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  • Java - How to make a set of JInternalFrame independant of each other?

    - by Amokrane
    Hello, I'm programming a short Paint program like and I'm trying to make an MDI architecture for it. To make that happen, I used JInternalFrame inside a JDesktopPane. Although I kind of obtain multiple frames, there are not really working properly. Basically, if I have 2 JInternalFrame I can draw only on the last one. The other one seems to be disabled. Here is a short video illustrating the problem. http://bit.ly/9ydiwM Here are some part of the code. Panneau.java public class Panneau extends JDesktopPane { /** La liste de fenêtres ouvertes */ private static ArrayList<Cadre> cadres; /** Le pannel comportant la liste des formes à dessiner*/ private Pannel pannel; /** La barre d'outils */ private ToolBox toolBox; public Panneau() { this.setLayout(new BorderLayout()); // Initialisations des listes de cadres cadres = new ArrayList<Cadre>(); // En haut ToolBox toolBox = new ToolBox(); this.add(toolBox, BorderLayout.NORTH); **// Intialisation de la première internal frame Cadre cadre = new Cadre(); this.add(cadre, BorderLayout.CENTER);** cadres.add(cadre); // Ajout du pannel à gauche pannel = new Pannel(); this.add(pannel, BorderLayout.WEST); } /** * Crée une nouvelle fenêtre de dessin * */ **public void createNewInternalFrame() { Cadre cadre = new Cadre(); this.add(cadre, BorderLayout.CENTER); cadres.add(cadre); }** } public class Cadre extends JInternalFrame { /** Largeur par d'une fenêtre interne */ private int width; /** Hauteur d'une fenêtre interne */ private int height; /** Titre d'une fenêtre interne */ private String title; /** Toile associée à la fenêtre interne */ private Toile toile; public Cadre() { width = 400; height = 400; title = "Form"; toile = new Toile(); this.setTitle(title); this.setSize(width, height); this.setEnabled(true); this.setResizable(true); this.setAutoscrolls(true); this.setClosable(true); this.setIconifiable(true); this.setDoubleBuffered(true); this.setContentPane(toile); this.setVisible(true); this.pack(); } } Basically, Panneau is the main Window that contains all the differents parts of the GUI. I can create as much JInternalFrame that I want, using : Panneau.createNewInternalFrame(). Toile is basically where I draw my shapes. Any idea ? Thanks

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  • Is it normal for a programmer with 2 years experience to take a long time to code simple programs?

    - by ajax81
    Hi all, I'm a relatively new programmer (18 months on the scene), and I'm finally getting to the point where I'm comfortable accepting projects and developing solutions under minimal supervision. Unfortunately, this also means that I've become acutely aware of my performance shortfalls, the most prevalent of which is the amount of time it takes me to develop, test, and submit algorithms for review. A great example of what I'm talking about occurred this week when I was tasked with developing a simple XML web service (asp.net 3.5) callable via client-side JavaScript, that accepts a single parameter and returns a dataset output to a modal window (please note this is the first time I've had to develop a web service and have had ZERO experience creating/consuming them...let alone calling them from JS client side). Keeping a long story short -- I worked on it for 4 days straight, all day each day, for a grand total of 36 hours, not including the time I spent dwelling on the problem in the shower, the morning commute, and laying awake in bed at night. I learned a great deal about web services and xml/json/javascript...but was called in for a management review to discuss the length of time it took me to develop the solution. In the meeting, I was praised for the quality of my work and was in fact told that my effort was commendable. However, they (senior leads and pm's) weren't impressed with the amount of time it took me to develop the solution and expressed that they would have liked to see the solution in roughly 1/3 of the time it took me. I guess what concerns me the most is that I've identified this pattern as common for myself. Between online videos, book research, and trial/error coding...if its something I haven't seen before, I can spend up to two weeks on a problem that seems to only take the pros in the videos moments to code up. And of course, knowing that management isn't happy with this pattern has shaken me up a bit. To sum up, I have some very specific questions I'd like to ask, and would greatly appreciate your objective professional feedback. Is my experience as a junior programmer common among new developers? Or is it possible that I'm just not cut out for the work? If you suspect that my experience is not common and that there may be an aptitude issue, do you have any suggestions/solutions that I could propose to management to help bring me up to speed? Do seasoned, professional programmers ever encounter knowledge barriers that considerably delay deliverables? When you started out in the industry, did you know how to "do it all"? If not, how long did it take you to be perceived as "proficient"? Was it a natural progression of trial and error, or was there a particular zen moment when you knew you had achieved super saiyen power level? Anyways, thanks for taking the time to read my question(s). I don't know if this is the right place to ask for professional career guidance, but I greatly appreciate your willingness to help me out. Cheers, Daniel

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  • Am I using EJBs properly?

    - by kgrad
    I am using a JEE6 stack including JPA 2.0, JSF 2.0, EJB 3.1 etc. The way my architecture is setup is the following: I have JPA annotated DAOs using hibernate as my JPA provider. I have JSF Managed beans which correspond to my facelet/xhtml pages. I have EJBs that handle all of my database requests. My XHTML pages have JSF EL which make calls to my Managed beans. My managed beans contain references to my DAO entities which are managed by EJBs. For example, I have a user entity which is mapped to a db table. I have a user EJB which handles all CRUD operations that return Users. I have a page that edits a user. The highlevel workflow would be: navigate to user edit page - EL calls a method located in the managed bean that loads a user. The method calls userEJB.loadUser(user) from the EJB to get the user from the database. The user is edited and submit - a function is called in the managed bean which calls a function in the EJB to save the user. etc. I am running into issues accessing my data within my JSF pages using EJBs. I am having a lot of problems with lazy initialization errors, which I believe is due to how I have set things up. For example, I have a Client entity that has a List of users which are lazily loaded. In order to get a client I call a method in my EJB which goes to the database, finds a client and returns it. Later on i wish to access this clients list of users, in order to do so i have to go back to the EJB by calling some sort of method in order to load those users (since they are lazily loaded). This means that I have to create a method such as public List<User> getUserListByClient(Client c) { c = em.merge(c); return c.getUserList(); } The only purpose of this method is to load the users (and I'm not even positive this approach is good or works). If i was doing session management myself, I would like just leave the session open for the entire request and access the property directly, this would be fine as the session would be open anyway, there seems to be this one extra layer of indirection in EJBs which is making things difficult for me. I do like EJBs as I like the fact that they are controlled by the container, pooled, offer transaction management for free etc. However, I get the feeling that I am using them incorrectly, or I have set up my JSF app incorrectly. Any feedback would be greatly appreciated. thanks,

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  • Drupal Override Custom Menu Template

    - by JaZz
    Hi Guys, I created a custom menu called "sub-top-nav" and now I'd like to override the html output. In particular I would like to add an unique class to each item like. This is how it looks atm: <div class="clear-block block block-menu" id="block-menu-menu-sub-top-nav"> <div class="content"> <ul class="menu"> <li class="leaf first"><a title="Test 1" href="/test1">Test 1</a></li> <li class="leaf"><a title="Test 2" href="/test2">Test 2</a></li> <li class="leaf active-trail"><a class="active" title="Test 3" href="/test3">Test 3</a></li> <li class="leaf last"><a title="Test 4" href="/test4">Test 4</a></li> </ul> </div> </div> And I'd like to change it into: <div class="clear-block block block-menu" id="block-menu-menu-sub-top-nav"> <div class="content"> <ul class="menu"> <li class="leaf test1 first"><a title="Test 1" href="/test1">Test 1</a></li> <li class="leaf test2"><a title="Test 2" href="/test2">Test 2</a></li> <li class="leaf test3 active-trail"><a class="active" title="Test 3" href="/test3">Test 3</a></li> <li class="leaf test4 last"><a title="Test 4" href="/test4">Test 4</a></li> </ul> </div> </div> This would give me more styling power. Any idea how that works? Thanks in advance!

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  • Should I use Python or Assembly for a super fast copy program

    - by PyNEwbie
    As a maintenance issue I need to routinely (3-5 times per year) copy a repository that is now has over 20 million files and exceeds 1.5 terabytes in total disk space. I am currently using RICHCOPY, but have tried others. RICHCOPY seems the fastest but I do not believe I am getting close to the limits of the capabilities of my XP machine. I am toying around with using what I have read in The Art of Assembly Language to write a program to copy my files. My other thought is to start learning how to multi-thread in Python to do the copies. I am toying around with the idea of doing this in Assembly because it seems interesting, but while my time is not incredibly precious it is precious enough that I am trying to get a sense of whether or not I will see significant enough gains in copy speed. I am assuming that I would but I only started really learning to program 18 months and it is still more or less a hobby. Thus I may be missing some fundamental concept of what happens with interpreted languages. Any observations or experiences would be appreciated. Note, I am not looking for any code. I have already written a basic copy program in Python 2.6 that is no slower than RICHCOPY. I am looking for some observations on which will give me more speed. Right now it takes me over 50 hours to make a copy from a disk to a Drobo and then back from the Drobo to a disk. I have a LogicCube for when I am simply duplicating a disk but sometimes I need to go from a disk to Drobo or the reverse. I am thinking that given that I can sector copy a 3/4 full 2 terabyte drive using the LogicCube in under seven hours I should be able to get close to that using Assembly, but I don't know enough to know if this is valid. (Yes, sometimes ignorance is bliss) The reason I need to speed it up is I have had two or three cycles where something has happened during copy (fifty hours is a long time to expect the world to hold still) that has caused me to have to trash the copy and start over. For example, last week the water main broke under our building and shorted out the power.

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  • MySQL table organization and optimization (Rails)

    - by aguynamedloren
    I've been learning Ruby on Rails over the past few months with no prior programming experience. Lately, I've been thinking about database optimization and table organization. I know there are great books on the subject, but I typically learn by example / as I go. Here's a hypothetical situation: Let's say I am building a social network for a niche community with 250,000 members (users). The users have the ability to attend events. Let's say there are 50,000 past/present/future events. Much like Facebook events, a user can attend any number of events and an event can have any number of attendees. In the database, there would be a table for users and a table for events. Somehow I would have to create an association between the users and events. I could create an "events" column in the users table such that each user row would contain a hash of event IDs, or I could create an "attendees" column in the events table such that each event row would contain a hash of user IDs. Neither of these solutions seem ideal, however. On a users profile page, I want to display the list of events they are associated with, which would require scanning the 50,000 event rows for the user ID of said user if I include an "attendees" column in the events table. Likewise, on an event page, I want to display a list of attendees for the event, which would require scanning the 250,000 user rows for the event ID of said event if I include an "events" column in the users table. Option 3 would be to create a third table that contains the attendee information for each and every event - but I don't see how this would solve any problems. Are these non-issues? Rails makes accessing all of this information easy, but I guess I'm worried about scale. It is entirely possible that I am under-estimating the speed and processing power of modern databases / servers / etc. How long would it take to scan 250,000 user rows for specific event IDs - 10ms? 100ms? 1,000ms? I guess that's not that bad. Am I just over-thinking this?

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  • QT vs. Net - REAL comparisons for R.A.D. projects

    - by Pirate for Profit
    Man in all these Qt vs. .NET discussions 90% these people argue about the dumbest crap. Trying to get a real comparison chart here, because I know a little about both frameworks but I don't know everything. I believe Qt and .NET both have strengths and weaknesses. This is to make a comparison that highlights these so people can make more informed decisions before embarking on a project, in the spirit of R.A.D. Event Handling In Qt the event handling system is very simple. You just emit signals when something cool happens and then catch them in slots. ie. // run some calculations, then emit valueChanged(30, false, 20.2); and then catching it, any object can make a slot to recieve that message easily void MyObj::valueChanged(int percent, bool ok, float timeRemaining). It's easy to "block" an event or "disconnect" when needed, and works seamlessly across threads... once you get the hang of it, it just seems a lot more natural and intuitive than the way the .NET event handling is set up (you know, void valueChanged(object sender, CustomEventArgs e). And I'm not just talking about syntax, because in the end the .NET anonymous delegates are the bomb. I'm also talking about in more than just reflection (because, yes, .NET obviously has much stronger reflection capabilities). I'm talking about in the way the system feels to a human being. Qt wins hands down for the simplest yet still flexible event handling system ever i m o. Plugins and such I do love some of the ease of C# compared to C++, as well as .NET's assembly architecture, even though it leads to a bunch of .dll's (there's ways to combine everything into a single exe though). That is a big bonus for modular projects, which are a PITA to import stuff in C++ as far as RAD is concerned. Database Ease of Doing Crap Also what about datasets and database manipulations. I think .net wins here but I'm not sure. Threading/Conccurency How do you guys think of the threading? In .NET, all I've ever done is make like a list of master worker threads with locks. I like QConcurrentFramework, you don't worry about locks or anything, and with the ease of the signal slot system across threads it's nice to get notified about the progress of things. QConcurrent is the simplest threading mechanism I've ever played with. Memory Usage Also what do you think of the overall memory usage comparison. Is the .NET garbage collector pretty on the ball and quick compared to the instantaneous nature of native memory management? Or does it just let programs leak up a storm and lag the computer then clean it up when it's about to really lag? Doesn't the just-in-time compiler make native code that is pretty good, like and that only happens the first time the program is run? However, I am a n00b who doesn't know what I'm talking about, please school me on the subject.

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  • Microsoft Access and Java JDBC-ODBC Error

    - by user1638362
    Trying to insert some values in a Microsoft access database using java. I can an error however, java.sql.SQLException: [Microsoft][ODBC Driver Manager] The specified DSN contains an architecture mismatch between the Driver and Application Exception in thread "main" java.lang.NullPointerException To create the data source im using SysWoW64 odbcad32 and adding it the datasource to system DNS. I say this as i have seen else where there are problems which occur with 64bit systems. However it still doesn't work for me. Microsoft Office 32bit. import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.Statement; public class RMIAuctionHouseJDBC { /** * @param args */ public static void main(String[] args) { String theItem = "Car"; String theClient="KHAN"; String theMessage="1001"; Connection conn =null; // Create connection object try{ Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); System.out.println("Driver Found"); } catch(Exception e) { System.out.println("Driver Not Found"); System.err.println(e); } // connecting to database try{ String database ="jdbc:odbc:Driver={Microsoft Access Driver (*.accdb)};DBQ=AuctionHouseDatabase.accdb;"; conn = DriverManager.getConnection(database,"",""); System.out.println("Conn Found"); } catch(SQLException se) { System.out.println("Conn Not Found"); System.err.println(se); } // Create select statement and execute it try{ /*String insertSQL = "INSERT INTO AuctionHouse VALUES ( " +"'" +theItem+"', " +"'" +theClient+"', " +"'" +theMessage+"')"; */ Statement stmt = conn.createStatement(); String insertSQL = "Insert into AuctionHouse VALUES ('Item','Name','Price')"; stmt.executeUpdate(insertSQL); // Retrieve the results conn.close(); } catch(SQLException se) { System.out.println("SqlStatment Not Found"); System.err.println(se); } } } java.sql.SQLException: [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified at sun.jdbc.odbc.JdbcOdbc.createSQLException(Unknown Source) at sun.jdbc.odbc.JdbcOdbc.standardError(Unknown Source) at sun.jdbc.odbc.JdbcOdbc.SQLDriverConnect(Unknown Source) at sun.jdbc.odbc.JdbcOdbcConnection.initialize(Unknown Source)

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  • Agilent E4426B signal generator locks up during multiple GPIB *SAV operations

    - by aspiehler
    I have a test fixture with an Agilent E4426B RF signal generator connected to a PC via a National Instrument Ethernet-to-GPIB bridge. My software is attempting to sanitize the instrument by presetting it and then saving the current state to all of the memory locations writable via the standard SCPI command "*SAV x,y". The loop works to a point, but eventually the instrument responds with an error and continuously displays the "L" icon on the front display and a "Remote preset" message at the bottom. At that point it won't respond to any more remote commands and I have to either cycle power or press LOCAL, then PRESET at which point it takes about 3 minutes to finish presetting. At that point the "L" icon is still present and and the next GPIB command sent to the instrument causes it to report a -113 error (undefined header) in the instrument error queue. I fired up NI spy to see what was happening, and found that the error was happening at the same point in the loop - "*SAV 6,2" in this case. From NI Spy: Send (0, 0x0017, "*SAV 6,2", 8 (0x8), NLend (0,0x01)) Process ID: 0x00000520 Thread ID: 0x00000518 ibsta:0xc168 iberr: 6 ibcntl: 2(0x2) And here's the code from the instrument driver: int CHP_E4426b::Erase() { if ((m_StatusCode = Initialize()) != GPIB_SUCCESS) // basically just sends "*RST" return m_StatusCode; m_SaveState = "*SAV %d, %d"; for (int i=0; i < 10; i++) for (int j=0; j < 100; j++) { sprintf(m_CmdString, m_SaveState, j, i); if ((m_StatusCode = Send(m_CmdString, strlen(m_CmdString))) != GPIB_SUCCESS) return m_StatusCode; } return GPIB_SUCCESS; } I tried putting a small Sleep() delay (10-20 ms) at the end of the inner loop, and to my surprise it caused the error to show up earlier rather than later. 10 ms caused the loop to error out at 44,1 and 20 ms was even sooner. I've already eliminated faulty cabling or the instrument as the culprit. This same type of sequence works without any error on a higher end signal generator, so I'm tempted to chalk this up to a bug in the instrument's firmware.

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  • FACING ERROR WHILE CALLING AXIS2 WEB SERVICE ...

    - by darshanv
    Hello , I am new to axis ,I have created a web servcie with couple of methods using axis2 and deployed it on tomcat.And am calling that web service from my android program with the help of ksoap.But wen i call a method which doesn't take any parameter am gettin fine reply from web service which i can able to see on my screen,But wen i call anothr method which takes a string argument am getting namespace exception on server WEB SERVICE CODE IS ..... package Guru; public class DarshanSays { public String getMsg(String h) { return h+" ..the power of change is eVolution..."; } public String getEmpty(String d)throws Exception { return "empty string from tomcattttttttttt"; } } //AND program is String soap_action="http://Guru/getEmpty"; String method_nm="getEmpty"; String nmspc="http://Guru/"; String url7="//192.168.10.182:8080/axis2/services/Friday";//http: SoapObject request = new SoapObject(url7,method_nm); /*sending method parameters with SoapObject */ request.newInstance(); request.addProperty("h","darshan.....");//sending a parameter to a method SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11); envelope.bodyOut=request; envelope.dotNet = true; envelope.encodingStyle = SoapSerializationEnvelope.XSD; Log.d("Step","3"); envelope.dotNet=true; /*setting outputsoap object sending request */ envelope.setOutputSoapObject(request); /*HttpTransportSE object creating sending it url */ androidHttpTransport = new HttpTransportSE(url7); //androidHttpTransport.setXmlVersionTag(""); Log.d("Step","4"); try{ androidHttpTransport.debug=true; androidHttpTransport.call(nmspc,envelope); } catch(Exception e) { Log.d("Transportcall",""+e); alert=new AlertDialog.Builder(this); alert.setMessage(""+e); alert.show(); } //exception is throw. Log.d("Step","5"); try { Log.d("giving...","resp"); SoapPrimitive sp=(SoapPrimitive)envelope.getResponse(); String hh=sp.toString(); Log.d("reply from web ser",".."+hh.toString()); //and erorr msg is SoapFault - faultcode:'soapenv:Server' faultstring: 'namespace mismatch require http://Guru found 192.168.10.182:8080/axis2/services/Friday' faultactor: 'null' detail: org.kxml2.kdom.Node@43d31390 ERROR IS coming only when am calling parameterized method. I am facing this issue only when am giving a call to parameterized method. Please Help.. thanks Darshan V

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  • Why do I get rows of zeros in my 2D fft?

    - by Nicholas Pringle
    I am trying to replicate the results from a paper. "Two-dimensional Fourier Transform (2D-FT) in space and time along sections of constant latitude (east-west) and longitude (north-south) were used to characterize the spectrum of the simulated flux variability south of 40degS." - Lenton et al(2006) The figures published show "the log of the variance of the 2D-FT". I have tried to create an array consisting of the seasonal cycle of similar data as well as the noise. I have defined the noise as the original array minus the signal array. Here is the code that I used to plot the 2D-FT of the signal array averaged in latitude: import numpy as np from numpy import ma from matplotlib import pyplot as plt from Scientific.IO.NetCDF import NetCDFFile ### input directory indir = '/home/nicholas/data/' ### get the flux data which is in ### [time(5day ave for 10 years),latitude,longitude] nc = NetCDFFile(indir + 'CFLX_2000_2009.nc','r') cflux_southern_ocean = nc.variables['Cflx'][:,10:50,:] cflux_southern_ocean = ma.masked_values(cflux_southern_ocean,1e+20) # mask land nc.close() cflux = cflux_southern_ocean*1e08 # change units of data from mmol/m^2/s ### create an array that consists of the seasonal signal fro each pixel year_stack = np.split(cflux, 10, axis=0) year_stack = np.array(year_stack) signal_array = np.tile(np.mean(year_stack, axis=0), (10, 1, 1)) signal_array = ma.masked_where(signal_array > 1e20, signal_array) # need to mask ### average the array over latitude(or longitude) signal_time_lon = ma.mean(signal_array, axis=1) ### do a 2D Fourier Transform of the time/space image ft = np.fft.fft2(signal_time_lon) mgft = np.abs(ft) ps = mgft**2 log_ps = np.log(mgft) log_mgft= np.log(mgft) Every second row of the ft consists completely of zeros. Why is this? Would it be acceptable to add a randomly small number to the signal to avoid this. signal_time_lon = signal_time_lon + np.random.randint(0,9,size=(730, 182))*1e-05 EDIT: Adding images and clarify meaning The output of rfft2 still appears to be a complex array. Using fftshift shifts the edges of the image to the centre; I still have a power spectrum regardless. I expect that the reason that I get rows of zeros is that I have re-created the timeseries for each pixel. The ft[0, 0] pixel contains the mean of the signal. So the ft[1, 0] corresponds to a sinusoid with one cycle over the entire signal in the rows of the starting image. Here are is the starting image using following code: plt.pcolormesh(signal_time_lon); plt.colorbar(); plt.axis('tight') Here is result using following code: ft = np.fft.rfft2(signal_time_lon) mgft = np.abs(ft) ps = mgft**2 log_ps = np.log1p(mgft) plt.pcolormesh(log_ps); plt.colorbar(); plt.axis('tight') It may not be clear in the image but it is only every second row that contains completely zeros. Every tenth pixel (log_ps[10, 0]) is a high value. The other pixels (log_ps[2, 0], log_ps[4, 0] etc) have very low values.

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  • Is it too early to start designing for Task Parallel Library?

    - by Joe Erickson
    I have been following the development of the .NET Task Parallel Library (TPL) with great interest since Microsoft first announced it. There is no doubt in my mind that we will eventually take advantage of TPL. What I am questioning is whether it makes sense to start taking advantage of TPL when Visual Studio 2010 and .NET 4.0 are released, or whether it makes sense to wait a while longer. Why Start Now? The .NET 4.0 Task Parallel Library appears to be well designed and some relatively simple tests demonstrate that it works well on today's multi-core CPUs. I have been very interested in the potential advantages of using multiple lightweight threads to speed up our software since buying my first quad processor Dell Poweredge 6400 about seven years ago. Experiments at that time indicated that it was not worth the effort, which I attributed largely to the overhead of moving data between each CPU's cache (there was no shared cache back then) and RAM. Competitive advantage - some of our customers can never get enough performance and there is no doubt that we can build a faster product using TPL today. It sounds fun. Yes, I realize that some developers would rather poke themselves in the eye with a sharp stick, but we really enjoy maximizing performance. Why Wait? Are today's Intel Nehalem CPUs representative of where we are going as multi-core support matures? You can purchase a Nehalem CPU with 4 cores which share a single level 3 cache today, and most likely a 6 core CPU sharing a single level 3 cache by the time Visual Studio 2010 / .NET 4.0 are released. Obviously, the number of cores will go up over time, but what about the architecture? As the number of cores goes up, will they still share a cache? One issue with Nehalem is the fact that, even though there is a very fast interconnect between the cores, they have non-uniform memory access (NUMA) which can lead to lower performance and less predictable results. Will future multi-core architectures be able to do away with NUMA? Similarly, will the .NET Task Parallel Library change as it matures, requiring modifications to code to fully take advantage of it? Limitations Our core engine is 100% C# and has to run without full trust, so we are limited to using .NET APIs.

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  • Qt vs .NET - a few comparisons [closed]

    - by Pirate for Profit
    Event Handling In Qt the event handling system you just emit signals when something cool happens and then catch them in slots, for instance emit valueChanged(int percent, bool something); and void MyCatcherObj::valueChanged(int p, bool ok){} blocking them and disconnecting them when needed, doing it across threads... once you get the hang of it, it just seems a lot more natural and intuitive than the way the .NET event handling is set up (you know, object sender, CustomEventArgs e). And I'm not just talking about syntax, because in the end the .NET delegate crap is the bomb. I'm also talking about in more than just reflection (because, yes, .NET obviously has much stronger reflection capabilities). I'm talking about in the way the system feels to a human being. Qt wins hands down i m o. Basically, the footprints make more sense and you can visualize the project easier without the clunky event handling system. I wish I could it explain it better. The only thing is, I do love some of the ease of C# compared to C++ and .NET's assembly architecture. That is a big bonus for modular projects, which are a PITA to do in C++. Database Ease of Doing Crap Also what about datasets and database manipulations. I think .net wins here but I'm not sure. Threading/Conccurency How do you guys think of the threading? In .NET, all I've ever done is make like a list of master worker threads with locks. I like QConcurrentFramework, you don't worry about locks or anything, and with the ease of the signal slot system across threads it's nice to get notified about the progress of things. Memory Usage Also what do you think of the overall memory usage comparison. Is the .NET garbage collector pretty on the ball and quick compared to the instantaneous nature of native memory management? Or does it just let programs leak up a storm and lag the computer then clean it up when it's about to really lag? However, I am a n00b who doesn't know what I'm talking about, please school me on the subject.

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  • How can I limit the cache used by copying so there is still memory available for other cache?

    - by Peter
    Basic situation: I am copying some NTFS disks in openSuSE. Each one is 2TB. When I do this, the system runs slow. My guesses: I believe it is likely due to caching. Linux decides to discard useful cache (eg. kde4 bloat, virtual machine disks, LibreOffice binaries, Thunderbird binaries, etc.) and instead fill all available memory (24 GB total) with stuff from the copying disks, which will be read only once, then written and never used again. So then any time I use these apps (or kde4), the disk needs to be read again, and reading the bloat off the disk again makes things freeze/hiccup. Due to the cache being gone and the fact that these bloated applications need lots of cache, this makes the system horribly slow. Since it is USB,the disk and disk controller are not the bottleneck, so using ionice does not make it faster. I believe it is the cache rather than just the motherboard going too slow, because if I stop everything copying, it still runs choppy for a while until it recaches everything. And if I restart the copying, it takes a minute before it is choppy again. But also, I can limit it to around 40 MB/s, and it runs faster again (not because it has the right things cached, but because the motherboard busses have lots of extra bandwidth for the system disks). I can fully accept a performance loss from my motherboard's IO capability being completely consumed (which is 100% used, meaning 0% wasted power which makes me happy), but I can't accept that this caching mechanism performs so terribly in this specific use case. # free total used free shared buffers cached Mem: 24731556 24531876 199680 0 8834056 12998916 -/+ buffers/cache: 2698904 22032652 Swap: 4194300 24764 4169536 I also tried the same thing on Ubuntu, which causes a total system hang instead. ;) And to clarify, I am not asking how to leave memory free for the "system", but for "cache". I know that cache memory is automatically given back to the system when needed, but my problem is that it is not reserved for caching of specific things. Question: Is there some way to tell these copy operations to limit memory usage so some important things remain cached, and therefore any slowdowns are a result of normal disk usage and not rereading the same commonly used files? For example, is there a setting of max memory per process/user/file system allowed to be used as cache/buffers?

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  • Make a compiled binary run at native speed flawlessly without recompiling from source on a another system?

    - by unknownthreat
    I know that many people, at a first glance of the question, may immediately yell out "Java", but no, I know Java's qualities. Allow me to elaborate my question first. Normally, when we want our program to run at a native speed on a system, whether it be Windows, Mac OS X, or Linux, we need to compile from source codes. If you want to run a program of another system in your system, you need to use a virtual machine or an emulator. While these tools allow you to use the program you need on the non-native OS, they sometimes have problems of performance and glitches. We also have a newer compiler called "JIT Compiler", where the compiler will parse the bytecode program to native machine language before execution. The performance may increase to a very good extent with JIT Compiler, but the performance is still not the same as running it on a native system. Another program on Linux, WINE, is also a good tool for running Windows program on Linux system. I have tried running Team Fortress 2 on it, and tried experiment with some settings. I got ~40 fps on Windows at its mid-high setting on 1280 x 1024. On Linux, I need to turn everything low at 1280 x 1024 to get ~40 fps. There are 2 notable things though: Polygon model settings do not seem to affect framerate whether I set it low or high. When there are post-processing effects or some special effects that require manipulation of drawn pixels of the current frame, the framerate will drop to 10-20 fps. From this point, I can see that normal polygon rendering is just fine, but when it comes to newer rendering methods that requires graphic card to the job, it slows down to a crawl. Anyway, this question is rather theoretical. Is there anything we can do at all? I see that WINE can run STEAM and Team Fortress 2. Although there are flaws, they can run at lower setting. Or perhaps, I should also ask, "is it possible to translate one whole program on a system to another system without recompiling from source and get native speed?" I see that we also have AOT Compiler, is it possible to use it for something like this? Or there are so many constraints (such as DirectX call or differences in software architecture) that make it impossible to have a flawless and not native to the system program that runs at native speed?

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  • Binding functions of derived class with luabind

    - by Anamon
    I am currently developing a plugin-based system in C++ which provides a Lua scripting interface, for which I chose to use luabind. I'm using Lua 5 and luabind 0.9, both statically linked and compiled with MSVC++ 8. I am now having trouble binding functions with luabind when they are defined in a derived class, but not its parent class. More specifically, I have an abstract base class called 'IPlugin' from which all plugin classes inherit. When the plugin manager initialises, it registers that class and its functions like this: luabind::open(L); luabind::module(L) [ luabind::class_("IPlugin") .def("start", (void(IPlugin::*)())&IPlugin::start) ]; As it is only known at runtime what effective plugin classes are available, I had to solve loading plugins in a kind of roundabout way. The plugin manager exposes a factory function to Lua, which takes the name of a plugin class and a desired object name. The factory then creates the object, registers the plugin's class as inheriting from the 'IPlugin' base class, and immediately calls a function on the created object that registers itself as a global with the Lua state, like this: void PluginExample::registerLuaObject(lua_State *L, string a_name) { luabind::globals(L)[a_name] = (PluginExample*)this; } I initially did this because I had problems with Lua determining the most derived class of the object, as if I register it from the StreamManager it is only known as a subtype of 'IPlugin' and not the specific subtype. I'm not sure anymore if this is even necessary though, but it works and the created object is subsequently accessible from Lua under 'a_name'. The problem I have, though, is that functions defined in the derived class, which were not declared at all in the parent class, cannot be used. Virtual functions defined in the base class, such as 'start' above, work fine, and calling them from Lua on the new object runs the respective redefined code from the 'PluginExample' class. But if I add a new function to 'PluginExample', here for example a function taking no arguments and returning void, and register it like this: luabind::module(L) [ luabind::class_("PluginExample") .def(luabind::constructor()) .def("func", &PluginExample::func) ]; calling 'func' on the new object yields the following Lua runtime error: No matching overload found, candidates: void func(PluginExample&) I am correctly using the ':' syntax so the 'self' argument is not needed and it seems suddenly Lua cannot determine the derived type of the object anymore. I am sure I am doing something wrong, probably having to do with the two-step binding required by my system architecture, but I can't figure out where. I'd much appreciate some help =)

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  • In a DDD approach, is this example modelled correctly?

    - by Tag
    Just created an acc on SO to ask this :) Assuming this simplified example: building a web application to manage projects... The application has the following requirements/rules. 1) Users should be able to create projects inserting the project name. 2) Project names cannot be empty. 3) Two projects can't have the same name. I'm using a 4-layered architecture (User Interface, Application, Domain, Infrastructure). On my Application Layer i have the following ProjectService.cs class: public class ProjectService { private IProjectRepository ProjectRepo { get; set; } public ProjectService(IProjectRepository projectRepo) { ProjectRepo = projectRepo; } public void CreateNewProject(string name) { IList<Project> projects = ProjectRepo.GetProjectsByName(name); if (projects.Count > 0) throw new Exception("Project name already exists."); Project project = new Project(name); ProjectRepo.InsertProject(project); } } On my Domain Layer, i have the Project.cs class and the IProjectRepository.cs interface: public class Project { public int ProjectID { get; private set; } public string Name { get; private set; } public Project(string name) { ValidateName(name); Name = name; } private void ValidateName(string name) { if (name == null || name.Equals(string.Empty)) { throw new Exception("Project name cannot be empty or null."); } } } public interface IProjectRepository { void InsertProject(Project project); IList<Project> GetProjectsByName(string projectName); } On my Infrastructure layer, i have the implementation of IProjectRepository which does the actual querying (the code is irrelevant). I don't like two things about this design: 1) I've read that the repository interfaces should be a part of the domain but the implementations should not. That makes no sense to me since i think the domain shouldn't call the repository methods (persistence ignorance), that should be a responsability of the services in the application layer. (Something tells me i'm terribly wrong.) 2) The process of creating a new project involves two validations (not null and not duplicate). In my design above, those two validations are scattered in two different places making it harder (imho) to see whats going on. So, my question is, from a DDD perspective, is this modelled correctly or would you do it in a different way?

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  • Square Peg Web: Gets you the traffic to where it matters most: Your Website!

    - by demetriusalwyn
    Have you decided to start your business online or is your business not reaching the targeted audience? Come to Square Peg Web; where you will find what you want to make your business reach new heights. The team at Square Peg Web is professionals who understand what you want and make sure you get it right. Our confidence stems from the fact of thousands of satisfied clients who keep referring friends and business associates to us and we do not let our clients down. Many companies promise the sky but how far is does their work live up to the promises? We do not know about the others however, we are sure that we strive to put together all our ideas and thoughts to make your website rank among the top. Web hosting is something that needs to have a personal touch; Square Peg Web customizes everything to suit your requirements so that you do not have to look further. With Square Peg Web you have a host of features to make your Business go viral. Some of the product details that are offered with Square Peg Web are unlimited product options/ variants/ properties giving you an option on price modifiers. You get unlimited customized input fields for your products and you can also Customer-define the prices. Square Peg Web provides you an option of using multiple product images with zoom features and one can also list a particular product in several categories. There are other aspects which make Square Peg Web the best choice for your website needs; every sale of yours’ is important to you and to us. We make sure that each sale is tracked by the product and also the list of bestsellers that appeal to the audience. Other comprehensive statistics of Square Peg Web includes searchable order data, an interface for shipments and order fulfillments, export sales & customer data for usage in a spreadsheet and the ability to export orders to QuickBooks format. With Square Peg Web; Admin Panel is a lot simpler. Administrative access is completely password protected and any changes done are all in real-time. You can have absolute control on the cart from anywhere around the world using your web browser and the topping on the cake is the unlimited amount of admin accounts that can be created for you. Square Peg Web offers you a world of experience with the options of choosing from marketing websites to e-commerce and from customized applications to community oriented sites. Some of the projects which appear in the portfolio of Square Peg Web are Online Marketing Web Sites, E-Commerce Web Sites, customized web applications, Blog designing and programming, video sharing and the option of downloading web sites, online advertisements, flash animation, customer and product support web sites, web site re-designing and planning and complete information architecture.

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  • AJAX response not valid in C++ but Apache

    - by fehergeri
    I want to make a server written in C++ to power my game. I learned the basics of sockets and wrote a basic chat program that worked well. Now I want to create an HTTP server like Apache, but only for the AJAX request-response part. I think just for the beginning i copied one Apache response text, and i sent the exact response with the C++ server program. The problem that is that the browser (Firefox) connnects to the apache and everything works fine, except all of the requests get a correct response. But if i send this with the C++ client, then FireBug tells me that the response status is OK (200) but there is no actual response text. (How is this possible?) This response-text is exactly the same what apache sends. I made a bit-bit comparison and they were the same. The php file wich is the original response <?php echo "AS";echo rand(0,9); ?> And the origional source code: Socket.h http://pastebin.com/bW9qxtrR Socket.cpp http://pastebin.com/S3c8RFM7 main.cpp http://pastebin.com/ckExuXsR index.html http://pastebin.com/mcfEEqPP < this is the requester file. ajax.js http://pastebin.com/uXJe9hVC benchmark.js http://pastebin.com/djSYtKg9 jQuery is not needed. The main.cpp there is lot of trash code like main3 and main4 functions, these do not affect the result. I know that the response stuff in the C++ code is not really good because the connection closing is not the best; I will fix that later now I want to send a success response first. UPDATE: now i tested today a lot again and i find out there is no problem with the socket. I used the fiddler program to capture the the good answer and to capture the bad. They were the same. After this i turned off my socket application, and forced fiddler to auto respond, and the answer from the 'bad' answer still bat. So after that i replaced the bad with the good and nothing happedned. The bad answer with the good text still bad on the :8888 port but the other on the original :80 port was good, but they were absolutly the same and the same program sended it (fiddler) i think there is something missing if the response is not on the same server address (even not the same port). UPDATE: oh my god! i cant send ajax request to a remote server. now i know this.

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  • Error building C program

    - by John
    Here are my 2 source files: main.c: #include <stdio.h> #include "part2.c" extern int var1; extern int array1[]; int main() { var1 = 4; array1[0] = 2; array1[1] = 4; array1[2] = 5; array1[3] = 7; display(); printf("---------------"); printf("Var1: %d", var1); printf("array elements:"); int x; for(x = 0;x < 4;++x) printf("%d: %d", x, array1[x]); return 0; } part2.c #include <stdio.h> int var1; int array1[4]; void display(void); void display(void) { printf("Var1: %d", var1); printf("array elements:"); int x; for(x = 0;x < 4;++x) printf("%d: %d", x, array1[x]); } When i try to compile the program this is what i get: Ld /Users/John/Library/Developer/Xcode/DerivedData/Test-blxrdmnozbbrbwhcekmouessaprf/Build/Products/Debug/Test normal x86_64 cd /Users/John/Xcode/Test setenv MACOSX_DEPLOYMENT_TARGET 10.7 /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.7.sdk -L/Users/John/Library/Developer/Xcode/DerivedData/Test-blxrdmnozbbrbwhcekmouessaprf/Build/Products/Debug -F/Users/John/Library/Developer/Xcode/DerivedData/Test-blxrdmnozbbrbwhcekmouessaprf/Build/Products/Debug -filelist /Users/John/Library/Developer/Xcode/DerivedData/Test-blxrdmnozbbrbwhcekmouessaprf/Build/Intermediates/Test.build/Debug/Test.build/Objects-normal/x86_64/Test.LinkFileList -mmacosx-version-min=10.7 -o /Users/John/Library/Developer/Xcode/DerivedData/Test-blxrdmnozbbrbwhcekmouessaprf/Build/Products/Debug/Test ld: duplicate symbol _display in /Users/John/Library/Developer/Xcode/DerivedData/Test-blxrdmnozbbrbwhcekmouessaprf/Build/Intermediates/Test.build/Debug/Test.build/Objects-normal/x86_64/part2.o and /Users/John/Library/Developer/Xcode/DerivedData/Test-blxrdmnozbbrbwhcekmouessaprf/Build/Intermediates/Test.build/Debug/Test.build/Objects-normal/x86_64/main.o for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) I am using Xcode and both files are inside of a C project called Test What is causing the error and how do i fix it?

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  • Hide a base class method from derived class, but still visible outside of assembly

    - by clintp
    This is a question about tidyness. The project is already working, I'm satisfied with the design but I have a couple of loose ends that I'd like to tie up. My project has a plugin architecture. The main body of the program dispatches work to the plugins that each reside in their own AppDomain. The plugins are described with an interface, which is used by the main program (to get the signature for invoking DispatchTaskToPlugin) and by the plugins themselves as an API contract: namespace AppServer.Plugin.Common { public interface IAppServerPlugin { void Register(); void DispatchTaskToPlugin(Task t); // Other methods omitted } } In the main body of the program Register() is called so that the plugin can register its callback methods with the base class, and then later DispatchTaskToPlugin() is called to get the plugin running. The plugins themselves are in two parts. There's a base class that implements the framework for the plugin (setup, housekeeping, teardown, etc..). This is where DispatchTaskToPlugin is actually defined: namespace AppServer.Plugin { abstract public class BasePlugin : MarshalByRefObject, AppServer.Plugin.Common.IAppServerPlugin { public void DispatchTaskToPlugin(Task t) { // ... // Eventual call to actual plugin code // } // Other methods omitted } } The actual plugins themselves only need to implement a Register() method (to give the base class the delegates to call eventually) and then their business logic. namespace AppServer.Plugin { public class Plugin : BasePlugin { override public void Register() { // Calls a method in the base class to register itself. } // Various callback methods, business logic, etc... } } Now in the base class (BasePlugin) I've implemented all kinds of convenience methods, collected data, etc.. for the plugins to use. Everything's kosher except for that lingering method DispatchTaskToPlugin(). It's not supposed to be callable from the Plugin class implementations -- they have no use for it. It's only needed by the dispatcher in the main body of the program. How can I prevent the derived classes (Plugin) from seeing the method in the base class (BasePlugin/DispatchTaskToPlugin) but still have it visible from outside of the assembly? I can split hairs and have DispatchTaskToPlugin() throw an exception if it's called from the derived classes, but that's closing the barn door a little late. I'd like to keep it out of Intellisense or possibly have the compiler take care of this for me. Suggestions?

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  • Why do some questions get closed for no reason? [closed]

    - by IVlad
    Recently there was a question asking about generating all subsets of a set using a stack and a queue, which was closed (and now deleted it seems) as not a real question for no good reason, since it didn't fit into any of these conditions: It's difficult to tell what is being asked here. No, it was clear what was being asked. This question is ambiguous, vague, incomplete, or rhetorical and cannot be reasonably answered in its current form. Not ambiguous, not vague, not incomplete, definitely not rhetorical and could easily be answered if one knew the solution. Now, the exact same thing has happened with this question: http://stackoverflow.com/questions/2791982/a-shortest-path-problem-with-superheroes-and-intergalactic-journeys/2793746#2793746 I am interested in hearing a logical argument for why that question is either ambiguous, vague, incomplete, rhetorical or cannot reasonably be answered in its current form. It seems that (the same bunch of) people like to close questions that they think are homework questions, especially when they think people want to be served the solution on a platter, which is also not the case: Any suggestions or ideas of how this problem might be solved would be most welcomed. Most of the time the people asking these questions are very reasonable and appreciate even the most vague idea, yet their question is closed. Let's go further and assume that it IS a homework problem. So what? When I registered here I didn't see any rule that said not to post homework problems, nor do I see such a rule now. What is wrong with posting homework problems that makes people hunt them down with a passion to close them without even reading the entire question body? This site is full of questions asked by people who get paid to know the things they are asking, yet their questions are considered fine. How is solving someone's homework problem worse? In some places (like where I live), computer science is a mandatory high school subject, and not everyone is interested in it. How is helping at least those people worse than doing someone's JOB? Not answering homework questions is fine and it's everyone's choice, but I consider closing them to be an act of power abuse, selfishness, and an insult to the fellow community members who are also interested in a solution or want feedback on their proposed solution. So my questions are: - Why do questions like the above get closed for reasons that do not apply? Why do you close them? Why don't you? - Why doesn't a vote to reopen a question reopen it automatically? Needing 5 votes for a reopen takes too long, and it's not fair because one reopen vote basically cancels out a close vote, making it 4 close votes (or 5 to 1, which is the same as only 4 people wanting to close the question), which isn't enough to close the question. I think a question should only be closed when CloseVotes - ReopenVotes >= 5. I'm hoping this will stay up, but I realize it probably won't. In either case, I think this is worth saying and discussing, since it IS community-related.

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  • WLI domain with 3 servers - issues on JPD process startup

    - by XpiritO
    Hi there. I'm currently working on a clustered WLI environment which comprehends 3 servers: 1 admin server ("AdminServer") and 2 managed servers ("mn1" and "mn2") grouped as a cluster, as follows: Architecture diagram: http://img72.imageshack.us/img72/4112/clusterdiagram.jpg I've developed a JPD process to execute some scheduled tasks, invoked using a Message Broker. I've deployed this project into a single-server WLI domain (with AdminServer only) and it works as expected: the JPD process is invoked (I've configured a Timer Event Generator instance to start it up). Message broker: http://img532.imageshack.us/img532/1443/wlimessagebroker.jpg Timer event generator: http://img408.imageshack.us/img408/7358/wlitimereventgenerator.jpg In order to achieve fail-over and load-balancing capabilities, I'm currently trying to deploy this JPD process into this clustered WLI environment. Although, I'm having some issues with this, as I cannot get it to work properly, even if it still works. Here is a screenshot of the "WLI Process Instance Monitor" (with AdminServer and mn1 instances up and running): http://img710.imageshack.us/img710/8477/wliprocessinstancemonit.jpg According to this screen the process seems to be running, as it shows in this instance monitor screen. However, I don't see any output coming out neither at AdminServer console or mn1 console. In single-server domain it was visible output from JPD process "timeout" callback method, wich implementation is shown below: @com.bea.wli.control.broker.MessageBroker.StaticSubscription(xquery = "", filterValueMatch = "", channelName = "/SamplePrefix/Samples/SampleStringChannel", messageBody = "{x0}") public void subscription(java.lang.String x0) { String toReturn=""; try { Context myCtx = new InitialContext(); MBeanHome mbeanHome = (MBeanHome)myCtx.lookup("weblogic.management.home.localhome"); toReturn=mbeanHome.getMBeanServer().getServerName(); System.out.println("**** executed at **** " + System.currentTimeMillis() + " by: " + toReturn); } catch (Exception e) { System.out.println("Exception!"); e.printStackTrace(); } } (...) @org.apache.beehive.controls.api.events.EventHandler(field = "myT", eventSet = com.bea.control.WliTimerControl.Callback.class, eventName = "onTimeout") public void myT_onTimeout(long time, java.io.Serializable data) { // #START: CODE GENERATED - PROTECTED SECTION - you can safely add code above this comment in this method. #// // input transform System.out.println("**** published at **** " + System.currentTimeMillis()); publishControl.publish("aaaa"); // parameter assignment // #END : CODE GENERATED - PROTECTED SECTION - you can safely add code below this comment in this method. #// } and here is the output visible at "AdminServer" console in single-server domain testing: **** published at **** 1273238090713 **** executed at **** 1273238132123 by: AdminServer **** published at **** 1273238152462 **** executed at **** 1273238152562 by: AdminServer (...) What may be wrong with my clustered configuration? Am I missing something to accomplish clustered deployment? Thanks in advance for your help.

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  • Implementing coroutines in Java

    - by JUST MY correct OPINION
    This question is related to my question on existing coroutine implementations in Java. If, as I suspect, it turns out that there is no full implementation of coroutines currently available in Java, what would be required to implement them? As I said in that question, I know about the following: You can implement "coroutines" as threads/thread pools behind the scenes. You can do tricksy things with JVM bytecode behind the scenes to make coroutines possible. The so-called "Da Vinci Machine" JVM implementation has primitives that make coroutines doable without bytecode manipulation. There are various JNI-based approaches to coroutines also possible. I'll address each one's deficiencies in turn. Thread-based coroutines This "solution" is pathological. The whole point of coroutines is to avoid the overhead of threading, locking, kernel scheduling, etc. Coroutines are supposed to be light and fast and to execute only in user space. Implementing them in terms of full-tilt threads with tight restrictions gets rid of all the advantages. JVM bytecode manipulation This solution is more practical, albeit a bit difficult to pull off. This is roughly the same as jumping down into assembly language for coroutine libraries in C (which is how many of them work) with the advantage that you have only one architecture to worry about and get right. It also ties you down to only running your code on fully-compliant JVM stacks (which means, for example, no Android) unless you can find a way to do the same thing on the non-compliant stack. If you do find a way to do this, however, you have now doubled your system complexity and testing needs. The Da Vinci Machine The Da Vinci Machine is cool for experimentation, but since it is not a standard JVM its features aren't going to be available everywhere. Indeed I suspect most production environments would specifically forbid the use of the Da Vinci Machine. Thus I could use this to make cool experiments but not for any code I expect to release to the real world. This also has the added problem similar to the JVM bytecode manipulation solution above: won't work on alternative stacks (like Android's). JNI implementation This solution renders the point of doing this in Java at all moot. Each combination of CPU and operating system requires independent testing and each is a point of potentially frustrating subtle failure. Alternatively, of course, I could tie myself down to one platform entirely but this, too, makes the point of doing things in Java entirely moot. So... Is there any way to implement coroutines in Java without using one of these four techniques? Or will I be forced to use the one of those four that smells the least (JVM manipulation) instead?

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  • Problem updating through LINQtoSQL in MVC application using StructureMap, Repository Pattern and UoW

    - by matt
    I have an ASP MVC application using LINQ to SQL for data access. I am trying to use the Repository and Unit of Work patterns, with a service layer consuming the repositories and unit of work. I am experiencing a problem when attempting to perform updates on a particular repository. My application architecture is as follows: My service class: public class MyService { private IRepositoryA _RepositoryA; private IRepositoryB _RepositoryB; private IUnitOfWork _unitOfWork; public MyService(IRepositoryA ARepositoryA, IRepositoryB ARepositoryB, IUnitOfWork AUnitOfWork) { _unitOfWork = AUnitOfWork; _RepositoryA = ARepositoryA; _RepositoryB = ARepositoryB; } public PerformActionOnObject(Guid AID) { MyObject obj = _RepositoryA.GetRecords() .WithID(AID); obj.SomeProperty = "Changed to new value"; _RepositoryA.UpdateRecord(obj); _unitOfWork.Save(); } } Repository interface: public interface IRepositoryA { IQueryable<MyObject> GetRecords(); UpdateRecord(MyObject obj); } Repository LINQtoSQL implementation: public class LINQtoSQLRepositoryA : IRepositoryA { private MyDataContext _DBContext; public LINQtoSQLRepositoryA(IUnitOfWork AUnitOfWork) { _DBConext = AUnitOfWork as MyDataContext; } public IQueryable<MyObject> GetRecords() { return from records in _DBContext.MyTable select new MyObject { ID = records.ID, SomeProperty = records.SomeProperty } } public bool UpdateRecord(MyObject AObj) { MyTableRecord record = (from u in _DB.MyTable where u.ID == AObj.ID select u).SingleOrDefault(); if (record == null) { return false; } record.SomeProperty = AObj.SomePropery; return true; } } Unit of work interface: public interface IUnitOfWork { void Save(); } Unit of work implemented in data context extension. public partial class MyDataContext : DataContext, IUnitOfWork { public void Save() { SubmitChanges(); } } StructureMap registry: public class DataServiceRegistry : Registry { public DataServiceRegistry() { // Unit of work For<IUnitOfWork>() .HttpContextScoped() .TheDefault.Is.ConstructedBy(() => new MyDataContext()); // RepositoryA For<IRepositoryA>() .Singleton() .Use<LINQtoSQLRepositoryA>(); // RepositoryB For<IRepositoryB>() .Singleton() .Use<LINQtoSQLRepositoryB>(); } } My problem is that when I call PerformActionOnObject on my service object, the update never fires any SQL. I think this is because the datacontext in the UnitofWork object is different to the one in RepositoryA where the data is changed. So when the service calls Save() on it's IUnitOfWork, the underlying datacontext does not have any updated data so no update SQL is fired. Is there something I've done wrong in the StrutureMap registry setup? Or is there a more fundamental problem with the design? Many thanks.

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