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  • What difference between Web Apps & Descktop app shoud one keep in mind to model the system right?

    - by simple
    Sometimes it seems like some architectural techniques are not for the Web application I am building and then I just go and code =(, Though I really want to make a habit to architect system before moving to the code, as when I just code I endup writing some useless components which then I rewrite =(, So can you just point out some differences between web apps and desktop ones ?

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  • DTOs Collections mapping Problem

    - by the_knight5000
    I'm working now on a multi-tier project which has layers as following : DAL BLL GUI Layer and Shared DTOs between BLL and GUI layers. I'm facing a problem in mapping the Objects from DAO To DTO, No problem in the simple objects. The problem is in the Objects who have child collections of another objects. ex: Author Category --Categories --Authors the execution goes in an infinite loop of mapping and it get more complex when I want model Self-join tables ex: Safe Safe --TransferSafe(Collection<Safe>) --TransferSafe(Collection<Safe>) the execution goes in an infinite loop of mapping any suggestions about a good solution or a practical mapping pattern?

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  • In Ruby, is there a better way of selecting a constant (or avoiding the constant altogether) based o

    - by Vertis
    Not sure the title fully describes the problem/question I'm trying to ask, sorry. One of my fellow developers has created classes as such: class Widget attr_accessor :model_type ... end and: class ModelType MODEL1 = "model1" MODEL2 = "model2" MODEL3 = "model3" end Now he wants me to convert a retrieved string "MODEL1" to the constant. So that when he is referencing that model elsewhere he can use ModelType::MODEL1. Obviously I've got to convert from the string I'm being given with something like the following: case model_type when 'MODEL1' @model_type = ModelType::MODEL1 ... end I feel like this is clunky, so I'd like to know if there is a better DRYer way of providing this kind of functionality.

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  • iPhone app -- are plists the way to handle default values and other languages?

    - by d_CFO
    I wrote my first program almost fifty years ago (yes, coding is still a blast, managing big projects with many programmers was not), but my Von Neumann thinking gets in the way. I want to (a) load default values and (b) account for multiple languages more elegantly (?) than 60-plus iterations of NSLocalizedString. Can I park all of this data into what amounts to a record with fields like this: (key value stuff), (tweak-able user prompt / screen name / whatever), (tasteful default), (user-supplied value)? NSUserDefault has worked well so far; Core Data looks like overkill (?), and sql lite, well, where's Oracle when you need it?

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  • Design pattern for loading multiple message types

    - by lukem00
    As I was looking through SO I came across a question about handling multiple message types. My concern is - how do I load such a message in a neat way? I decided to have a separate class with a method which loads one message each time it's invoked. This method should create a new instance of a concrete message type (say AlphaMessage, BetaMessage, GammaMessage, etc.) and return it as a Message. class MessageLoader { public Message Load() { // ... } } The code inside the method is something which looks really awful to me and I would very much like to refactor it/get rid of it: Message msg = Message.Load(...); // load yourself from whatever source if (msg.Type == MessageType.Alpha) return new AlphaMessage(msg); if (msg.Type == MessageType.Beta) return new BetaMessage(msg); // ... In fact, if the whole design looks just too messy and you guys have a better solution, I'm ready to restructure the whole thing. If my description is too chaotic, please let me know what it's missing and I shall edit the question. Thank you all.

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  • Is a web-server (e.g servlets) a good solution for an IM server?

    - by John
    I'm looking at a new app, broadly speaking an IM application with a strong client-server model - all communications go through a server so they can be logged centrally. The server will be Java in some form, clients could at this point be anything from a .NET Desktop app to Flex/Silverlight, to a simple web-interface using JS/AJAX. I had anticipated doing the server using standard J2EE so I get a thread-safe, multi-user server for 'free'... to make things simple let's say using Servlets (but in practice SpringMVC would be likely). This all seemed very neat but I'm concerned if the stateless nature of Servlets is the best approach. If my memory of servlets (been a year or two) is right, each time a client sent a HTTP request, typically a new message entered by the user, the servlet could not assume it had the user/chat in memory and might have to get it from the DB... regardless it has to look it up. Then it either has to use some PUSH system to inform other members of the chat, or cache that there are new messages, for other clients who poll the server using AJAX or similar - and when they poll it again has to lookup the chat, including new messages, and send the new data. I'm wondering if a better system would be the server is running core Java, and implements a socket-based communication with clients. This allows much more immediate data transfer and is more flexible if say the IM client included some game you could play. But then you're writing a custom server and sockets don't sound very friendly to a browser-based client on current browsers. Am I missing some big piece of the puzzle here, it kind of feels like I am? Perhaps a better way to ask the question would simply be "if the client was browser-based using HTML/JS and had to run on IE7+,FF2+ (i.e no HTML5), how would you implement the server?" edit: if you are going to suggest using XMPP, I have been trying to get my head around this in another question, so please consider if that's a more appropriate place to discuss this specifically.

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  • How can I setup a flexible local web development environment I can easily sync with a production, Amazon AWS based environment?

    - by user607057
    I'm running on an OS X environment and would like to create a flexible web development environment locally... including the option to run on an Nginx server for my PHP-based application. At the end of the day (or, development cycle), I'd like to be able to hit a switch and have it all sync over to Amazon AWS hosting (EC2, S3) - instances, databases, files, configurations, and all. Are there any simple ways to do this?

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  • Forward a call to a webservice to another webservice?

    - by Luhmann
    If I have an https webservice behind a firewall on a machine (A) that I cannot access, but access to a machine on the same network (B), from where I can call the webservice on machine A. What is the best way of talking with the webservice on machine A, from the outside via machine B (that I access via VPN)? I can obviously create a service with a matching interface on machine B, and call the methods on the webservice on machine A, and return the result. But I fear for the overhead. Is there another way? Can i somehow forward the request?

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  • SQL Server concurrency and generated sequence

    - by Goyuix
    I need a sequence of numbers for an application, and I am hoping to leverage the abilities of SQL Server to do it. I have created the following table and procedure (in SQL Server 2005): CREATE TABLE sequences ( seq_name varchar(50) NOT NULL, seq_value int NOT NULL ) CREATE PROCEDURE nextval @seq_name varchar(50) AS BEGIN DECLARE @seq_value INT SET @seq_value = -1 UPDATE sequences SET @seq_value = seq_value = seq_value + 1 WHERE seq_name = @seq_name RETURN @seq_value END I am a little concerned that without locking the table/row another request could happen concurrently and end up returning the same number to another thread or client. This would be very bad obviously. Is this design safe in this regard? Is there something I can add that would add the necessary locking to make it safe? Note: I am aware of IDENTITY inserts in SQL Server - and that is not what I am looking for this in particular case. Specifically, I don't want to be inserting/deleting rows. This is basically to have a central table that manages the sequential number generator for a bunch of sequences.

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  • Beginner Question ; About Prime Generation in "C" - What is wrong with my code ? -

    - by alorsoncode
    I'm a third year irregular CS student and ,i just realized that i have to start coding. I passed my coding classes with lower bound grades so that i haven't a good background in coding&programming. I'm trying to write a code that generates prime numbers between given upper and lower bounds. Not knowing C well, enforce me to write a rough code then go over it to solve. I can easily set up the logic for intended function but i probably create a wrong algorithm through several different ways. Here I share my last code, i intend to calculate that when a number gives remainder Zero , it should be it self and 1 , so that count==2; What is wrong with my implementation and with my solution generating style? I hope you will warm me up to programming world, i couldn't find enough motivation and courage to get deep into programming. Thanks in Advance :) Stdio and Math.h is Included int primegen(int down,int up) { int divisor,candidate,count=0,k; for(candidate=down;candidate<=up;candidate++) { for(divisor=1;divisor<=candidate;divisor++) { k=(candidate%divisor); } if (k==0) count++; if(count==2) { printf("%d\n", candidate); count=0; } else { continue; } } } int main() { primegen(3,15); return 0; }

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  • Can a variable like 'int' be considered a primitive/fundamental data structure?

    - by Ravi Gupta
    A rough definition of a data structure is that it allows you to store data and apply a set of operations on that data while preserving consistency of data before and after the operation. However some people insist that a primitive variable like 'int' can also be considered as a data structure. I get that part where it allows you to store data but I guess the operation part is missing. Primitive variables don't have operations attached to them. So I feel that unless you have a set of operations defined and attached to it you cannot call it a data structure. 'int' doesn't have any operation attached to it, it can be operated upon with a set of generic operators. Please advise if I got something wrong here.

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  • What makes my code DDD (domain-driven design) qualified?

    - by oykuo
    Hi All, I'm new to DDD and am thinking about using this design technique in my project. However, what strikes me about DDD is that how basic the idea is. Unlike other design techniques such as MVC and TDD, it doesn't seems to contain any ground breaking ideas. For example, I'm sure some of you will have the same feeling that the idea of root aggregates and repositories are nothing new because when you are was writing MVC web applications you have to have one single master object (i.e. the root aggregate) that contain other minor objects (i.e. value objects and entities) in the model layer in order to send data to a strongly typed view. To me, the only new idea in DDD is probably the "Smart" entities (i.e. you are supposed to have business rules on root aggregates) Separation between value object, root aggregate and entities. Can anyone tell me if I have missed out anything here? If that's all there is to DDD, if I update one of my existing MVC application with the above 2 new ideas, can I claim it's an TDD, MVC and DDD applcation?

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  • How security of the systems might be improved using database procedures?

    - by Centurion
    The usage of Oracle PL/SQL procedures for controlling access to data often emphasized in PL/SQL books and other sources as being more secure approach. I'v seen several systems where all business logic related with data is performed through packages, procedures and functions, so application code becomes quite "dumb" and is only responsible for visualization part. I even heard some devs call such approaches and driving architects as database nazi :) because all logic code resides in database. I do know about DB procedure performance benefits, but now I'm interested in a "better security" when using thick client model. I assume such design mostly used when Oracle (and maybe MS SQL Server) databases are used. I do agree such approach improves security but only if there are not much users and every system user has a database account, so we might control and monitor data access through standard database user security. However, how such approach could increase the security for an average web system where thick clients are used: for example one database user with DML grants on all tables, and other users are handled using "users" and"user_rights" tables? We could use DB procedures, save usernames into context use that for filtering but vulnerability resides at the root - if the main database account is compromised than nothing will help. Of course in a real system we might consider at least several main users (for example frontend_db_user, backend_db_user).

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  • how to organize classes in ruby if they are literal subclasses

    - by RetroNoodle
    I know that title didn't make sense, Im sorry! Its hard to word what I am trying to ask. I had trouble googling it for the same reason. So this isn't even Ruby specific, but I am working in ruby and I am new to it, so bear with me. So you have a class that is a document. Inside each document, you have sentences, and each sentence has words. Words will have properties, like "noun" or a count of how many times they are used in the document, etc. I would like each of the elements, document, sentence, word be an object. Now, if you think literally - sentences are in documents, and words are in sentences. Should this be organized literally like this as well? Like inside the document class you will define and instantiate the sentence objects, and inside the sentence class you will define and instantiate the words? Or, should everything be separate and reference each other? Like the word class would sit outside the sentence class but the sentence class would be able to instantiate and work with words? This is a basic OOP question I guess, and I suppose you could argue to do it either way. What do you guys think? Each sentence in the document could be stored in a hash of sentence objects inside the document object, and each word in the sentence could be stored in a hash of word objects inside the sentence. I dont want to code myself into a corner here, thats why I am asking, plus I have wondered this before in other situations. Thank you!

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  • What is the business case for a dependency injection (DI) framework?

    - by kalkie
    At my company we want to start using a dependency injection (DI) framework for managing our dependencies. I have some difficulty with explaining the business value of such a framework. Currently I have come up with these reasons. Less source code, delete all the builder patterns in the code. Increase in flexibility. Easier to switch dependencies. Better separation of concern. The framework is responsible for creating instances instead of our code. Has anybody else had to persuade management? How did you do that? What reasons did you use?

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  • Using SimpleDB (with SimpleSavant) with POCO / existing entities, not attributes on my classes

    - by alex
    I'm trying to use Simple Savant within my application, to use SimpleDB I currently have (for example) public class Person { public Guid Id { get; set; } public string Name { get; set; } public string Description { get; set; } public DateTime DateOfBirth { get; set; } } To use this with Simple Savant, i'd have to put attributes above the class declaration, and property - [DomainName("Person")] above the class, and [ItemName] above the Id property. I have all my entities in a seperate assembly. I also have my Data access classes an a seperate assembly, and a class factory selects, based on config, the IRepository (in this case, IRepository I want to be able to use my existing simple class - without having attributes on the properties etc.. In case I switch out of simple db, to something else - then I only need to create a different implementation of IRepository. Should I create a "DTO" type class to map the two together? Is there a better way?

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  • Good assembly tutorial for windows with eiter fasm or nasm

    - by The new guy
    I have spent the last 3 hours google and bing for a good asm tutorial(x86 variety). I have been on this site for many of these results. Non have really been sufficient. Mainly because while i like learning theory, i learn it best via practice, while for example pc-asm has about 20-30 pages of theroy before anything practical. I was wondering if there was a tutorial or online pdf (or cheap book(<£20)) that i could use that suits my style of learning. Please state if this is not possibke Thank you for your time

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  • What Design Pattern is this?

    - by 01
    I know that everything we do in programming can be described as design pattern(even abstract method has design pattern called template method) public class Guicer extends AbstractModule { private static Injector injector = Guice.createInjector(new Guicer()); public static void setInjector(Injector injector) { Guicer.injector = injector; } public static T getInstance(Class c) { return injector.getInstance(c); } @Override protected void configure() { } } What design patterns are used in this code?

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  • In web project can we write core services layer without knowledge of UI ?

    - by Silent Warrior
    I am working on web project. We are using flex as UI layer. My question is often we are writing core service layer separately from web/UI layer so we can reuse same services for different UI layer/technology. So practically is it possible to reuse same core layer services without any changes/addition in API with different kind of UI technologies/layers. For e.g. same core service layer with UI technology which supports synchronized request response (e.g. jsp etc.) and non synchronize or event driven UI technology (e.g Ajax, Flex, GWT etc.) or with multiple devices like (computers, mobiles, pdas etc.). Personally I feel its very tough to write core service layer without any knowledge of UI. Looking for thoughts from other people.

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