Search Results

Search found 71115 results on 2845 pages for 'file patterns'.

Page 66/2845 | < Previous Page | 62 63 64 65 66 67 68 69 70 71 72 73  | Next Page >

• Event Aggregator.. not getting a response, how to determine completion?

  - by Duncan_m

  I'm rewriting a vehicle tracking application, a google maps based thing.. The users are able to search for a vehicle by typing a few characters of the vehicles "callsign". My application is based around a sort of "event bus" within Backbone.. when a search occurs I send a message on the bus saying something like "does anyone match this?".. If a marker matches the search term it responds with a sort of "yes, I match!".. My challenge arises when no-one matches, I get no response.. it feels a little hacky to "wait a little while" and check if a response has been recieved.. The application is based around Backbone.js and using the Event Aggregator pattern described in the answer to this question on Stack Overflow: http://stackoverflow.com/questions/7708195/access-function-in-one-view-from-another-in-backbone-js Is there a well defined design pattern that might assist me here? Sending a request for a response and not getting any responses?

  Read the article

• Guidelines or Design pattern to develop configurable software

  - by Rumit Parakhiya

  I want to develop an application which would have it's own framework, using which developer can implement functionality very easily. Developer shouldn't have to code for each and every page or report. But, he can do it very easily by just configuring it using the framework provided. Some nice examples of it is SAP and Tally. They have got their own framework, using which anybody having knowledge of it can customize or extend functionality of the product. But, as I am beginner in this direction, I don't have any idea about where to start. Can anybody point me to some design pattern which I can follow or some similar open source software which I can refer?

  Read the article

• Dynamic Strategy Pattern [migrated]

  - by Karl Barker

  So I'm writing a web service architecture which includes FunctionProvider classes which do the actual processing of requests, and a main Endpoint class which receives and delegates requests to the proper FunctionProvider. I don't know exactly the FunctionProviders available at runtime, so I need to be able to 'register' (if that's the right word) them with my main Endpoint class, and query them to see if they match an incoming request. public class MyFunc implements FunctionProvider{ static { MyEndpoint.register(MyFunc); } public Boolean matchesRequest(Request req){...} public void processRequest(Request req){...} } public class MyEndpoint{ private static ArrayList<FunctionProvider> functions = new ArrayList<FunctionProvider>(); public void register(Class clz){ functions.add(clz); } public void doPost(Request request){ //find the FunctionProvider in functions //matching the request } } I've really not done much reflective Java like this (and the above is likely wrong, but hopefully demonstrates my intentions). What's the nicest way to implement this without getting hacky?

  Read the article

• Design Pattern for Data Validation

  - by melodui

  What would be the best design pattern for this problem: I have an Object A. Object A can either be registered or deleted from the database depending on the user request. Data validation is performed before registration or deletion of the object. There are a set of rules to be checked before the object can be registered and another set of rules for deletion. Some of these rules are common for both operations. So far, I think the Chain of Responsibility design pattern fits the most but I'm having trouble implementing it.

  Read the article

• DDD: service contains two repository

  - by tikhop

  Does it correct way to have two repository inside one service and will it be an application or domain service? Suppose I have a Passenger object that should contains Passport (government id) object. I am getting Passenger from PassengerRepository. PassengerRepository create request to server and obtain data (json) than parse received data and store inside repository. I have confused because I want to store Passport as Entity and put it to PassportRepository but all information about password contains inside json than i received above. I guess that I should create a PassengerService that will be include PassengerRepository and PassportRepository with several methods like removePassport, addPassport, getAllPassenger and etc. UPDATE: So I guess that the better way is represent Passport as VO and store all passports inside Passenger aggregate. However there is another question: Where I should put the methods (methods calls server api) for management passenger's passport. I think the better place is so within Passenger aggregate.

  Read the article

• How can I bind an interface to a class decided by an xml or database configuration at the launch of the application?

  - by ipohfly

  I'm re-working on the design of an existing application which is build using WebForms. Currently the plan is to work it into a MVP pattern application while using Ninject as the IoC container. The reason for Ninject to be there is that the boss had wanted a certain flexibility within the system so that we can build in different flavor of business logic in the model and let the programmer to choose which to use based on the client request, either via XML configuration or database setting. I know that Ninject have no need for XML configuration, however I'm confused on how it can help to dynamically inject the dependency into the system? Imagine I have a interface IMember and I need to bind this interface to the class decided by a xml or database configuration at the launch of the application, how can I achieve that?

  Read the article

• How to separate and maintain customer specific code

  - by WYSIWYG

  I am implementing customer specific code and currently following simple approach like if (cusomterId == 23) do it. I want to separate out all the customer related code in separate place. But I have following problems. In code is in 1. Stored procs 2. Plain old classes. 3. Controllers 4. Views I came up with two solutions. First is to create table CustomerFunctionlity with columns CustomerId, FunctionalityName, method/Proc, inputs/outputs With this table I can simply check if exists, execute given function. Another way is creating a factory which returns customer related object for an interface. I am writting small end to end customer specific functionalities. How can I write maintenable code. Thanks

  Read the article

• What's is the point of PImpl pattern while we can use interface for same purpose in C++?

  - by ZijingWu

  I see a lot of source code which using PIMPL idiom in C++. I assume Its purposes are hidden the private data/type/implementation, so it can resolve dependence, and then reduce compile time and header include issue. But interface class in C++ also have this capability, it can also used to hidden data/type and implementation. And to hidden let the caller just see the interface when create object, we can add an factory method in it declaration in interface header. The comparison is: Cost: The interface way cost is lower, because you doesn't even need to repeat the public wrapper function implementation void Bar::doWork() { return m_impl->doWork(); }, you just need to define the signature in the interface. Well understand: The interface technology is more well understand by every C++ developer. Performance: Interface way performance not worse than PIMPL idiom, both an extra memory access. I assume the performance is same. Following is the pseudocode code to illustrate my question: // Forward declaration can help you avoid include BarImpl header, and those included in BarImpl header. class BarImpl; class Bar { public: // public functions void doWork(); private: // You doesn't need to compile Bar.cpp after change the implementation in BarImpl.cpp BarImpl* m_impl; }; The same purpose can be implement using interface: // Bar.h class IBar { public: virtual ~IBar(){} // public functions virtual void doWork() = 0; }; // to only expose the interface instead of class name to caller IBar* createObject(); So what's the point of PIMPL?

  Read the article

• Is it better to return NULL or empty values from functions/methods where the return value is not present?

  - by P B

  I am looking for a recommendation here. I am struggling with whether it is better to return NULL or an empty value from a method when the return value is not present or cannot be determined. Take the following two methods as an examples: string ReverseString(string stringToReverse) // takes a string and reverses it. Person FindPerson(int personID) // finds a Person with a matching personID. In ReverseString(), I would say return an empty string because the return type is string, so the caller is expecting that. Also, this way, the caller would not have to check to see if a NULL was returned. In FindPerson(), returning NULL seems like a better fit. Regardless of whether or not NULL or an empty Person Object (new Person()) is returned the caller is going to have to check to see if the Person Object is NULL or empty before doing anything to it (like calling UpdateName()). So why not just return NULL here and then the caller only has to check for NULL. Does anyone else struggle with this? Any help or insight is appreciated.

  Read the article

• Separating Db from business with Inherited classes using multiple views

  - by catalinux

  I have a software that has a car model that will be used in different views (listing, ads, detail page, carousel, up sell widget,etc). class CarModel extends DbModel{ } I look for a "nice way" (a combination of flexible, easy to maintain,etc) to have this used in views. I'm thinking at two different ways Having object views for each context CarViewBase{ var car;// of type CarModel function constructor(args){ //will instantienta internal variable car based on args } function getThumb(){ } function getTitle(){ } } CarListingView extends CarViewBase{ function getListing(){ } } CarAdsView extends CarViewBase{ //the busines rule changes for ads widget function getThumb(){ } } Extending directly the CarModel The challenges comes when My Car Model might need an abstract factory. Let's say I have a field on my car object that states the type of the car : a truck, or a bike, or van. How would affect that my object view? Let's say that getTitle() rule would be different for each type of it. How would you do it?

  Read the article

• Is there a pattern to restrict which classes can update another class?

  - by Mike

  Say I have a class ImportantInfo with a public writable property Data. Many classes will read this property but only a few will ever set it. Basically, if you want to update Data you should really know what you're doing. Is there a pattern I could use to make this explicit other than by documenting it? For example, some way to enforce that only classes that implement IUpdateImportantData can do it (this is just an example)? I'm not talking about security here, but more of a "hey, are you sure you want to do that?" kind of thing.

  Read the article

• Creating a Predicate Builder extension method

  - by Rippo

  I have a Kendo UI Grid that I am currently allowing filtering on multiple columns. I am wondering if there is a an alternative approach removing the outer switch statement? Basically I want to able to create an extension method so I can filter on a IQueryable<T> and I want to drop the outer case statement so I don't have to switch column names. private static IQueryable<Contact> FilterContactList(FilterDescriptor filter, IQueryable<Contact> contactList) { switch (filter.Member) { case "Name": switch (filter.Operator) { case FilterOperator.StartsWith: contactList = contactList.Where(w => w.Firstname.StartsWith(filter.Value.ToString()) || w.Lastname.StartsWith(filter.Value.ToString()) || (w.Firstname + " " + w.Lastname).StartsWith(filter.Value.ToString())); break; case FilterOperator.Contains: contactList = contactList.Where(w => w.Firstname.Contains(filter.Value.ToString()) || w.Lastname.Contains(filter.Value.ToString()) || (w.Firstname + " " + w.Lastname).Contains( filter.Value.ToString())); break; case FilterOperator.IsEqualTo: contactList = contactList.Where(w => w.Firstname == filter.Value.ToString() || w.Lastname == filter.Value.ToString() || (w.Firstname + " " + w.Lastname) == filter.Value.ToString()); break; } break; case "Company": switch (filter.Operator) { case FilterOperator.StartsWith: contactList = contactList.Where(w => w.Company.StartsWith(filter.Value.ToString())); break; case FilterOperator.Contains: contactList = contactList.Where(w => w.Company.Contains(filter.Value.ToString())); break; case FilterOperator.IsEqualTo: contactList = contactList.Where(w => w.Company == filter.Value.ToString()); break; } break; } return contactList; } Some additional information, I am using NHibernate Linq. Also another problem is that the "Name" column on my grid is actually "Firstname" + " " + "LastName" on my contact entity. We can also assume that all filterable columns will be strings.

  Read the article

• Hide or Show singleton?

  - by Sinker

  Singleton is a common pattern implemented in both native libraries of .NET and Java. You will see it as such: C#: MyClass.Instance Java: MyClass.getInstance() The question is: when writing APIs, is it better to expose the singleton through a property or getter, or should I hide it as much as possible? Here are the alternatives for illustrative purposes: Exposed(C#): private static MyClass instance; public static MyClass Instance { get { if (instance == null) instance = new MyClass(); return instance; } } public void PerformOperation() { ... } Hidden (C#): private static MyClass instance; public static void PerformOperation() { if (instance == null) { instance = new MyClass(); } ... } EDIT: There seems to be a number of detractors of the Singleton design. Great! Please tell me why and what is the better alternative. Here is my scenario: My whole application utilises one logger (log4net/log4j). Whenever, the program has something to log, it utilises the Logger class (e.g. Logger.Instance.Warn(...) or Logger.Instance.Error(...) etc. Should I use Logger.Warn(...) or Logger.Warn(...) instead? If you have an alternative to singletons that addresses my concern, then please write an answer for it. Thank you :)

  Read the article

• What is the preferred pattern when attaching a 'runtime object'?

  - by sebf

  In my application I have the following: public class NeatObject { /* lots of static data, and configuration flags */ } public class NeatObjectConsumer { void DoCleverStuffWithObjectOnGPU(NeatObject obj); } Where NeatObject and its consumer are used to control the GPU. The idea being that, the configuration of an instance of NeatObject and its members, define how the consumer instance behaves. The object can be passed around, edited, and most importantly serialised/deserialised by the application, with and without knowledge of NeatObjectConsumer, then provided back to the consumer to do something else. The purpose of this seperation is: The consumer manages hardware resources, which change depending on the computer, and even on the execution of the application, making preserving the state of an object which does everything difficult. Avoids circular references if the assembly that contains the consumer needs to reference one that only needs to know about NeatObject. However, there is a complication in that the consumer creates hardware resources and needs to associate them with NeatObject. These don't need to be preserved, but still need to be retrieved. DoCleverStuffWithObjectOnGPU() will be called many, many times during execution and so any bottleneck is a concern, therefore I would like to avoid dictionary lookups. What is the preferred method of attaching this information to NeatObject? By preferred, I mean intuitive - other coders can see immediately what is going on - and robust - method doesn't invite playing with the resources or present them in such a way as to make them easily corruptible. Essentially, I want to add my own metadata - how should I do it? Try to use 'actual metadata' functionality like Reflection? A member of the type of an abstract class? Unmanaged pointers? If you took on a project that used this pattern, what would you have liked the previous developer to do?

  Read the article

• Moving from mock to real objects?

  - by jjchiw

  I'm like doing TDD so I started everything mocking objects, creating interface, stubbing, great. The design seems to work, now I'll implement the stuff, a lot of the code used in the stubs are going to be reused in my real implementation yay! Now should I duplicate the tests to use the real object implementation (but keeping the mocks object of the sensitive stuff like Database and "services" that are out of my context (http calls, etc...)) Or just change the mocks and stubs of the actual tests to use the real objects....... So the question is that, keep two tests or replace the stubs, mocks? And after that, I should keep designing with the mocks, stubs or just go with real objects? (Just making myself clear I'll keep the mock object of the sensitive stuff like database and services that are out of my context, in both situations.)

  Read the article

• "Never do in code what you can get the SQL server to do well for you" - Is this a recipe for a bad design?

  - by PhonicUK

  It's an idea I've heard repeated in a handful of places. Some more or less acknowledging that once trying to solve a problem purely in SQL exceeds a certain level of complexity you should indeed be handling it in code. The logic behind the idea is that for the large majority of cases, the database engine will do a better job at finding the most efficient way of completing your task than you could in code. Especially when it comes to things like making the results conditional on operations performed on the data. Arguably with modern engines effectively JIT'ing + caching the compiled version of your query it'd make sense on the surface. The question is whether or not leveraging your database engine in this way is inherently bad design practice (and why). The lines become blurred further when all the logic exists inside the database and you're just hitting it via an ORM.

  Read the article

• Why using Fragments?

  - by ahmed_khan_89

  I have read the documentation and some other questions' threads about this topic and I don't really feel convinced; I don't see clearly the limits of use of this technique. Fragments are now seen as a Best Practice; every Activity should be basically a support for one or more Fragments and not call a layout directly. Fragments are created in order to: allow the Activity to use many fragments, to change between them, to reuse these units... == the Fragment is totally dependent to the Context of an activity , so if I need something generic that I can reuse and handle in many Activities, I can create my own custom layouts or Views ... I will not care about this additional Complexity Developing Layer that fragments would add. a better handling to different resolution == OK for tablets/phones in case of long process that we can show two (or more) fragments in the same Activity in Tablets, and one by one in phones. But why would I use fragments always ? handling callbacks to navigate between Fragments (i.e: if the user is Logged-in I show a fragment else I show another fragment). === Just try to see how many bugs facebook SDK Log-in have because of this, to understand that it is really (?) ... considering that an Android Application is based on Activities... Adding another life cycles in the Activity would be better to design an Application... I mean the modules, the scenarios, the data management and the connectivity would be better designed, in that way. === This is an answer of someone who's used to see the Android SDK and Android Framework with a Fragments vision. I don't think it's wrong, but I am not sure it will give good results... And it is really abstract... ==== Why would I complicate my life, coding more, in using them always? else, why is it a best practice if it's just a tool for some cases? what are these cases?

  Read the article

• How can I refactor my code to use fewer singletons?

  - by fish

  I started a component based, networked game (so far only working on the server). I know why singletons can be bad, but I can't think of another way to implement the same thing. So far I have: A GameState singleton (for managing the global state of the game, i.e. pre-game, running, exiting). A World singleton, which is the root entity for my entity graph An EntityFactory A ComponentFactory I'm thinking about adding a "MessageDispatcher" so individual components can subscribe to network messages. The factories do not have state, so I suppose they aren't so bad. However, the others do have global state, which is asking for trouble. How can I refactor my code so it uses fewer singletons?

  Read the article

• Which is a better design pattern for a database wrapper: Save as you go or Save when your done?

  - by izuriel

  I know this is probably a bad way to ask this question. I was unable to find another question that addressed this. The full question is this: We're producing a wrapper for a database and have two different viewpoints on managing data with the wrapper. The first is that all changes made to a data object in code must be persisted in the database by calling a "save" method to actually save the changes. The other side is that these changes should be save as they are made, so if I change a property it's saved, I change another it's save as well. What are the pros/cons of either choice and which is the "proper" way to manage the data?

  Read the article

• Legal Applications of Metamorphic Code

  - by V_P

  Firstly, I would like to state that I already understand the 'vx' applications for Metamorphic code. I am not here to ask a question related to any of those topics as that would be inappropriate in this context. I would like to know if anyone has ever used 'Metamorphic' code in practice, for purposes other than those previously stated, if so, what was the reasoning for using said concept. In essence I am trying to discover a purpose for this concept, if any, other than circumventing anti-virus scanners and the like.

  Read the article

• How to create a manager class without global variables nor singletons?

  - by Omega

  I would like to implement some kind of manager class in my application. It will be in charge of loading textures, processing them, distributing them etc... At first, I wanted to make a global variable that simply contains an instance of my manager class. I found this question: http://stackoverflow.com/questions/4646577/global-variables-in-java. However, the users there seem to recommend to never use global variables. Fine then, I once heard about Singletons, so I though I could use that instead. I mean, creating just one instance of my manager class sounds good. However, I found this other question: When is Singleton appropriate?, which basically tells me that Singletons are, in most scenarios, some kind of anti-pattern. Now I am a bit lost - what other approach can I take to create my manager class, whose only requirement is to be accessible from anywhere?

  Read the article

• Name for this antipattern? Fields as local variables

  - by JSB????

  In some code I'm reviewing, I'm seeing stuff that's the moral equivalent of the following: public class Foo { private Bar bar; public MethodA() { bar = new Bar(); bar.A(); bar = null; } public MethodB() { bar = new Bar(); bar.B(); bar = null; } } The field bar here is logically a local variable, as its value is never intended to persist across method calls. However, since many of the methods in Foo need an object of type Bar, the original code author has just made a field of type Bar. This is obviously bad, right? Is there a name for this antipattern?

  Read the article

• In some games, we just let the main() loop be the Player object or Table object?

  - by ????

  I was thinking that let's say if there is a game of Blackjack or MasterMind, then we should have a class called Dealer or ComputerPal, which is how the computer interact with us (as a dealer for Blackjack or as the person giving hints for MasterMind). And then there should be a Player object, and the way to play one game is aPlayer.playGame but I noticed that a book was just using the main() loop to act as the player (or as the Controller of the game), calling the Dealer methods to dealer the cards, ask for player's action, etc... 1) Is this just a lazy way to model all the proper objects? 2) If more objects are to be added, who should call the aDealer.dealCards and then ask for aPlayer.askForAction? (because it is strange to let the Player handle all the logical steps). Should there be a Table object that handle all these logic and then to play one round of game, use aTable.playGame? What is a good object design for such game?

  Read the article

• Does C++ support subtyping?

  - by the_naive

  I know it might be a silly question to ask, but I didn't quite get an a absolute clear answer on this matter, so I thought I'd put it here. Does c++ support the subtyping in the sense that it fulfills Liskov's principle fully? I understand how parametric polymorphism, inclusion polymorphism(subclassing and overriding) work in c++ but I'm not entirely sure or understand if subtyping exists in the context of C++. Could you please explain?

  Read the article

• Testing complex compositions

  - by phlipsy

  I have a rather large collection of classes which check and mutate a given data structure. They can be composed via the composition pattern into arbitrarily complex tree-like structures. The final product contains a lot of these composed structures. My question is now: How can I test those? Albeit it is easy to test every single unit of these compositions, it is rather expensive to test the whole compositions in the following sense: Testing the correct layout of the composition-tree results in a huge number of test cases Changes in the compositions result in a very laborious review of every single test case What is the general guideline here?

  Read the article

< Previous Page | 62 63 64 65 66 67 68 69 70 71 72 73  | Next Page >