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  • Best practice for combining a Java Applet/ Android interface?

    - by Pearsonartphoto
    I'm working on an online game, which I am seriously considering writing a Java Applet for it. The game is not overly complex on the features. I'm considering at some point having at least 3 versions of the game, which include a Java stand alone, applet, and Android game. I know from Design Patterns that the best way to use differing things like buttons and the like is to use a Bridge interface, where I have a common template for the common buttons. However, I'm having a bit of difficulty understanding what to do about the following. I know that Android programs use an Activity structure, which I am well familiar with, and that Applets extend the Applet interface, which I am not as familiar with. I also know that a stand alone java program uses basically a main() function, which doesn't have much structure. I'm convinced that there should be a way to design a common design pattern between the two, but somehow I'm missing what that is exactly. What can I do to make the different frameworks work with as much common code as possible?

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  • How should I structure moving from overworld to menu system / combat?

    - by persepolis
    I'm making a text-based "Arena" game where the player is the owner of 5 creatures that battle other teams for loot, experience and glory. The game is very simple, using Python and a curses emulator. I have a static ASCII map of an "overworld" of sorts. My character, represented by a glyph, can move about this static map. There are locations all over the map that the character can visit, that break down into two types: 1) Towns, which are a series of menus that will allow the player to buy equipment for his team, hire new recruits or do other things. 2) Arenas, where the player's team will have a "battle" interface with actions he can perform, messages about the fight, etc. Maybe later, an ASCII representation of the fight but for now, just screens of information with action prompts. My main problem is what kind of design or structure I should use to implement this? Right now, the game goes through a master loop which waits for keyboard input and then moves the player about the screen. My current thinking is this: 1) Upon keyboard input, the Player coordinates are checked against a list of Location objects and if the Player coords match the Location coords then... 2) ??? I'm not sure if I should then call a seperate function to initiate a "menu" or "combat" mode. Or should I create some kind of new GameMode object that contains a method itself for drawing the screen, printing the necessary info? How do I pass my player's team data into this object? My main concern is passing around the program flow into all these objects. Should I be calling straight functions for different parts of my game, and objects to represent "things" within my game? I was reading about the MVC pattern and how this kind of problem might benefit - decouple the GUI from the game logic and user input but I have no idea how this applies to my game.

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  • How to identify process that's sending error messages to terminal?

    - by kjo
    The following error message occasionally appears in my terminal: Failed to open VDPAU backend libvdpau_nvidia.so: cannot open shared object file: No such file or directory ...which is pretty annoying. I have searched online for solutions to this error, without success. Is there any way to at least identify the process responsible for sending these error messages to my terminal? EDIT: Let me clarify that, as far as I can tell, these error messages appear "out of the blue". In fact, they appear asynchronously with respect to my interactions with the terminal (more often than not see them for the first time when I return to a terminal window that has been unattended for some time). I'm sure there's a definite, deterministic cause for these messages, but it is not one that I can readily identify. In short, I have not noticed any pattern or regularity to their occurrence. In particular, in my case their occurrence has nothing to do with running mplayer, or any other video playback program. (Please my earlier post about it here.) For one thing, the machine in question is a work machine, and I rarely watch any videos with it. In the very few instances in which I've watched a video on this machine I've used VLC, not mplayer, and these errors never appeared in these rare occasions that I used VLC.

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  • the requested resource is not available [closed]

    - by James Pj
    I have written a Java servlet program and run it through local Tomcat 7, But it was showing following error : HTTP Status 404 - /skypark/registration type Status report message /skypark/registration description The requested resource is not available. Apache Tomcat/7.0.33 I don't know what was the reason for it my Html page is <html> <head> <title> User registration </title> </head> <body> <form action="registration" method="post"> <center> <h2><b>Skypark User Registration</b></h2> <table border="0"> <tr><td> First Name </td><td> <input type="text" name="fname"/></br> </td></tr><tr><td> Last Name </td><td> <input type="text" name="lname"/></br> </td></tr><tr><td> UserName </td><td> <input type="text" name="uname"></br> </td></tr><tr><td> Enter Password </td><td> <input type="password" name="pass"></br> </td></tr><tr><td> Re-Type Password </td><td> <input type="password" name="pass1"></br> </td></tr><tr><td> Enter Email ID </td><td> <input type="email" name="email1"></br> </td></tr><tr><td> Phone Number </td><td> <input type="number" name="phone"> </td></tr><tr><td> Gender<br> </td></tr><tr><td> <input type="radio" name="gender" value="Male">Male</input></br> </td></tr><tr><td> <input type="radio" name="gender" value="Female">Female</input></br> </td></tr><tr><td> Enter Your Date of Birth<br> </td><td> <Table Border=0> <tr> <td> Date </td> <td>Month</td> <td>Year</td> </tr><tr> <td> <select name="date"> <option value="1">1</option> <option value="2">2</option> <option value="3">3</option> <option value="4">4</option> <option value="5">5</option> . . . have some code . . . </table> <input type="submit" value="Submit"></br> </center> </form> </body> </html> My servlet is : package skypark; import skypark.*; import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.sql.*; public class Registration extends HttpServlet { public static Connection prepareConnection()throws ClassNotFoundException,SQLException { String dcn="oracle.jdbc.driver.OracleDriver"; String url="jdbc:oracle:thin:@JamesPJ-PC:1521:skypark"; String usname="system"; String pass="tiger"; Class.forName(dcn); return DriverManager.getConnection(url,usname,pass); } public void doPost(HttpServletRequest req,HttpServletResponse resp)throws ServletException,IOException { resp.setContentType("text/html"); PrintWriter out=resp.getWriter(); try { String phone1,uname,fname,lname,dob,address,city,state,country,pin,email,password,gender,lang,qual,relegion,privacy,hobbies,fav; uname=req.getParameter("uname"); fname=req.getParameter("fname"); lname=req.getParameter("lname"); dob=req.getParameter("date"); address=req.getParameter("address"); city=req.getParameter("city"); state=req.getParameter("state"); country=req.getParameter("country"); pin=req.getParameter("pin"); email=req.getParameter("email1"); password=req.getParameter("password"); gender=req.getParameter("gender"); phone1=req.getParameter("phone"); lang=""; qual=""; relegion=""; privacy=""; hobbies=""; fav=""; int phone=Integer.parseInt(phone1); Connection con=prepareConnection(); String Query="Insert into regdetails values(?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)"; PreparedStatement ps=con.prepareStatement(Query); ps.setString(1,uname); ps.setString(2,fname); ps.setString(3,lname); ps.setString(4,dob); ps.setString(5,address); ps.setString(6,city); ps.setString(7,state); ps.setString(8,country); ps.setString(9,pin); ps.setString(10,lang); ps.setString(11,qual); ps.setString(12,relegion); ps.setString(13,privacy); ps.setString(14,hobbies); ps.setString(15,fav); ps.setString(16,gender); int c=ps.executeUpdate(); String query="insert into passmanager values(?,?,?,?)"; PreparedStatement ps1=con.prepareStatement(query); ps1.setString(1,uname); ps1.setString(2,password); ps1.setString(3,email); ps1.setInt(4,phone); int i=ps1.executeUpdate(); if(c==1||c==Statement.SUCCESS_NO_INFO && i==1||i==Statement.SUCCESS_NO_INFO) { out.println("<html><head><title>Login</title></head><body>"); out.println("<center><h2>Skypark.com</h2>"); out.println("<table border=0><tr>"); out.println("<td>UserName/E-Mail</td>"); out.println("<form action=login method=post"); out.println("<td><input type=text name=uname></td>"); out.println("</tr><tr><td>Password</td>"); out.println("<td><input type=password name=pass></td></tr></table>"); out.println("<input type=submit value=Login>"); out.println("</form></body></html>"); } else { out.println("<html><head><title>Error!</title></head><body>"); out.println("<center><b>Given details are incorrect</b>"); out.println(" Please try again</center></body></html>"); RequestDispatcher rd=req.getRequestDispatcher("registration.html"); rd.include(req,resp); return; } } catch(Exception e) { out.println("<html><head><title>Error!</title><body>"); out.println("<b><i>Unable to process try after some time</i></b>"); out.println("</body></html>"); RequestDispatcher rd=req.getRequestDispatcher("registration.html"); rd.include(req,resp); return; } out.flush(); out.close(); } } And the web.xml file is <?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0" metadata-complete="true"> <servlet> <servlet-name>reg</servlet-name> <servlet-class>skypark.Registration</servlet-class> </servlet> <servlet-mapping> <servlet-name>reg</servlet-name> <url-pattern>/registration</url-pattern> </servlet-mapping> This i kept in C:\Program Files\Apache Software Foundation\Tomcat 7.0\webapps\skypark\WEB_INF\web.xml and servlet class in C:\Program Files\Apache Software Foundation\Tomcat 7.0\webapps\skypark\WEB_INF\classes\skypark and registration.html in C:\Program Files\Apache Software Foundation\Tomcat 7.0\webapps\skypark\ if any mistake in this makes above error means please help me.Thanks in advance....

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  • List all BPM Processes for a user

    - by kasriniv
    Hello, Happy to start contributing to this blog..  The title of the blog is probably deceptively simple and warrants an elaboration. Customized BPM workspaces/user interfaces are a fairly common requirement. One of our marquee customers in the online stock trading business, envisioned this user interaction for their BPM application: User logs in to the internal portal Use will have list of roles which he is granted as a drop down list Once user selects the role, a list of processes which user is part of appear. Logged in user can be part of any swimlane role of the process This can be a fairly common/reasonable user-UI interaction pattern. 1. and 2. are easily achievable and hence the subject matter of this blog is the requirement in 3. Objective: Given a username and a role, list all the BPM processes that the user is part of, in any swimlane of any process. Here is quick overview of the major steps/logic in the code: Intialize workflow/BPM  context as usual Get a handle on InstanceQueryService(getInstanceQueryService), InstanceManagementService,        ProcessMetadataService and ProcessModelService List all Processes for that bpmcontext (listProcessMetadataSumary) and get Granted roles to that user For each of the processes [method  getAccessibleProcesss(ProcessMetadataSummary, Set)]for each of the lanes in the process, check if the role granted to the user, matches the roleName for that swimlane. If so, add to output. Notes: The usual caveats apply including BPM APIs are subject to change.  JDeveloper method introspection is your better friend than API documentation :-)... (I am going to try upload the source code  and if it doesnt work, will follow this blog up with the corresponding source code.) Hope this helps.  Ack: Yogesh K, BPM Dev team.

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  • best way to send messages to all subscribers with multiple subscriptions and multiple providers

    - by coding_idiot
    I'm writing an application in which - Many users can subsribe to posts made by another users. So for a single publisher there can be many subscribers. When a message is posted by an user X, all users who have subscribed to messages of User X will be sent an email. How to achieve this ? I'm thinking of using publish-subscribe pattern. And then I came through JMS. Which is the best JMS implementation to use according to your experience ? Or else what else solution do you propose to the given problem ? Shall I go for a straight-forward solution ?: User x posts a message, I find all users (from database) who subscribe to user x and then for every user, I call the sendEmail() method. [EDIT] My intention here is not to send-emails. I'm really sorry if it wasn't clear. I also have to send kind of system-notifications apart from Email to all subscribers. Right now, I've implemented the email-sending as a threadPool

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  • Anemic Domain Model, Business Logic and DataMapper (PHP)

    - by sunwukung
    I've implemented a rudimentary ORM layer based on DataMapper (I don't want to use a full blown ORM like Propel/Doctrine - for anything beyond simple fetch/save ops I prefer to access the data directly layer using a SQL abstraction layer). Following the DataMapper pattern, I've endeavoured to keep all persistence operations in the Mapper - including the location of related entities. My Entities have access to their Mapper, although I try not to call Mapper logic from the Entity interface (although this would be simple enough). The result is: // get a mapper and produce an entity $ProductMapper = $di->get('product_mapper'); $Product = $ProductMapper->find('[email protected]','email'); //.. mutaute some values.. save $ProductMapper->save($Product) // uses __get to trigger relation acquisition $Manufacturer = $Product->manufacturer; I've read some articles regarding the concept of an Anemic Domain model, i.e. a Model that does not contain any "business logic". When demonstrating the sort of business logic ideally suited to a Domain Model, however, acquiring related data items is a common example. Therefore I wanted to ask this question: Is persistence logic appropriate in Domain Model objects?

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  • How do I start working as a programmer - what do I need?

    - by giorgo
    Hello, i am currently learning Java and PHP as I have some projects from university, which require me to apply both languages. Specifically, a Java GUI application, connecting to a MySQL database and a web application that will be implemented in PHP/MySQL. I have started learning the MVC pattern, Struts, Spring and I am also learning PHP with zend. My first question is: How can I find employment as a programmer/software engineer? The reason I ask is because I have sent my CV into many companys, but all of them stated that I required work experience. I really need some guidance on how to improve my career opportunites. At present, I work on my own and haven't worked in collaboration with anyone on a particular project. I'm assuming most people create projects and submit them along with their CVs. My second question is: Everyone has to make a start from somewhere, but what if this somewhere doesn't come? What do I need to do to create the circumstances where I can easily progress forward? Thanks

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  • Have there been attempts to make object containers that search for valid programs by auto wiring compatible components?

    - by Aaron Anodide
    I hope this post isn't too "Fringe" - I'm sure someone will just kill it if it is :) Three things made me want to reach out about this now: Decoupling is so in the forefront of design. TDD inspires the idea that it doesn't matter how a program comes to exist as long as it works. Seeing how often the adapter pattern is applied to achieve (1). I'm almost sure this has been tried from a memory of reading about it around the year 2000 or so. If I had to guess, it was maybe about and earlier version of the Java Spring framework. At this time we were not so far from days when the belief was that computer programs could exhibit useful emergent behavior. I think the article said it didn't work, but it didn't say it was impossible. I wonder if since then it has been deemed impossible or simply an illusion due to a false assumption of similarity between a brain and a CPU. I know this illusion existed because I had an internship in 1996 where I programmed neural nets that were supposedly going to exhibit "brain damage". STILL, after all that, I'm sitting around this morning and not able to shake the idea that it should be possible to have a method of programming to allow autonomous components to find each other, attempt to collaborate and their outputs evaluated against a set desired results.

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  • MVC: How to Implement Linked Views?

    - by cw'
    I'm developing a java application to visualize time series. I need (at least) three linked views, meaning that interaction with one of them updates the others. The views are: A list represents the available and currently selected time series. The selected time series are used as input for subsequent computations. Changing the selection should update the other views. A line chart displays the available and selected time series. Time series should be selectable from here by clicking on them. A bar chart shows aggregated data on time series. When zooming in to a period of time, the line chart should zoom in to the same period (and vice versa). How to implement this nicely, from a software engineering point of view? I.e. I'd like to write reusable and clear, maintainable code. So I thought of the MVC pattern. At first I liked the idea of having the three view components observing my model class and to refresh views upon being notified. But then, it didn't feel right to store view related data in the model. Storing e.g. the time series selection or plot zoom level in the model makes implications about the view which I wouldn't want in a reusable model. On the other hand, having the controllers observe each other results in a lot of dependencies. When adding another view, I'd have to register all other views as observer of the new view and vice versa, passing around many references and introducing dependencies. Maybe another "model" storing only view-related data would be the solution?

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  • Triggering Data Changes in N-Tier

    - by Ryan Kinal
    I've been studying n-tier architectures as of late, particularly in VB.NET with Entity Framework and/or LINQ to SQL. I understand the basic concepts, but have been wondering about best practices in regard to triggering CRUD-type operations from user input/action. So, the arcitecture looks something like the following: [presentation layer] - [business layer] - [data layer] - (database) Getting information from the database into the presentation layer is simple and abstracted. It's just a matter of instantiating a new object from the business layer, which in turn uses the data layer to get at the correct information. However, saving (updating and inserting), and deleting seem to require particular APIs on the relevant business objects. I have to assume this is standard practice, unless a business object will save itself on various operations (which seems inefficient), or on disposal (which seems like it just wouldn't work, or may be unwieldy and unreliable). Should my "savable" business objects all implement a particular "ISavable" or "IDatabaseObject" interface? Is this a recognized (anti-)pattern? Are there other, better patterns I should be using that I'm just unaware of? The TLDR question, I suppose, is How does the presentation layer trigger database changes?

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  • Not able to track traffic on subdomain using Google Analytics

    - by Steven
    I'm trying to track traffic for my sub-domain, but it's not happening. This is how it's set up. My partner has a domain called sub1.partner.com. This domain points to partner1.mydomain.com. The idea is that users think they are browsing my partners website, when they are in fact browsing pages on my server. My tracking code looks like this: var _gaq = _gaq || []; _gaq.push(['_setAccount', 'UA-xxxxxxxx-x']); _gaq.push(['_setDomainName', '.mysite.com']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); In Google analytics I've created a new account under my main account and called in partner1.mysite.com. On this account I have created a filter: Filter type: include Filter field: Host name Filter pattern: partner1.mysite.no Case sensetive: No What more can I try to track traffic on my subdomain? UPDATE Question 1 Is this line correct? _gaq.push(['_setDomainName', '.mysite.com']); Question 2 Is it correct that I have to add \ before any punctuations like so \. in filters?

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  • How to switch off? [closed]

    - by Xophmeister
    While I've programmed software for many years, I've only recently started doing so professionally and have noticed a bit of a problematic pattern. I hope this is the best place to pose such a question, as I am interested in others' experiences and solutions... Writing software is, by its nature, a cerebral exercise. When coding for my own sake, I would do so until I was satisfied; even if that meant going all night. Now I'm coding in exchange for goods and services, on projects that are inherently uninteresting to me, I want to 'switch off' when it's time to go home. Maybe you consider that to be a 'bad attitude', but I just don't feel that whatever I'm working on is worth caring about after-hours. Besides, my employer doesn't exactly have the infrastructure required to make out-of-office changes; I can't just clone a repo and even remote login is a PITA. Anyway, the problem I'm experiencing is that, while I'm not particularly overworked or stressed, if I'm faced with a problem, my brain will work on a solution. Generally, it won't give up. Hence I can't switch off and, sometimes, the problem or the solution is significant enough that it disrupts my sleep. While, paradoxically, this doesn't seem to affect my coding ability, it can have a profound impact of the rest of my life. I get increasingly low as I get tired. So far, the best solutions I've found are writing little notes on the matter (and, say, e-mailing them back to my work address) and exercise. Neither of these can switch me off entirely and, as the week progresses, exercise especially becomes untenable due to tiredness. TL;DR How can you stop from being a coding zombie?

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  • ifconfig can't see USB wireless

    - by Alex
    I have a wifi USB dongle which I have previously used on a Raspberry Pi (this it is what it is target at). I am trying to get it working on an Nvidia Jetson TK1, however I am having some problems. When I run ifconfig I can't see the wifi, only the ethernet and local loopback. iwconfig reports no wireless extensions on all devices. lsusb does find the device: Bus 002 Device 008: ID 148f:5370 Ralink Technology, Corp. RT5370 Wireless Adapter So I am not sure why the network tools can't see it. I have tried logging on with a GUI and opening up the network settings through Unity, but cannot see any wireless devices either. Not sure if this is useful, but output of lsmod: Module Size Used by nvhost_vi 2940 0 How can I enable wireless networking on this computer? Command line approach is preferred, but either is fine. UPDATE I don't have the kernel module rt2800usb anywhere on my system. If I do an apt-file search for rt2800usb it lists a number of packages of the pattern: linux-image-3.13.0-*. Perhaps installing one of these will do the trick, but can anyone tell me if its safe to do so?

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  • Modular Architecture for Processing Pipeline

    - by anjruu
    I am trying to design the architecture of a system that I will be implementing in C++, and I was wondering if people could think of a good approach, or critique the approach that I have designed so far. First of all, the general problem is an image processing pipeline. It contains several stages, and the goal is to design a highly modular solution, so that any of the stages can be easily swapped out and replaced with a piece of custom code (so that the user can have a speed increase if s/he knows that a certain stage is constrained in a certain way in his or her problem). The current thinking is something like this: struct output; /*Contains the output values from the pipeline.*/ class input_routines{ public: virtual foo stage1(...){...} virtual bar stage2(...){...} virtual qux stage3(...){...} ... } output pipeline(input_routines stages); This would allow people to subclass input_routines and override whichever stage they wanted. That said, I've worked in systems like this before, and I find the subclassing and the default stuff tends to get messy, and can be difficult to use, so I'm not giddy about writing one myself. I was also thinking about a more STLish approach, where the different stages (there are 6 or 7) would be defaulted template parameters. Can anyone offer a critique of the pattern above, thoughts on the template approach, or any other architecture that comes to mind?

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

    - by Gianluca78
    I'm developing a web calendar in php (using Symfony2) inspired by iCal for a project of mine. At this moment, I have two classes: a class "Calendar" and a class "CalendarCell". Here you are the two classes properties and method declarations. class Calendar { private $month; private $monthName; private $year; private $calendarCellList = array(); private $translator; public function __construct($month, $year, $translator) {} public function getCalendarCellList() {} public function getMonth() {} public function getMonthName() {} public function getNextMonth() {} public function getNextYear() {} public function getPreviousMonth() {} public function getPreviousYear() {} public function getYear() {} private function calculateDaysPreviousMonth() {} private function calculateNumericDayOfTheFirstDayOfTheWeek() {} private function isCurrentDay(\DateTime $dateTime) {} private function isDifferentMonth(\DateTime $dateTime) {} } class CalendarCell { private $day; private $month; private $dayNameAbbreviation; private $numericDayOfTheWeek; private $isCurrentDay; private $isDifferentMonth; private $translator; public function __construct(array $parameters) {} public function getDay() {} public function getMonth() {} public function getDayNameAbbreviation() {} public function isCurrentDay() {} public function isDifferentMonth() {} } Each calendar day can includes many calendar events (such as appointments or schedules) stored in a database. My question is: which is the best way to manage these calendar events in my classes? I think to add a eventList property in CalendarCell and populate it with an array of CalendarEvent objects fetched by the database. This kind of solution doesn't allow other coders to reuse the classes without db (because I should inject at least a repository services also) just to create and visualize a calendar... so maybe it could be better to extend CalendarCell (for instance in CalendarCellEvent) and add the database features? I feel like I'm missing some crucial design pattern! Any suggestion will be very appreciated!

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  • Suggestion for setting web application parameters

    - by user40730
    I'm creating a web application on GWT. I'm using MVP pattern with activities and places. I have a xml config file containing some parameters to be used by the application. Content of this xml file is sent to the client using HttpRequest; I'm using a singleton class to hold the information from the xml file. Right now, the application is getting the data when the user starts the application in the home page, that is working well. Now, since I'm using activities and places, a user can bookmark a page and starts the application in any other page (Place). And here comes the problem: Since I'm using some of the information from the xml file to set some ui widgets, I have to check if the xml config file was read and the application already has the parameters (I do this by checking the singleton class). But the xml file is read by using an HttpRequest, so I got errors 'cause the application needs some parameters to initialize some ui widgets, but these parameters aren't ready on time. I was thinking on using an synchronous request to fix the problem, but it seems complicated and not recommendable to do that. So, I'd like to hear some other suggestions. Thanks.

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  • Is there a common programming term for the problems of adding features to an already-featureful program?

    - by Jeremy Friesner
    I'm looking for a commonly used programming term to describe a software-engineering phenomenon, which (for lack of a better way to describe it) I'll illustrate first with a couple of examples-by-analogy: Scenario 1: We want to build/extend a subway system on the outskirts of a small town in Wyoming. There are the usual subway-problems to solve, of course (hiring the right construction company, choosing the best route, buying the subway cars), but other than that it's pretty straightforward to implement the system because there aren't a huge number of constraints to satisfy. Scenario 2: Same as above, except now we need to build/extend the subway system in downtown Los Angeles. Here we face all of the problems we did in case (1), but also additional problems -- most of the applicable space is already in use, and has a vocal constituency which will protest loudly if we inconvenience them by repurposing, redesigning, or otherwise modifying the infrastructure that they rely on. Because of this, extensions to the system happen either very slowly and expensively, or they don't happen at all. I sometimes see a similar pattern with software development -- adding a new feature to a small/simple program is straightforward, but as the program grows, adding further new features becomes more and more difficult, if only because it is difficult to integrate the new feature without adversely affecting any of the large number of existing use-cases or user-constituencies. (even with a robust, adaptable program design, you run into the problem of the user interface becoming so elaborate that the program becomes difficult to learn or use) Is there a term for this phenomenon?

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  • Resource Acquisition is Initialization in C#

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

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  • Should I care about Junit redundancy when using setUp() with @Before annotation?

    - by c_maker
    Even though developers have switched from junit 3.x to 4.x I still see the following 99% of the time: @Before public void setUp(){/*some setup code*/} @After public void tearDown(){/*some clean up code*/} Just to clarify my point... in Junit 4.x, when the runners are set up correctly, the framework will pick up the @Before and @After annotations no matter the method name. So why do developers keep using the same conventional junit 3.x names? Is there any harm keeping the old names while also using the annotations (other than it makes me feel like devs do not know how this really works and just in case, use the same name AND annotate as well)? Is there any harm in changing the names to something maybe more meaningful, like eachTestMethod() (which looks great with @Before since it reads 'before each test method') or initializeEachTestMethod()? What do you do and why? I know this is a tiny thing (and may probably be even unimportant to some), but it is always in the back of my mind when I write a test and see this. I want to either follow this pattern or not but I want to know why I am doing it and not just because 99% of my fellow developers do it as well.

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  • Random touchpad and keyboard freezes on new 10.10 installation

    - by ancaleth
    My touchpad and keyboard freeze up on my newly installed Ubuntu 10.10. I was using Ubuntu 10.4 via wubi before on this Laptop where this problem never occurred. (I did not migrate wubi or upgrade to 10.10, it's a fresh start. 64-bit on Dell Studio, plenty of RAM, plenty of free space on partition etc.) I can't say there is a pattern yet, once it happened during the download of packages with the Update Manager, once it was just using Firefox, no other program running. I was forced to shut down manually. In between these crashes the laptop was booted once, updates were installed etc., firefox was used and there weren't any problems. Both crashes should be in the attached kern.log and I noticed there were some error problems before the last crash (at the end, obviously). It seems the wireless was experiencing problems. This wasn't noticed on the user end, since the touchpad + keyboard were already frozen. kern.log: http://paste.ubuntu.com/552617/ How can the freezes be fixed?

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  • design an extendible and pluggable business logic flow handler in php

    - by Broncha
    I am working on a project where I need to allow a pluggable way to inject business processes in the normal data flow. eg There is an ordering system. The standard flow of the application is A consumer orders an item. Pays for it and card is authorized. Admin captures the payment. Order is marked as complete and item is shipped. But this process may vary (extra steps in between) for different clients. Say a client would need to validate the location of the consumer before he is presented with a credit card form, OR his policies might require some other processes in between. I am thinking of using State Pattern for processing orders, saving the current state of the order in database, and initializing the state of order from the saved state. I would also need some mechanism, where a small plugin would be able to inject business specific states in the state machine. Am I thinking the right way? Are there already implemented patterns for this kind of situation? I am working with Codeigniter and basically this would mean for me, to redirect to proper controller according to the current state of the order. Like, if the state of the order is unconfirmed then redirect the user to details page and then change the state to pending. If some client would need to do some validation, then register an intermediate state between unconfirmed and pending Please suggest.

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  • WordPress mod_rewrite redirect specific folders

    - by Ps Cjef
    As a new user, I'm not allowed to post more than two hyperlinks here. So I have added a space after every http (ignore them and read as full URLs). System: Debian Etch, Apache 2.2 I have a WordPress instance with multiple blogs. I would like to redirect some of the folders based on the year and month, while leaving other folders go to the actual locations. Example: I have archives for a few years, like 2010, 2011 and 2012: http ://mydomain.com/wordpress/myblog/2010/02 http ://mydomain.com/wordpress/myblog/2011/01 http ://mydomain.com/wordpress/myblog/2012/01 I would like to redirect all 2010 and 2011 posts to another blog with the same folder structure: http ://mydomain.com/wordpress/myotherblog/2010/02 http ://mydomain.com/wordpress/myotherblog/2011/01 and so on. I would like to have 2012 and beyond to go to the actual site (http ://mydomain.com/wordpress/myblog/2012/01). I tried mod_rewrite with the following, one rule at a time to test redirection for just one year (and to expand later for other years), and none of them worked! * RewriteEngine is already on since there are some default WordPress rewrites. * RewriteBase is set to http://mydomain.com/wordpress/ . * I put my rule before all the other default WordPress rules are processed. Didn't work solution #1 RedirectMatch 301 /myblog/2010/(.*) /myotherblog/2010/$1 Didn't work solution #2 RewriteRule /myblog/2010/(.*) http ://mydomain.com/myotherblog/2010/$1 [R=301] Didn't work solution #3 RedirectPermanent /myblog/2010/(.*) http ://mydomain.com/myotherblog/2010/$1 I've also tried the above rules with and without a fully qualified URL for the new location. The rewrite log, with log level set to 9, did not provide any useful information. It shows that it looks at the pattern specified against the URL (as mentioned in the rule), but finally what happens is a passthrough to http ://mydomain.com/myblog/ for all URLs or a 500 Internal Server Error. Any ideas on where I could be going wrong or any alternative solutions?

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

    - by Gianluca78
    I'm developing a web calendar in php (using Symfony2) inspired by iCal for a project of mine. At this moment, I have two classes: a class "Calendar" and a class "CalendarCell". Here you are the two classes properties and method declarations. class Calendar { private $month; private $monthName; private $year; private $calendarCellList = array(); private $translator; public function __construct($month, $year, $translator) {} public function getCalendarCells() {} public function getMonth() {} public function getMonthName() {} public function getNextMonth() {} public function getNextYear() {} public function getPreviousMonth() {} public function getPreviousYear() {} public function getYear() {} private function calculateDaysPreviousMonth() {} private function calculateNumericDayOfTheFirstDayOfTheWeek() {} private function isCurrentDay(\DateTime $dateTime) {} private function isDifferentMonth(\DateTime $dateTime) {} } class CalendarCell { private $day; private $month; private $dayNameAbbreviation; private $numericDayOfTheWeek; private $isCurrentDay; private $isDifferentMonth; private $translator; public function __construct(array $parameters) {} public function getDay() {} public function getMonth() {} public function getDayNameAbbreviation() {} public function isCurrentDay() {} public function isDifferentMonth() {} } Each calendar day can includes many events stored in a database. My question is: which is the best way to manage these events in my classes? I think to add a eventList property in CalendarCell and populate it with an array of CalendarEvent objects fetched by the database. This kind of solution doesn't allow other coders to reuse the classes without db (because I should inject at least a repository services also) just to create and visualize a calendar... so maybe it could be better to extend CalendarCell (for instance in CalendarCellEvent) and add the database features? I feel like I'm missing some crucial design pattern! Any suggestion will be very appreciated!

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  • Making a class pseudo-immutable by setting a flag

    - by scott_fakename
    I have a java project that involves building some pretty complex objects. There are quite a lot (dozens) of different ones and some of them have a HUGE number of parameters. They also need to be immutable. So I was thinking the builder pattern would work, but it ends up require a lot of boilerplate. Another potential solution I thought of was to make a mutable class, but give it a "frozen" flag, a-la ruby. Here is a simple example: public class EqualRule extends Rule { private boolean frozen; private int target; public EqualRule() { frozen = false; } public void setTarget(int i) { if (frozen) throw new IllegalStateException( "Can't change frozen rule."); target = i; } public int getTarget() { return target; } public void freeze() { frozen = true; } @Override public boolean checkRule(int i) { return (target == i); } } and "Rule" is just an abstract class that has an abstract "checkRule" method. This cuts way down on the number of objects I need to write, while also giving me an object that becomes immutable for all intents and purposes. This kind of act like the object was its own Builder... But not quite. I'm not too excited, however, about having an immutable being disguised as a bean however. So I had two questions: 1. Before I go too far down this path, are there any huge problems that anyone sees right off the bat? For what it's worth, it is planned that this behavior will be well documented... 2. If so, is there a better solution? Thanks

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