Search Results

Search found 14074 results on 563 pages for 'programmers'.

Page 177/563 | < Previous Page | 173 174 175 176 177 178 179 180 181 182 183 184  | Next Page >

  • Best Persistence choice for J2EE-App with frequently changing Data Model

    - by Ben-G
    Whenever I develop a J2EE-Application, I at some point decide to switch from my dummy Persistence (Simply Using Lists and other Data Structures) to some Sort of Database Persistence. Mostly when I hope the Data Model is more or less complete. From this point on, changes to the data model become exhausting, but unluckily they occur rather often. I've used different Object-Relational-Mappers (iBatis, Hibernate) for my projects. They definitely reduce the pain coming with Data Model changes, but they anyway let me adjust code/configuration at 3 or 4 places for every single change. To me, that's cumbersome and error prone. I made a better experience with DB4O, which simply persists Java Objects as they are, but I believe it's performance does not scale for huge applications. Is there anyway to maintain performance while letting out all the ugly configuration work? I'm seeking a performant framework which really hides persistence from my code. Wish for thinking? Or am I missing out THE technology? Hope you can help.

    Read the article

  • What happens if you're unable to solve a problem?

    - by gablin
    I'm a year away from graduating from university, and I'm really looking forward to solving practical problems. Especially non-trivial ones which require a bit of research and a lot of thinking. But at the same time, that is also my greatest fear - being faced with a problem that I'm unable to solve, no matter how hard I try. And with pressure to deliver code on impending deadlines just around the corner, it does look a bit scary when viewing it from the safe playgrounds on uni (where the worst thing that can happen is that you have to redo a course or exam). So for those who have been in industry for any longer length of time, what would happen if you were told to solve a problem that you couldn't? Has it happened, and if so, what did happen? Did they just drop it and said "Oh well, guess we can make do with something else"? Were there consequences? Were you reprimanded, or even fired?

    Read the article

  • Why is C++ predominant in programming contests and competitions?

    - by daniels
    I understand that C++ is a very fast language, but ain't C just as fast, or faster in some cases? Then you might say that C++ has OOP, but the amount of OOP you need for most programming puzzles is not that big, and in my opinion C would be able handle that. Here's why I am asking this: I am very interested in programming contests and competitions, and I am used to coding in C on those. However, I noticed that the vast majority of people use C++ (e.g., 17 out of 25 finalists on Google Code Jam 2011 used it, while no one used C), so I am wondering if I am at a disadvantage going with C. Apart from the Object Orientation, what makes C++ a more suitable language for programming competitions? What are the features of the language I should learn and use to perform better on the competitions? For background, I consider myself pretty proficient in C, but I am just starting to learn C++.

    Read the article

  • Applications affected by memory performance

    - by robotron
    I'm writing a paper on the topic of applications affected more by memory performance than processor performance. I've got a lot written regarding the gap between the two, however I can't seem to find anything about the applications that might be affected more by memory performance than by processor speed. I suppose these are applications that make a large amount of memory references, but I have no idea what kind of applications would make such large number of references to make it stand out? Perhaps databases? Can you please give me any pointers on how to proceed, some links to papers? I'm really stuck.

    Read the article

  • How to avoid big and clumsy UITableViewController on iOS?

    - by Johan Karlsson
    I have a problem when implementing the MVC-pattern on iOS. I have searched the Internet but seems not to find any nice solution to this problem. Many UITableViewController implementations seems to be rather big. Most examples I have seen lets the UITableViewController implement <UITableViewDelegate> and <UITableViewDataSource>. These implementations are a big reason why UITableViewControlleris getting big. One solution would be to create separate classes that implements <UITableViewDelegate> and <UITableViewDataSource>. Of course these classes would have to have a reference to the UITableViewController. Are there any drawbacks using this solution? In general I think you should delegate the functionality to other "Helper" classes or similar, using the delegate pattern. Are there any well established ways of solving this problem? I do not want the model to contain too much functionality, nor the view. I believe that the logic should really be in the controller class, since this is one of the cornerstones of the MVC-pattern. But the big question is: How should you divide the controller of a MVC-implementation into smaller manageable pieces? (Applies to MVC in iOS in this case) There might be a general pattern for solving this, although I am specifically looking for a solution for iOS. Please give an example of a good pattern for solving this issue. Please provide an argument why your solution is awesome.

    Read the article

  • how to integrate plastic scm with jira? [closed]

    - by bilal fazlani
    I am trying to migrate from VSS to Plastic SCM and want to use it with JIRA. I have reached this far. http://i.stack.imgur.com/h1wSw.png I tried referring to their help documentation. but that did not help. Does someone know how to link a new branch to an issue in JIRA ? I tried to giving same name to Issue and Branch. That din't work. If the Issue key is : "DEMO-7", what should be the "Branch Prefix" & "Branch Name" in Plastic SCM ? I am sure I am missing something.

    Read the article

  • Opensource showcase for MVC in Java Swing

    - by Regular John
    I've allready created small desktop CRUD applications using Java/Swing. In hindsight I'm not quite sure if the overall design of these applications is good. I've also done some reading on MVC and looked at different Swing-tutorials. My problem is, that I've got a very theroatical knowledge of MVC and on the other hand, most Swing-resources don't implement the MVC-pattern. Now I would like to get my hands dirty and see how MVC is implemented in Swing in a real-world-application. Are there any opensource project you could recommend? It would be also interesting to have more than one project, to see different approaches. Best fit would be a software, that uses a relational database in the backend, to see an overall design, that I can compare to my former applications.

    Read the article

  • Any language where every class instance is a class too?

    - by Dokkat
    Taking inspiration from Javascript prototypes, I had the idea of a language where every instance can be used as a class. Before I potentially reinvent the wheel, I would like to ask if there is a language already using this concept: //To declare a Class, extend the base class (in this case, Type) Type(Weapon,{price:0}); //Same syntax to inherit; simply extend the parent: Weapon(Sword,{price:3}); Weapon(Axe,{price:4}); Sword(Katana,{price:7}); Sword(Dagger,{price:3}); //And the same to create an instance: Katana(myKatana,{nickname:"Leon"}); myKatana.price; // 7 myKatana.nickname; // Leon // An operator to return children of a class; Sword_; // [Katana, Dagger] // An operator to return array of descendants; Sword__; // [Katana, Dagger, myKatana] // An operator to return array of parents; Sword^; // Weapon // Arrays can be used as elements Sword__.price += 1; //increases price of Sword's descendants by 1 mySword.price; //8 // And to access specific element (using its name instead of index) var name = "mySword" Katana_[name]; // [mySword] Katana_[name].nickname; // Leon Has this kind of approach been already studied/implemented?

    Read the article

  • How can I separate the user interface from the business logic while still maintaining efficiency?

    - by Uri
    Let's say that I want to show a form that represents 10 different objects on a combobox. For example, I want the user to pick one hamburguer from 10 different ones that contain tomatoes. Since I want to separate UI and logic, I'd have to pass the form a string representation of the hamburguers in order to display them on the combobox. Otherwise, the UI would have to dig into the objects fields. Then the user would pick a hamburguer from the combobox, and submit it back to the controller. Now the controller would have to find again said hamburguer based on the string representation used by the form (maybe an ID?). Isn't that incredibly inefficient? You already had the objects you wanted to pick one from. If you submited to the form the whole objects, and then returned a specific object, you wouldn't have to refind it later on since the form already returned a reference to that object. Moreover, if I'm wrong and you actually should send the whole object to the form, how can I isolate UI from logic?

    Read the article

  • Software Licenses: No Distribution and Private Selling Using Dual Licenses

    - by user102945
    Hi I recently wrote a couple of WordPress Themes in PHP and was wondering what license i should put on it. I don't mind users reusing my code but i don't want them to be able to sell and redistribute my themes as i want to retain that right. I heard somewhere that an all rights reserved link would stop the distributing etc. Is that true or do i need to include another license and dual license my Themes. So to sum it up i want to use a license to stop others from selling and distributing my themes, while at the same time letting others use the code if they want to.

    Read the article

  • Help in (re)designing my Swing application

    - by Harihar Das
    I have developed a Swing application that controls execution of several script like jobs. I need to display the interim output of the jobs concurrently. I have followed MVC while writing the application. The application is working as expected. But off late I have the following requirements in hand: A few of the script jobs need special user privileges to execute so as to access specialized resources. There seems to be now way in Java to impersonate as a different user while running an application.[examined in this question]. Also trying to run the Swing application as a scheduled task in windows is not helping. Once started the jobs should be running even if the user logs off after starting the jobs. I am thinking of separating the execution logic from the UI and run that as a service; and introduce JMS in between the two layers so as to store/retrieve the interim the output. Note: I need to run this application on windows Any ideas on meeting my requirements will be highly appreciated.

    Read the article

  • How can I select an appropriate licensing/obfuscation system for .NET?

    - by Adam
    I saw someone suggesting .NET Reactor once as a good obfuscator. I went to their website to check it out and saw they have a product called IntelliLock which is advertised as a pretty robust licensing system which has code protection/obfuscation built in. With that said, I tried to contact them and ask them a few questions regarding the product, but have not had any response. This is kind of a red flag for me. However, it seems like there is some user base for this product whom are satisfied. What .NET licensing system(s) with .NET code protection/obfuscation are you using? What are its pros & cons that you have encountered? Are there things I should be looking for or looking to avoid when evaluating these systems?

    Read the article

  • How to set up a one-man research in the difference between BDD and Waterfall?

    - by Martijn van der Maas
    Earlier, I asked a question about how to measure the quality of a project. The outcome of that question was that the quality of the project can be divided into two parts: Internal quality (code quality, measurable by code quality metrics) External quality (Acceptance test, how well the software meets the requirements) So based on that, I want to set up some research and validate the outcome of the project. The problem is, I will conduct this research on my own, so it's not possible to run the project once in BDD style and the other one in waterfall by myself. It's also not possible to compare BDD and waterfall projects on a larger scale, due to the fact that there are not enough BDD projects that can be measured because of the age of BDD. So, my question is: did anybody face this problem? How could I execute my experiment in such a way that it is of scientific value?

    Read the article

  • Is throwing an error in unpredictable subclass-specific circumstances a violation of LSP?

    - by Motti Strom
    Say, I wanted to create a Java List<String> (see spec) implementation that uses a complex subsystem, such as a database or file system, for its store so that it becomes a simple persistent collection rather than an basic in-memory one. (We're limiting it specifically to a List of Strings for the purposes of discussion, but it could extended to automatically de-/serialise any object, with some help. We can also provide persistent Sets, Maps and so on in this way too.) So here's a skeleton implementation: class DbBackedList implements List<String> { private DbBackedList() {} /** Returns a list, possibly non-empty */ public static getList() { return new DbBackedList(); } public String get(int index) { return Db.getTable().getRow(i).asString(); // may throw DbExceptions! } // add(String), add(int, String), etc. ... } My problem lies with the fact that the underlying DB API may encounter connection errors that are not specified in the List interface that it should throw. My problem is whether this violates Liskov's Substitution Principle (LSP). Bob Martin actually gives an example of a PersistentSet in his paper on LSP that violates LSP. The difference is that his newly-specified Exception there is determined by the inserted value and so is strengthening the precondition. In my case the connection/read error is unpredictable and due to external factors and so is not technically a new precondition, merely an error of circumstance, perhaps like OutOfMemoryError which can occur even when unspecified. In normal circumstances, the new Error/Exception might never be thrown. (The caller could catch if it is aware of the possibility, just as a memory-restricted Java program might specifically catch OOME.) Is this therefore a valid argument for throwing an extra error and can I still claim to be a valid java.util.List (or pick your SDK/language/collection in general) and not in violation of LSP? If this does indeed violate LSP and thus not practically usable, I have provided two less-palatable alternative solutions as answers that you can comment on, see below. Footnote: Use Cases In the simplest case, the goal is to provide a familiar interface for cases when (say) a database is just being used as a persistent list, and allow regular List operations such as search, subList and iteration. Another, more adventurous, use-case is as a slot-in replacement for libraries that work with basic Lists, e.g if we have a third-party task queue that usually works with a plain List: new TaskWorkQueue(new ArrayList<String>()).start() which is susceptible to losing all it's queue in event of a crash, if we just replace this with: new TaskWorkQueue(new DbBackedList()).start() we get a instant persistence and the ability to share the tasks amongst more than one machine. In either case, we could either handle connection/read exceptions that are thrown, perhaps retrying the connection/read first, or allow them to throw and crash the program (e.g. if we can't change the TaskWorkQueue code).

    Read the article

  • Is defining every method/state per object in a series of UML diagrams representative of MDA in general?

    - by Max
    I am currently working on a project where we use a framework that combines code generation and ORM together with UML to develop software. Methods are added to UML classes and are generated into partial classes where "stuff happens". For example, an UML class "Content" could have the method DeleteFromFileSystem(void). Which could be implemented like this: public partial class Content { public void DeleteFromFileSystem() { File.Delete(...); } } All methods are designed like this. Everything happens in these gargantuan logic-bomb domain classes. Is this how MDA or DDD or similar usually is done? For now my impression of MDA/DDD (which this has been called by higherups) is that it severely stunts my productivity (everything must be done The Way) and that it hinders maintenance work since all logic are roped, entrenched, interspersed into the mentioned gargantuan bombs. Please refrain from interpreting this as a rant - I am merely curious if this is typical MDA or some sort of extreme MDA UPDATE Concerning the example above, in my opinion Content shouldn't handle deleting itself as such. What if we change from local storage to Amazon S3, in that case we would have to reimplement this functionality scattered over multiple places instead of one single interface which we can provide a second implementation for.

    Read the article

  • Drawing shapes dynamically on an image through web browser

    - by Tom Beech
    We have a scenario where we create floor plans of locations when we visit. The floor plan is finally shown on the web. It's come to the point now where we want to show floor plans but have a key with various items on them, when an item on the key is clicked, the image should highlight all the areas of the floorplan that have that specific item. I guess we're looking for some sort of open standard javascript lib to deal with SVG (has to work pre IE9 so pure SVG wont cut it) and the floor plans have to be able to be created through a .net application to be deployed on the web. I'd rather stay away from flash if at all possible to be honest. Below are a few conceptual images of what we're trying to achieve.

    Read the article

  • Would you refactor this and if so, would you charge your client?

    - by Julius
    I am working on a freelance job at home. The client wants me to write some new functionality for his CMS, but it is taking me a lot of time to figure out what the code is doing, because it is written in a very unreadable style. Below is just an example of what I mean. The previous programmer made extensive use of anonymous functions, of eval(), he uses deeply nested ternary operators, he didn't indent code, didn't use comments, and he uses funny constructions like misusing the behaviour of logical operators || and && for creating if/else conditions (the second condition of && only gets tested if the first one is true, opening the possibility to use && as an if/else construction). All in all it's insane code and it's costing me a lot of time to find out how the current code works. return ($this->main->context != "ajax" || in_array($this->type, $this->definition->ajax)) ? eval('return method_exists($this,"Show'.ucfirst($this->type).'") ? $this->Show'.ucfirst($this->type).'('.(count($args) ? join(",",array_map(create_function('$a','return (is_numeric($a) || preg_match("/^array/",$a)) ? $a : "\"".$a."\"";'),$args)) : "").') : null;') : ''; Would you refactor this code and how would you handle this sort of thing with your client, I mean financially?

    Read the article

  • Is there a design pattern for chained observers?

    - by sharakan
    Several times, I've found myself in a situation where I want to add functionality to an existing Observer-Observable relationship. For example, let's say I have an Observable class called PriceFeed, instances of which are created by a variety of PriceSources. Observers on this are notified whenever the underlying PriceSource updates the PriceFeed with a new price. Now I want to add a feature that allows a (temporary) override to be set on the PriceFeed. The PriceSource should still update prices on the PriceFeed, but for as long as the override is set, whenever a consumer asks PriceFeed for it's current value, it should get the override. The way I did this was to introduce a new OverrideablePriceFeed that is itself both an Observer and an Observable, and that decorates the actual PriceFeed. It's implementation of .getPrice() is straight from Chain of Responsibility, but how about the handling of Observable events? When an override is set or cleared, it should issue it's own event to Observers, as well as forwarding events from the underlying PriceFeed. I think of this as some kind of a chained observer, and was curious if there's a more definitive description of a similar pattern.

    Read the article

  • How to setup the c++ rule of three in a virtual base class

    - by Minion91
    I am trying to create a pure virtual base class (or simulated pure virtual) my goal: User can't create instances of BaseClass. Derived classes have to implement default constructor, copy constructor, copy assignment operator and destructor. My attempt: class Base { public: virtual ~Base() {}; /* some pure virtual functions */ private: Base() = default; Base(const Base& base) = default; Base& operator=(const Base& base) = default; } This gives some errors complaining that (for one) the copy constructor is private. But i don't want this mimicked constructor to be called. Can anyone give me the correct construction to do this if this is at all possible?

    Read the article

  • responsibility for storage

    - by Stefano Borini
    A colleague and I were brainstorming about where to put the responsibility of an object to store itself on the disk in our own file format. There are basically two choices: object.store(file) fileformatWriter.store(object) The first one gives the responsibility of serialization on the disk to the object itself. This is similar to the approach used by python pickle. The second groups the representation responsibility on a file format writer object. The data object is just a plain data container (eventually with additional methods not relevant for storage). We agreed on the second methodology, because it centralizes the writing logic from generic data. We also have cases of objects implementing complex logic that need to store info while the logic is in progress. For these cases, the fileformatwriter object can be passed and used as a delegate, calling storage operations on it. With the first pattern, the complex logic object would instead accept the raw file, and implement the writing logic itself. The first method, however, has the advantage that the object knows how to write and read itself from any file containing it, which may also be convenient. I would like to hear your opinion before starting a rather complex refactoring.

    Read the article

  • Distributed transactions and queues, ruby, erlang

    - by chrispanda
    I have a problem that involves several machines, message queues, and transactions. So for example a user clicks on a web page, the click sends a message to another machine which adds a payment to the user's account. There may be many thousands of clicks per second. All aspects of the transaction should be fault tolerant. I've never had to deal with anything like this before, but a bit of reading suggests this is a well known problem. So to my questions. Am I correct in assuming that secure way of doing this is with a two phase commit, but the protocol is blocking and so I won't get the required performance? It appears that DBs like redis and message queuing system like Rescue, RabbitMQ etc don't really help me a lot - even if I implement some sort of two phase commit, the data will be lost if redis crashes because it is essentially memory-only. All of this has led me to look at erlang - but before I wade in and start learning a new language, I would really like to understand better if this is worth the effort. Specifically, am I right in thinking that because of its parallel processing capabilities, erlang is a better choice for implementing a blocking protocol like two phase commit, or am I confused?

    Read the article

  • PHP developer wanting to learn python

    - by dclowd9901
    I'm pretty familiar at this point with PHP (Javascript, too), up to the point of OOP in PHP, and am looking to branch out my knowledge. I'm looking at Python next, but a lot of it is a bit alien to me as a PHP developer. I'm less concerned about learning the language itself. I'm positive there's plenty of good resources, documentation and libraries to help me get the code down. I'm less sure about the technical aspects of how to set up a dev environment, unit testing and other more mundane details that are very important, aid in rapid development, but aren't as widely covered. Are there any good resources out there for this?

    Read the article

  • When following SRP, how should I deal with validating and saving entities?

    - by Kristof Claes
    I've been reading Clean Code and various online articles about SOLID lately, and the more I read about it, the more I feel like I don't know anything. Let's say I'm building a web application using ASP.NET MVC 3. Let's say I have a UsersController with a Create action like this: public class UsersController : Controller { public ActionResult Create(CreateUserViewModel viewModel) { } } In that action method I want to save a user to the database if the data that was entered is valid. Now, according to the Single Responsibility Principle an object should have a single responsibility, and that responsibility should be entirely encapsulated by the class. All its services should be narrowly aligned with that responsibility. Since validation and saving to the database are two separate responsibilities, I guess I should create to separate class to handle them like this: public class UsersController : Controller { private ICreateUserValidator validator; private IUserService service; public UsersController(ICreateUserValidator validator, IUserService service) { this.validator = validator; this.service= service; } public ActionResult Create(CreateUserViewModel viewModel) { ValidationResult result = validator.IsValid(viewModel); if (result.IsValid) { service.CreateUser(viewModel); return RedirectToAction("Index"); } else { foreach (var errorMessage in result.ErrorMessages) { ModelState.AddModelError(String.Empty, errorMessage); } return View(viewModel); } } } That makes some sense to me, but I'm not at all sure that this is the right way to handle things like this. It is for example entirely possible to pass an invalid instance of CreateUserViewModel to the IUserService class. I know I could use the built in DataAnnotations, but what when they aren't enough? Image that my ICreateUserValidator checks the database to see if there already is another user with the same name... Another option is to let the IUserService take care of the validation like this: public class UserService : IUserService { private ICreateUserValidator validator; public UserService(ICreateUserValidator validator) { this.validator = validator; } public ValidationResult CreateUser(CreateUserViewModel viewModel) { var result = validator.IsValid(viewModel); if (result.IsValid) { // Save the user } return result; } } But I feel I'm violating the Single Responsibility Principle here. How should I deal with something like this?

    Read the article

  • IDE for visually impaired

    - by Eli Rosencruft
    A visually impaired colleague has asked me to recommend an IDE with easy-to-find and easy-to-use controls for: font size background and foreground colors changing syntax color scheme support for at least C/C++ and Java He would prefer an IDE that is either portable or that has similar versions for Linux, Windows and Mac. He prefers a dark background and light colored fonts and needs to sit very close to the display.

    Read the article

  • Starting a career in mobile development in next 5 months?

    - by Jungle Hunter
    I will be starting my career shortly and have the opportunity to being my career in mobility. I have an option to be in more traditional fields (the ones that have been around for quite some time now like web development and Java apps development). What are the pros and cons of both? Also, if I do choose mobility, then I might be presented with the option of iOS or Android. Pros and cons of choosing each? Period: Joining in next 5 months. Mobility company profile: Major consulting company.

    Read the article

< Previous Page | 173 174 175 176 177 178 179 180 181 182 183 184  | Next Page >