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  • connecting to MySQL using JDBC in eclipse

    - by Noona
    Hello, So I want to create a JDBC connection to MySQL server that is installed on my pc, here are the steps, I installed MySQL with the username and password "root", downloaded mysql-connector-java and from theere I coped the JAR "mysql-connector-java-5.1.12-bin" to "C:\Sun\SDK\jdk\jre\lib\ext", I then added it as an external JAR in my project in eclipse, now in my class I have this code: public void initialiseDatabase() { try { // Load the Driver class. Class.forName("com.mysql.jdbc.Driver"); //Create the connection using the static getConnection method databaseConnection = DriverManager.getConnection (databaseUrl+databaseName, dbUserName, dbPassword); sqlStatement = databaseConnection.createStatement(); } catch (SQLException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();} } (this is going to be psuedocode cause I am reading from a properties file and don't want the one helping me reading through long lines of code from main to figure out all the variables), where databaseUrl = "127.0.0.1" dbUserName = "root" dbPassword = "root" databaseName = "MySQL" //this one I am not sure of, do I need to create it or is it set inherenrly? now the MySQL server is up and running, but when I call the method initialiseDatabase the following exception is thrown: "java.sql.SQLException: No suitable driver found for rootroot at java.sql.DriverManager.getConnection(Unknown Source) at java.sql.DriverManager.getConnection(Unknown Source) at Proxy$JDBCConnection.initialiseDatabase(Proxy.java:721)" when line 721 is: sqlStatement = databaseConnection.createStatement(); Where have I gone wrong? thanks

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  • .Net Remoting: Serialize Object and implementation

    - by flogo
    Hi, In my scenario there is a client-side assembly that contains a class (Task). This class implements an interface (ITask) that is known on the server. I'm trying to send a Task object from client to server without copying the assembly of the client manually to the server. If I just serialize the task object, the server obviously complains about the missing assembly. I then tried to serialze typeof(Task).Assembly but could not derserialize it on the server. Next I tried to File.ReadAllBytes(typeof(Task).Assembly.Location) and saved it to a temporary file on the server, which threw an exception on Assembly.LoadFrom(@".\temporary.dll"); Why am I doing this? Java RMI has a neat feature to request the implementation of an object that is received through remoting but is stil "unkown" (this JVM doesn't have the *.class file). This can be used for a compute server that just knows the interface of a "task" containing a run() method and downloads the implementation of this method on demand. This way the server doesn't have to be changed for new tasks. I'm trying to achieve something like this in .Net.

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  • Connecting an overloaded PyQT signal using new-style syntax

    - by Claudio
    I am designing a custom widget which is basically a QGroupBox holding a configurable number of QCheckBox buttons, where each one of them should control a particular bit in a bitmask represented by a QBitArray. In order to do that, I added the QCheckBox instances to a QButtonGroup, with each button given an integer ID: def populate(self, num_bits, parent = None): """ Adds check boxes to the GroupBox according to the bitmask size """ self.bitArray.resize(num_bits) layout = QHBoxLayout() for i in range(num_bits): cb = QCheckBox() cb.setText(QString.number(i)) self.buttonGroup.addButton(cb, i) layout.addWidget(cb) self.setLayout(layout) Then, each time a user would click on a checkbox contained in self.buttonGroup, I'd like self.bitArray to be notified so I can set/unset the corresponding bit in the array. For that I intended to connect QButtonGroup's buttonClicked(int) signal to QBitArray's toggleBit(int) method and, to be as pythonic as possible, I wanted to use new-style signals syntax, so I tried this: self.buttonGroup.buttonClicked.connect(self.bitArray.toggleBit) The problem is that buttonClicked is an overloaded signal, so there is also the buttonClicked(QAbstractButton*) signature. In fact, when the program is executing I get this error when I click a check box: The debugged program raised the exception unhandled TypeError "QBitArray.toggleBit(int): argument 1 has unexpected type 'QCheckBox'" which clearly shows the toggleBit method received the buttonClicked(QAbstractButton*) signal instead of the buttonClicked(int) one. So, the question is, how can we specify, using new-style syntax, that self.buttonGroup emits the buttonClicked(int) signal instead of the default overload - buttonClicked(QAbstractButton*)?

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  • Performance of map overlay in conjunction with ItemizedOverlay is very poor

    - by oviroa
    I am trying to display one png (drawable) on a map in about 300 points. I am retrieving the coordinates from a Sqlite table, dumping them in a cursor. When I try to display them by parsing through the cursor, it takes for ever for the images to be drawn, about .5 second per image. I find that to be suspiciously slow, so some insight on how I can increase performance would help. Here is the snippet of my code that does the rendering: while (!mFlavorsCursor.isAfterLast()) { Log.d("cursor",""+(i++)); point = new GeoPoint( (int)(mFlavorsCursor.getFloat(mFlavorsCursor.getColumnIndex(DataBaseHelper.KEY_LATITUDE))*1000000), (int)(mFlavorsCursor.getFloat(mFlavorsCursor.getColumnIndex(DataBaseHelper.KEY_LONGITUDE))*1000000)); overlayitem = new OverlayItem(point, "", ""); itemizedoverlay.addOverlay(overlayitem); itemizedoverlay.doPopulate(); mFlavorsCursor.moveToNext(); } mapOverlays.add(itemizedoverlay); I tried to isolate all the steps and it looks like the slow one is this: itemizedoverlay.doPopulate(); This is a public method in my class that extends ItemizedOverlay that runs the private populate() method.

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  • django hidden field error

    - by dana
    hi, there, i'm building a message system for a virtual community, but i can't take the userprofile id i have in views.py def save_message(request): if request.method == 'POST': form = MessageForm(request.POST) if form.is_valid(): new_obj = form.save(commit=False) new_obj.sender = request.user u = UserProfile.objects.get(request.POST['userprofile_id']) new_obj.owner = u new_obj.save() return HttpResponseRedirect('.') else: form = MessageForm() return render_to_response('messages/messages.html', { 'form': form, }, context_instance=RequestContext(request)) and the template: {% block primary %} <form action="." method="post"> {{ form.as_p }} <p><input type="hidden" value="{{ userprofile.id }}" name = "owner" /></p> <p><input type="submit" value="Send Message!" /></p> </form> {% endblock %} forms.py: class MessageForm(ModelForm): class Meta: model = Messages fields = ['message'] models.py: class Messages(models.Model): message = models.CharField(max_length = 300) read = models.BooleanField(default=False) owner = models.ForeignKey(UserProfile) sender = models.ForeignKey(User) I don't figure out why i get this error,since i'm just trying to get the profileId of a user, using a hiddeen field. the error is: Key 'UserProfile_id' not found in <QueryDict: {u'owner': [u''], u'message': [u'fdghjkl']}> and i'm getting it after i fill out the message text field. Thanks!

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  • how do I insert an hidden token in my form to prevent double posts? (PHP)

    - by jpjp
    I want to prevent users from accidentally posting a comment twice. I use the PRG (post redirect get) method, so that I insert the data on another page then redirect the user back to the page which shows the comment. This allows users to refresh as many times as they want. However this doesn't work when the user goes back and clicks submit again or when they click submit 100 times really fast. I don't want 100 of the same comments. I looked at related questions on SO and found that a token is best. But I am having trouble using it. //makerandomtoken(20) returns a random 20 length char. <form method="post" ... > <input type="text" id="comments" name="comments" class="commentbox" /><br/> <input type="hidden" name="_token" value="<?php echo $token=makerandomtoken(20); ?>" /> <input type="submit" value="submit" name="submit" /> </form> if (isset($_POST['submit']) && !empty($comments)) { $comments= mysqli_real_escape_string($dbc,trim($_POST['comments'])); //how do I make the if-statment to check if the token has been already set once? if ( ____________){ //don't insert comment because already clicked submit } else{ //insert the comment into the database } } So I have the token as a hidden value, but how do I use that to prevent multiple clicking of submit.

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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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  • Memory leak when returning object

    - by Yakattak
    I have this memory leak that has been very stubborn for the past week or so. I have a class method I use in a class called "ArchiveManager" that will unarchive a specific .dat file for me, and return an array with it's contents. Here is the method: +(NSMutableArray *)unarchiveCustomObject { NSMutableArray *array = [NSMutableArray arrayWithArray:[NSKeyedUnarchiver unarchiveObjectWithFile:/* Archive Path */]]; return array; } I understand I don't have ownership of it at this point, and I return it. CustomObject *myObject = [[ArchiveManager unarchiveCustomObject] objectAtIndex:0]; Then, later when I unarchive it in a view controller to be used (I don't even create an array of it, nor do I make a pointer to it, I just reference it to get something out of the array returned by unarchiveCustomIbject (objectAtIndex). This is where Instruments is calling a memory leak, yet I don't see how this can leak! Any ideas? Thanks in advance. Edit: CustomObject initWithCoder added: -(id)initWithCoder:(NSCoder *)aDecoder { if (self = [super init]) { self.string1 = [aDecoder decodeObjectForKey:kString1]; self.string2 = [aDecoder decodeObjectForKey:kString2]; self.string3 = [aDecoder decodeObjectForKey:kString3]; UIImage *picture = [[UIImage alloc] initWithData:[aDecoder decodeObjectForKey:kPicture]]; self.picture = picture; self.array = [aDecoder decodeObjectForKey:kArray]; [picture release]; } return self; }

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  • C# Multithreaded Domain Design

    - by Thijs Cramer
    Let's say i have a Domain Model that im trying to make compatible with multithreading. The prototype domain is a game domain that consists of Space, SpaceObject, and Location objects. A SpaceObject has the Move method and Asteroid and Ship extend this object with specific properties for the object (Ship has a name and Asteroid has a color) Let's say i want to make the Move method for each object run in a seperate thread. That would be stupid because with 10000 objects, i would have 10000 threads. What would be the best way to seperate the workload between cores/threads? I'm trying to learn the basics of concurrency, and building a small game to prototype a lot of concepts. What i've already done, is build a domain, and a threading model with a timer that launches events based on intervals. If the event occurs i want to update my entire model with the new locations of any SpaceObject. But i don't know how and when to launch new threads with workloads when the event occurs. Some people at work told me that u can't update your core domain multithreaded, because you have to synch everything. But in that case i can't run my game on a dual quadcore server, because it would only use 1 CPU for the hardest tasks. Anyone know what to do here?

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  • Question about making Asynchronous call in C# (WPF) to COM object

    - by Andrew
    Hi, Sorry to ask such a basic question but I seem to have a brain freeze on this one! I'm calling a COM (ATL) object from my WPF project. The COM method might take a long time to complete. I thought I'd try and call it asychronously. I have a few demo lines that show the problem. private void checkBox1_Checked(object sender, RoutedEventArgs e) { //DoSomeWork(); AsyncDoWork caller = new AsyncDoWork(DoSomeWork); IAsyncResult result = caller.BeginInvoke(null, null); } private delegate void AsyncDoWork(); private void DoSomeWork() { _Server.DoWork(); } The ATL method DoWork is very exciting. It is: STDMETHODIMP CSimpleObject::DoWork(void) { Sleep(5000); return S_OK; } I had expectations that running this way would result in the checkbox being checked right away (instead of in 5 seconds) and me being able to move the WPF gui around the screen. I can't - for 5 seconds. What am I doing wrong? I'm sure it's something pretty simple. Delegate signature wrong? Thanks.

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  • How to interrupt a thread performing a blocking socket connect?

    - by Jason R
    I have some code that spawns a pthread that attempts to maintain a socket connection to a remote host. If the connection is ever lost, it attempts to reconnect using a blocking connect() call on its socket. Since the code runs in a separate thread, I don't really care about the fact that it uses the synchronous socket API. That is, until it comes time for my application to exit. I would like to perform some semblance of an orderly shutdown, so I use thread synchronization primitives to wake up the thread and signal for it to exit, then perform a pthread_join() on the thread to wait for it to complete. This works great, unless the thread is in the middle of a connect() call when I command the shutdown. In that case, I have to wait for the connect to time out, which could be a long time. This makes the application appear to take a long time to shut down. What I would like to do is to interrupt the call to connect() in some way. After the call returns, the thread will notice my exit signal and shut down cleanly. Since connect() is a system call, I thought that I might be able to intentionally interrupt it using a signal (thus making the call return EINTR), but I'm not sure if this is a robust method in a POSIX threads environment. Does anyone have any recommendations on how to do this, either using signals or via some other method? As a note, the connect() call is down in some library code that I cannot modify, so changing to a non-blocking socket is not an option.

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  • TransactionScope Prematurely Completed

    - by Chris
    I have a block of code that runs within a TransactionScope and within this block of code I make several calls to the DB. Selects, Updates, Creates, and Deletes, the whole gamut. When I execute my delete I execute it using an extension method of the SqlCommand that will automatically resubmit the query if it deadlocks as this query could potentially hit a deadlock. I believe the problem occurs when a deadlock is hit and the function tries to resubmit the query. This is the error I receive: The transaction associated with the current connection has completed but has not been disposed. The transaction must be disposed before the connection can be used to execute SQL statements. This is the simple code that executes the query (all of the code below executes within the using of the TransactionScope): using (sqlCommand.Connection = new SqlConnection(ConnectionStrings.App)) { sqlCommand.Connection.Open(); sqlCommand.ExecuteNonQueryWithDeadlockHandling(); } Here is the extension method that resubmits the deadlocked query: public static class SqlCommandExtender { private const int DEADLOCK_ERROR = 1205; private const int MAXIMUM_DEADLOCK_RETRIES = 5; private const int SLEEP_INCREMENT = 100; public static void ExecuteNonQueryWithDeadlockHandling(this SqlCommand sqlCommand) { int count = 0; SqlException deadlockException = null; do { if (count > 0) Thread.Sleep(count * SLEEP_INCREMENT); deadlockException = ExecuteNonQuery(sqlCommand); count++; } while (deadlockException != null && count < MAXIMUM_DEADLOCK_RETRIES); if (deadlockException != null) throw deadlockException; } private static SqlException ExecuteNonQuery(SqlCommand sqlCommand) { try { sqlCommand.ExecuteNonQuery(); } catch (SqlException exception) { if (exception.Number == DEADLOCK_ERROR) return exception; throw; } return null; } } The error occurs on the line that executes the nonquery: sqlCommand.ExecuteNonQuery();

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  • [iPhone] UIScrollView notifications

    - by ryyst
    Hi, I'm coding an app that works much like Apple's Weather.app: There's a UIPageControl at the bottom and a UIScrollView in the middle of the screen. In my code, I implemented the - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView method to figure out when the user did move to a new page. If they move to a new page, I load the adjacent pages' data, as to make further page-switching faster. (In one of Apple's examples, the - (void)scrollViewDidScroll:(UIScrollView *)sender is used, but that causes my app to shortly hang when loading a new page, so it's not suitable.) That code works very well. I'm using scrollRectToVisible:: to programmatically scroll inside the scrollview when the user clicks the UIPageControl. The problem is that the scrollRectToVisible: doesn't post a notification to the UIScrollViewDelegate when it's done scrolling - so the code responsible for loading adjacent pages never get's called when using the UIPageControl. Is there any way to make the UIScrollView notify its delegate when it gets called by the scrollRectToVisible: method? Or will I have to use threads in order to prevent my app from freezing? Thanks! -- Ry

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  • Python __subclasses__() not listing subclasses

    - by Mridang Agarwalla
    I cant seem to list all derived classes using the __subclasses__() method. Here's my directory layout: import.py backends __init__.py --digger __init__.py base.py test.py --plugins plugina_plugin.py From import.py i'm calling test.py. test.py in turn iterates over all the files in the plugins directory and loads all of them. test.py looks like this: import os import sys import re sys.path.append(os.path.join(os.path.abspath(os.path.dirname(os.path.abspath( __file__ ))))) sys.path.append(os.path.join(os.path.abspath(os.path.dirname(os.path.abspath( __file__ ))), 'plugins')) from base import BasePlugin class TestImport: def __init__(self): print 'heeeeello' PLUGIN_DIRECTORY = os.path.join(os.path.abspath(os.path.dirname(os.path.abspath( __file__ ))), 'plugins') for filename in os.listdir (PLUGIN_DIRECTORY): # Ignore subfolders if os.path.isdir (os.path.join(PLUGIN_DIRECTORY, filename)): continue else: if re.match(r".*?_plugin\.py$", filename): print ('Initialising plugin : ' + filename) __import__(re.sub(r".py", r"", filename)) print ('Plugin system initialized') print BasePlugin.__subclasses__() The problem us that the __subclasses__() method doesn't show any derived classes. All plugins in the plugins directory derive from a base class in the base.py file. base.py looks like this: class BasePlugin(object): """ Base """ def __init__(self): pass plugina_plugin.py looks like this: from base import BasePlugin class PluginA(BasePlugin): """ Plugin A """ def __init__(self): pass Could anyone help me out with this? Whatm am i doing wrong? I've racked my brains over this but I cant seem to figure it out Thanks.

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  • How to store a file on a server(web container) through a Java EE web application?

    - by Yatendra Goel
    I have developed a Java EE web application. This application allows a user to upload a file with the help of a browser. Once the user has uploaded his file, this application first stores the uploaded file on the server (on which it is running) and then processes it. At present, I am storing the file on the server as follows: try { FormFile formFile = programForm.getTheFile(); // formFile represents the uploaded file String path = getServlet().getServletContext().getRealPath("") + "/" + formFile.getFileName(); System.out.println(path); file = new File(path); outputStream = new FileOutputStream(file); outputStream.write(formFile.getFileData()); } where, the formFile represents the uploaded file. Now, the problem is that it is running fine on some servers but on some servers the getServlet().getServletContext().getRealPath("") is returning null so the final path that I am getting is null/filename and the file doesn't store on the server. When I checked the API for ServletContext.getRealPath() method, I found the following: public java.lang.String getRealPath(java.lang.String path) Returns a String containing the real path for a given virtual path. For example, the path "/index.html" returns the absolute file path on the server's filesystem would be served by a request for "http://host/contextPath/index.html", where contextPath is the context path of this ServletContext. The real path returned will be in a form appropriate to the computer and operating system on which the servlet container is running, including the proper path separators. This method returns null if the servlet container cannot translate the virtual path to a real path for any reason (such as when the content is being made available from a .war archive). So, Is there any other way by which I can store files on those servers also which is returning null for getServlet().getServletContext().getRealPath("")

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  • Best practice PHP Form Action

    - by Rob
    Hi there i've built a new script (from scratch not a CMS) and i've done alot of work on reducing memory usage and the time it takes for the page to be displayed (caching HTML etc) There's one thing that i'm not sure about though. Take a simple example of an article with a comments section. If the comment form posts to another page that then redirects back to the article page I won't have the problem of people clicking refresh and resending the information. However if I do it that way, I have to load up my script twice use twice as much memory and it takes twice as long whilst i'm still only displaying the page once. Here's an example from my load log. The first load of the article is from the cache, the second rebuilds the page after the comment is posted. Example 1 0 queries using 650856 bytes of memory in 0.018667 - domain.com/article/1/my_article.html 9 queries using 1325723 bytes of memory in 0.075825 - domain.com/article/1/my_article/newcomment.html 0 queries using 650856 bytes of memory in 0.029449 - domain.com/article/1/my_article.html Example 2 0 queries using 650856 bytes of memory in 0.023526 - domain.com/article/1/my_article.html 9 queries using 1659096 bytes of memory in 0.060032 - domain.com/article/1/my_article.html Obviously the time fluctuates so you can't really compare that. But as you can see with the first method I use more memory and it takes longer to load. BUT the first method avoides the refresh problem. Does anyone have any suggestions for the best approach or for alternative ways to avoid the extra load (admittadely minimal but i'd still like to avoid it) whilst also avoiding the refresh problem?

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  • Run JavaScript code at ASP.NET page load

    - by vaibhav
    I have a radiobox <asp:RadioButtonList CssClass="list" Style="width: 150px" ID="rdo_RSD_ExcerciseRoT" runat="server" Font-Bold="false" RepeatDirection="Horizontal" RepeatLayout="Table" TextAlign="Left" > <asp:ListItem Text="Yes" onclick="en();" Value="Y"></asp:ListItem> <asp:ListItem Text="No" onclick="dis();" Value="N" Selected="True"></asp:ListItem> </asp:RadioButtonList> AS you may see second listitem is selected by default. But issue is, when my page is getting load dis() is not getting called. I want to run dis() on page load too. I tried google, some blogs suggest the use of Page.RegisterStartupScript Method. But I dont exactly know what is the problem and why we should use this above mentioned method. I would appreciate if someone please tell me why this function is not getting called and how to call it. Edit: I am giving Javascript code also, if it helps. <script type="text/javascript"> function dis() { ValidatorEnable(document.getElementById('<%=RequiredFieldValidator32.ClientID%>'), false); } function en() { ValidatorEnable(document.getElementById('<%=RequiredFieldValidator32.ClientID%>'), true); } </script>

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  • Django formset doesn't validate

    - by tsoporan
    Hello, I am trying to save a formset but it seems to be bypassing is_valid() even though there are required fields. To test this I have a simple form: class AlbumForm(forms.Form): name = forms.CharField(required=True) The view: @login_required def add_album(request, artist): artist = Artist.objects.get(slug__iexact=artist) AlbumFormSet = formset_factory(AlbumForm) if request.method == 'POST': formset = AlbumFormSet(request.POST, request.FILES) if formset.is_valid(): return HttpResponse('worked') else: formset = AlbumFormSet() return render_to_response('submissions/addalbum.html', { 'artist': artist, 'formset': formset, }, context_instance=RequestContext(request)) And the template: <form action="" method="post" enctype="multipart/form-data">{% csrf_token %} {{ formset.management_form }} {% for form in formset.forms %} <ul class="addalbumlist"> {% for field in form %} <li> {{ field.label_tag }} {{ field }} {{ field.errors }} </li> {% endfor %} </ul> {% endfor %} <div class="inpwrap"> <input type="button" value="add another"> <input type="submit" value="add"> </div> </form> What ends up happening is I hit "add" without entering a name then HttpResponse('worked') get's called seemingly assuming it's a valid form. I might be missing something here, but I can't see what's wrong. What I want to happen is, just like any other form if the field is required to spit out an error if its not filled in. Any ideas?

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  • debugging scaffolding contingent upon degbugging boolean (java)

    - by David
    Recently i've found myself writing a lot of methods with what i can only think to call debugging scaffolding. Here's an example: public static void printArray (String[] array, boolean bug) { for (int i = 0; i<array.lenght; i++) { if (bug) System.out.print (i) ; //this line is what i'm calling the debugging scaffolding i guess. System.out.println(array[i]) ; } } in this method if i set bug to true, wherever its being called from maybe by some kind of user imput, then i get the special debugging text to let me know what index the string being printed as at just in case i needed to know for the sake of my debugging (pretend a state of affairs exists where its helpful). All of my questions more or less boil down to the question: is this a good idea? but with a tad bit more objectivity: Is this an effective way to test my methods and debug them? i mean effective in terms of efficiency and not messing up my code. Is it acceptable to leave the if (bug) stuff ; code in place after i've got my method up and working? (if a definition of "acceptability" is needed to make this question objective then use "is not a matter of programing controversy such as ommiting brackets in an if(boolean) with only one line after it, though if you've got something better go ahead and use your definition i won't mind) Is there a more effective way to accomplish the gole of making debugging easier than what i'm doing? Anything you know i mean to ask but that i have forgotten too (as much information as makes sense is appreciated).

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  • special debugging lines (java)

    - by David
    Recently i've found myself writing a lot of methods with what i can only think to call debugging scaffolding. Here's an example: public static void printArray (String[] array, boolean bug) { for (int i = 0; i<array.lenght; i++) { if (bug) System.out.print (i) ; //this line is what i'm calling the debugging scaffolding i guess. System.out.println(array[i]) ; } } in this method if i set bug to true, wherever its being called from maybe by some kind of user imput, then i get the special debugging text to let me know what index the string being printed as at just in case i needed to know for the sake of my debugging (pretend a state of affairs exists where its helpful). All of my questions more or less boil down to the question: is this a good idea? but with a tad bit more objectivity: Is this an effective way to test my methods and debug them? i mean effective in terms of efficiency and not messing up my code. Is it acceptable to leave the if (bug) stuff ; code in place after i've got my method up and working? (if a definition of "acceptability" is needed to make this question objective then use "is not a matter of programing controversy such as ommiting brackets in an if(boolean) with only one line after it, though if you've got something better go ahead and use your definition i won't mind) Is there a more effective way to accomplish the gole of making debugging easier than what i'm doing? Anything you know i mean to ask but that i have forgotten too (as much information as makes sense is appreciated).

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  • Return enum instead of bool from function for clarity ?

    - by Moe Sisko
    This is similar to : http://stackoverflow.com/questions/2908876/net-bool-vs-enum-as-a-method-parameter but concerns returning a bool from a function in some situations. e.g. Function which returns bool : public bool Poll() { bool isFinished = false; // do something, then determine if finished or not. return isFinished; } Used like this : while (!Poll()) { // do stuff during wait. } Its not obvious from the calling context what the bool returned from Poll() means. It might be clearer in some ways if the "Poll" function was renamed "IsFinished()", but the method does a bit of work, and (IMO) would not really reflect what the function actually does. Names like "IsFinished" also seem more appropriate for properties. Another option might be to rename it to something like : "PollAndReturnIsFinished" but this doesn't feel right either. So an option might be to return an enum. e.g : public enum Status { Running, Finished } public Status Poll() { Status status = Status.Running; // do something, then determine if finished or not. return status; } Called like this : while (Poll() == Status.Running) { // do stuff during wait. } But this feels like overkill. Any ideas ?

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  • Returning an array of culture formatted dates C# MVC3

    - by user1875797
    I'm new to programming and trying to do an exercise that formats a date to the Thai culture in a variety of formats this is what I have for my code so far: public String[] FormatAsSpecified(DateTime theDate, String theCulture, String[] formats) { String[] dateResults = new String[formats.Length]; CultureInfo culture = CultureInfo.GetCultureInfo(theCulture); for (int i = 0; i < formats.Length; i++) { String culture_formatted_date = theDate.ToString(formats[i], culture); dateResults[i] = culture_formatted_date; } return dateResults; } This is the test method that goes with it: [TestMethod] public void FormatAsSpecifiedReturnsDateLiteralsInSpecifiedFormatForAllStandardFormatStrings() { //Arrange var controller = new DateController(); var theDate = new DateTime(2014, 2, 14, 9, 15, 32, 376); String theCulture = "th-TH"; // Array of all supported standard date and time format specifiers. String[] formats = { "d", "D", "f", "F", "g", "G", "m", "o", "r", "s", "t", "T", "u", "U", "Y" }; //Corresponding date literals for the standard Thai regional settings String[] expectedResults = {"14/2/2557" , "14 ?????????? 2557" , "14 ?????????? 2557 9:15" , "14 ?????????? 2557 9:15:32" , "14/2/2557 9:15" , "14/2/2557 9:15:32" , "14 ??????????" , "2014-02-14T09:15:32.3760000" , "Fri, 14 Feb 2014 09:15:32 GMT" , "2014-02-14T09:15:32" , "9:15" , "9:15:32" , "2014-02-14 09:15:32Z" , "??????????? 14 ?????????? 2014 9:15:32" , "?????????? 2557"}; //Act String[] actualResults = new String[15]; for (int i = 0; i < formats.Length; i++) { actualResults[i] = controller.FormatAsSpecified(theDate, theCulture, formats[i]); } //Assert CollectionAssert.AreEqual(expectedResults, actualResults); } I get an error in the test method at 'controller.FormatAsSpecified(theDate, theCulture, formats[i]);' that says "Argument 3, cannot convert from 'string' to 'string[]'" What am I doing wrong?

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  • new Statefull session bean instance without calling lookup

    - by kislo_metal
    Hi! Scenario: I have @Singleton UserFactory (@Stateless could be) , it`s method createSession() generating @Statefull UserSession bean by manual lookup. If I am injecting by DI @EJB - i will get same instance during calling fromFactory() method(as it should be) What I want - is to get new instance of UserSession without preforming lookup. Q1: how could I call new instance of @Statefull session bean? Code: @Singleton @Startup @LocalBean public class UserFactory { @EJB private UserSession session; public UserFactory() { } @Schedule(second = "*/1", minute = "*", hour = "*") public void creatingInstances(){ try { InitialContext ctx = new InitialContext(); UserSession session2 = (UserSession) ctx.lookup("java:global/inferno/lic/UserSession"); System.out.println("in singleton UUID " +session2.getSessionUUID()); } catch (NamingException e) { e.printStackTrace(); } } @Schedule(second = "*/1", minute = "*", hour = "*") public void fromFactory(){ System.out.println("in singleton UUID " +session.getSessionUUID()); } public UserSession creatSession(){ UserSession session2 = null; try { InitialContext ctx = new InitialContext(); session2 = (UserSession) ctx.lookup("java:global/inferno/lic/UserSession"); System.out.println("in singleton UUID " +session2.getSessionUUID()); } catch (NamingException e) { e.printStackTrace(); } return session2; } } As I understand, calling of session.getClass().newInstance(); is not a best idea Q2 : is it true? I am using glassfish v3, ejb 3.1.

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  • PPR in tr:selectOneChoice does not work

    - by Nhut Le
    Hi, I have a simple testing page that test my PPR on a selectOneChoice component. when select a value from selectOnechoice 1, the selected value will display on a output label and also reset the selected value and the other selectOneChoice. However, it prints the selected values to the label correctly but it can't set the selected value for the other selectOneChoice. and Here are my page and my value change event method. <tr:form id="nhutForm"> <tr:selectOneChoice id="one" value="#{nhutTestBean.one}" autoSubmit="true" immediate="true" valueChangeListener="#{nhutTestBean.onMyValueChanged}"> <tr:selectItem label="0" value="0"/> <tr:selectItem label="1" value="1"/> <tr:selectItem label="2" value="2"/> <tr:selectItem label="3" value="3"/> </tr:selectOneChoice> <tr:selectOneChoice id="two" value="#{nhutTestBean.two}" partialTriggers="one"> <f:selectItems value="#{nhutTestBean.myList}"/> </tr:selectOneChoice> <tr:outputText id="nhutTextBox" value="hello: #{nhutTestBean.output}" partialTriggers="one"/></tr:form> and my valueChangeEvent method: public void onMyValueChanged(ValueChangeEvent event) { this.setOutput((String)event.getNewValue()); this.setTwo((String)event.getNewValue()); } One thing I realize is that it calls my setTwo twice, the first the set the correct values, but the second time set it to null so that nothing would be selected for the two drop down box. please help. thank you so much.

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  • How can I find out if two arguments are instances of the same, but unknown class?

    - by Ingmar
    Let us say we have a method which accepts two arguments o1 and o2 of type Object and returns a boolean value. I want this method to return true only when the arguments are instances of the same class, e.g.: foo(new Integer(4),new Integer(5)); Should return true, however: foo(new SomeClass(), new SubtypeSomeClass()); should return false and also: foo(new Integer(3),"zoo"); should return false. I believe one way is to compare the fully qualified class names: public boolean foo(Object o1, Object o2){ Class<? extends Object> c1 = o1.getClass(); Class<? extends Object> c2 = o2.getClass(); if(c1.getName().equals(c2.getName()){ return true;} return false; } An alternative conditional statement would be : if (c1.isAssignableFrom(c2) && c2.isAssignableFrom(c1)){ return true; } The latter alternative is rather slow. Are there other alternatives to this problem?

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