Out.WriteLine("Some resource allocated here."); using (new DisposableDelegate(() => Console.Out.WriteLine("Resource deallocated here."))) { Console.Out.WriteLine("Resource used here."); throw new InvalidOperationException("Test for resource leaks."); } } } } The output of this program is: Some resource allocated here. Resource used here. Unhandled Exception: System.InvalidOperationException: Test for resource leaks. at RAII.Program.Main(String[] args) in c:\Dev\RAII\RAII\Program.cs:line 40 Resource deallocated here. Code without fear! --Don

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• Understanding interfaces [closed]

  - by user985482

  Possible Duplicate: When to use abstract classes instead of interfaces and extension methods in C#? Why are interfaces useful? What is the point of an interface? What other reasons are there to write interfaces rather than abstract classes? What is the point of having every service class have an interface? Is it bad habit not using interfaces? I am reading Microsoft Visual C# 2010 Step by Step which I feel it is a very good book on introducing you to the C# language. I have just finished reading a chapter on interfaces and although I understood the syntax of creating and using interfaces I have trouble of understanding the point on why should I use them? Correct me If I am wrong but in an interface you can only declare methods names and parameters.The body of the method should be declared in the class that inherits the interface. So in this case why should I declare an interface if I am going to declare the entire method in the class that inherits that interface? What is the point? Does this have something to do with the fact that a class can inherit multiple interfaces?

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• Oracle College Rehire Program -China by Camilla!!

  - by Nadiya

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 In China,for the R&D campus hire, we launched a Oracle College Hire Program, all the new graduates in R&D team could join it, the purpose is to let them understand Oracle’s culture and value, get them quickly to be familiar and productive on their new work, provide meaningful events and get them engaged.  They’re divided into classes by location, each class would have around 20 people, and each class would have a monitor, who is in charge of the whole class activity, the program has 3 modules, including social activity, Speaker Series and Career Development. The pictures show one class, which is having the social activity session,exciting isnt it?   /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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• How can I design my classes for a calendar based on database events?

  - by Gianluca78

  I'm developing a web calendar in php (using Symfony2) inspired by iCal for a project of mine. At this moment, I have two classes: a class "Calendar" and a class "CalendarCell". Here you are the two classes properties and method declarations. class Calendar { private $month; private $monthName; private $year; private $calendarCellList = array(); private $translator; public function __construct($month, $year, $translator) {} public function getCalendarCells() {} public function getMonth() {} public function getMonthName() {} public function getNextMonth() {} public function getNextYear() {} public function getPreviousMonth() {} public function getPreviousYear() {} public function getYear() {} private function calculateDaysPreviousMonth() {} private function calculateNumericDayOfTheFirstDayOfTheWeek() {} private function isCurrentDay(\DateTime $dateTime) {} private function isDifferentMonth(\DateTime $dateTime) {} } class CalendarCell { private $day; private $month; private $dayNameAbbreviation; private $numericDayOfTheWeek; private $isCurrentDay; private $isDifferentMonth; private $translator; public function __construct(array $parameters) {} public function getDay() {} public function getMonth() {} public function getDayNameAbbreviation() {} public function isCurrentDay() {} public function isDifferentMonth() {} } Each calendar day can includes many events stored in a database. My question is: which is the best way to manage these events in my classes? I think to add a eventList property in CalendarCell and populate it with an array of CalendarEvent objects fetched by the database. This kind of solution doesn't allow other coders to reuse the classes without db (because I should inject at least a repository services also) just to create and visualize a calendar... so maybe it could be better to extend CalendarCell (for instance in CalendarCellEvent) and add the database features? I feel like I'm missing some crucial design pattern! Any suggestion will be very appreciated!

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• Add & Show data in Java ArrayList [closed]

  - by Kaidul Islam Sazal

  I have a class inside a main class : static class Graph{ static int u, v, cost; } I have instantiated an arraylist of the class: static List<Graph> g = new ArrayList<Graph>(); And I insert several values into the arraylist like this: Scanner input = new Scanner(System.in); for (int i = 0; i < edge_no; i++) { Graph e = new Graph(); e.u = input.nextInt(); e.v = input.nextInt(); e.cost = input.nextInt(); g.add(e); } And I print it like this: for (int i = 0; i < edge_no; i++) { System.out.println(g.get(i).u + " " + g.get(i).v + " " + g.get(i).cost); } But the problem is that, when I print it, only the last value is shown all the time.It seems that, all the previous values are over-written with it. Input : 1 2 5 1 3 8 2 3 9 Output: 2 3 9 2 3 9 2 3 9 Expected output is just like the input.But I can't fix the problem as I am novice in java.

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• Using nested public classes to organize constants

  - by FrustratedWithFormsDesigner

  I'm working on an application with many constants. At the last code review it came up that the constants are too scattered and should all be organized into a single "master" constants file. The disagreement is about how to organize them. The majority feel that using the constant name should be good enough, but this will lead to code that looks like this: public static final String CREDITCARD_ACTION_SUBMITDATA = "6767"; public static final String CREDITCARD_UIFIELDID_CARDHOLDER_NAME = "3959854"; public static final String CREDITCARD_UIFIELDID_EXPIRY_MONTH = "3524"; public static final String CREDITCARD_UIFIELDID_ACCOUNT_ID = "3524"; ... public static final String BANKPAYMENT_UIFIELDID_ACCOUNT_ID = "9987"; I find this type of naming convention to be cumbersome. I thought it might be easier to use public nested class, and have something like this: public class IntegrationSystemConstants { public class CreditCard { public static final String UI_EXPIRY_MONTH = "3524"; public static final String UI_ACCOUNT_ID = "3524"; ... } public class BankAccount { public static final String UI_ACCOUNT_ID = "9987"; ... } } This idea wasn't well received because it was "too complicated" (I didn't get much detail as to why this might be too complicated). I think this creates a better division between groups of related constants and the auto-complete makes it easier to find these as well. I've never seen this done though, so I'm wondering if this is an accepted practice or if there's better reasons that it shouldn't be done.

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• PyQt application architecture

  - by L. De Leo

  I'm trying to give a sound structure to a PyQt application that implements a card game. So far I have the following classes: Ui_Game: this describes the ui of course and is responsible of reacting to the events emitted by my CardWidget instances MainController: this is responsible for managing the whole application: setup and all the subsequent states of the application (like starting a new hand, displaying the notification of state changes on the ui or ending the game) GameEngine: this is a set of classes that implement the whole game logic Now, the way I concretely coded this in Python is the following: class CardWidget(QtGui.QLabel): def __init__(self, filename, *args, **kwargs): QtGui.QLabel.__init__(self, *args, **kwargs) self.setPixmap(QtGui.QPixmap(':/res/res/' + filename)) def mouseReleaseEvent(self, ev): self.emit(QtCore.SIGNAL('card_clicked'), self) class Ui_Game(QtGui.QWidget): def __init__(self, window, *args, **kwargs): QtGui.QWidget.__init__(self, *args, **kwargs) self.setupUi(window) self.controller = None def place_card(self, card): cards_on_table = self.played_cards.count() + 1 print cards_on_table if cards_on_table <= 2: self.played_cards.addWidget(card) if cards_on_table == 2: self.controller.play_hand() class MainController(object): def __init__(self): self.app = QtGui.QApplication(sys.argv) self.window = QtGui.QMainWindow() self.ui = Ui_Game(self.window) self.ui.controller = self self.game_setup() Is there a better way other than injecting the controller into the Ui_Game class in the Ui_Game.controller? Or am I totally off-road?

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• Integrating Amazon EC2 in Java via NetBeans IDE

  - by Geertjan

  Next, having looked at Amazon Associates services and Amazon S3, let's take a look at Amazon EC2, the elastic compute cloud which provides remote computing services. I started by launching an instance of Ubuntu Server 14.04 on Amazon EC2, which looks a bit like this in the on-line AWS Management Console, though I whitened out most of the details: Now that I have at least one running instance available on Amazon EC2, it makes sense to use the services that are integrated into NetBeans IDE:  I created a new application with one class, named "AmazonEC2Demo". Then I dragged the "describeInstances" service that you see above, with the mouse, into the class. Then the IDE automatically created all the other files you see below, i.e., 4 Java classes and one properties file: In the properties file, register the access ID and secret keys. These are read by the other generated Java classes. Signing and authentication are done automatically by the code that is generated, i.e., there's nothing generic you need to do and you can immediately begin working on your domain-specific code. Finally, you're now able to rewrite the code in "AmazonEC2Demo" to connect to Amazon EC2 and obtain information about your running instance: public class AmazonEC2Demo { public static void main(String[] args) { String instanceId1 = "i-something"; RestResponse result; try { result = AmazonEC2Service.describeInstances(instanceId1); System.out.println(result.getDataAsString()); } catch (IOException ex) { Logger.getLogger(AmazonEC2Demo.class.getName()).log(Level.SEVERE, null, ex); } } } From the above, you'll receive a chunk of XML with data about the running instance, it's name, status, dates, etc. In other words, you're now ready to integrate Amazon EC2 features directly into the applications you're writing, without very much work to get started. Within about 5 minutes, you're working on your business logic, rather than on the generic code that anyone needs when integrating with Amazon EC2.

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• Authenticate with Django 1.5

  - by gorjuce

  I'm currently testing django 1.5 and a custom User model, but I've some problems. I've created a User class in my account app, which looks like: class User(AbstractBaseUser): email = models.EmailField() activation_key = models.CharField(max_length=255) is_active = models.BooleanField(default=False) is_admin = models.BooleanField(default=False) USERNAME_FIELD = 'email' I can correctly register a user, who is stored in my account_user table. Now, how can I log in? I've tried with: def login(request): form = AuthenticationForm() if request.method == 'POST': form = AuthenticationForm(request.POST) email = request.POST['username'] password = request.POST['password'] user = authenticate(username=email, password=password) if user is not None: if user.is_active: login(user) else: message = 'disabled account, check validation email' return render( request, 'account-login-failed.html', {'message': message} ) return render(request, 'account-login.html', {'form': form}) I can correctly register a new User My forms.py which contains my register form class RegisterForm(forms.ModelForm): """ a form to create user""" password = forms.CharField( label="Password", widget=forms.PasswordInput() ) password_confirm = forms.CharField( label="Password Repeat", widget=forms.PasswordInput() ) class Meta: model = User exclude = ('last_login', 'activation_key') def clean_password_confirm(self): password = self.cleaned_data.get("password") password_confirm = self.cleaned_data.get("password_confirm") if password and password_confirm and password != password_confirm: raise forms.ValidationError("Password don't math") return password_confirm def clean_email(self): if User.objects.filter(email__iexact=self.cleaned_data.get("email")): raise forms.ValidationError("email already exists") return self.cleaned_data['email'] def save(self): user = super(RegisterForm, self).save(commit=False) user.password = self.cleaned_data['password'] user.activation_key = generate_sha1(user.email) user.save() return user My question is: Why does authenticate give me None? I know I'm trying to authenticate() with an email as username but is that not one of the reasons to use a custom User model?

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• Reasons behind polymorphism related behaviour in java

  - by Shades88

  I read this code somewhere class Foo { public int a; public Foo() { a = 3; } public void addFive() { a += 5; } public int getA() { System.out.println("we are here in base class!"); return a; } } public class Polymorphism extends Foo{ public int a; public Poylmorphism() { a = 5; } public void addFive() { System.out.println("we are here !" + a); a += 5; } public int getA() { System.out.println("we are here in sub class!"); return a; } public static void main(String [] main) { Foo f = new Polymorphism(); f.addFive(); System.out.println(f.getA()); // SOP 1 System.out.println(f.a); // SOP 2 } } For SOP1 we get answer 10 and for SOP2 we get answer 3. Reason for this is that you can't override variables whereas you can do so for methods. This happens because type of the reference variable is checked when a variable is accessed and type of the object is checked when a method is accessed. But I am wondering, just why is it that way? Can anyone explain me what is the reason for this behaviour

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• Interface (contract), Generics (universality), and extension methods (ease of use). Is it a right design?

  - by Saeed Neamati

  I'm trying to design a simple conversion framework based on these requirements: All developers should follow a predefined set of rules to convert from the source entity to the target entity Some overall policies should be able to be applied in a central place, without interference with developers' code Both the creation of converters and usage of converter classes should be easy To solve these problems in C# language, A thought came to my mind. I'm writing it here, though it doesn't compile at all. But let's assume that C# compiles this code: I'll create a generic interface called IConverter public interface IConverter<TSource, TTarget> where TSource : class, new() where TTarget : class, new() { TTarget Convert(TSource source); List<TTarget> Convert(List<TSource> sourceItems); } Developers would implement this interface to create converters. For example: public class PhoneToCommunicationChannelConverter : IConverter<Phone, CommunicationChannle> { public CommunicationChannel Convert(Phone phone) { // conversion logic } public List<CommunicationChannel> Convert(List<Phone> phones) { // conversion logic } } And to make the usage of this conversion class easier, imagine that we add static and this keywords to methods to turn them into Extension Methods, and use them this way: List<Phone> phones = GetPhones(); List<CommunicationChannel> channels = phones.Convert(); However, this doesn't even compile. With those requirements, I can think of some other designs, but they each lack an aspect. Either the implementation would become more difficult or chaotic and out of control, or the usage would become truly hard. Is this design right at all? What alternatives I might have to achieve those requirements?

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• Help with design structure choice: Using classes or library of functions

  - by roverred

  So I have GUI Class that will call another class called ImageProcessor that contains a bunch functions that will perform image processing algorithms like edgeDetection, gaussianblur, contourfinding, contour map generations, etc. The GUI passes an image to ImageProcessor, which performs one of those algorithm on it and it returns the image back to the GUI to display. So essentially ImageProcessor is a library of independent image processing functions right now. It is called in the GUI like so Image image = ImageProcessor.EdgeDetection(oldImage); Some of the algorithms procedures require many functions, and some can be done in a single function or even one line. All these functions for the algorithms jam packed into ImageProcessor can be pretty messy, and ImageProcessor doesn't sound it should be a library. So I was thinking about making every algorithm be a class with a shared interface say IAlgorithm. Then I pass the IAlgorithm interface from the GUI to the ImageProcessor. public interface IAlgorithm{ public Image Process(); } public class ImageProcessor{ public Image Process(IAlgorithm TheAlgorithm){ return IAlgorithm.Process(); } } Calling in the GUI like so Image image = ImageProcessor.Process(new EdgeDetection(oldImage)); I think it makes sense in an object point of view, but the problem is I'll end up with some classes that are just one function. What do you think is a better design, or are they both crap and you have a much better idea? Thanks!

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• Facebook contest policy no-no?

  - by Fred

  I would like to post a link on a Facebook page where it will exit Facebook entirely and go to a client's website, where people will be on a page (client's) where they can enter their e-mail address to be entered in a temporary database file with rules and disclosures etc., for a draw once the number of entries reaches 100 for instance. Once the number of entries reaches 100, a random winner is picked and notified via E-mail. The functionality is as follows: A link is place on a Facebook page leading to an external page The page is a form to merely enter their email address for a contest The email is placed in a temporary file An automatic E-mail is sent to the address used for confirmation using SHAH-256 hash The person receives the Email saying something to the affect "Please confirm your Email address etc. - If you did not authorize this, simply ignore this message and no further action will be taken". If the person clicks on the confirmation link, the Email is then stored in the database and the person is again notified saying "Thank you for signing up etc." Once others do the same process and the database reaches a certain number, the form is no longer accessible and automatically picks a random Email. Once picked, an Email is automatically sent to the winner stating the instructions, and notifying me also. Once that person clicks yet another confirmation link, the database is then automatically deleted. I have built this myself and have no intentions of breaking any rules, nor jeopardize the work/time/energy I have put into this project. Is this allowed?

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• Repository query conditions, dependencies and DRY

  - by vFragosop

  To keep it simple, let's suppose an application which has Accounts and Users. Each account may have any number of users. There's also 3 consumers of UserRepository: An admin interface which may list all users Public front-end which may list all users An account authenticated API which should only list it's own users Assuming UserRepository is something like this: class UsersRepository extends DatabaseAbstraction { private function query() { return $this->database()->select('users.*'); } public function getAll() { return $this->query()->exec(); } // IMPORTANT: // Tons of other methods for searching, filtering, // joining of other tables, ordering and such... } Keeping in mind the comment above, and the necessity to abstract user querying conditions, How should I handle querying of users filtering by account_id? I can picture three possible roads: 1. Should I create an AccountUsersRepository? class AccountUsersRepository extends UserRepository { public function __construct(Account $account) { $this->account = $account; } private function query() { return parent::query() ->where('account_id', '=', $this->account->id); } } This has the advantage of reducing the duplication of UsersRepository methods, but doesn't quite fit into anything I've read about DDD so far (I'm rookie by the way) 2. Should I put it as a method on AccountsRepository? class AccountsRepository extends DatabaseAbstraction { public function getAccountUsers(Account $account) { return $this->database() ->select('users.*') ->where('account_id', '=', $account->id) ->exec(); } } This requires the duplication of all UserRepository methods and may need another UserQuery layer, that implements those querying logic on chainable way. 3. Should I query UserRepository from within my account entity? class Account extends Entity { public function getUsers() { return UserRepository::findByAccountId($this->id); } } This feels more like an aggregate root for me, but introduces dependency of UserRepository on Account entity, which may violate a few principles. 4. Or am I missing the point completely? Maybe there's an even better solution? Footnotes: Besides permissions being a Service concern, in my understanding, they shouldn't implement SQL query but leave that to repositories since those may not even be SQL driven.

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• Generic Pop and Push for List<T>

  - by Bil Simser

  Here's a little snippet I use to extend a generic List class to have similar capabilites to the Stack class. The Stack<T> class is great but it lives in its own world under System.Object. Wouldn't it be nice to have a List<T> that could do the same? Here's the code: .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: Consolas, "Courier New", Courier, Monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 1: public static class ExtensionMethods 2: { 3: public static T Pop<T>(this List<T> theList) 4: { 5: var local = theList[theList.Count - 1]; 6: theList.RemoveAt(theList.Count - 1); 7: return local; 8: } 9:   10: public static void Push<T>(this List<T> theList, T item) 11: { 12: theList.Add(item); 13: } 14: } It's a simple extension but I've found it useful, hopefully you will too! Enjoy.

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• In C++ Good reasons for NOT using symmetrical memory management (i.e. new and delete)

  - by Jim G

  I try to learn C++ and programming in general. Currently I am studying open source with help of UML. Learning is my hobby and great one too. My understanding of memory allocation in C++ is that it should be symmetrical. A class is responsible for its resources. If memory is allocated using new it should be returned using delete in the same class. It is like in a library you, the class, are responsibility for the books you have borrowed and you return them then you are done. This, in my mind, makes sense. It makes memory management more manageable so to speak. So far so good. The problem is that this is not how it works in the real world. In Qt for instance, you create QtObjects with new and then hand over the ownership of the object to Qt. In other words you create QtObjects and Qt destroys them for you. Thus unsymmetrical memory management. Obviously the people behind Qt must have a good reason for doing this. It must be beneficial in some kind of way, My questions is: What is the problem with Bjarne Stroustrups idea about a symmetrical memory management contained within a class? What do you gain by splitting new and delete so you create an object and destroy it in different classes like you do in Qt. Is it common to split new and delete and why in such case, in other projects not involving Qt? Thanks for any help shedding light on this mystery!

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