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  • Python: Does one of these examples waste more memory?

    - by orokusaki
    In a Django view function which uses manual transaction committing, I have: context = RequestContext(request, data) transaction.commit() return render_to_response('basic.html', data, context) # Returns a Django ``HttpResponse`` object which is similar to a dictionary. I think it is a better idea to do this: context = RequestContext(request, data) response = render_to_response('basic.html', data, context) transaction.commit() return response If the page isn't rendered correctly in the second version, the transaction is rolled back. This seems like the logical way of doing it albeit there won't likely be many exceptions at that point in the function when the application is in production. But... I fear that this might cost more and this will be replete through a number of functions since the application is heavy with custom transaction handling, so now is the time to figure out. If the HttpResponse instance is in memory already (at the point of render_to_response()), then what does another reference cost? When the function ends, doesn't the reference (response variable) go away so that when Django is done converting the HttpResponse into a string for output Python can immediately garbage collect it? Is there any reason I would want to use the first version (other than "It's 1 less line of code.")?

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  • Async task ASP.net HttpContext.Current.Items is empty - How do handle this?

    - by GuruC
    We are running a very large web application in asp.net MVC .NET 4.0. Recently we had an audit done and the performance team says that there were a lot of null reference exceptions. So I started investigating it from the dumps and event viewer. My understanding was as follows: We are using Asyn Tasks in our controllers. We rely on HttpContext.Current.Items hashtable to store a lot of Application level values. Task<Articles>.Factory.StartNew(() => { System.Web.HttpContext.Current = ControllerContext.HttpContext.ApplicationInstance.Context; var service = new ArticlesService(page); return service.GetArticles(); }).ContinueWith(t => SetResult(t, "articles")); So we are copying the context object onto the new thread that is spawned from Task factory. This context.Items is used again in the thread wherever necessary. Say for ex: public class SomeClass { internal static int StreamID { get { if (HttpContext.Current != null) { return (int)HttpContext.Current.Items["StreamID"]; } else { return DEFAULT_STREAM_ID; } } } This runs fine as long as number of parallel requests are optimal. My questions are as follows: 1. When the load is more and there are too many parallel requests, I notice that HttpContext.Current.Items is empty. I am not able to figure out a reason for this and this causes all the null reference exceptions. 2. How do we make sure it is not null ? Any workaround if present ? NOTE: I read through in StackOverflow and people have questions like HttpContext.Current is null - but in my case it is not null and its empty. I was reading one more article where the author says that sometimes request object is terminated and it may cause problems since dispose is already called on objects. I am doing a copy of Context object - its just a shallow copy and not a deep copy.

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  • Convenient way to do "wrong way rebase" in git?

    - by Kaz
    I want to pull in newer commits from master into topic, but not in such a way that topic changes are replayed over top of master, but rather vice versa. I want the new changes from master to be played on top of topic, and the result to be installed as the new topic head. I can get exactly the right object if I rebase master to topic, the only problem being that the object is installed as the new head of master rather than topic. Is there some nice way to do this without manually shuffling around temporary head pointers? Edit: Here is how it can be achieved using a temporary branch head, but it's clumsy: git checkout master git checkout -b temp # temp points to master git rebase topic # topic is brought into temp, temp changes played on top Now we have the object we want, and it's pointed at by temp. git checkout topic git reset --hard temp Now topic has it; and all that is left is to tidy up by deleting temp: git branch -d temp Another way is to to do away with temp and just rebase master, and then reset topic to master. Finally, reset master back to what it was by pulling its old head from the reflog, or a cut-and-paste buffer.

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  • java: retrieving the "canonical value" from a Set<T> where T has a custom equals()

    - by Jason S
    I have a class Foo which overrides equals() and hashCode() properly. I would like to also would like to use a HashSet<Foo> to keep track of "canonical values" e.g. I have a class that I would like to write like this, so that if I have two separate objects that are equivalent I can coalesce them into references to the same object: class Canonicalizer<T> { final private Set<T> values = new HashSet<T>(); public T findCanonicalValue(T value) { T canonical = this.values.get(value); if (canonical == null) { // not in the set, so put it there for the future this.values.add(value); return value; } else { return canonical; } } } except that Set doesn't have a "get" method that would return the actual value stored in the set, just the "contains" method that returns true or false. (I guess that it assumes that if you have an object that is equal to a separate object in the set, you don't need to retrieve the one in the set) Is there a convenient way to do this? The only other thing I can think of is to use a map and a list: class Canonicalizer<T> { // warning: neglects concurrency issues final private Map<T, Integer> valueIndex = new HashMap<T, Integer>(); final private List<T> values = new ArrayList<T>(); public T findCanonicalValue(T value) { Integer i = this.valueIndex.get(value); if (i == null) { // not in the set, so put it there for the future i = this.values.size(); this.values.add(value); this.valueIndex.put(value, i); return value; } else { // in the set return this.values.get(i); } } }

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  • define a closure as method from class

    - by user272839
    Hi, i'm trying to play with php5.3 and closure. I see here (Listing 7. Closure inside an object : http://www.ibm.com/developerworks/opensource/library/os-php-5.3new2/index.html) that it's possible to use $this in the callback function, but it's not. So I try to give $this as use variable : $self = $this; $foo = function() use($self) { //do something with $self } So to use the same example : class Dog { private $_name; protected $_color; public function __construct($name, $color) { $this->_name = $name; $this->_color = $color; } public function greet($greeting) { $self = $this; return function() use ($greeting, $self) { echo "$greeting, I am a {$self->_color} dog named {$self->_name}."; }; } } $dog = new Dog("Rover","red"); $dog->greet("Hello"); Output: Hello, I am a red dog named Rover. First of all this example does not print the string but return the function, but that's not my problem. Secondly I can't access to private or protected, because the callback function is a global function and not in the context from the Dog object. Tha't my problem. It's the same as : function greet($greeting, $object) { echo "$greeting, I am a {$self->_color} dog named {$self->_name}."; } And I want : public function greet($greeting) { echo "$greeting, I am a {$self->_color} dog named {$self->_name}."; } Which is from Dog and not global. I hope that I am clear ...

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  • IBM WESB/WAS JCA security configuration

    - by user594883
    I'm working with IBM tools. I have a Websphere ESB (WESB) and a CICS transaction gateway (CTG). The basic set-up is as follows: A SOAP service needs data from CICS. The SOAP-service is connecting to service bus (WESB) to handle data and protocol transformation and then WESB calls the CTG which in turn calls CICS and the reply is handled vice verse (synchronously). WESB calls the CTG using Resource Adapter and JCA connector (or CICS adapter as it is called in WESB). Now, I have all the pieces in place and working. My question is about the security, and even though I'm working with WESB, the answer is probably the same as in Websphere Application Server (WAS). The Resource Adaper is secured using JAAS - J2C authentication data. I have configured the security using J2C authentication data entry, so basically I have a reference in the application I'm running and at runtime the application does a lookup for the security attributes from the server. So basically I'm always accessing the CICS adapter with the same security reference. My problem is that I need to access the resource in more dynamic way in the future. The security cannot be welded into the application anymore but instead given as a parameter. Could some WESB or WAS guru help me out, how this could be done in WESB/WAS exactly?

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  • ScaleTransform transforms non-linearly

    - by Chris
    I am using scale transform to allow a user to resize a control. What happens though is that when you start to move the mouse the control jumps to a new size, and then scales oddly. The further you move your mouse from the starting location the larger the increase in size becomes. I expect its the way I calculate the scale to be applied. Here is the code: private void ResizeGrip_MouseDown(object sender, MouseButtonEventArgs e) { ResizeHandle.CaptureMouse(); //Get the initial coordinate cursor location on the window initBtmX = e.GetPosition(this).X; bottomResize = true; } private void ResizeGrip_MouseUp(object sender, MouseButtonEventArgs e) { bottomResize = false; ResizeHandle.ReleaseMouseCapture(); } private void ResizeGrip_MouseMove(object sender, MouseEventArgs e) { if( bottomResize == true) { //Get the new Y coordinate cursor location double newBtmX = e.GetPosition(this).X; //Get the smallest change between the initial and new cursor location double diffX = initBtmX - newBtmX; // Let our rectangle capture the mouse ResizeHandle.CaptureMouse(); double newWidth = e.GetPosition(this).X - diffX; double scaler = newWidth / ResizeContainer.ActualWidth; Console.WriteLine("newWidth: {0}, scalar: {1}", newWidth, scaler); if (scaler < 0.75 || scaler > 3) return; ScaleTransform scale = new ScaleTransform(scaler, scaler); ResizeContainer.LayoutTransform = scale; } }

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  • How to add a service to the type descriptor context of a property grid in .Net?

    - by Jules
    I have an app that allows the user to choose an image, at design time, either as a straight image, or from an image list. All cool so far, except that this is not happening from the visual studio property browser, its happening from a property grid that is a part of a type editor. My problem is, both the image picker (actually resource picker), and the imagelist type converter rely on some design-time services to get the job done. In the case of imagelist, its the IReferenceService and in the case of the resource picker its a service called _DTE. In the first instance of an edit from the visual studio property browser, I could get a reference to these services but (1) how can I add them to the type descriptor context of my property grid? It would be better, for future proofing, if I could just copy a reference to all of the services in the type descriptor context. (2) Where does the property browser get these services from in the first place? ETA: I still don't know how to do it, but I now know it is possible. (1) Sub-class control and add a property whose type is an array of buttons. (2) Add it to a form. (3) Select the new control on the design service and edit the new property in the property browser. (4) The collection editor dialog pops-up (5) Add a button (6) Edit image and image list - the type editor and type converter, respectively, behave as they should.

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  • Custom button with property as StaticResource

    - by alin
    I am trying to achieve the following thing: use an svg image into a custom button. In order to do this I created a Custom button: public class MainButton : Button { static MainButton() { DefaultStyleKeyProperty.OverrideMetadata(typeof(MainButton), new FrameworkPropertyMetadata(typeof(MainButton))); } public string Text { get { return (string)GetValue(TextProperty); } set { SetValue(TextProperty, value); } } public static readonly DependencyProperty TextProperty = DependencyProperty.Register("Text", typeof(string), typeof(MainButton), new UIPropertyMetadata("")); public object Image { get { return (object)GetValue(ImageProperty); } set { SetValue(ImageProperty, value); } } public static readonly DependencyProperty ImageProperty = DependencyProperty.Register("Image", typeof(object), typeof(MainButton), new UIPropertyMetadata("")); } I took a svg file, opened it in inkscape and saved it as xaml file. I opened Themes.xaml and added the created xaml image as a ControlTemplate And the button style is: Style TargetType="{x:Type local:MainButton}" <StackPanel Canvas.Top="12" Canvas.Left="0" Canvas.ZIndex="2" Width="80"> <ContentControl x:Name="Img" Template="{StaticResource Home}" /> </StackPanel> <StackPanel x:Name="spText" Canvas.Top="45" Canvas.Left="1" Canvas.ZIndex="1" Width="80"> <TextBlock x:Name="Txt" Text="{Binding Path=(local:MainButton.Text), RelativeSource ={RelativeSource FindAncestor, AncestorType ={x:Type Button}}}" VerticalAlignment="Center" HorizontalAlignment="Center" Foreground="White" FontSize="14"/> </StackPanel> ... As you can see I have hardcoded the StaticResource name I want to be able to have a binding with property Image on this Template, something like So that I can set the Image property of the button with the name of the StaticResource I want. For example, having beside "Home" image, another one "Back" I would have two buttons in MainWindow declared like this: Any advice is kindly taken. Thank you for your time.

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  • Method in RootViewController not Storing Array

    - by Antonio
    I have an array initialized in my RootViewController and a method that addsObjects to an array. I created a RootViewController object in my SecondViewController. The method runs (outputs a message) but it doesn't add anything to the array, and the array seems empty. Code is below, any suggestions? RootViewController.h #import "RootViewController.h" #import "SecondViewController.h" @implementation RootViewController - (void)viewDidLoad { [super viewDidLoad]; myArray2 = [[NSMutableArray alloc] init]; NSLog(@"View was loaded"); } -(void)addToArray2{ NSLog(@"Array triggered from SecondViewController"); [myArray2 addObject:@"Test"]; [self showArray2]; } -(void)showArray2{ NSLog(@"Array Count: %d", [myArray2 count]); } -(IBAction)switchViews{ SecondViewController *screen = [[SecondViewController alloc] initWithNibName:nil bundle:nil]; screen.modalTransitionStyle = UIModalTransitionStyleCoverVertical; [self presentModalViewController:screen animated:YES]; [screen release]; } SecondViewController.m #import "SecondViewController.h" #import "RootViewController.h" @implementation SecondViewController -(IBAction)addToArray{ RootViewController *object = [[RootViewController alloc] init]; [object addToArray2]; } -(IBAction)switchBack{ [self dismissModalViewControllerAnimated:YES]; } EDIT***** With Matt's code I got the following error: " expected specifier-qualifier-list before 'RootViewController' "

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  • ADO.NET DataTable/DataRow Thread Safety

    - by Allen E. Scharfenberg
    Introduction A user reported to me this morning that he was having an issue with inconsistent results (namely, column values sometimes coming out null when they should not be) of some parallel execution code that we provide as part of an internal framework. This code has worked fine in the past and has not been tampered with lately, but it got me to thinking about the following snippet: Code Sample lock (ResultTable) { newRow = ResultTable.NewRow(); } newRow["Key"] = currentKey; foreach (KeyValuePair<string, object> output in outputs) { object resultValue = output.Value; newRow[output.Name] = resultValue != null ? resultValue : DBNull.Value; } lock (ResultTable) { ResultTable.Rows.Add(newRow); } (No guarantees that that compiles, hand-edited to mask proprietery information.) Explanation We have this cascading type of locking code other places in our system, and it works fine, but this is the first instance of cascading locking code that I have come across that interacts with ADO .NET. As we all know, members of framework objects are usually not thread safe (which is the case in this situation), but the cascading locking should ensure that we are not reading and writing to ResultTable.Rows concurrently. We are safe, right? Hypothesis Well, the cascading lock code does not ensure that we are not reading from or writing to ResultTable.Rows at the same time that we are assigning values to columns in the new row. What if ADO .NET uses some kind of buffer for assigning column values that is not thread safe--even when different object types are involved (DataTable vs. DataRow)? Has anyone run into anything like this before? I thought I would ask here at StackOverflow before beating my head against this for hours on end :) Conclusion Well, the consensus appears to be that changing the cascading lock to a full lock has resolved the issue. That is not the result that I expected, but the full lock version has not produced the issue after many, many, many tests. The lesson: be wary of cascading locks used on APIs that you do not control. Who knows what may be going on under the covers!

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  • Java abstract visitor - guarantueed to succeed? If so, why?

    - by disown
    I was dealing with hibernate, trying to figure out the run-time class behind proxied instances by using the visitor pattern. I then came up with an AbstractVisitable approach, but I wonder if it will always produce correct results. Consider the following code: interface Visitable { public void accept(Visitor v); } interface Visitor { public void visit(Visitable visitorHost); } abstract class AbstractVisitable implements Visitable { @Override public void accept(Visitor v) { v.visit(this); } } class ConcreteVisitable extends AbstractVisitable { public static void main(String[] args) { final Visitable visitable = new ConcreteVisitable(); final Visitable proxyVisitable = (Visitable) Proxy.newProxyInstance( Thread.currentThread().getContextClassLoader(), new Class<?>[] { Visitable.class }, new InvocationHandler() { @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { return method.invoke(visitable, args); } }); proxyVisitable.accept(new Visitor() { @Override public void visit(Visitable visitorHost) { System.out.println(visitorHost.getClass()); } }); } } This makes a ConcreteVisitable which inherits the accept method from AbstractVisitable. In c++, I would consider this risky, since this in AbstractVisitable could be referencing to AbstractVisitable::this, and not ConcreteVisitable::this. I was worried that the code under certain circumstances would print class AbstractVisible. Yet the code above outputs class ConcreteVisitable, even though I hid the real type behind a dynamic proxy (the most difficult case I could come up with). Is the abstract visitor approach above guaranteed to work, or are there some pitfalls with this approach? What guarantees are given in Java with respect to the this pointer?

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  • jquery script that used to work is not working with jquery 1.4.2

    - by Zayatzz
    ... and i cant figure out why. The script is following: <script type="text/javascript" src="http://path/to/js/jquery-1.4.2.min.js"></script> <script type="text/javascript"> function openMediaPlayer() { $('#flashMovie').animate({'height':'333px'}); } function closeMediaPlayer() { $('#flashMovie').animate({'height':'80px'}); } jQuery(function($){ $('#videoholder').bind('mouseenter', function(){ openMediaPlayer(); }); $('#videoholder').bind('mouseleave', function(){ closeMediaPlayer(); }); }); </script> <div id="videoholder" style="height:80px;width:412px;"> <object width="412" height="80" type="application/x-shockwave-flash" id="flashMovie" name="flashMovie" style="height: 80px;" data="http://path/to/Player.swf"><param name="menu" value="false"><param name="bgcolor" value="#666666"><param name="allowFullscreen" value="true"><param name="flashvars" value="playlistURL=http://path/to/Player/data/playlist.xml"></object> </div> pure and simple resizing flash object. It worked with older(1.3.2) jquery verision. The animate just does not work. Can anyone tell me what i should change to get it working again? Alan.

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  • Why does using the Asynchronous Programming Model in .Net not lead to StackOverflow exceptions?

    - by uriDium
    For example, we call BeginReceive and have the callback method that BeginReceive executes when it has completed. If that callback method once again calls BeginReceive in my mind it would be very similar to recursion. How is that this does not cause a stackoverflow exception. Example code from MSDN: private static void Receive(Socket client) { try { // Create the state object. StateObject state = new StateObject(); state.workSocket = client; // Begin receiving the data from the remote device. client.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback), state); } catch (Exception e) { Console.WriteLine(e.ToString()); } } private static void ReceiveCallback( IAsyncResult ar ) { try { // Retrieve the state object and the client socket // from the asynchronous state object. StateObject state = (StateObject) ar.AsyncState; Socket client = state.workSocket; // Read data from the remote device. int bytesRead = client.EndReceive(ar); if (bytesRead > 0) { // There might be more data, so store the data received so far. state.sb.Append(Encoding.ASCII.GetString(state.buffer,0,bytesRead)); // Get the rest of the data. client.BeginReceive(state.buffer,0,StateObject.BufferSize,0, new AsyncCallback(ReceiveCallback), state); } else { // All the data has arrived; put it in response. if (state.sb.Length > 1) { response = state.sb.ToString(); } // Signal that all bytes have been received. receiveDone.Set(); } } catch (Exception e) { Console.WriteLine(e.ToString()); } }

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  • Combining two-part SQL query into one query

    - by user332523
    Hello, I have a SQL query that I'm currently solving by doing two queries. I am wondering if there is a way to do it in a single query that makes it more efficient. Consider two tables: Transaction_Entries table and Transactions, each one defined below: Transactions - id - reference_number (varchar) Transaction_Entries - id - account_id - transaction_id (references Transactions table) Notes: There are multiple transaction entries per transaction. Some transactions are related, and will have the same reference_number string. To get all transaction entries for Account X, then I would do SELECT E.*, T.reference_number FROM Transaction_Entries E JOIN Transactions T ON (E.transaction_id=T.id) where E.account_id = X The next part is the hard part. I want to find all related transactions, regardless of the account id. First I make a list of all the unique reference numbers I found in the previous result set. Then for each one, I can query all the transactions that have that reference number. Assume that I hold all the rows from the previous query in PreviousResultSet UniqueReferenceNumbers = GetUniqueReferenceNumbers(PreviousResultSet) // in Java foreach R in UniqueReferenceNumbers // in Java SELECT * FROM Transaction_Entries where transaction_id IN (SELECT * FROM Transactions WHERE reference_number=R Any suggestions how I can put this into a single efficient query?

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  • webpart context.session is null

    - by tbischel
    I've been using the session array to store a state variable for my webpart... so I have a property like this: public INode RootNode { get { return this.Context.Session["RootNode"] as INode; } set { this.Context.Session["RootNode"] = value as object; } } This usually works fine. I've discovered that sometimes, the context.session variable will be null. I'd like to know what are the conditions that cause the session to be null in the first place, and whats the best way to persist my object when this happens? Can I just assign a new HttpSessionState object to the context, or does that screw things up? Edit: Ok, so its not just the session that is null... the whole context is screwed up. When the webpart enters the init, the context is fine... but when it reaches the dropbox selectedindexchange postback event (the dropbox contains node id's to use to set the rootnode variable), the context contains mostly null properties. also, it only seems to happen when certain id's are selected. This looks more like some kind of weird bug on my end than a problem with my understanding of the session.

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  • Dynamically cast a control type in runtime

    - by JayT
    Hello, I have an application whereby I dynamically create controls on a form from a database. This works well, but my problem is the following: private Type activeControlType; private void addControl(ContainerControl inputControl, string ControlName, string Namespace, string ControlDisplayText, DataRow drow, string cntrlName) { Assembly assem; Type myType = Type.GetType(ControlName + ", " + Namespace); assem = Assembly.GetAssembly(myType); Type controlType = assem.GetType(ControlName); object obj = Activator.CreateInstance(controlType); Control tb = (Control)obj; tb.Click += new EventHandler(Cntrl_Click); inputControl.Controls.Add(tb); activeControlType = controlType; } private void Cntrl_Click(object sender, EventArgs e) { string test = ((activeControlType)sender).Text; //Problem ??? } How do I dynamically cast the sender object to a class that I can reference the property fields of it. I have googled, and found myself trying everything I have come across..... Now I am extremely confused... and in need of some help Thnx JT

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  • Obtaining FontMetrics before getting a Graphics instance

    - by Tom Castle
    Typically, I'd obtain a graphics instance something like this: BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB); Graphics2D g = img.createGraphics(); However, in the current project I'm working on, the width and height variables above are dependent upon the size of a number of text fragments that will later be drawn onto the graphics instance. But, to obtain the dimensions of the font being used I would usually use the FontMetrics that I get from the graphics object. FontMetrics metrics = g.getFontMetrics(); So, I have a nasty little dependency cycle. I cannot create the graphics object until I know the size of the text, and I cannot know the size of the text until I have a graphics object. One solution is just to create another BufferedImage/Graphics pair first in order to get the FontMetrics instance I need, but this seems unnecessary. So, is there a nicer way? Or is it the case that the width, height etc. properties for a Font are somehow dependent upon what (graphics, component...) the text is to be drawn on?

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  • sqlalchemy dynamic mapping

    - by adancu
    Hi, I have the following problem: I have the class: class Word(object): def __init__(self): self.id = None self.columns = {} def __str__(self): return "(%s, %s)" % (str(self.id), str(self.columns)) self.columns is a dict which will hold (columnName:columnValue) values. The name of the columns are known at runtime and they are loaded in a wordColumns list, for example wordColumns = ['english', 'korean', 'romanian'] wordTable = Table('word', metadata, Column('id', Integer, primary_key = True) ) for columnName in wordColumns: wordTable.append_column(Column(columnName, String(255), nullable = False)) I even created a explicit mapper properties to "force" the table columns to be mapped on word.columns[columnName], instead of word.columnName, I don't get any error on mapping, but it seems that doesn't work. mapperProperties = {} for column in wordColumns: mapperProperties['columns[\'%']' % column] = wordTable.columns[column] mapper(Word, wordTable, mapperProperties) When I load a word object, SQLAlchemy creates an object which has the word.columns['english'], word.columns['korean'] etc. properties instead of loading them into word.columns dict. So for each column, it creates a new property. Moreover word.columns dictionary doesn't even exists. The same way, when I try to persist a word, SQLAlchemy expects to find the column values in properties named like word.columns['english'] (string type) instead of the dictionary word.columns. I have to say that my experience with Python and SQLAlchemy is quite limited, maybe it isn't possible to do what I'm trying to do. Any help appreciated, Thanks in advance.

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  • Ensuring that all callbacks were completed before sending a new request through a DuplexChannel usin

    - by Etan
    I am experiencing some issues when using a Callback in a WCF project. First, the server invokes some function Foo on the client which then forwards the request to a Windows Forms GUI: GUI CLASS delegate void DoForward(); public void ForwardToGui() { if (this.cmdSomeButton.InvokeRequired) { DoForward d = new DoForward(ForwardToGui); this.Invoke(d); } else { Process(); // sets result variable in callback class as soon as done } } } CALLBACK CLASS object _m = new object(); private int _result; public int result { get { return _result; } set { _result = value; lock(_m) { Monitor.PulseAll(_m); } } } [OperationContract] public int Foo() { result = 0; Program.Gui.ForwardToGui(); lock(_m) { Monitor.Wait(_m, 30000); } return result; } The problem now is that the user should be able to cancel the process, which doesn't work properly: SERVER INTERFACE [OperationContract] void Cleanup(); GUI CLASS private void Gui_FormClosed(object sender, EventArgs e) { Program.callbackclass.nextAction = -1; // so that the monitor pulses and Foo() returns Program.server.Cleanup(); } The problem with this is that Cleanup() hangs. However, when I close the form when Process() is not running, it works properly. The source seems to be that the Cleanup() is called before the monitor pulses etc and therefore a new request is sent to the server before the last request from the server has not yet been responded. How can I solve this problem? How can I ensure before calling Cleanup() that no Foo() is currently being executed?

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  • How does one gets started with Winforms style applications on Win32?

    - by Billy ONeal
    EDIT: I'm extremely tired and frustrated at the moment -- please ignore that bit in this question -- I'll edit it in the morning to be better. Okay -- a bit of background: I'm a C++ programmer mostly, but the only GUI stuff I've ever done was on top of .NET's WinForms platform. I'm completely new to Windows GUI programming, and despite Petzold's excellent book, I'm extremely confused. Namely, it seems that most every reference on getting started with Win32 is all about drawing lines and curves and things -- a topic about which (at least at present time) I couldn't care less. I need a checked list box, a splitter, and a textbox -- something that would take less than 10 minutes to do in Winforms land. It has been recommended to me to use the WTL library, which provides an implementation of all three of these controls -- but I keep getting hung up on simple things, such as getting the damn controls to use the right font, and getting High DPI working correctly. I've spent two freaking days on this, and I can't help but think there has to be a better reference for these kinds of things than I've been able to find. Petzold's book is good, but it hasn't been updated since Windows 95 days, and there's been a LOT changed w.r.t. how applications should be correctly developed since it was published. I guess what I'm looking for is a modern Petzold book. Where can I find such a resource, if any?

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  • Explanation of `self` usage during dealloc?

    - by Greg
    I'm trying to lock down my understanding of proper memory management within Objective-C. I've gotten into the habit of explicitly declaring self.myProperty rather than just myProperty because I was encountering occasional scenarios where a property would not be set to the reference that I intended. Now, I'm reading Apple documentation on releasing IBOutlets, and they say that all outlets should be set to nil during dealloc. So, I put this in place as follows and experienced crashes as a result: - (void)dealloc { [self.dataModel close]; [self.dataModel release], self.dataModel = nil; [super dealloc]; } So, I tried taking out the "self" references, like so: - (void)dealloc { [dataModel close]; [dataModel release], dataModel = nil; [super dealloc]; } This second system seems to work as expected. However, it has me a bit confused. Why would self cause a crash in that case, when I thought self was a fairly benign reference more used as a formality than anything else? Also, if self is not appropriate in this case, then I have to ask: when should you include self references, and when should you not?

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  • How do I create an exception-wrapping fubumvc behaviour?

    - by Jon M
    How can I create a fubumvc behaviour that wraps actions with a particular return type, and if an exception occurs while executing the action, then the behaviour logs the exception and populates some fields on the return object? I have tried the following: public class JsonExceptionHandlingBehaviour : IActionBehavior { private static readonly Logger logger = LogManager.GetCurrentClassLogger(); private readonly IActionBehavior _innerBehavior; private readonly IFubuRequest _request; public JsonExceptionHandlingBehaviour(IActionBehavior innerBehavior, IFubuRequest request) { _innerBehavior = innerBehavior; _request = request; } public void Invoke() { try { _innerBehavior.Invoke(); var response = _request.Get<AjaxResponse>(); response.Success = true; } catch(Exception ex) { logger.ErrorException("Error processing JSON request", ex); var response = _request.Get<AjaxResponse>(); response.Success = false; response.Exception = ex.ToString(); } } public void InvokePartial() { _innerBehavior.InvokePartial(); } } But, although I get the AjaxResponse object from the request, any changes I make don't get sent back to the client. Also, any exceptions thrown by the action don't make it as far as this, the request is terminated before execution gets to the catch block. What am I doing wrong? For completeness, the behaviour is wired up with the following in my WebRegistry: Policies .EnrichCallsWith<JsonExceptionHandlingBehaviour>(action => typeof(AjaxResponse).IsAssignableFrom(action.Method.ReturnType)); And AjaxResponse looks like: public class AjaxResponse { public bool Success { get; set; } public object Data { get; set; } public string Exception { get; set; } }

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  • Rendering maps from raw SVG data in Java

    - by Lunikon
    In an application of mine I have to display locations and great circle paths in a map which is rendered to PNG and then displayed on the web. For this I simply use a world map (NASA's Blue Marbel in fact) scaled to various "zoom levels" as base image and only display the a part of it matching the final image size and fitting all items to be displayed. Straight forward so far. Now I came across Wikipedia's awesome blank SVG maps which contain all the country codes for easy reference and I was wondering whether it was possible to use those to have more customized colors and to highliht countries etc. So I did a bit of googling and was looking for Java libraries which would enable me to load the blank SVG map to memory allows for easy reference/selection of certain paths do manipulations of coloring, stroke widths etc render to a buffered image as the background for the great-circle paths/nodes What I came across quite often was Batik, but it looks like a really heavy framework and I'm not quite sure whether it is what I'm looking for. I have recently played around with Raphaël a bit and I like the way it handles working with vector graphics in code. If the Java framework for my purpose would feature a similar interface, that would be a nice-to-have. Any recommendations what toolset would be approriate for my purposes?

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  • Using Maven for maintaining product documentation

    - by Waldheinz
    We are using Maven for building a Java server-style application. It consists of several modules (in a single Maven "reactor") which can be plugged together to generate a final product (essentially a .jar) with the features enabled that the customer needs. All the internals are documented using JavaDoc and all, but that's not what you can give to the customer to find out how to get the thing running. Currently we have an OpenOffice document which serves as end-user documentation. I'd like to integrate this documentation into the Maven build process where each module's documentation is maintained (hand-edited) together with the Module's sources and the final document can reference the required Module documentation sections, add some friendly foreword and, if possible at all, can reference into the JavaDocs. Ultimately, the document should be output as a PDF. Is there any experience on Maven plugins can help with this? Is DocBook the right tool? Maybe Latex? Or something completely different? A sound "stick with OpenOffice and some text blocks" could be an answer, too.

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