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  • Entity Framework - Foreign key constraints not added for inherited entity

    - by Tri Q
    Hello, It appears to me that a strange phenomenon is occurring with inherited entities (TPT) in EF4. I have three entities. 1. Asset 2. Property 3. Activity Property is a derived-type of Asset. Property has many activities (many-to-many) When modeling this in my EDMX, everything seems fine until I try to insert a new Property into the database. If the property does not contain any Activity, it works, but all hell breaks loose when I add some new activities to the new Property. As it turns out after 2 days of crawling the web and fiddling around, I noticed that in the EF store (SSDL) some of the constraints between entities were not picked up during the update process. Property_Activity table which links properties and activities show only one constraint FK_Property_Activity_Activity but FK_Property_Activity_Property was missing. I knew this is an Entity Framework anomoly because when I switched the relationship in the database to: Asset <-- Asset_Activity <-- Activity After an update, all foreign key constraints are picked up and the save is successful, with or without activities in the new property. Is this intended or a bug in EF? How do I get around this problem? Should I abandon inheritance altogether?

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  • Question about WeakReferences

    - by Impz0r
    Hey there, I've got a question regarding WeakReferences. I'm right now in the process of writing a "Resource Manager" who hast to keep references to created texture objects. I have a Dictionary like: Dictionary<uint, WeakReference> Where the first is, as you allready may guessed, the Resource Id and the second param is a WeakReference to the Resource itself. Right now my Resources do have a method to free themselfes from their Owner (i.e. Resource Manager). They do so in calling a method at the Resource Manger while passing a this reference to it. The ResMgr does lookup if it is a resource he keeps bookmark of and if so, does something like this: WeakReference result; if (m_Resources.TryGetValue(ResourceId, out result)) { if (result.IsAlive) return; (result.Target as Resource).free(); // free for good m_Resources.Remove(ResourceId); } The Problem I'm having is that the part after: if (result.IsAlive) is never reached because there are still leftover references to the Resource. The thing is, I do only have one Reference of the Resource in question and it releases itself like: resource.free(); // calls internally its owner (i.e. ResMgr) resource = null; I guess the left over reference would be the "resource" variable, but I cannot set it to null, because I do have to call free first. Quite a dilema... Well what I wanted to achive with this is a Resource Manager who keeps references to its owning Resources and release them ONLY if there is no reference left to not screw up something. Any idea how I may solve this in a clean fashion? Thanks in advance! Mfg Imp

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  • Node.js fetching Twitter Streaming API - EADDRNOTAVAIL

    - by Jordan Scales
    I have the following code written in node.js to access to the Twitter Streaming API. If I curl the URL below, it works. However, I cannot get it to work with my code. var https = require('https'); https.request('https://USERNAME:[email protected]/1.1/statuses/sample.json', function(res) { res.on('data', function(chunk) { var d = JSON.parse(chunk); console.log(d); }); }); But I receive the following node.js:201 throw e; // process.nextTick error, or 'error' event on first tick ^ Error: connect EADDRNOTAVAIL at errnoException (net.js:642:11) at connect (net.js:525:18) at Socket.connect (net.js:589:5) at Object.<anonymous> (net.js:77:12) at new ClientRequest (http.js:1073:25) at Object.request (https.js:80:10) at Object.<anonymous> (/Users/jordan/Projects/twitter-stream/app.js:3:7) at Module._compile (module.js:441:26) at Object..js (module.js:459:10) at Module.load (module.js:348:31) If anyone can offer an alternative solution, or explain to me why this doesn't work, I would be very grateful.

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  • RemoteRef.invoke implementation

    - by phill
    Just finished a basic implementation of RMI for a class project, and now I am interested in how it is actually done. Sun is kind enough to provide the source for the majority of the Java classes with the JDK, however an implementation of RemoteRef doesn't seem to be there. I have the source for the interface RemoteRef along with the ServerRef interface and one implementation, ProxyRef, which just calls invoke on another RemoteRef, but none of the classes that implement actual code, ActivatableRef or UnicastRef for example, are included. I mention ActivatableRef and UnicastRef because I believe these have proper implementations of invoke thanks to the wonder that is Eclipse and its class file editor showing that it is more then just a method declaration. Although I can tell that it is more then a declaration, I can't get much more out of it, building a string here, throw exception there, but nothing about the process that is taking place to send the remote method call. Would anyone here happen to know where I can get this code, or if its even available? If it is not available, would anyone happen to know what the message being sent to the server looks like? phill

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  • Code Explanation (MPICH)

    - by user243680
    #include "mpi.h" #include <stdio.h> #include <math.h> double f(double a) { return (4.0 / (1.0 + a*a)); } void main(int argc, char *argv[]) { int done = 0, n, myid, numprocs,i; double PI25DT = 3.141592653589793238462643; double mypi, pi, h, sum, x; double startwtime, endwtime; int namelen; char processor_name[MPI_MAX_PROCESSOR_NAME]; MPI_Init(&argc,&argv); MPI_Comm_size(MPI_COMM_WORLD,&numprocs); MPI_Comm_rank(MPI_COMM_WORLD,&myid); MPI_Get_processor_name(processor_name,&namelen); fprintf(stderr,"Process %d on %s\n", myid, processor_name); fflush(stderr); n = 0; while (!done) { if (myid == 0) { printf("Enter the number of intervals: (0 quits) ");fflush(stdout); scanf("%d",&n); startwtime = MPI_Wtime(); } MPI_Bcast(&n, 1, MPI_INT, 0, MPI_COMM_WORLD); if (n == 0) done = 1; else { h = 1.0 / (double) n; sum = 0.0; for (i = myid + 1; i <= n; i += numprocs) { x = h * ((double)i - 0.5); sum += f(x); } mypi = h * sum; MPI_Reduce(&mypi, &pi, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD); if (myid == 0) { printf("pi is approximately %.16f, Error is %.16f\n", pi, fabs(pi - PI25DT)); endwtime = MPI_Wtime(); printf("wall clock time = %f\n", endwtime-startwtime); } } } MPI_Finalize(); } Can anyone explain me the above code what it does??I am in lab and my miss has asked me to explain and i dont know what it is.please help

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  • How to call stored proc from ASP.Net MVC stack via the ORM & return them in json?

    - by melaos
    Hi guys, i'm a total newbie with asp.net mvc and here's my jam: i have a 3 level list box which selection on box A shows options on box B and selection on box B will show the options for box C. I'm trying to do the whole thing in asp.net MVC and what i see is that the nerd dinner tutorial uses the ORM method. so i created a dbml to the database and drag the stored proc inside. i create a datacontext object but i don't quite know how to connect the result from the stored proce which should be multiple rows of data and make it into a json. so i can keep all the json data inside the html page and using jquery i could make the selection process faster. i don't expect the data inside the three boxes to change so often thus i think this method should be quite viable. Questions: So how do i get the stored proc part to return the data as json? i've noticed some tutorial online that the json return result part is at the controller and not at the model end. Why is that?

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  • Applescript from Mac App says "Expected end of line but found \U201c\"\U201d."

    - by Rasmus Styrk
    I am trying to perform a copy/paste for my to the the last active app, here's my code: NSString *appleScriptSource = [NSString stringWithFormat:@"\ntell application \"%@\" to activate\ntell application \"System Events\" to tell process \"%@\"\nkeystroke \"v\" using command down\nend tell", [lastApp localizedName], [lastApp localizedName]]; NSDictionary *error; NSAppleScript *aScript = [[NSAppleScript alloc] initWithSource:appleScriptSource]; NSAppleEventDescriptor *aDescriptor = [aScript executeAndReturnError:&error]; The problem is that on some computers it works just fine, but on others it fails. My error output from error that is returned by executeAndReturnError is: 2012-06-13 17:43:19.875 Mini Translator[1206:303] (null) (error: { NSAppleScriptErrorBriefMessage = "Expected end of line but found \U201c\"\U201d."; NSAppleScriptErrorMessage = "Expected end of line but found \U201c\"\U201d."; NSAppleScriptErrorNumber = "-2741"; NSAppleScriptErrorRange = "NSRange: {95, 1}"; }) I can't seem to figure out what it means or why it happens. We tried copying the generated apple-script code into the Apple Script editor, and here it works just fine. My App is sandboxed - i have added the bundle identifiers for the key "com.apple.security.temporary-exception.apple-events" for the apps i want to support. Any suggestions?

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  • Making a 64 bit shared library that dynamically links to a 32 bit library on Mac OS X Snow Leopard

    - by carneades
    Update: After some more reading I see that this problem is totally general, you can't mix architectures in the same process, so 64 bit Java cannot dlopen() a 32 bit library like FMOD. Is there any possible workaround for this, keeping in mind I'm writing my own C interface to the FMOD library? I need to make a 64-bit dylib on Max OS X because Java Native Access only likes 64-bit libraries on 64-bit machines. The problem is, my C source code dynamically includes FMOD which on Mac only provides 32-bit dylibs. When I try to compile without the -m32 option (since I must output a 64-bit dylib) I get the following error: gcc -dynamiclib -std=c99 -pedantic -Wall -O3 -fPIC -pthread -o ../bin/libpenntotalrecall_fmod.dylib ../../src/libpenntotalrecall_fmod.c -lfmodex -L../../lib/osx/ ld: warning: in /usr/lib/libfmodex.dylib, missing required architecture x86_64 in file Undefined symbols: "_FMOD_System_CreateSound", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_Channel_GetPosition", referenced from: _streamPosition in ccJnlwrd.o "_FMOD_System_Create", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_System_PlaySound", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_Sound_Release", referenced from: _stopPlayback in ccJnlwrd.o "_FMOD_Channel_IsPlaying", referenced from: _playbackInProgress in ccJnlwrd.o "_FMOD_System_Update", referenced from: _streamPosition in ccJnlwrd.o _startPlayback in ccJnlwrd.o "_FMOD_Channel_SetPaused", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_System_Release", referenced from: _stopPlayback in ccJnlwrd.o "_FMOD_System_Init", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_Channel_SetVolume", referenced from: _startPlayback in ccJnlwrd.o "_FMOD_System_Close", referenced from: _stopPlayback in ccJnlwrd.o "_FMOD_Channel_SetCallback", referenced from: _startPlayback in ccJnlwrd.o ld: symbol(s) not found collect2: ld returned 1 exit status make: *** [all] Error 1 Shouldn't it be possible to get a 64 bit dylib from my source code that dynamically includes 32 bit libraries?!

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  • Is it possible to write a class that interacts with controls on my WPF form?

    - by Adam S
    Hi all, I'm trying to write a class that I can use to interact with a group of similar controls in my wpf application. I have hit a few roadblocks and now I am wondering if this is a poor approach to begin with. I want to do this primarily to make my code more manageable - I have to interact with around 200 - 300 controls with my code, and it could get very tricky to have all my code in the main window class. Here's something I'd like to be able to do: class ProcControl { private CheckBox * [] Boxes = new CheckBox[10]; ProcControl() { //set boxes 0-9 to point to the actual checkboxes } //provides mass checking/unchecking functionality public void Refactor(CheckBox box) { //see what box it is int box_index = 0; while (Boxes[box_index] != box) { box_index++; } } } This doesn't work as it is right now. I have not figured out how to get my Boxes[] array to point to the actual checkboxes on my form, so I can't interact with them yet. Is it even possible to make an array that points to a bunch of controls so that I may process their properties in a nice manner? Why can't I access the controls at all from inside my class?

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  • Multithreading and Interrupts

    - by Nicholas Flynt
    I'm doing some work on the input buffers for my kernel, and I had some questions. On Dual Core machines, I know that more than one "process" can be running simultaneously. What I don't know is how the OS and the individual programs work to protect collisions in data. There are two things I'd like to know on this topic: (1) Where do interrupts occur? Are they guaranteed to occur on one core and not the other, and could this be used to make sure that real-time operations on one core were not interrupted by, say, file IO which could be handled on the other core? (I'd logically assume that the interrupts would happen on the 1st core, but is that always true, and how would you tell? Or perhaps does each core have its own settings for interrupts? Wouldn't that lead to a scenario where each core could react simultaneously to the same interrupt, possibly in different ways?) (2) How does the dual core processor handle opcode memory collision? If one core is reading an address in memory at exactly the same time that another core is writing to that same address in memory, what happens? Is an exception thrown, or is a value read? (I'd assume the write would work either way.) If a value is read, is it guaranteed to be either the old or new value at the time of the collision? I understand that programs should ideally be written to avoid these kinds of complications, but the OS certainly can't expect that, and will need to be able to handle such events without choking on itself.

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  • Integrating ASP.NET MVC 2 with classic ASP

    - by David Lively
    I'm in the process of moving a large classic ASP application to ASP.NET MVC 2. Questions: My question is about project organization. I would prefer to not mix the MVC code with the ASP code in the same VS project. I'd like to have an MVC WAP with areas that match the parts of the website that I'm migrating. For instance, the old site has a folder /products/default.asp..... /products/productName/default.asp etc. In the MVC WAP, I'd like to have an area called "products", which I could then, either through a rewrite, routing, or preferably through some IIS configuration, point the "products" folder on the ASP site to. In this way, I could gradually move root folders from the ASP site to the MVC application. However, if I create the MVC WAP in a virtual folder, then my routes wind up looking like http://localhost/virtualFolder/products instead of http://localhost/products Any suggestions on how to conquer this? I know that, during deployment, I could deploy the MVC WAP into the root of the ASP site, but this doesn't help with debugging.

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  • How do the XMPP modules work in perl?

    - by TheGNUGuy
    Hey everybody, I am trying to make my own jabber bot but i have run into a little trouble. I have gotten my bot to respond to messages, however, if I try to change the bot's presence then it seems as though all of the messages you send to the bot get delayed. What I mean is when I run the script I change the presence so I can see that it is online. Then When I send it a message it takes 3 before the callback subroutine i have set up for messages gets called. After the 3rd message is sent and the chat subroutine is called it still process the first message I sent. This really doesn't pose TOO much of a problem except that I have it set up to log out when I send the message "logout" and it has to be followed by two more messages in order to log out. I am not sure what it is that I have to do to fix this but i think it has something to do with iq packets because I have an iq callback set as well and it gets called 2 times after setting the presence. Here is my source code: http://pastebin.com/MgKMhTML Thanks for your help!

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  • MS Source Server - source stream is apparently not there when viewing with srctool

    - by Tim Peel
    Hi, I have been playing around with the MS Source Server stuff in the MS Debugging Tools install. At present, I am running my code/pdbs through the Subversion indexing command, which is now running as expected. It creates the stream for a given pdb file and writes it to the pdb file. However when I use that DLL and associated pdb in visual studio 2008, it says the source code cannot be retrieved. If I check the pdb against srctool is says none of the source files contained are indexed, which is very strange as the process prior ran fine. If I check the stream that was generated from the svnindex.cmd run for the pdb, srctool says all source files are indexed. Why would there be a difference? I have opened the pdb file in a text editor and I can see the original references to the source files on my machine (also under the srcsrv header name) and the new "injected" source server links to my subversion repository). Should both references still exist in the pdb? I would have expected one to be removed? Either way, visual studio 2008 will not pick up my source references so I am a bit lost as to what to try next. As far as I can tell, I have done everything I should have. Anyone have similar experiences? Many thanks.

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  • Why doesn't Perl file glob() work outside of a loop in scalar context?

    - by Rob
    According to the Perl documentation on file globbing, the <*> operator or glob() function, when used in a scalar context, should iterate through the list of files matching the specified pattern, returning the next file name each time it is called or undef when there are no more files. But, the iterating process only seems to work from within a loop. If it isn't in a loop, then it seems to start over immediately before all values have been read. From the Perl docs: In scalar context, glob iterates through such filename expansions, returning undef when the list is exhausted. http://perldoc.perl.org/functions/glob.html However, in scalar context the operator returns the next value each time it's called, or undef when the list has run out. http://perldoc.perl.org/perlop.html#I/O-Operators Example code: use warnings; use strict; my $filename; # in scalar context, <*> should return the next file name # each time it is called or undef when the list has run out $filename = <*>; print "$filename\n"; $filename = <*>; # doesn't work as documented, starts over and print "$filename\n"; # always returns the same file name $filename = <*>; print "$filename\n"; print "\n"; print "$filename\n" while $filename = <*>; # works in a loop, returns next file # each time it is called In a directory with 3 files...file1.txt, file2.txt, and file3.txt, the above code will output: file1.txt file1.txt file1.txt file1.txt file2.txt file3.txt Note: The actual perl script should be outside the test directory, or you will see the file name of the script in the output as well. Am I doing something wrong here, or is this how it is supposed to work?

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  • PHP database simulation

    - by Emdiesse
    I have a PHP script that works by calling items from a database based upon the time they were placed in there and it deletes them if they are older than 5 minutes. Basically, I want to now simulate what would happen if this database was being updated regularly. So I was considering sticking in some code that loads an XML file then goes through and parses that into the database based upon the time data located within a node of the xml data... but the problem there is I want it to continually loop through an enter this data so it'll never actually run the other processes So I was thinking of having another PHP script do that that could do this independantly of the php script that is going to display this data... In theory: I am looking to have a button that I can press and it will then run some php code to load up an XML file from a directory on my web server and then iterate though the data sending the data, to a database, based upon the time within a node in the PHP script and when the script was first called So back to my page that displayed the data... if I continually hit refresh it will contain different results each time because data is being added by the other process and this php script removes the older data when it is refreshed Any information on this? Is there a way I can silently, and safely, run a php script without it being loaded into a browser... like a thread!?

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  • Static variables and long running thread on IIS 7.5

    - by Dmitry
    Hello people. Help me solve next problem. I have ASP .NET MVC2 application. I run it on IIS 7.5. In one page user clicks button and handler for this button sends request to server (jquery.ajax). At server action in controller starts new thread (it makes long time import): var thread = new Thread(RefreshCitiesInDatabase); thread.Start(); State of import is available in static variable. New thread changes value of variable in the begin of work. User can check state of import too with the help of this variable, which is used in view. And user sees import's state. When I start this function few minutes everything is okey. On page I see right state of import, quantity of imported records is changed, I see changes in logs. But after few minutes begin troubles. When I refresh page with import state sometimes I see that import is okey but sometimes I see page with default values about import (like application is just started), but after that again I can see page with normal import's state. I tried to attach Visual Studio to IIS process and debug application. But when request comes to controller sometimes static variables have right values and sometimes they have default values (static int has 0, static string has "" etc.). Tell me what I do wrong. May be I must start additional thread in other way? Thanks in advance, Dmitry

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  • Dispatch request to an Async Servlet from managed bean generate exception

    - by Thang Pham
    when a button click, I need to have stuff running in my background, so I have a async Servlet. From my managed bean, if I do redirect, it works great (meaning that it execute my run() method inside my class that extends Runnable correctly). Like this String url = externalContext.getRequestContextPath() + "/ReportExecutionServlet"; externalContext.redirect(url); But if I switch to dispatch, like this externalContext.redirect("/ReportExecutionServlet"); it fail when I try to obtain the AsyncContext AsyncContext aCtx = request.startAsync(request, response); The error is below Caused By: java.lang.IllegalStateException: The async-support is disabled on this request: weblogic.servlet.internal.ServletRequestImpl Any idea how to fix this please? NOTE: This is how to execute my async servlet, just in case: AsyncContext aCtx = request.startAsync(request, response); //delegate long running process to an "async" thread aCtx.addListener(new AsyncListener() { @Override public void onComplete(AsyncEvent event) throws IOException { logger.log(Level.INFO, "ReportExecutionServlet handle async request - onComplete"); } @Override public void onTimeout(AsyncEvent event) throws IOException { logger.log(Level.WARNING, "ReportExecutionServlet handle async request - onTimeout"); } @Override public void onError(AsyncEvent event) throws IOException { logger.log(Level.SEVERE, "ReportExecutionServlet handle async request - onError"); } @Override public void onStartAsync(AsyncEvent event) throws IOException { logger.log(Level.INFO, "ReportExecutionServlet handle async request - onStartAsync"); } }); // Start another service ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(10); executor.execute(new AsyncRequestReportProcessor(aCtx));

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  • Quality assurance in small developer teams

    - by Kim L
    Ideally, in a project you will developers, testers, QA manager(s) etc which all make their contribution to the quality of the code. But what if you don't have that kind of resources? If you just have, for example, three developers and don't have the resources to hire a full time QA manager, how do you assure that the code quality meets set standards? What kind of things do you pay attention to in quality assurance? Quality isn't just about the code doing what it is supposed to do (code is properly tested with automatic tests). Quality is also about the code being clean (readable, maintainable, well structured, documented, etc). I'm looking forward to hear what kind of processes you have applied to your team to assure that the quality meets the set standards. We've applied a process where we rotate the QA role between the developers. Each developer is responsible for QA one week at a time. Each changeset is revised and checked that existing tests pass, required new tests have been written, that the code is clean and, of course, that the project builds.

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  • Linq to SQL generates StackOverflowException in tight Insert loop

    - by ChrisW
    I'm parsing an XML file and inserting the rows into a table (and related tables) using LinqToSQL. I parse the XML file using LinqToXml into IEnumerable. Then, I create a foreach loop, where I build my LinqToSQL objects and call InsertOnSubmit and SubmitChanges at the end of each loop. Nothing special here. Usually, I make it through around 4,100 records before receiving a StackOverflowException from LinqToSql, right as I call SubmitChanges. It's not always on 4,100... sometimes it's 4102, sometimes, less, etc. I've tried inserting the records that generate the failure individually, but putting them in their own Xml file, but that inserts fine... so it's not the data. I'm running the whole process from an MVC2 app that is uploading the Xml file to the server. I've adjusted my WebRequest timeouts to appropriate values, and again, I'm not getting timeout errors, just StackOverflowExceptions. So is there some pattern that I should follow for times when I have to do many insertions into the database? I never encounter this exception on smaller Xml files, just larger ones.

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  • Can't create new xib files in Xcode projects

    - by Reed Olsen
    This one is a doozy... My buddy just downloaded the iPhone SDK on his Snow Leopard MacBook Pro. No matter what kind of project he creates (Window Based, View Based, etc...,) he can't create or use his own xib files. The project will compile and run fine until he adds a new xib file. Here are some symptoms: When he selects a pre-generated xib in Xcode (such as MainWindow.xib), no preview is shown on the right hand side. Double clicking on this file will open it in interface builder (This is correct behavior). When he selects his own custom xib, the preview pane displays the XML content of the xib. Double clicking on his custom xib opens up the XML file in Xcode - as if it were a standard code file (This is jacked up). Opening his custom xib from finder opens it in Interface Builder. When building the application, the build warning says something to the effect of "Warning: No rule to process file /path/to/CustomXib of type sourcecode.xib for architecture i386" At runtime he gets the error: Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIViewController _loadViewFromNibNamed:bundle:] was unable to load a nib named "MyCustomXib"' We've uninstalled Xcode from the command line and reinstalled. I've verified that it's the right version for his machine. I'm stumped!

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  • Efficient data importing?

    - by Kevin
    We work with a lot of real estate, and while rearchitecting how the data is imported, I came across an interesting issue. Firstly, the way our system works (loosely speaking) is we run a Coldfusion process once a day that retrieves data provided from an IDX vendor via FTP. They push the data to us. Whatever they send us is what we get. Over the years, this has proven to be rather unstable. I am rearchitecting it with PHP on the RETS standard, which uses SOAP methods of retrieving data, which is already proven to be much better than what we had. When it comes to 'updating' existing data, my initial thought was to query only for data that was updated. There is a field for 'Modified' that tells you when a listing was last updated, and the code I have will grab any listing updated within the last 6 hours (give myself a window in case something goes wrong). However, I see a lot of real estate developers suggest creating 'batch' processes that run through all listings regardless of updated status that is constantly running. Is this the better way to do it? Or am I fine with just grabbing the data I know I need? It doesn't make a lot of sense to me to do more processing than necessary. Thoughts?

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  • Good patterns for loose coupling in Java?

    - by Eye of Hell
    Hello. I'm new to java, and while reading documentation so far i can't find any good ways for programming with loose coupling between objects. For majority of languages i know (C++, C#, python, javascript) i can manage objects as having 'signals' (notification about something happens/something needed) and 'slots' (method that can be connected to signal and process notification/do some work). In all mentioned languages i can write something like this: Object1 = new Object1Class(); Object2 = new Object2Class(); Connect( Object1.ItemAdded, Object2.OnItemAdded ); Now if object1 calls/emits ItemAdded, the OnItemAdded method of Object2 will be called. Such loose coupling technique is often referred as 'delegates', 'signal-slot' or 'inversion of control'. Compared to interface pattern, technique mentioned don't need to group signals into some interfaces. Any object's methods can be connected to any delegate as long as signatures match ( C++Qt even extends this by allowing only partial signature match ). So i don't need to write additional interface code for each methods / groups of methods, provide default implementation for interface methods not used etc. And i can't see anything like this in Java :(. Maybe i'm looking a wrong way?

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  • JConsole does not connect when a program is waiting for a console input

    - by Calm Storm
    Hi, I have a problem similar to the one mentioned here. I have a program which launches a selenium browser and refreshes it every 2 seconds. My idea here was to monitor the memory usage of my application as the page is being hit. This console program does a "System.in.read" and when a user presses enter key, this stops the browser refresh thread. I run the program and it runs as I would expect it to. But when I fire jconsole and attach it to the process, it looks like jconsole waits forever to attach. This is because of the "System.in.read", apparently as shown in the JConsole source. In my code it makes perfect sense for me to terminte the browser when user presses something so is there any alternative available at all ? (Posted code sample below) package com.ekanathk; import java.util.ArrayList; import java.util.List; import org.junit.Test; public class MultiThread { @Test public void testSimple() throws Exception { List<Integer> x = new ArrayList<Integer>(); for(int i = 0; i < 1000; i++) { x.add(i); } System.out.print("Press Enter to stop (try attach a jconsole now...."); System.in.read(); } } The problem here seems to be that any System.in.read (either in Main thread or any threads) seems to completely block jconsole. I guess the problem essentially boils down to multiple threads requesting system inputs at the same time? Is there a solution ?

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  • How do I fork a maximum of 5 child processes of the parent at any one time?

    - by bstullkid
    I have the following code, which I'm trying to only allow a maximum of 5 children to run at a time, but I can't figure out how to decrement the child count when a child exits. struct { char *s1; char *s2; } s[] = { {"one", "oneB"}, {"two", "twoB"}, {"three", "thr4eeB"}, {"asdf", "3th43reeB"}, {"asdfasdf", "thr33eeB"}, {"asdfasdfasdf", "thdfdreeB"}, {"af3c3", "thrasdfeeB"}, {"fec33", "threfdeB"}, {NULL, NULL} }; int main(int argc, char *argv[]) { int i, im5, children = 0; int pid = fork(); for (i = 0; s[i].s2; i++) { im5 = 0; switch (pid) { case -1: { printf("Error\n"); exit(255); } case 0: { printf("%s -> %s\n", s[i].s1, s[i].s2); if (i==5) im5 = 1; printf("%d\n", im5); sleep(i); exit(1); } default: { // Here is where I need to sleep the parent until chilren < 5 // so where do i decrement children so that it gets modified in the parent process? while(children > 5) sleep(1); children++; pid = fork(); } } } return 1; }

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  • Speed up SQL Server Fulltext Index through Text Duplication of Non-Indexed Columns

    - by Alex
    1) I have the text fields FirstName, LastName, and City. They are fulltext indexed. 2) I also have the FK int fields AuthorId and EditorId, not fulltext indexed. A search on FirstName = 'abc' AND AuthorId = 1 will first search the entire fulltext index for 'abc', and then narrow the resultset for AuthorId = 1. This is bad because it is a huge waste of resources as the fulltext search will be performed on many records that won't be applicable. Unfortunately, to my knowledge, this can't be turned around (narrow by AuthorId first and then fulltext-search the subset that matches) because the FTS process is separate from SQL Server. Now my proposed solution that I seek feedback on: Does it make sense to create another computed column which will be included in the fulltext search which will identify the Author as text (e.g. AUTHORONE). That way I could get rid of the AuthorId restriction, and instead make it part of my fulltext search (a search for 'abc' would be 'abc' and 'AUTHORONE' - all executed as part of the fulltext search). Is this a good idea or not? Why?

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