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  • Why is there no autorelease pool when I do performSelectorInBackground: ?

    - by Thanks
    I am calling a method that goes in a background thread: [self performSelectorInBackground:@selector(loadViewControllerWithIndex:) withObject:[NSNumber numberWithInt:viewControllerIndex]]; then, I have this method implementation that gets called by the selector: - (void) loadViewControllerWithIndex:(NSNumber *)indexNumberObj { NSAutoreleasePool *arPool = [[NSAutoreleasePool alloc] init]; NSInteger vcIndex = [indexNumberObj intValue]; Class c; UIViewController *controller = [viewControllers objectAtIndex:vcIndex]; switch (vcIndex) { case 0: c = [MyFirstViewController class]; break; case 1: c = [MySecondViewController class]; break; default: NSLog(@"unknown index for loading view controller: %d", vcIndex); // error break; } if ((NSNull *)controller == [NSNull null]) { controller = [[c alloc] initWithNib]; [viewControllers replaceObjectAtIndex:vcIndex withObject:controller]; [controller release]; } if (controller.view.superview == nil) { UIView *placeholderView = [viewControllerPlaceholderViews objectAtIndex:vcIndex]; [placeholderView addSubview:controller.view]; } [arPool release]; } Althoug I do create an autorelease pool there for that thread, I always get this error: 2009-05-30 12:03:09.910 Demo[1827:3f03] *** _NSAutoreleaseNoPool(): Object 0x523e50 of class NSCFNumber autoreleased with no pool in place - just leaking Stack: (0x95c83f0f 0x95b90442 0x28d3 0x2d42 0x95b96e0d 0x95b969b4 0x93a00155 0x93a00012) If I take away the autorelease pool, I get a whole bunch of messages like these. I also tried to create an autorelease pool around the call of the performSelectorInBackground:, but that doesn't help. I suspect the parameter, but I don't know why the compiler complains about an NSCFNumber. Am I missing something? My Instance variables are all "nonatomic". Can that be a problem? UPDATE: I may also suspect that some variable has been added to an autorelease pool of the main thread (maybe an ivar), and now it trys to release that one inside the wrong autorelease pool? If so, how could I fix that? (damn, this threading stuff is complex ;) )

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  • Is it normal for C++ static initialization to appear twice in the same backtrace?

    - by Joseph Garvin
    I'm trying to debug a C++ program compiled with GCC that freezes at startup. GCC mutex protects function's static local variables, and it appears that waiting to acquire such a lock is why it freezes. How this happens is rather confusing. First module A's static initialization occurs (there are __static_init functions GCC invokes that are visible in the backtrace), which calls a function Foo(), that has a static local variable. The static local variable is an object who's constructor calls through several layers of functions, then suddenly the backtrace has a few ??'s, and then it's is in the static initialization of a second module B (the __static functions occur all over again), which then calls Foo(), but since Foo() never returned the first time the mutex on the local static variable is still set, and it locks. How can one static init trigger another? My first theory was shared libraries -- that module A would be calling some function in module B that would cause module B to load, thus triggering B's static init, but that doesn't appear to be the case. Module A doesn't use module B at all. So I have a second (and horrifying) guess. Say that: Module A uses some templated function or a function in a templated class, e.g. foo<int>::bar() Module B also uses foo<int>::bar() Module A doesn't depend on module B at all At link time, the linker has two instances of foo<int>::bar(), but this is OK because template functions are marked as weak symbols... At runtime, module A calls foo<int>::bar, and the static init of module B is triggered, even though module B doesn't depend on module A! Why? Because the linker decided to go with module B's instance of foo::bar instead of module A's instance at link time. Is this particular scenario valid? Or should one module's static init never trigger static init in another module?

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  • How to make gcc on SUN calculate floating points the same way as in Linux

    - by Marina
    I have a project where I have to perform some mathematics calculations with double variables. The problem is that I get different results on SUN Solaris 9 and Linux. There are a lot of ways (explained here and other forums) how to make Linux work as Sun, but not the other way around. I cannot touch the Linux code, so it is only SUN I can change. Is there any way to make SUN to behave as Linux? The code I run(compile with gcc on both systems): int hash_func(char *long_id) { double product, lnum, gold; while (*long_id) lnum = lnum * 10.0 + (*long_id++ - '0'); printf("lnum => %20.20f\n", lnum); lnum = lnum * 10.0E-8; printf("lnum => %20.20f\n", lnum); gold = 0.6125423371582974; product = lnum * gold; printf("product => %20.20f\n", product); ... } if the input is 339886769243483 the output in Linux: lnum => 339886769243**483**.00000000000000000000 lnum => 33988676.9243**4829473495483398** product => 20819503.600158**59827399253845** When on SUN: lnum => 339886769243483.00000000000000000000 lnum => 33988676.92434830218553543091 product = 20819503.600158**60199928283691** Note: The result is not always different, moreover most of the times it is the same. Just 10 15-digit numbers out of 60000 have this problem. Please help!!!

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  • Accessing functions in a swf-file through javascript [chatroulette.com]

    - by RadiantHeart
    Lately I have been interested in the code behind chatroulette.com. As you probably know it is a peer-to-peer webcam-chat-service written in actionscript, as I understand. What i have been wondering about is weather its possible to extract the ip-address of whomever you are currently communicating with. I have seen services that do that, but they require that you install a program that runs alongside on your computer sniffing UDP-packages. I was wondering if there was a simpler method. What I do know is that the javascript on the page communicates with the application via "ExternalInterface". On this area I am pretty much a novice but according to my limited understanding you cant get information from the flash-application unless you have configured a listener for a call from javascript and then attach a callback to that event. Is this correct or can you access public functions and variables directly through javascript? There is for example a public function like this: public function get outgoingAddress():String{ return (this.__info.outgoingAddress); } Can it be accessed directly through javascript? If it cant be done so easily, is it possible to decompile the .swf-file, change it (add some functions) and recompile it and run it instead? I am hoping someone can satisfy my curiosity here. Here are two links to a decompiled version of the swf-file. The first with line numbering and one without. With line numbering ˜ 3.5 Mbyte Without line numbering ˜ 2.1 Mbyte

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  • Heroku: bash: bundle: command not found

    - by Space Monkey
    My heroku deployment is crashing with following errors. 2012-12-12T17:16:18+00:00 app[web.1]: bash: bundle: command not found 2012-12-12T17:16:19+00:00 heroku[web.1]: Process exited with status 127 2012-12-12T17:16:19+00:00 heroku[web.1]: State changed from starting to crashed The Heroku documentation for this error is to set PATH and GEM variables as described in https://devcenter.heroku.com/articles/changing-ruby-version-breaks-path I tried that, however that too is not helping. ? heroku config:add PATH=bin:vendor/bundle/ruby/1.9.1/bin:/usr/local/bin:/usr/bin:/bin ? heroku config:add GEM_PATH=vendor/bundle/ruby/1.9.1 ? heroku run rake db:migrate Running rake db:migrate attached to terminal... up, run.7130 bash: bundle: command not found Next, I tried setting Ruby version in my Heroku app. This increased the slugsize. But app was still not up. Gemfile ruby "1.9.2" Pushed to Heroku -----> Using Ruby version: ruby-1.9.2 -----> Installing dependencies using Bundler version 1.2.2 heroku run "ruby -v" Running `ruby -v` attached to terminal... up, run.4483 ruby 1.9.2p320 (2012-04-20 revision 35421) [x86_64-linux] Can someone please advice

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  • unable to compile a servlet in ubuntu

    - by codeomnitrix
    I am newbie to j2ee. I have download and installed j2eesdk-1_4_03-linux.bin in my ubuntu 10.04 distribution. and then i tried to code my first servlet in it as: import java.io.*; import javax.servelet.*; import javax.servelet.http.*; public class HowdyServelet extends HttpServelet{ public void doGet(HttpServeletRequest request, HttpServeletResponse response) throws IOException, ServeletException{ PrintWriter out = response.getWriter(); response.setContentType("text/html"); out.println("<html>"); out.println("<head><title>howdy</title></head>"); out.println("<body>"); out.println("<center><h1>Howdy</h1></center>"); out.println("</body>"); out.println("</html>"); } } and here are the environment variables i set after installation: 1. J2EE_HOME=/home/vinit/SUNWappserver 2. JAVA_HOME=/home/vinit/SUNWappserver/jdk 3. CLASSPATH=/home/vinit/SUNWappserver/lib and now i tried to compile the servlet using javac HowdyServelet.java But i got following errors: HowdyServelet.java:2: package javax.servelet does not exist import javax.servelet.*; ^ HowdyServelet.java:3: package javax.servelet.http does not exist import javax.servelet.http.*; ^ HowdyServelet.java:5: cannot find symbol symbol: class HttpServelet public class HowdyServelet extends HttpServelet{ ^ HowdyServelet.java:6: cannot find symbol symbol : class HttpServeletRequest location: class HowdyServelet public void doGet(HttpServeletRequest request, HttpServeletResponse response) throws IOException, ServeletException{ ^ HowdyServelet.java:6: cannot find symbol symbol : class HttpServeletResponse location: class HowdyServelet public void doGet(HttpServeletRequest request, HttpServeletResponse response) throws IOException, ServeletException{ ^ HowdyServelet.java:6: cannot find symbol symbol : class ServeletException location: class HowdyServelet public void doGet(HttpServeletRequest request, HttpServeletResponse response) throws IOException, ServeletException{ ^ 6 errors So how to compile this servlet. Thanks in advance.

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  • Trying to set up nested while loops using a boolean switch

    - by thorn100
    First time posting. I'm trying to set up a while loop that will ask the user for the employee name, hours worked and hourly wage until the user enters 'DONE'. Eventually I'll modify the code to calculate the weekly pay and write it to a list, but one thing at a time. The problem is once the main while loop executes once, it just stops. Doesn't error out but just stops. I have to kill the program to get it to stop. I want it to ask the three questions again and again until the user is finished. Thoughts? Please note that this is just an exercise and not meant for any real world application. def getName(): """Asks for the employee's full name""" firstName=raw_input("\nWhat is your first name? ") lastName=raw_input("\nWhat is your last name? ") fullName=firstName.title() + " " + lastName.title() return fullName def getHours(): """Asks for the number of hours the employee worked""" hoursWorked=0 while int(hoursWorked)<1 or int(hoursWorked) > 60: hoursWorked=raw_input("\nHow many hours did the employee work: ") if int(hoursWorked)<1 or int(hoursWorked) > 60: print "Please enter an integer between 1 and 60." else: return hoursWorked def getWage(): """Asks for the employee's hourly wage""" wage=0 while float(wage)<6.00 or float(wage)>20.00: wage=raw_input("\nWhat is the employee's hourly wage: ") if float(wage)<6.00 or float(wage)>20.00: print ("Please enter an hourly wage between $6.00 and $20.00") else: return wage ##sentry variables employeeName="" employeeHours=0 employeeWage=0 booleanDone=False #Enter employee info print "Please enter payroll information for an employee or enter 'DONE' to quit." while booleanDone==False: while employeeName=="": employeeName=getName() if employeeName.lower()=="done": booleanDone=True break print "The employee's name is", employeeName while employeeHours==0: employeeHours=getHours() if employeeHours.lower()=="done": booleanDone=True break print employeeName, "worked", employeeHours, "this week." while employeeWage==0: employeeWage=getWage() if employeeWage.lower()=="done": booleanDone=True break print employeeName + "'s hourly wage is $" + employeeWage

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  • Is it legal to extend the Class class?

    - by spiralganglion
    I've been writing a system that generates some templates, and then generates some objects based on those templates. I had the idea that the templates could be extensions of the Class class, but that resulted in some magnificent errors: VerifyError: Error #1107: The ABC data is corrupt, attempt to read out of bounds. What I'm wondering is if subclassing Class is even possible, if there is perhaps some case where doing this would be appropriate, and not just a gross misuse of OOP. I believe it should be possible, as ActionScript allows you to create variables of the Class type. This use is described in the LiveDocs entry for Class, yet I've seen no mentions of subclassing Class. Here's a pseudocode example: class Foo extends Class var a:Foo = new Foo(); trace(a is Class) // true, right? var b = new a(); I have no idea what the type of b would be. In summary: can you subclass the Class class? If so, how can you do it without errors, and what type are the instances of the instances of the Class subclass?

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  • How to increase the performance of a loop which runs for every 'n' minutes.

    - by GustlyWind
    Hi Giving small background to my requirement and what i had accomplished so far: There are 18 Scheduler tasks run at regular intervals (least being 30 mins) takes input of nearly 5000 eligible employees run into a static method for iteration and generates a mail content for that employee and mails. An average task takes about 9 min multiplied by 18 will be roughly 162 mins meanwhile there would be next tasks which will be in queue (I assume). So my plan is something like the below loop try { // Handle Arraylist of alerts eligible employees Iterator employee = empIDs.iterator(); while (employee.hasNext()) { ScheduledImplementation.getInstance().sendAlertInfoToEmpForGivenAlertType((Long)employee.next(), configType,schedType); } } catch (Exception vEx) { _log.error("Exception Caught During sending " + configType + " messages:" + configType, vEx); } Since I know how many employees would come to my method I will divide the while loop into two and perform simultaneous operations on two or three employees at a time. Is this possible. Or is there any other ways I can improve the performance. Some of the things I had implemented so far 1.Wherever possible made methods static and variables too Didn't bother to catch exceptions and send back because these are background tasks. (And I assume this improves performance) Get the DB values in one query instead of multiple hits. If am successful in optimizing the while loop I think i can save couple of mins. Thanks

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  • Setting classpath and installing database via batch file

    - by Supereme
    Hi, I want my classpath to be set via a batch file. I'm working on Windows XP. I have two questions: My first question: I made a batch file in which I typed "set classpath = C:\WINDOWS\system32\;.;C:\jdk1.5.0\lib\tools.jar;C:\poi-3.6\poi-3.6-20091214.jar;C:\poi-3.6\poi-contrib-3.6-20091214.jar;C:\poi-3.6\poi-ooxml-3.6-20091214.jar;C:\poi-3.6\poi-ooxml-schemas-3.6-20091214.jar;C:\poi-3.6\poi-scratchpad-3.6-20091214.jar;E:\jdbc\postgresql-8.2-505.jdbc3.jar;C:\xmlbeans-2.5.0\lib\jsr173_1.0_api.jar;C:\xmlbeans-2.5.0\lib\resolver.jar;C:\xmlbeans-2.5.0\lib\xbean.jar;C:\xmlbeans-2.5.0\lib\xbean_xpath.jar;C:\xmlbeans-2.5.0\lib\xmlbeans-qname.jar;C:\xmlbeans-2.5.0\lib\xmlpublic.jar;C:\dom4j-1.6.1\dom4j-1.6.1.jar; exit" When I tried to run this file it ran but when I went into control panel systemadvancedenvironment variables and then selected classpath, it didn't show me the classpath I did set. What is the correct way to set the classpath via batch file? My second question: Is there any way by which we can install database via batch file say for eg: postgresql8.2? Thank you.

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  • Monotouch threads, GC, WCF

    - by cvista
    Hi This is a question about best practices i guess but it applies directly to my current MT project. I'm using WCF services to communicate with the server. To do this i do the following: services.MethodToCall(params); and the asynch: services.OnMethodToCallCompleted += delegate{ //do stuff and ting }; This can lead to issues if you're not careful in that variables defined within the scope of the asynch callback can sometimes be cleaned up by the gc and this can cause crashes. So - I am making it a practice to declare these outside of the scope of the callback unless I am 100% sure they are not needed. Now - when doing stuff and ting implies changing the ui - i wrap it all in an InvokeOnMainThread call. I guess wrapping everything in this would slow the main thread down and rubbish the point of having multi threads. Even though I'm being careful about all this i am still getting crashes and I have no idea why! I am certain it has something to do with threads, scope and all that. Now - the only thing I can think of outside of updating the UI that may need to happen inside of InvokeOnMainThread is that I have a singleton 'Database' class. This is based on the version 5 code from this thread http://www.yoda.arachsys.com/csharp/singleton.html So now if the service method returns data that needs to be added/updated to the Database class -I also wrap this inside an InvokeOnMainThread call. Still getting random crashes. So... My question is this: I am new to thick client dev - I'm coming from a web dev perspective where we don't need to worry about threads so much :) Aside from what I have mentioned -are there any other things I should be aware of? Is the above stuff correct? Or am i miss-understanding something? Cheers w://

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  • Javascript string replace with calculations

    - by Chris
    Is there a way to resolve mathematical expressions in strings in javascript? For example, suppose I want to produce the string "Tom has 2 apples, Lucy has 3 apples. Together they have 5 apples" but I want to be able to substitute in the variables. I can do this with a string replacement: string = "Tom has X apples, Lucy has Y apples. Together they have Z apples"; string2 = string.replace(/X/, '2').replace(/Y/, '3').replace(/Z/, '5'); However, it would be better if, instead of having a variable Z, I could use X+Y. Now, I could also do a string replace for X+Y and replace it with the correct value, but that would become messy when trying to deal with all the possible in-string calculations I might want to do. I suppose I'm looking for a way to achieve this: string = "Something [X], something [Y]. Something [(X+Y^2)/5X]"; And for the [_] parts to be understood as expressions to be resolved before substituting back into the string. Thanks for your help.

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  • PowerShell PSCX Read-Archive: Cannot bind parameter... problem

    - by Robert
    I'm running across a problem I can't seem to wrap my head around using the Read-Archive cmdlet available via PowerShell Community Extensions (v2.0.3782.38614). Here is a cut down sample used to exhibit the problem I'm running into: $mainPath = "p:\temp" $dest = Join-Path $mainPath "ps\CenCodes.zip" Read-Archive -Path $dest -Format zip Running the above produces the following error: Read-Archive : Cannot bind parameter 'Path'. Cannot convert the "p:\temp\ps\CenCodes.zip" value of type "System.String" to type "Pscx.IO.PscxPathInfo". At line:3 char:19 + Read-Archive -Path <<<< $dest -Format zip + CategoryInfo : InvalidArgument: (:) [Read-Archive], ParameterBindingException + FullyQualifiedErrorId : CannotConvertArgumentNoMessage,Pscx.Commands.IO.Compression.ReadArchiveCommand If I do not use Join-Path to build the path passed to Read-Archive it works, as in this example: $mainPath = "p:\temp" $path = $mainPath + "\ps\CenCodes.zip" Read-Archive -Path $path -Format zip Output from above: ZIP Folder: CenCodes.zip#\ Index LastWriteTime Size Ratio Name ----- ------------- ---- ----- ---- 0 6/17/2010 2:03 AM 3009106 24.53 % CenCodes.xls Even more confusing is if I compare the two variables passed as the Path argument in the two Read-Archive samples above, they seem identical: This... Write-Host "dest=$dest" Write-Host "path=$path" Write-Host ("path -eq dest is " + ($dest -eq $path).ToString()) Outputs... dest=p:\temp\ps\CenCodes.zip path=p:\temp\ps\CenCodes.zip path -eq dest is True Anyone have any ideas as to why the first sample gripes but the second one works fine?

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  • C# parameters by reference and .net garbage collection

    - by Yarko
    I have been trying to figure out the intricacies of the .NET garbage collection system and I have a question related to C# reference parameters. If I understand correctly, variables defined in a method are stored on the stack and are not affected by garbage collection. So, in this example: public class Test { public Test() { } public int DoIt() { int t = 7; Increment(ref t); return t; } private int Increment(ref int p) { p++; } } the return value of DoIt() will be 8. Since the location of t is on the stack, then that memory cannot be garbage collected or compacted and the reference variable in Increment() will always point to the proper contents of t. However, suppose we have: public class Test { private int t = 7; public Test() { } public int DoIt() { Increment(ref t); return t; } private int Increment(ref int p) { p++; } } Now, t is stored on the heap as it is a value of a specific instance of my class. Isn't this possibly a problem if I pass this value as a reference parameter? If I pass t as a reference parameter, p will point to the current location of t. However, if the garbage collector moves this object during a compact, won't that mess up the reference to t in Increment()? Or does the garbage collector update even references created by passing reference parameters? Do I have to worry about this at all? The only mention of worrying about memory being compacted on MSDN (that I can find) is in relation to passing managed references to unmanaged code. Hopefully that's because I don't have to worry about any managed references in managed code. :)

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  • Awkward looking uses of Contract.ValueAtReturn()

    - by devoured elysium
    I am designing a method that will add an element to an internal list. The structure of the class is something along the lines of: class MyCustomerDatabase { private IList<Customer> _customers = new List<Customer>(); public int NumberOfCustomers { get { return _customers; } } public void AddCustomer(Customer customer) { _customers.Add(customer); } } Now, I was thinking of adding a Contract.Ensures() about the size of the _customers growing by 1 with this call. The problem is that I end up with some weird looking code: public void AddCustomer(Customer customer) { int numberOfCustomersAtReturn; Contract.Ensures(Contract.ValueAtReturn<int>(out numberOfCustomersAtReturn) == Contract.OldValue<int>(NumberOfCustomers) + 1); _customers.Add(customer); numberOfCustomersAtReturn = NumberOfCustomers; } The main problem is that properties are in fact methods, so you can't just reference them direcly when using Contract.ValueAtReturn() as its only parameter accepts variables as out. The situation gets even odder if I want to achieve the same but this time with a method that should return a value: public int MyReturningMethod() { ... return abc(); //abc will add by one the number of customers in list } //gets converted to public int MyReturningMethod() { int numberOfCustomersAtReturn; Contract.Ensures(Contract.ValueAtReturn<int>(out numberOfCustomersAtReturn) == Contract.OldValue<int>(NumberOfCustomers) + 1); int returnValue = abc(); numberOfCustomersAtReturn = NumberOfCustomers; return returnValue; } This seems pretty clumsy :( Code Contracts should aim to get things clearer and this seems right the opposite. Am I doing something wrong? Thanks

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  • PHP & cUrl - POST problems in while loop.

    - by Max Hoff
    I have a while loop, with cUrl inside. (I can't use curl_multi for various reasons.) The problem is that cUrl seems to save the data it POSTS after each loop traversal. For instance, if parameter X is One the first loop through, and if it's Two the second loop through, cUrl posts: "One,Two". It should just POST "Two".(This is despite closing and unsetting the curl handle.) Here's a simplified version of the code (with unecessary info stripped out): while(true){ // code to form the $url. this code is local to the loop. so the variables should be "erased" and made new for each loop through. $ch = curl_init(); $userAgent = 'Googlebot/2.1 (http://www.googlebot.com/bot.html)'; curl_setopt($ch,CURLOPT_USERAGENT, $userAgent); curl_setopt($ch,CURLOPT_URL,$url); curl_setopt($ch,CURLOPT_POST,count($fields)); curl_setopt($ch,CURLOPT_POSTFIELDS,$fields_string); curl_setopt($ch, CURLOPT_FAILONERROR, true); curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true); curl_setopt($ch, CURLOPT_AUTOREFERER, true); curl_setopt($ch, CURLOPT_RETURNTRANSFER,true); curl_setopt($ch, CURLOPT_TIMEOUT, 10); $html = curl_exec($ch); curl_close($ch); unset($ch); $dom = new DOMDocument(); @$dom->loadHTML($html); $xpath = new DOMXPath($dom); $resultTable = $xpath->evaluate("/html/body//table"); // $resultTable is 20 the first time through the loop, and 0 everytime thereafter becauset he POSTing doesn't work right with the "saved" parameters. What am I doing wrong here?

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  • Interface vs Abstract Class (general OO)

    - by Kave
    Hi, I have had recently two telephone interviews where I've been asked about the differences between an Interface and an Abstract class. I have explained every aspect of them I could think of, but it seems they are waiting for me to mention something specific, and I dont know what it is. From my experience I think the following is true, if i am missing a major point please let me know: Interface: Every single Method declared in an Interface will have to be implemented in the subclass. Only Events, Delegates, Properties (C#) and Methods can exist in a Interface. A class can implement multiple Interfaces. Abstract Class Only Abstract methods have to be implemented by the subclass. An Abstract class can have normal methods with implementations. Abstract class can also have class variables beside Events, Delegates, Properties and Methods. A class can only implement one abstract class only due non-existence of Multi-inheritance in C#. 1) After all that the interviewer came up with the question What if you had an Abstract class with only abstract methods, how would that be different from an interface? I didnt know the answer but I think its the inheritance as mentioned above right? 2) An another interviewer asked me what if you had a Public variable inside the interface, how would that be different than in Abstract Class? I insisted you can't have a public variable inside an interface. I didn't know what he wanted to hear but he wasn't satisfied either. Many Thanks for clarification, Kave See Also: When to use an interface instead of an abstract class and vice versa Interfaces vs. Abstract Classes How do you decide between using an Abstract Class and an Interface?

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  • jQuery attribute question

    - by Nick Simone
    I'm trying to select a series of divs one at a time. I'm sure theres a better way to do this, but I gave them all unique rels and I'm using the rels to select them one at a time. I want to move them over the width of the div, then animate it dropping down the screen. What I have is: $(document).ready(function(){ var totalbricks = 7; var index = 2; $(".brick").animate({top:"600px"}); while(index < totalbricks) { var postion = 45*index; $(".brick[rel='+index+']").css('left', postion+'px'); $(".brick[rel='+index+']").animate({top:"600px"}); index++; } }); All the divs are in a container div. Jquery docs say, 'Variables can be used using the following syntax: [name='" +MyVar+ "']' What am I doing wrong? Here is the HTML that is being used by the jQuery <body> <div id="container"> <div id="canvas"> <div class="brick" rel="1"> </div> <div class="brick" rel="2"> </div> <div class="brick" rel="3"> </div> <div class="brick" rel="4"> </div> <div class="brick" rel="5"> </div> <div class="brick" rel="6"> </div> <div class="brick" rel="7"> </div> </div> </div> </body>

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  • using volatile keyword

    - by sap
    As i understand, if we declare a variable as volatile, then it will not be stored in the local cache. Whenever thread are updating the values, it is updated to the main memory. So, other threads can access the updated value. But in the following program both volatile and non-volatile variables are displaying same value. The volatile variable is not updated for the second thread. Can anybody plz explain this why testValue is not changed. class ExampleThread extends Thread { private int testValue1; private volatile int testValue; public ExampleThread(String str){ super(str); } public void run() { if (getName().equals("Thread 1 ")) { testValue = 10; testValue1= 10; System.out.println( "Thread 1 testValue1 : " + testValue1); System.out.println( "Thread 1 testValue : " + testValue); } if (getName().equals("Thread 2 ")) { System.out.println( "Thread 2 testValue1 : " + testValue1); System.out.println( "Thread 2 testValue : " + testValue); } } } public class VolatileExample { public static void main(String args[]) { new ExampleThread("Thread 1 ").start(); new ExampleThread("Thread 2 ").start(); } } output: Thread 1 testValue1 : 10 Thread 1 testValue : 10 Thread 2 testValue1 : 0 Thread 2 testValue : 0

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  • Does this language feature already exists?

    - by Pindatjuh
    I'm currently developing a new language for programming in a continuous environment (compare it to electrical engineering), and I've got some ideas on a certain language construction. Let me explain the feature by explanation and then by definition; x = a | b; Where x is a variable and a and b are other variables (or static values). if(x == a) { // all references to "x" are essentially references to "a". } if(x == b) { // same but with "b" } if(x != a) { // ... } if(x == a | b) { // guaranteed that "x" is '"a" | "b"'; interacting with "x" // will interact with both "a" and "b". } // etc. In the above, all code-blocks are executed, but the "scope" changes in each block how x is interpreted. In the first block, x is guaranteed to be a: thus interacting with x inside that block will interact on a. The second and the third code-block are only equal in this situation (because not b only remains a). The last block guarantees that x is at least a or b. Further more; | is not the "bitwise or operator", but I've called it the "and/or"-operator. It's definition is: "|" = "and" | "or" (On my blog, http://cplang.wordpress.com/2009/12/19/binop-and-or/, is more (mathematical) background information on this operator. It's loosely based on sets.) I do not know if this construction already exists, so that's my question: does this language feature already exists?

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  • Optimizing a shared buffer in a producer/consumer multithreaded environment

    - by Etan
    I have some project where I have a single producer thread which writes events into a buffer, and an additional single consumer thread which takes events from the buffer. My goal is to optimize this thing for a single machine to achieve maximum throughput. Currently, I am using some simple lock-free ring buffer (lock-free is possible since I have only one consumer and one producer thread and therefore the pointers are only updated by a single thread). #define BUF_SIZE 32768 struct buf_t { volatile int writepos; volatile void * buffer[BUF_SIZE]; volatile int readpos;) }; void produce (buf_t *b, void * e) { int next = (b->writepos+1) % BUF_SIZE; while (b->readpos == next); // queue is full. wait b->buffer[b->writepos] = e; b->writepos = next; } void * consume (buf_t *b) { while (b->readpos == b->writepos); // nothing to consume. wait int next = (b->readpos+1) % BUF_SIZE; void * res = b->buffer[b->readpos]; b->readpos = next; return res; } buf_t *alloc () { buf_t *b = (buf_t *)malloc(sizeof(buf_t)); b->writepos = 0; b->readpos = 0; return b; } However, this implementation is not yet fast enough and should be optimized further. I've tried with different BUF_SIZE values and got some speed-up. Additionaly, I've moved writepos before the buffer and readpos after the buffer to ensure that both variables are on different cache lines which resulted also in some speed. What I need is a speedup of about 400 %. Do you have any ideas how I could achieve this using things like padding etc?

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  • Mysqli connection trying with different users

    - by gerardo
    I'm trying to create a PHP class extending mysqli that is capable of connecting with another user if the connection fails. It is probably easier to explain with code: public function __construct() { $users = new ArrayObject(self::$user); $passwords = new ArrayObject(self::$pass); $itUser = $users->getIterator(); $itPass = $passwords->getIterator(); parent::__construct(self::$host, $itUser->current(), $itPass->current(), self::$prefix.self::$db); while($this->connect_errno && $itUser->valid()){ $itUser->next(); $itPass->next(); $this->change_user($itUser->current(), $itPass->current(), self::$prefix.self::$db); } if($this->connect_errno) throw new Exception("Error", $this->connect_errno); } $user and $pass are static variables containing arrays of users and passwords. If the first user fails to connect, I try with the next one. The problem here is with $this->connect_errno. It says it cannot find Mysqli. Is there any solution to this or should I create a Factory class?

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  • Javascript: I can get the text of a selection, now how do I get the text outside the selection?

    - by DavidR
    I have a bit of code that returns the text of a selection and I can assign that string to a variable, but now all I need are two variables, one for the text before the selection and one for the text after the selection. Here is the code for getting the selection: function findSelection(){ //returns the selection object. var userSelection; if (window.getSelection) {userSelection = window.getSelection();} // Mozilla Selection object. else if (document.selection){userSelection = document.selection.createRange();} //gets Microsoft Text Range, should be second b/c Opera has poor support for it. if (userSelection.text){return userSelection.text} //for Microsoft Objects. else {return userSelection} //For Mozilla Objects. } Then I find the anchorOffset and focusOffset to find the caret positions. I tried using these to modify a range object, like this: var range = document.createRange(); range.setStart(textdiv,0); range.setEnd(textdiv,5); Where textdiv is a variable holding the last div the user clicked on. The problem is firefox just gives me a "Security error" code: "1000" at the line range.setStart(textdiv,0);. Is there an easier way to go about doing this? I really just need the text and nothing more.

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  • Maven: properties not being substituted

    - by jobrahms
    I'm using a maven plugin for install4j in my project, located here. That plugin lets you pass variables to install4j using the <compilerVariables> section. Here's the relevant section of my pom: <plugin> <groupId>com.google.code.maven-install4j</groupId> <artifactId>maven-install4j-plugin</artifactId> <version>0.1.1</version> <configuration> <executable>${devenv.install4jc}</executable> <configFile>${basedir}/newinstaller/ehd.install4j</configFile> <releaseId>${project.version}</releaseId> <attach>false</attach> <skipOnMissingExecutable>false</skipOnMissingExecutable> <compilerVariables> <property> <name>m2_home</name> <value>${settings.localRepository}</value> </property> </compilerVariables> </configuration> </plugin> The problem is that ${settings.localRepository} is not being substituted with the actual directory when I run the plugin. Here's the command line script that install4j is generating: [INFO] Running the following command for install4j compile: /bin/sh -c /home/zach/install4j/bin/install4jc --release=9.1-SNAPSHOT --destination="/home/zach/projects/java/ehdtrunk/target/install4j" -D m2_home=${settings.localRepository} /home/zach/projects/java/ehdtrunk/newinstaller/ehd.install4j Is this the fault of the plugin? If so, what needs to change to allow the substitution to happen?

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  • Can a C# method chain be "too long"?

    - by ccornet
    Not in terms of readability, naturally, since you can always arrange the separate methods into separate lines. Rather, is it dangerous, for any reason, to chain an excessively large number of methods together? I use method chaining primarily to save space on declaring individual one-use variables, and traditionally using return methods instead of methods that modify the caller. Except for string methods, those I kinda chain mercilessly. In any case, I worry sometimes about the impact of using exceptionally long method chains all in one line. Let's say I need to update the value of one item based on someone's username. Unfortunately, the shortest method to retrieve the correct user looks something like the following. SPWeb web = GetWorkflowWeb(); SPList list2 = web.Lists["Wars"]; SPListItem item2 = list2.GetItemById(3); SPListItem item3 = item2.GetItemFromLookup("Armies", "Allied Army"); SPUser user2 = item2.GetSPUser("Commander"); SPUser user3 = user2.GetAssociate("Spouse"); string username2 = user3.Name; item1["Contact"] = username2; Everything with a 2 or 3 lasts for only one call, so I might condense it as the following (which also lets me get rid of a would-be-superfluous 1): SPWeb web = GetWorkflowWeb(); item["Contact"] = web.Lists["Armies"] .GetItemById(3) .GetItemFromLookup("Armies", "Allied Army") .GetSPUser("Commander") .GetAssociate("Spouse") .Name; Admittedly, it looks a lot longer when it is all in one line and when you have int.Parse(ddlArmy.SelectedValue.CutBefore(";#", false)) instead of 3. Nevertheless, this is one of the average lengths of these chains, and I can easily foresee some of exceptionally longer counts. Excluding readability, is there anything I should be worried about for these 10+ method chains? Or is there no harm in using really really long method chains?

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