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• Am I bored with programming? [closed]

  - by user1167074

  I have started programming 2 years back and I have learnt web programming while working for big corporate companies. I was very passionate and I even did couple of side projects which were well appreciated by my friends and colleagues. But for the past 2 months I am not doing anything really interesting with programming, even if I get good ideas I am not feeling like coding, sub consciously I am feeling like "So What?" if I do this project. I would like to know from the more experienced programmers if this is just a phase or am I really missing something? Thanks

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• How to store prices that have effective dates?

  - by lal00

  I have a list of products. Each of them is offered by N providers. Each providers quotes us a price for a specific date. That price is effective until that provider decides to set a new price. In that case, the provider will give the new price with a new date. The MySQL table header currently looks like: provider_id, product_id, price, date_price_effective Every other day, we compile a list of products/prices that are effective for the current day. For each product, the list contains a sorted list of the providers that have that particular product. In that way, we can order certain products from whoever happens to offer the best price. To get the effective prices, I have a SQL statement that returns all rows that have date_price_effective >= NOW(). That result set is processed with a ruby script that does the sorting and filtering necessary to obtain a file that looks like this: product_id_1,provider_1,provider_3,provider8,provider_10... product_id_2,provider_3,provider_2,provider1,provider_10... This works fine for our purposes, but I still have an itch that a SQL table is probably not the best way to store this kind of information. I have that feeling that this kind of problema has been solved previously in other more creative ways. Is there a better way to store this information other than in SQL? or, if using SQL, is there a better approach than the one I'm using?

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• Is it bad practice to call a controller action from a view that was rendered by another controller?

  - by marco-fiset

  Let's say I have an OrderController which handles orders. The user adds products to it through the view, and then the final price gets calculated through an AJAX call to a controller action. The price calculation logic is implemented in a seperate class and used in a controller action. What happens is that I have many views from different controllers that need to use that particular action. I'd like to have some kind of a PriceController that I could call an action on. But then the view would have to know about that PriceController and call an action on it. Is it bad practice for a view to call an action on a different controller from which it was rendered?

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• ViewController in programming

  - by Vishwas Gagrani

  ViewController is a term for classes that handle views in a framework. This is especially used in MVC frameworks. I go through various projects, written by various programmers, who implement MVC in different ways. Especially, i get confused, about the relation between the MainView ( parent view ) and some CustomView ( widget etc) in the framework. I personally pass reference of the MainView into the ViewController to be instantiated. All the subviews of ViewController are added to that reference of MainView. Additionally, ViewController itself is added as a child of MainView. Like this : Want to know, if this is the right way to relate each other ?

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• Should a primary key be immutable?

  - by Vincent Malgrat

  A recent question on stackoverflow provoked a discussion about the immutability of primary keys. I had thought that it was a kind of rule that primary keys should be immutable. If there is a chance that some day a primary key would be updated, I thought you should use a surrogate key. However it is not in the SQL standard and some RDBMS' "cascade update" feature allows a primary key to change. So my question is: is it still a bad practice to have a primary key that may change ? What are the cons, if any, of having a mutable primary key ?

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• Object oriented wrapper around a dll

  - by Tom Davies

  So, I'm writing a C# managed wrapper around a native dll. The dll contains several hundred functions. In most cases, the first argument to each function is an opaque handle to a type internal to the dll. So, an obvious starting point for defining some classes in the wrapper would be to define classes corresponding to each of these opaque types, with each instance holding and managing the opaque handle (passed to its constructor) Things are a little awkward when dealing with callbacks from the dll. Naturally, the callback handlers in my wrapper have to be static, but the callbacks arguments invariable contain an opaque handle. In order to get from the static callback back to an object instance, I've created a static dictionary in each class, associating handles with class instances. In the constructor of each class, an entry is put into the dictionary, and this entry is then removed in the Destructors. When I receive a callback, I can then consult the dictionary to retrieve the class instance corresponding to the opaque reference. Are there any obvious flaws to this? Something that seems to be a problem is that the existence static dictionary means that the garbage collector will not act on my class instances that are otherwise unreachable. As they are never garbage collected, they never get removed from the dictionary, so the dictionary grows. It seems I might have to manually dispose of my objects, which is something absolutely would like to avoid. Can anyone suggest a good design that allows me to avoid having to do this?

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• What's the best way to expose a Model object in a ViewModel?

  - by Angel

  In a WPF MVVM application, I exposed my model object into my viewModel by creating an instance of Model class (which cause dependency) into ViewModel. Instead of creating separate VM properties, I wrap the Model properties inside my ViewModel Property. My model is just an entity framework generated proxy class: public partial class TblProduct { public TblProduct() { this.TblPurchaseDetails = new HashSet<TblPurchaseDetail>(); this.TblPurchaseOrderDetails = new HashSet<TblPurchaseOrderDetail>(); this.TblSalesInvoiceDetails = new HashSet<TblSalesInvoiceDetail>(); this.TblSalesOrderDetails = new HashSet<TblSalesOrderDetail>(); } public int ProductId { get; set; } public string ProductCode { get; set; } public string ProductName { get; set; } public int CategoryId { get; set; } public string Color { get; set; } public Nullable<decimal> PurchaseRate { get; set; } public Nullable<decimal> SalesRate { get; set; } public string ImagePath { get; set; } public bool IsActive { get; set; } public virtual TblCompany TblCompany { get; set; } public virtual TblProductCategory TblProductCategory { get; set; } public virtual TblUser TblUser { get; set; } public virtual ICollection<TblPurchaseDetail> TblPurchaseDetails { get; set; } public virtual ICollection<TblPurchaseOrderDetail> TblPurchaseOrderDetails { get; set; } public virtual ICollection<TblSalesInvoiceDetail> TblSalesInvoiceDetails { get; set; } public virtual ICollection<TblSalesOrderDetail> TblSalesOrderDetails { get; set; } } Here is my ViewModel: public class ProductViewModel : WorkspaceViewModel { #region Constructor public ProductViewModel() { StartApp(); } #endregion //Constructor #region Properties private IProductDataService _dataService; public IProductDataService DataService { get { if (_dataService == null) { if (IsInDesignMode) { _dataService = new ProductDataServiceMock(); } else { _dataService = new ProductDataService(); } } return _dataService; } } //Get and set Model object private TblProduct _product; public TblProduct Product { get { return _product ?? (_product = new TblProduct()); } set { _product = value; } } #region Public Properties public int ProductId { get { return Product.ProductId; } set { if (Product.ProductId == value) { return; } Product.ProductId = value; RaisePropertyChanged("ProductId"); } } public string ProductName { get { return Product.ProductName; } set { if (Product.ProductName == value) { return; } Product.ProductName = value; RaisePropertyChanged(() => ProductName); } } private ObservableCollection<TblProduct> _productRecords; public ObservableCollection<TblProduct> ProductRecords { get { return _productRecords; } set { _productRecords = value; RaisePropertyChanged("ProductRecords"); } } //Selected Product private TblProduct _selectedProduct; public TblProduct SelectedProduct { get { return _selectedProduct; } set { _selectedProduct = value; if (_selectedProduct != null) { this.ProductId = _selectedProduct.ProductId; this.ProductCode = _selectedProduct.ProductCode; } RaisePropertyChanged("SelectedProduct"); } } #endregion //Public Properties #endregion // Properties #region Commands private ICommand _newCommand; public ICommand NewCommand { get { if (_newCommand == null) { _newCommand = new RelayCommand(() => ResetAll()); } return _newCommand; } } private ICommand _saveCommand; public ICommand SaveCommand { get { if (_saveCommand == null) { _saveCommand = new RelayCommand(() => Save()); } return _saveCommand; } } private ICommand _deleteCommand; public ICommand DeleteCommand { get { if (_deleteCommand == null) { _deleteCommand = new RelayCommand(() => Delete()); } return _deleteCommand; } } #endregion //Commands #region Methods private void StartApp() { LoadProductCollection(); } private void LoadProductCollection() { var q = DataService.GetAllProducts(); this.ProductRecords = new ObservableCollection<TblProduct>(q); } private void Save() { if (SelectedOperateMode == OperateModeEnum.OperateMode.New) { //Pass the Model object into Dataservice for save DataService.SaveProduct(this.Product); } else if (SelectedOperateMode == OperateModeEnum.OperateMode.Edit) { //Pass the Model object into Dataservice for Update DataService.UpdateProduct(this.Product); } ResetAll(); LoadProductCollection(); } #endregion //Methods } Here is my Service class: class ProductDataService:IProductDataService { /// <summary> /// Context object of Entity Framework model /// </summary> private MaizeEntities Context { get; set; } public ProductDataService() { Context = new MaizeEntities(); } public IEnumerable<TblProduct> GetAllProducts() { using(var context=new R_MaizeEntities()) { var q = from p in context.TblProducts where p.IsDel == false select p; return new ObservableCollection<TblProduct>(q); } } public void SaveProduct(TblProduct _product) { using(var context=new R_MaizeEntities()) { _product.LastModUserId = GlobalObjects.LoggedUserID; _product.LastModDttm = DateTime.Now; _product.CompanyId = GlobalObjects.CompanyID; context.TblProducts.Add(_product); context.SaveChanges(); } } public void UpdateProduct(TblProduct _product) { using (var context = new R_MaizeEntities()) { context.TblProducts.Attach(_product); context.Entry(_product).State = EntityState.Modified; _product.LastModUserId = GlobalObjects.LoggedUserID; _product.LastModDttm = DateTime.Now; _product.CompanyId = GlobalObjects.CompanyID; context.SaveChanges(); } } public void DeleteProduct(int _productId) { using (var context = new R_MaizeEntities()) { var product = (from c in context.TblProducts where c.ProductId == _productId select c).First(); product.LastModUserId = GlobalObjects.LoggedUserID; product.LastModDttm = DateTime.Now; product.IsDel = true; context.SaveChanges(); } } } I exposed my model object in my viewModel by creating an instance of it using new keyword, also I instantiated my DataService class in VM. I know this will cause a strong dependency. So: What's the best way to expose a Model object in a ViewModel? What's the best way to use DataService in VM?

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• What is the best approach to solve a factory method problem which has to be an instance?

  - by Iago

  I have to add new funcionality in a web service legacy project and I'm thinking what is the best approach for a concrete situation. The web service is simple: It receives a XML file, unmarshalling, generates response's objects, marshalling and finally it sends the response as a XML file. For every XML files received, the web service always responds with the same XML structure. What I have to do is to generate a different XML file according to the XML received. So I have a controller class which has all marshalling/unmarshalling operations, but this controller class has to be an instance. Depending on XML received I need some marshalling methods or others. Trying to make few changes on legacy source, what is the best approach? My first approach was to do a factory method pattern with the controller class, but this class has to be an instance. I want to keep, as far as it goes, this structure: classController.doMarshalling(); I think this one is a bit smelly: if(XMLReceived.isTypeOne()) classController.doMarshallingOne(); else if(XMLReceived.isTypeTwo()) classController.doMarshallingTwo(); else if(XMLReceived.isTypeThree()) classController.doMarshallingThree(); else if ... I hope my question is well understood

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• Test driven development - convince me!

  - by Casebash

  I know some people are massive proponents of test driven development. I have used unit tests in the past, but only to test operations that can be tested easily or which I believe will quite possibly be correct. Complete or near complete code coverage sounds like it would take a lot of time. What projects do you use test-driven development for? Do you only use it for projects above a certain size? Should I be using it or not? Convince me!

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• How to get started in coding for JBoss

  - by Mister IT Guru

  I have an idea on how to revamp our internal application, after having accessed the needs of the users, addressing thier current issues, and the like. But I am not a coder. My last application I wrote was in college, in C, (java wasn't invented-ish!) and it was a booking system, with the option to add on other modules, blah blah. I got an A, but I became a system administrator instead, more intrested in designing and maintainend networks and infrastructure, but with the advent of virtualisation, and linux management tools such as puppet I can now manage infrastructure in my sleep! Now I want to write code - to put on my infastructure, and I want to build .... a booking system! This is just to get experience, but I am at a loss as to where to start. Setting up the environment, will take me about a day. Writing the spec, even how I want it to work, I already know, but as for actually coding in a decent manner, I can only guess. If anyone can recommend a book, website, blog, twitter person to follow, or just advice on how to build a kick butt basic jboss app, then please, "I AM READY TO LEARN" :)

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• Catching typos or other errors in web-based scripting languages

  - by foreyez

  Hi, My background is mainly strongly typed languages (java, c++, c#). Having recently gotten back to a bit of javascript, I found it a bit annoying that if I misspell something by accident (for example I'll type 'myvar' instead of 'myVar') my entire script crashes. The browser itself most of the time doesn't even tell me I have an error, my program will just be blank, etc. Then I have to hunt down my code line by line and find the error which is very time consuming. In the languages I am used to the compiler lets me know if I made a typo. My question to you is, how do you overcome this issue in scripting (javascript)? Can you give me some tips? (this question is mainly aimed at people that have also come from a strongly typed language). Note: I mainly use the terminal/VIM ... this is mainly b/c I like terminal and I SSH alot too

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• would a composite design pattern be useful for group membership?

  - by changokun

  I'm trying to think about the best way to handle group memberships on a website. People sign up and select checkboxes in a list of interests. Every week we send out interest-themed emails to those members that indicated that interest. however i store the information in the database, while i am working with the lists and generating lists of email addresses or manipulating group memberships, the composite design pattern looked interesting. it would be easy to populate the group, then do some aggregating functions that say... generate the list of email addresses based on the interests. but i'm not sure i'm seeing any other advantages. i do need something scalable, and flexible. thoughts?

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• Name for Osherove's modified singleton pattern?

  - by Kazark

  I'm pretty well sold on the "singletons are evil" line of thought. Nevertheless, there are limited occurrences when you want to limit the creation of an object. Roy Osherove advises, If you're planning to use a singleton in your design, separate the logic of the singleton class and the logic that makes it a singleton (the part that initializes a static variables, for example) into two separate classes. That way, you can keep the single responsibility principle (SRP) and also have a way to override singleton logic. (The Art of Unit Testing 261-262) This pattern still perpetuates the global state. However, it does result in a testable design, so it seems to me to be a good pattern for mitigating the damage of a singleton. However, Osherove does not give a name to this pattern; but naming a pattern, according to the Gang of Four, is important: Naming a pattern immediately increases our design vocabulary. It lets us design at a higher level of abstraction. (3) Is there a standard name for this pattern? It seems different enough from a standard singleton to deserve a separate name. Decoupled Singleton, perhaps?

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• Is there such a thing as having too many private functions/methods?

  - by shovonr

  I understand the importance of well documented code. But I also understand the importance of self-documenting code. The easier it is to visually read a particular function, the faster we can move on during software maintenance. With that said, I like to separate big functions into other smaller ones. But I do so to a point where a class can have upwards of five of them just to serve one public method. Now multiply five private methods by five public ones, and you get around twenty-five hidden methods that are probably going to be called only once by those public ones. Sure, it's now easier to read those public methods, but I can't help but think that having too many functions is bad practice.

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• Can a candidate be judged by asking to write a complex program on "paper"?

  - by iammilind

  Sometime back in an interview, I was asked to write following program: In a keypad of a mobile phone, there is a mapping between number and characters. e.g. 0 & 1 corresponds to nothing; 2 corresponds to 'a','b','c'; 3 corresponds to 'd','e','f'; ...; 9 corresponds to 'w','x','y','z'. User should input any number (e.g. 23, 389423, 927348923747293) and I should store all the combinations of these character mapping into some data structure. For example, if user enters "23" then possible character combinations are: ad, ae, af, bd, be, bf, cd, ce, cf or if user enters, "4676972" then it can be, gmpmwpa, gmpmwpb, ..., hnroxrc, ..., iosozrc Interviewer told that people have written code for this within 20-30 mins!! Also he insisted I have to write on paper. If I am writing a code then my tendency is as of I am writing production code, even though it may not be expected from me. So, I always try to think all the aspects like, optimization, readability, maintainability, extensible and so on. Considering all these, I felt that I should be writing on PC and it needs decent 2 hours. Finally after 25 mins, I was able to come up with just the concept and some shattered pieces of code (not to mention of my rejection). My question is not the answer for the above program. I want to know that is this a right way to judge the caliber of a person ? Am I wrong / too slow in the estimates ? Am I too idealistic ?

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• Which pattern is best for large project

  - by shamim

  I have several years of software development experience, but I am not a keen and adroit programmer, to perform better I need helping hands. Recently I engaged in an ERP project. For this project want a very effective structure, which will be easily maintainable and have no compromise about performance issue. Below structures are now present in my old projects. Entity Layer BusinessLogic Layer. DataLogic Layer UI Layer. Bellow picture describe how they are internally connected. For my new project want to change my project structure, I want to follow below steps: Core Layer(common) BLL DAL Model UI Bellow picture describe how they are internally connected. Though goggling some initial type question’s are obscure to me, they are : For new project want to use Entity framework, is it a good idea? Will it increase my project performance? Will it more maintainable than previous structure? Entity Framework core disadvantages/benefits are? For my project need help to select best structure. Will my new structure be better than the old one?

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• Should all, none, or some overridden methods call Super?

  - by JoJo

  When designing a class, how do you decide when all overridden methods should call super or when none of the overridden methods should call super? Also, is it considered bad practice if your code logic requires a mixture of supered and non-supered methods like the Javascript example below? ChildClass = new Class.create(ParentClass, { /** * @Override */ initialize: function($super) { $super(); this.foo = 99; }, /** * @Override */ methodOne: function($super) { $super(); this.foo++; }, /** * @Override */ methodTwo: function($super) { this.foo--; } }); After delving into the iPhone and Android SDKs, I noticed that super must be called on every overridden method, or else the program will crash because something wouldn't get initialized. When deriving from a template/delegate, none of the methods are supered (obviously). So what exactly are these "je ne sais quoi" qualities that determine whether a all, none, or some overriden methods should call super?

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• Passing data between engine layers

  - by spaceOwl

  I am building a software system (game engine with networking support ) that is made up of (roughly) these layers: Game Layer Messaging Layer Networking Layer Game related data is passed to the messaging layer (this could be anything that is game specific), where they are to be converted to network specific messages (which are then serialized to byte arrays). I'm looking for a way to be able to convert "game" data into "network" data, such that no strong coupling between these layers will exist. As it looks now, the Messaging layer sits between both layers (game and network) and "knows" both of them (it contains Converter objects that know how to translate between data objects of both layers back and forth). I am not sure this is the best solution. Is there a good design for passing objects between layers? I'd like to learn more about the different options.

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• Profiling and containing memory per system

  - by chadb

  I have been interesting in profiling and keeping a managed memory pool for each subsystem, so I could get statistic on how much memory was being used in something such as sounds or graphics. However, what is the best design for doing this? I was thinking of using multiple allocators and just using one per subsystem, however, that would result in global variables for my allocators (or so it would seem to me). Another approach I have seen/been suggested is to just overload new and pass in an allocator for a parameter. I had a similar question over on stackoverflow here with a bounty, however, it seems as if perhaps I was too vague or just there is not enough people with knowledge in the subject.

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• Do I have to write a lot of boilerplate code if I keep working using Java?

  - by edem

  I'm working for a company writing ERP applications. My problem is that I have to write tons of boilerplate code. I came up with ideas to automatize/prevent the drudgery but only some of them were accepted. I have been told by the lead developer that my ideas tend to be go far afield and I should write code everyone can understand. I had a discussion about this lately and it seems to me that this kind of code ramp is within java's philosophy. I have to write lots of code to achiveve simple things not because it is necessary but because this is the way most of the people at the company think. Is this universally applicable to most of the companies out there using java or this is just my company's view? Do I have to get used to the drudgery if I keep working for java-based firms?

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• How to have operations with character/items on binary with concrete operations on C++?

  - by Piperoman

  I have the next problem. A item can have a lot of states: NORMAL = 0000000 DRY = 0000001 HOT = 0000010 BURNING = 0000100 WET = 0001000 COLD = 0010000 FROZEN = 0100000 POISONED= 1000000 A item can have some states at same time but not all of them Is impossible to be dry and wet at same time. If you COLD a WET item, it turns into FROZEN. If you HOT a WET item, it turns into NORMAL A item can be BURNING and POISON Etc. I have tried to set binary flags to states, and use AND to combine different states, checking before if it is possible or not to do it, or change to another status. Does there exist a concrete approach to solve this problem efficiently without having an interminable switch that checks every state with every new state? It is relatively easy to check 2 different states, but if there exists a third state it is not trivial to do.

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• Getting graduates up to speed?

  - by Simon

  This question got me thinking about how comapnies deal with newly-hired graduated. Do experienced programmers expect CS graduates to write clean code (by clean I mean code easily understandable by others — maybe that is too much to expect?) Or do significant portion of graduates at your place (if any) just end up testing and fixing small bugs on existing applications? And, even if they do bug fixes, do you end up spending double the amount of time just checking they did not end up breaking anything and creating new bugs? How do you deal with such scenarios when pair programming and code reviews are not available options (for reasons such as personal deadlines), and also what techniques did you find to get fresh graduate up to speed? Some suggestions would be great.

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• Query something and return the reason if nothing has been found

  - by Daniel Hilgarth

  Assume I have a Query - as in CQS that is supposed to return a single value. Let's assume that the case that no value is found is not exceptional, so no exception will be thrown in this case. Instead, null is returned. However, if no value has been found, I need to act according to the reason why no value has been found. Assuming that the Query knows the reason, how would I communicate it to the caller of the Query? A simple solution would be not return the value directly but a container object that contains the value and the reason: public class QueryResult { public TValue Value { get; private set; } public TReason ReasonForNoValue { get; private set; } } But that feels clumsy, because if a value is found, ReasonForNoValue makes no sense and if no value has been found, Value makes no sense. What other options do I have to communicate the reason? What do you think of one event per reason? For reference: This is going to be implemented in C#.

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• How do you keep track of the authors of code?

  - by dustyprogrammer

  This is something I was never taught. I have seen alot of different types of authoring styles. I code primarily in Java and Python. I was wondering if there was a standard authoring style or if everything is freestyle. Also if you answer would you mind attaching the style you use to author files that your create at home or at work. I usually just go @author garbagecollector @company garbage inc.

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• What is a good design model for my new class?

  - by user66662

  I am a beginning programmer who, after trying to manage over 2000 lines of procedural php code, now has discovered the value of OOP. I have read a few books to get me up to speed on the beginning theory, but would like some advice on practical application. So,for example, let's say there are two types of content objects - an ad and a calendar event. what my application does is scan different websites (a predefined list), and, when it finds an ad or an event, it extracts the data and saves it to a database. All of my objects will share a $title and $description. However, the Ad object will have a $price and the Event object will have $startDate. Should I have two separate classes, one for each object? Should I have a 'superclass' with the $title and $description with two other Ad and Event classes with their own properties? The latter is at least the direction I am on now. My second question about this design is how to handle the logic that extracts the data for $title, $description, $price, and $date. For each website in my predefined list, there is a specific regex that returns the desired value for each property. Currently, I have an extremely large switch statement in my constructor which determines what website I am own, sets the regex variables accordingly, and continues on. Not only that, but now I have to repeat the logic to determine what site I am on in the constructor of each class. This doesn't feel right. Should I create another class Algorithms and store the logic there for each site? Should the functions of to handle that logic be in this class? or specific to the classes whos properties they set? I want to take into account in my design two things: 1) I will add different content objects in the future that share $title and $description, but will have their own properties, so, I want to be able to easily grow these as needed. 2) I will add more websites constantly (each with their own algorithms for data extraction) so I would like to plan efficienty managing and working with these now. I thought about extending the Ad or Event class with 'websiteX' class and store its functions there. But, this didn't feel right either as now I have to manage 100s of little website specific class files. Note, I didn't know if this was the correct site or stackoverflow was the better choice. If so, let me know and I'll post there.

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