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  • Why does this Object wonk out & get deleted ?

    - by brainydexter
    Stepping through the debugger, the BBox object is okay at the entry of the function, but as soon as it enters the function, the vfptr object points to 0xccccc. I don't get it. What is causing this ? Why is there a virtual table reference in there when the object is not derived from other class. (Though, it resides in GameObject from which my Player class inherits and I retrieve the BBox from within player. But, why does the BBox have the reference ? Shouldn't it be player who should be maintained in that reference ?) For 1; some code for reference: A. I retrieve the bounding box from player. This returns a bounding box as expected. I then send its address to GetGridCells. const BoundingBox& l_Bbox = l_pPlayer-GetBoundingBox(); boost::unordered_set < Cell*, CellPHash & l_GridCells = GetGridCells ( &l_Bbox ); B. This is where a_pBoundingBox goes crazy and gets that garbage value. boost::unordered_set< Cell*, CellPHash CollisionMgr::GetGridCells(const BoundingBox *a_pBoundingBox) { I think the following code is also pertinent, so I'm sticking this in here anyways: const BoundingBox& Player::GetBoundingBox(void) { return BoundingBox( &GetBoundingSphere() ); } const BoundingSphere& Player::GetBoundingSphere(void) { BoundingSphere& l_BSphere = m_pGeomMesh-m_BoundingSphere; l_BSphere.m_Center = GetPosition(); return l_BSphere; } // BoundingBox Constructor BoundingBox(const BoundingSphere* a_pBoundingSphere); Can anyone please give me some idea as to why this is happening? Also, if you want me to post more code, please do let me know. Thanks!

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  • What is the rationale to non allow overloading of C++ conversions operator with non-member functio

    - by Vicente Botet Escriba
    C++0x has added explicit conversion operators, but they must always be defined as members of the Source class. The same applies to the assignment operator, it must be defined on the Target class. When the Source and Target classes of the needed conversion are independent of each other, neither the Source can define a conversion operator, neither the Target can define a constructor from a Source. Usually we get it by defining a specific function such as Target ConvertToTarget(Source& v); If C++0x allowed to overload conversion operator by non member functions we could for example define the conversion implicitly or explicitly between unrelated types. template < typename To, typename From operator To(const From& val); For example we could specialize the conversion from chrono::time_point to posix_time::ptime as follows template < class Clock, class Duration operator boost::posix_time::ptime( const boost::chrono::time_point& from) { using namespace boost; typedef chrono::time_point time_point_t; typedef chrono::nanoseconds duration_t; typedef duration_t::rep rep_t; rep_t d = chrono::duration_cast( from.time_since_epoch()).count(); rep_t sec = d/1000000000; rep_t nsec = d%1000000000; return posix_time::from_time_t(0)+ posix_time::seconds(static_cast(sec))+ posix_time::nanoseconds(nsec); } And use the conversion as any other conversion. So the question is: What is the rationale to non allow overloading of C++ conversions operator with non-member functions?

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  • F# Async problem.

    - by chrisdew
    Hi, I've written a dummy http server as an exercise in F#. I'm using Mono 2.4.4 on Ubuntu 10.04 x86_64, with MonoDevelop. The following code fails to compile with the error: Error FS0039: The field, constructor or member 'Spawn' is not defined (FS0039) Could someone try this in VisualStudio please, I don't know whether this is a Mono problem, or my problem. I have tried several Async examples from the F# book, and they also all produce similar messages about Async.* methods. Thanks, Chris. #light open System open System.IO open System.Threading open System.Net open System.Net.Sockets open Microsoft.FSharp.Control.CommonExtensions printfn "%s" "Hello World!" let headers = System.Text.Encoding.ASCII.GetBytes("HTTP/1.0 200 OK\r\nContent-Type: text/html; charset=UTF-8\r\nContent-Length: 37\r\nDate: Sun, 13 Jun 2010 05:30:00 GMT\r\nServer: FSC/0.0.1\r\n\r\n") let content = System.Text.Encoding.ASCII.GetBytes("<html><body>Hello World</body></html>") let serveAsync (client : TcpClient) = async { let out = client.GetStream() do! out.AsyncWrite(headers) do! Async.Sleep 3000 do! out.AsyncWrite(content) do out.Close() } let http_server (ip, port) = let server = new TcpListener(IPAddress.Parse(ip),port) server.Start() while true do let client = server.AcceptTcpClient() printfn "new client" Async.Spawn (serveAsync client) http_server ("0.0.0.0", 1234)

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  • return value (not a reference) from the function, bound to a const reference in the calling function

    - by brainydexter
    "If you return a value (not a reference) from the function, then bind it to a const reference in the calling function, its lifetime would be extended to the scope of the calling function." So: const BoundingBox Player::GetBoundingBox(void) { return BoundingBox( &GetBoundingSphere() ); } Returns a value of type const BoundingBox from function GetBoundingBox() Called function: (From within function Update() the following is called:) variant I: (Bind it to a const reference) const BoundingBox& l_Bbox = l_pPlayer->GetBoundingBox(); variant II: (Bind it to a const copy) const BoundingBox l_Bbox = l_pPlayer->GetBoundingBox(); Both work fine and I don't see the l_Bbox object going out of scope. (Though, I understand in variant one, the copy constructor is not called and thus is slightly better than variant II). Also, for comparison, I made the following changes. BoundingBox Player::GetBoundingBox(void) { return BoundingBox( &GetBoundingSphere() ); } with Variants: I BoundingBox& l_Bbox = l_pPlayer->GetBoundingBox(); and II: BoundingBox l_Bbox = l_pPlayer->GetBoundingBox(); The objet l_Bbox still does not out scope. So, I don't see how "bind it to a const reference in the calling function, its lifetime would be extended to the scope of the calling function", really extends the lifetime of the object to the scope of the calling function ? Am I missing something trivial here..please explain .. Thanks a lot

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  • What is the most efficient way to display decoded video frames in Qt?

    - by Jason
    What is the fastest way to display images to a Qt widget? I have decoded the video using libavformat and libavcodec, so I already have raw RGB or YCbCr 4:2:0 frames. I am currently using a QGraphicsView with a QGraphicsScene object containing a QGraphicsPixmapItem. I am currently getting the frame data into a QPixmap by using the QImage constructor from a memory buffer and converting it to QPixmap using QPixmap::fromImage(). I like the results of this and it seems relatively fast, but I can't help but think that there must be a more efficient way. I've also heard that the QImage to QPixmap conversion is expensive. I have implemented a solution that uses an SDL overlay on a widget, but I'd like to stay with just Qt since I am able to easily capture clicks and other user interaction with the video display using the QGraphicsView. I am doing any required video scaling or colorspace conversions with libswscale so I would just like to know if anyone has a more efficient way to display the image data after all processing has been performed. Thanks.

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  • findViewById returns null in new Intent

    - by drozzy
    I am having a problem where in the started Intent, the findViewById returns null. Is there anything special I should know about starting a new intent? It goes something like this for me: //in the MainList class Intent stuffList = new Intent(this, StuffList.class); then in the new Stuff's constructor: public class StuffList extends ListActivity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); this.setContentView(R.layout.stuff_list); ... this.setListAdapter(new StuffAdapter(this, my_cursor)); and in the StuffAdapter I do my usual view and data retrieval. Note the line where findViewById returns null: class ViewWrapper{ View base; TextView label = null; ViewWrapper(View base){ this.base = base; } TextView getLabel(){ if(label == null){ label = (TextView)base.findViewById(R.id.my_label); // returns NULL } return label;} } class StuffAdapter extends CursorAdapter{ StuffAdapter(Context context, Cursor cursor){ super(context, cursor); } @Override public View newView(Context context, Cursor cursor, ViewGroup parent) { LayoutInflater inflater = getLayoutInflater(); View row = inflater.inflate(R.layout.stuff_list, parent, false); ViewWrapper wrapper = new ViewWrapper(row); row.setTag(wrapper); return(row); } @Override public void bindView(View row, Context context, Cursor cursor) { ViewWrapper wrapper = (ViewWrapper)row.getTag(); TextView label = wrapper.getLabel(); // also NULL //this throws exception of course label.setText(cursor.getString("title")); } } The curious thing is that in the class that calls intent (MainList class), I do Exactly the same thing (i list a bunch of objects), and it Works! however when I try to do it in an Intent - it can't seem to find the view by id.

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  • Is it safe to reuse javax.xml.ws.Service objects

    - by Noel Ang
    I have JAX-WS style web service client that was auto-generated with the NetBeans IDE. The generated proxy factory (extends javax.xml.ws.Service) delegates proxy creation to the various Service.getPort methods. The application that I am maintaining instantiates the factory and obtains a proxy each time it calls the targetted service. Creating the new proxy factory instances repeatedly has been shown to be expensive, given that the WSDL documentation supplied to the factory constructor, an HTTP URI, is re-retrieved for each instantiation. We had success in improving the performance by caching the WSDL. But this has ugly maintenance and packaging implications for us. I would like to explore the suitability of caching the proxy factory itself. Is it safe, e.g., can two different client classes, executing on the same JVM and targetting the same web service, safely use the same factory to obtain distinct proxy objects (or a shared, reentrant one)? I've been unable to find guidance from either the JAX-WS specification nor the javax.xml.ws API documentation. The factory-proxy multiplicity is unclear to me. Having Service.getPort rather than Service.createPort does not inspire confidence.

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  • Mixins, variadic templates, and CRTP in C++

    - by Eitan
    Here's the scenario: I'd like to have a host class that can have a variable number of mixins (not too hard with variadic templates--see for example http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.103.144). However, I'd also like the mixins to be parameterized by the host class, so that they can refer to its public types (using the CRTP idiom). The problem arises when trying to mix the too--the correct syntax is unclear to me. For example, the following code fails to compile with g++ 4.4.1: template <template<class> class... Mixins> class Host : public Mixins<Host<Mixins>>... { public: template <class... Args> Host(Args&&... args) : Mixins<Host>(std::forward<Args>(args))... {} }; template <class Host> struct Mix1 {}; template <class Host> struct Mix2 {}; typedef Host<Mix1, Mix2> TopHost; TopHost *th = new TopHost(Mix1<TopHost>(), Mix2<TopHost>()); With the error: tst.cpp: In constructor ‘Host<Mixins>::Host(Args&& ...) [with Args = Mix1<Host<Mix1, Mix2> >, Mix2<Host<Mix1, Mix2> >, Mixins = Mix1, Mix2]’: tst.cpp:33: instantiated from here tst.cpp:18: error: type ‘Mix1<Host<Mix1, Mix2> >’ is not a direct base of ‘Host<Mix1, Mix2>’ tst.cpp:18: error: type ‘Mix2<Host<Mix1, Mix2> >’ is not a direct base of ‘Host<Mix1, Mix2>’ Does anyone have successful experience mixing variadic templates with CRTP?

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  • Displaying music list using custom lists instead of array adapters

    - by Rahul Varma
    Hi, I have displayed the music list in a list view. The list is obtained from a website. I have done this using Arraylist. Now, i want to iterate the same program using custom lists and custom adapters instead of array list. The code i have written using array lists is... public class MusicListActivity extends Activity { MediaPlayer mp; File mediaFile; TextView tv; TextView albumtext; TextView artisttext; ArrayList<String> al=new ArrayList<String>(); //ArrayList<String> al=new ArrayList<String>(); ArrayList<String> node=new ArrayList<String>(); ArrayList<String> filepath=new ArrayList<String>(); ArrayList<String> imgal=new ArrayList<String>(); ArrayList<String> album=new ArrayList<String>(); ArrayList<String> artist=new ArrayList<String>(); ListView lv; Object[] webImgListObject; String[] stringArray; XMLRPCClient client; String loginsess; HashMap<?, ?> siteConn = null; //ImageView im; Bitmap img; String s; int d; int j; StreamingMediaPlayer sm; int start=0; Intent i; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.openadiuofile); lv=(ListView)findViewById(R.id.list1); al=getIntent().getStringArrayListExtra("titles"); //node=getIntent().getStringArrayListExtra("nodeid"); filepath=getIntent().getStringArrayListExtra("apath"); imgal=getIntent().getStringArrayListExtra("imgpath"); album=getIntent().getStringArrayListExtra("album"); artist=getIntent().getStringArrayListExtra("artist"); // ArrayAdapter<String> aa=new ArrayAdapter<String>(this,R.layout.row,R.id.text2,al); //lv.setAdapter(aa); try{ lv.setAdapter( new styleadapter(this,R.layout.row, R.id.text2,al)); }catch(Throwable e) { Log.e("openaudio error",""+e.toString()); goBlooey(e); } lv.setOnItemClickListener(new OnItemClickListener(){ @Override public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3){ j=1; try{ d=arg2; String filep=filepath.get(d); String tit=al.get(d); String image=imgal.get(d); String singer=artist.get(d); String movie=album.get(d); sendpath(filep,tit,image,singer,movie); // getpath(n); }catch(Throwable t) { goBlooey(t); } } }); } @Override protected void onPause() { // TODO Auto-generated method stub super.onPause(); if(j==0) {i=new Intent(this,gorinkadashboard.class); startActivity(i);} } @Override protected void onResume() { // TODO Auto-generated method stub super.onResume(); j=0; } @Override public boolean onKeyDown(int keyCode, KeyEvent event) { if (keyCode==KeyEvent.KEYCODE_SEARCH) { Log.i("go","go"); return true; } return(super.onKeyDown(keyCode, event)); } public void sendpath(String n,String nn,String image,String singer,String movie) { Intent ii=new Intent(this,MusicPlayerActivity.class); ii.putExtra("path",n); ii.putExtra("titletxt",nn); //ii.putStringArrayListExtra("playpath",filepath); ii.putExtra("pos",d); ii.putExtra("image",image); ii.putStringArrayListExtra("imagepath",imgal); ii.putStringArrayListExtra("filepath", filepath); ii.putStringArrayListExtra("imgal", imgal); ii.putExtra("movie" ,movie ); ii.putExtra("singer",singer); ii.putStringArrayListExtra("album", album); ii.putStringArrayListExtra("artist",artist); ii.putStringArrayListExtra("tittlearray",al); startActivity(ii); } class styleadapter extends ArrayAdapter<String> { Context context=null; public styleadapter(Context context, int resource, int textViewResourceId, List<String> objects) { super(context, resource, textViewResourceId, objects); this.context=context; } @Override public View getView(int position, View convertView, ViewGroup parent) { final int i=position; LayoutInflater inflater = ((Activity) context).getLayoutInflater(); View v = inflater.inflate(R.layout.row, null); tv=(TextView)v.findViewById(R.id.text2); albumtext=(TextView)v.findViewById(R.id.text3); artisttext=(TextView)v.findViewById(R.id.text1); tv.setText(al.get(i)); albumtext.setText(album.get(i)); artisttext.setText(artist.get(i)); final ImageView im=(ImageView)v.findViewById(R.id.image); s="http://www.gorinka.com/"+imgal.get(i); // displyimg(s,v); // new imageloader(s,im); String imgPath=s; AsyncImageLoaderv asyncImageLoaderv=new AsyncImageLoaderv(); Bitmap cachedImage = asyncImageLoaderv.loadDrawable(imgPath, new AsyncImageLoaderv.ImageCallback() { public void imageLoaded(Bitmap imageDrawable, String imageUrl) { im.setImageBitmap(imageDrawable); } }); im.setImageBitmap(cachedImage); return v; } } public class imageloader implements Runnable{ private String ss; //private View v; //private View v2; private ImageView im; public imageloader(String s, ImageView im) { this.ss=s; //this.v2=v2; this.im=im; Thread thread = new Thread(this); thread.start(); } public void run(){ try { // URL url = new URL(ss); // URLConnection conn = url.openConnection(); // conn.connect(); HttpGet httpRequest = null; httpRequest = new HttpGet(ss); HttpClient httpclient = new DefaultHttpClient(); HttpResponse response = (HttpResponse) httpclient.execute(httpRequest); HttpEntity entity = response.getEntity(); BufferedHttpEntity bufHttpEntity = new BufferedHttpEntity(entity); InputStream is = bufHttpEntity.getContent(); // BufferedInputStream bis = new BufferedInputStream(is); Bitmap bm = BitmapFactory.decodeStream(is); Log.d("img","img"); // bis.close(); is.close(); im.setImageBitmap(bm); // im.forceLayout(); // v2.postInvalidate(); // v2.requestLayout(); } catch (Exception t) { Log.e("bitmap url", "Exception in updateStatus()", t); //goBlooey(t); // throw new RuntimeException(t); } } } private void goBlooey(Throwable t) { AlertDialog.Builder builder=new AlertDialog.Builder(this); builder .setTitle("Exception!") .setMessage(t.toString()) .setPositiveButton("OK", null) .show(); } } I have created the SongList.java, SongsAdapter.java and also SongsAdapterView.java. Their code is... public class SongsList { private String titleName; private String movieName; private String singerName; private String imagePath; private String mediaPath; // Constructor for the SongsList class public SongsList(String titleName, String movieName, String singerName,String imagePath,String mediaPath ) { super(); this.titleName = titleName; this.movieName = movieName; this.singerName = singerName; this.imagePath = imagePath; this.mediaPath = mediaPath; } public String gettitleName() { return titleName; } public void settitleName(String titleName) { this.titleName = titleName; } public String getmovieName() { return movieName; } public void setmovieName(String movieName) { this.movieName = movieName; } public String getsingerName() { return singerName; } public void setsingerName(String singerName) { this.singerName = singerName; } public String getimagePath() { return imagePath; } public void setimagePath(String imagePath) { this.imagePath = imagePath; } public String getmediaPath() { return mediaPath; } public void setmediaPath(String mediaPath) { this.mediaPath = mediaPath; } } public class SongsAdapter extends BaseAdapter{ private Context context; private List<SongsList> listSongs; public SongsAdapter(Context context, List<SongsList> listPhonebook){ this.context = context; this.listSongs = listSongs; } public int getCount() { return listSongs.size(); } public Object getItem(int position) { return listSongs.get(position); } public long getItemId(int position) { return position; } public View getView(int position, View view, ViewGroup viewGroup) { SongsList entry = listSongs.get(position); return new SongsAdapterView(context,entry); } } public SongsAdapterView(Context context, SongsList entry) { super(context); this.setOrientation(VERTICAL); this.setTag(entry); // TODO Auto-generated constructor stub View v = inflate(context, R.layout.row, null); TextView tvTitle = (TextView)v.findViewById(R.id.text2); tvTitle.setText(entry.gettitleName()); TextView tvMovie = (TextView)v.findViewById(R.id.text3); tvTitle.setText(entry.getmovieName()); TextView tvSinger = (TextView)v.findViewById(R.id.text1); tvTitle.setText(entry.getsingerName()); addView(v); } } Can anyone please tell me how to display the list using custom lists and custom adapters using the code above???

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  • With PascalMock how do I mock a method with an untyped out parameter and an open array parameter?

    - by Oliver Giesen
    I'm currently in the process of getting started with unit testing and mocking for good and I stumbled over the following method that I can't seem to fabricate a working mock implementation for: function GetInstance(const AIID: TGUID; out AInstance; const AArgs: array of const; const AContextID: TImplContextID = CID_DEFAULT): Boolean; (TImplContextID is just an alias for Integer) I thought it would have to look something like this: function TImplementationProviderMock.GetInstance( const AIID: TGUID; out AInstance; const AArgs: array of const; const AContextID: TImplContextID): Boolean; begin Result := AddCall('GetInstance') .WithParams([@AIID, AContextID]) .ReturnsOutParams([AInstance]) .ReturnValue; end; But the compiler complains about the .ReturnsOutParams([AInstance]) saying "Bad argument type in variable type array constructor.". Also I haven't found a way to specify the open array parameter AArgs at all. Also, is using the @-notation for the TGUID-typed parameter the right way to go? Is it possible to mock this method with the current version of PascalMock at all?

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  • Java swing hold buttons

    - by Simon Charette
    Hi, I'm trying to create a subclass of JButton or AbstractButton that would call specified .actionPerformed as long as the mouse is held down on the button. So far I was thinking of extending JButton, adding a mouse listener on creation (inside constructor) and calling actionPerformed while the mouse is down. So far i came up with that but I was wondwering if I was on the right track and if so, how to correctly implement the "held down" logic. package components; import java.awt.event.ActionEvent; import java.awt.event.MouseEvent; import java.awt.event.MouseListener; import javax.swing.Action; import javax.swing.Icon; import javax.swing.JButton; public class HoldButton extends JButton { private class HeldDownMouseListener implements MouseListener { private boolean mouseIsHeldDown; private HoldButton button; private long millis; public HeldDownMouseListener(HoldButton button, long millis) { this.button = button; this.millis = millis; } @Override public void mouseClicked(MouseEvent arg0) { } @Override public void mouseEntered(MouseEvent arg0) { } @Override public void mouseExited(MouseEvent arg0) { } @Override public void mousePressed(MouseEvent arg0) { mouseIsHeldDown = true; // This should be run in a sub thread? // while (mouseIsHeldDown) { // button.fireActionPerformed(new ActionEvent(button, ActionEvent.ACTION_PERFORMED, "heldDown")); // try { // Thread.sleep(millis); // } catch (InterruptedException e) { // e.printStackTrace(); // continue; // } // } } @Override public void mouseReleased(MouseEvent arg0) { mouseIsHeldDown = false; } } public HoldButton() { addHeldDownMouseListener(); } public HoldButton(Icon icon) { super(icon); addHeldDownMouseListener(); } public HoldButton(String text) { super(text); addHeldDownMouseListener(); } public HoldButton(Action a) { super(a); addHeldDownMouseListener(); } private void addHeldDownMouseListener() { addMouseListener(new HeldDownMouseListener(this, 300)); } } Thanks a lot for your time.

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  • MEF and ASP.NET MVC

    - by denis_n
    I want to use MEF with asp.net mvc. I wrote following controller factory: public class MefControllerFactory : DefaultControllerFactory { private CompositionContainer _Container; public MefControllerFactory(Assembly assembly) { _Container = new CompositionContainer(new AssemblyCatalog(assembly)); } protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType) { if (controllerType != null) { var controllers = _Container.GetExports<IController>(); var controllerExport = controllers.Where(x => x.Value.GetType() == controllerType).FirstOrDefault(); if (controllerExport == null) { return base.GetControllerInstance(requestContext, controllerType); } return controllerExport.Value; } else { throw new HttpException((Int32)HttpStatusCode.NotFound, String.Format( "The controller for path '{0}' could not be found or it does not implement IController.", requestContext.HttpContext.Request.Path ) ); } } } In Global.asax.cs I'm setting my controller factory: protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterRoutes(RouteTable.Routes); ControllerBuilder.Current.SetControllerFactory(new MefControllerFactory.MefControllerFactory(Assembly.GetExecutingAssembly())); } I have an area: [Export(typeof(IController))] [PartCreationPolicy(CreationPolicy.NonShared)] public class HomeController : Controller { private readonly IArticleService _articleService; [ImportingConstructor] public HomeController(IArticleService articleService) { _articleService = articleService; } // // GET: /Articles/Home/ public ActionResult Index() { Article article = _articleService.GetById(55); return View(article); } } IArticleService is an interface. There is a class which implements IArticleService and Exports it. It works. Is this everything what I need for working with MEF? How can I skip setting PartCreationPolicy and ImportingConstructor for controller? I want to set my dependencies using constructor. When PartCreationPolicy is missing, I get following exception: A single instance of controller 'MvcApplication4.Areas.Articles.Controllers.HomeController' cannot be used to handle multiple requests. If a custom controller factory is in use, make sure that it creates a new instance of the controller for each request.

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  • How can I make a Maybe-Transformer MaybeT into an instance of MonadWriter?

    - by martingw
    I am trying to build a MaybeT-Transformer Monad, based on the example in the Real World Haskell, Chapter Monad Transformers: data MaybeT m a = MaybeT { runMT :: m (Maybe a) } instance (Monad m) => Monad (MaybeT m) where m >>= f = MaybeT $ do a <- runMT m case a of Just x -> runMT (f x) Nothing -> return Nothing return a = MaybeT $ return (Just a) instance MonadTrans MaybeT where lift m = MaybeT $ do a <- m return (Just a) This works fine, but now I want to make MaybeT an instance of MonadWriter: instance (MonadWriter w m) => MonadWriter w (MaybeT m) where tell = lift . tell listen m = MaybeT $ do unwrapped <- listen (runMT m) return (Just unwrapped) The tell is ok, but I can't get the listen function right. The best I could come up with after 1 1/2 days of constructor origami is the one you see above: unwrapped is supposed to be a tuple of (Maybe a, w), and that I want to wrap up in a Maybe-Type and put the whole thing in an empty MonadWriter. But the compiler complains with: Occurs check: cannot construct the infinite type: a = Maybe a When generalising the type(s) for `listen' In the instance declaration for `MonadWriter w (MaybeT m)' What am I missing?

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  • httpHandler - subfolder issue

    - by Patto
    Hi, I am trying to redirect my old typepad blog to my new blog (permanent 301 redirect) that runs with wordpress. The new blog will also be on a new server. the old Blog had the following structure: http://subdomain.domain.com/weblog/year/month/what-ever-article.html The new Blog looks like this: http://www.domain.com/Blog/year/month/what-ever-article.html I am using an http handler that I found online and tried to work with it: public class MyHttpModule :IHttpModule { public MyHttpModule() { // // TODO: Add constructor logic here // } #region IHttpModule Members public void Dispose() { } public void Init(HttpApplication context) { context.BeginRequest += new EventHandler(context_BeginRequest); } void context_BeginRequest(object sender, EventArgs e) { string oldURL = System.Web.HttpContext.Current.Request.Url.ToString(); string newURL = String.Empty; //oldURL = if (oldURL.ToString().ToLower().IndexOf("articles") >= 0 || System.Web.HttpContext.Current.Request.Url.ToString().ToLower().IndexOf("weblog") >= 0) { newURL = oldURL.Replace("subdomain.domain.com/weblog", "www.domain.com/Blog/index.php"); if (newURL.ToLower().Contains("subdomain")) { newURL = "http://www.domain.com/Blog"; } } else { newURL = "http://www.domain.com/Blog"; } System.Web.HttpContext.Current.Response.Clear(); System.Web.HttpContext.Current.Response.StatusCode = 301; System.Web.HttpContext.Current.Response.AddHeader("Location", newURL); System.Web.HttpContext.Current.Response.End(); } #endregion } To use this code, I put the handler into the web.config <httpModules> <add name="MyHttpModule" type="MyHttpModule, App_Code"/> </httpModules> The issue that I have is that when I want to redirect from the http://subdomain.domain.com/weblog/year/month/what-ever-article.html, I get an error that the folder would not exist. Is there any way to change my script or add an catch all to the web.config that forwards the URL to my script? When I use "http://subdomain.domain.com/weblog/year/month/what-ever-article.html" in oldURL string, then the redirect works just fine... so I must have some IIS or web.config settings wrong. Thanks in advance, Patrick

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  • XamlReader.Parse throws exception on empty String

    - by sub-jp
    In our app, we need to save properties of objects to the same database table regardless of the type of object, in the form of propertyName, propertyValue, propertyType. We decided to use XamlWriter to save all of the given object's properties. We then use XamlReader to load up the XAML that was created, and turn it back into the value for the property. This works fine for the most part, except for empty strings. The XamlWriter will save an empty string as below. <String xmlns="clr-namespace:System;assembly=mscorlib" xml:space="preserve" /> The XamlReader sees this string and tries to create a string, but can't find an empty constructor in the String object to use, so it throws a ParserException. The only workaround that I can think of is to not actually save the property if it is an empty string. Then, as I load up the properties, I can check for which ones did not exist, which means they would have been empty strings. Is there some workaround for this, or is there even a better way of doing this?

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  • Need Help with wxPython & pyGame

    - by Xavier
    Hi Guys, I'm actually in need of your help and advice here on my assignment that I am working on. First of all, I was task to do a program that runs langton's ant simulation. For that, I've managed to get the source code (from snippets.dzone.com/posts/show/5143) and edited it accordingly to my requirements. This was done and ran in pygame module extension. In addition, my task requires a GUI to interface for users to run and navigate through the screens effectively with the langton's ant program running. I used wxPython with the help of an IDE called BOA constructor to create the frames, buttons, textboxes, etc. Basically, all the stuff needed in the interfaces. However, I've ran into some problems listed below: Found problem integrating pyGame with wxPython. On this note, I've research the internet for answers and tutorials where I found out from website: wiki.wxpython.org/IntegratingPyGame & aspn.activestate.com/ASPN/Mail/Message/wxpython-users/3178042. I understand from the sites that integrating pyGame with wxPython will be a difficult task where it has caused common problems like the inability to placing other controls into the frames as the pyGame application will cover the entire panel. I really hope that you can clarify my doubts on this and advise me on the path that I should take from here. Therefore, I ask the following questions: Is it feasible to integrate pyGame with wxPython? If it is not feasible to integrate pyGame with wxPython, what other alternatives do I have to create a GUI interface integrating pyGame into it. If so how do I go about? If it is possible to go about integrating pyGame with wxPython, how do I go about doing so? Really need you guys opinion on this.

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  • SpringMvc Annotations for DAO interface and DAO implementation

    - by dev_darin
    I would like to know if I am annotating these classes correctly, since I am new to the annotations: Country.java @Component public class Country { private int countryId; private String countryName; private String countryCode; /** * No args constructor */ public Country() { } /** * @param countryId * @param countryName * @param countryCode */ public Country(int countryId, String countryName, String countryCode) { this.countryId = countryId; this.countryName = countryName; this.countryCode = countryCode; } //getters and setters } CountryDAO.java @Repository public interface CountryDAO { public List<Country> getCountryList(); public void saveCountry(Country country); public void updateCountry(Country country); } JdbcCountryDAO.java @Component public class JdbcCountryDAO extends JdbcDaoSupport implements CountryDAO{ private final Logger logger = Logger.getLogger(getClass()); @Autowired public List<Country> getCountryList() { int countryId = 6; String countryCode = "AI"; logger.debug("In getCountryList()"); String sql = "SELECT * FROM TBLCOUNTRY WHERE countryId = ? AND countryCode = ?"; logger.debug("Executing getCountryList String "+sql); Object[] parameters = new Object[] {countryId, countryCode}; logger.info(sql); //List<Country> countryList = getJdbcTemplate().query(sql,new CountryMapper()); List<Country> countryList = getJdbcTemplate().query(sql, parameters,new CountryMapper()); return countryList; } CountryManagerIFace.java @Repository public interface CountryManagerIFace extends Serializable{ public void saveCountry(Country country); public List<Country> getCountries(); } CountryManager.java @Component public class CountryManager implements CountryManagerIFace{ @Autowired private CountryDAO countryDao; public void saveCountry(Country country) { countryDao.saveCountry(country); } public List<Country> getCountries() { return countryDao.getCountryList(); } public void setCountryDao(CountryDAO countryDao){ this.countryDao = countryDao; } }

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  • .NET WebBrowser control with Adobe SVG Viewer

    I'm having problems with SVG files loading in a .NET 2.0 WebBrowser control. If I create a new WinForms application project, drag a WebBrowser control and a button onto the Form1.cs design surface, and add a line to the button's on-click handler to set the Url property of the WebBrowser control to an SVG file, I get two IE script errors at runtime (as in, the dialog you get when there is a Javascript problem). The only line of code I'm writing is therefore: webBrowser1.Url = new Uri(@"http://wiki.allegro.cc/pub/f/fb/Grozilla.svg"); This SVG file loads fine if I browse directly to the link with IE; the errors I get via my test app are: line 2, char 1, error: Invalid character, followed by line 1, char 1, error: Object expected (assuming I answer yes to the prompt to 'continue running scripts on this page'). I'm using IE 7.0.5730.13, Adobe SVG Viewer 3.03 build 94, Visual Studio 2008. Can anyone replicate this? Has anyone seen it/got any idea how to fix it? (edit: previously setting the URL in the constructor for the purposes of the example, but this raised the question of whether or not the control had finished initialising, so have changed the example to use a button - the problem still occurs. This bug originally appeared in production code so the example program I wrote was an attempt to isolate the issue and reproduce it as simply as possible.) (edit 2: having tested on several different machines, this problems seems to be related to IE7 - run IE6, and everything works fine.)

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  • How do I find Microsoft APIs?

    - by Stephen
    I'm a java programmer, and if I see something that: I don't know about or just want to find a method description without opening an ide or am on support I type java [classname] into google, and there it is. If I try this crazy stunt for C# I'll come up with a whole heap of tutorials (how do I use it etc). If I manage to get to MSDN, I have to wade through a page describing every .net technology to see how their syntax references the same object, and then I have to find the appropriate page from there ([class name] Constructor) for example. This is even more pronounced, because I don't have Visual Studio, so I've got nothing to make it easier. There must be something I'm missing or don't know... how does this situation work for Microsoft developers? how can I make my life easier/searches better? are there techniques that work no matter what computer I'm on (e.g. require no computer setup/downloads) Notes It could be thought that java is just "java", but it's just that the java apis are only referenced/defined in the core language. For all the other languages on the JVM, it's assumed that you will just learn the correct syntax to use the java apis. I presume that .Net only lists a whole heap of languages as the api classes are actually different and have different interfaces capabilities (or some approximation of this presumption). Edit While searching msdn works... in the java space I can type 'java [anyclass]' and it will generally be found... whether it's a java core api or a third party library

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  • Did the Unity Team fix that "generics handling" bug back in 2008?

    - by rasx
    At my level of experience with Unity it might be faster to ask whether the "generics handling" bug acknowledged by ctavares back in 2008 was fixed in a public release. Here was the problem (which might be my problem today): Hi, I get an exception when using .... container.RegisterType(typeof(IDictionary<,), typeof(Dictionary<,)); The exception is... "Resolution of the dependency failed, type = \"IDictionary2\", name = \"\". Exception message is: The current build operation (build key Build Key[System.Collections.Generic.Dictionary2[System.String,System.String], null]) failed: The current build operation (build key Build Key[System.Collections.Generic.Dictionary2[System.String,System.String], null]) failed: The type Dictionary2 has multiple constructors of length 2. Unable to disambiguate. When I attempt... IDictionary myExampleDictionary = container.Resolve(); Here was the moderated response: There are no books that'll help, Unity is a little too new for publishers to have caught up yet. Unfortunately, you've run into a bug in our generics handling. This is currently fixed in our internal version, but it'll be a little while before we can get the bits out. In the meantime, as a workaround you could do something like this instead: public class WorkaroundDictionary : Dictionary { public WorkaroundDictionary() { } } container.RegisterType(typeof(IDictionary<,),typeof(WorkaroundDictionary<,)); The WorkaroundDictionary only has the default constructor so it'll inject no problem. Since the rest of your app is written in terms of IDictionary, when we get the fixed version done you can just replace the registration with the real Dictionary class, throw out the workaround, and everything will still just work. Sorry about the bug, it'll be fixed soon!

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  • .Net Entity objectcontext thread error

    - by Chris Klepeis
    I have an n-layered asp.net application which returns an object from my DAL to the BAL like so: public IEnumerable<SourceKey> Get(SourceKey sk) { var query = from SourceKey in _dataContext.SourceKeys select SourceKey; if (sk.sourceKey1 != null) { query = from SourceKey in query where SourceKey.sourceKey1 == sk.sourceKey1 select SourceKey; } return query.AsEnumerable(); } This result passes through my business layer and hits the UI layer to display to the end users. I do not lazy load to prevent query execution in other layers of my application. I created another function in my DAL to delete objects: public void Delete(SourceKey sk) { try { _dataContext.DeleteObject(sk); _dataContext.SaveChanges(); } catch (Exception ex) { Debug.WriteLine(ex.Message + " " + ex.StackTrace + " " + ex.InnerException); } } When I try to call "Delete" after calling the "Get" function, I receive this error: New transaction is not allowed because there are other threads running in the session This is an ASP.Net app. My DAL contains an entity data model. The class in which I have the above functions share the same _dataContext, which is instantiated in my constructor. My guess is that the reader is still open from the "Get" function and was not closed. How can I close it?

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  • Strange GWT serialization exception when overiding method of serialized object

    - by Flueras Bogdan
    Hi there! I have a GWT serializable class, lets call it Foo. Foo implements IsSerializable, has primitive and serializable members as well as other transient members and a no-arg constructor. class Foo implements IsSerializable { // transient members // primitive members public Foo() {} public void bar() {} } Also a Service which handles RPC comunication. // server code public interface MyServiceImpl { public void doStuff(Foo foo); } public interface MyServiceAsync { void doStuff(Foo foo, AsyncCallback<Void> async); } How i use this: private MyServiceAsync myService = GWT.create(MyService.class); Foo foo = new Foo(); ... AsyncCallback callback = new new AsyncCallback {...}; myService.doStuff(foo, callback); In the above case the code is running, and the onSuccess() method of callback instance gets executed. But when I override the bar() method on foo instance like this: Foo foo = new Foo() { public void bar() { //do smthng different } } AsyncCallback callback = new new AsyncCallback {...}; myService.doStuff(foo, callback); I get the GWT SerializationException. Please enlighten me, because I really don't understand why.

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  • Hierarchy / Flyweight / Instancing Problem in Python

    - by Dan
    Here is the problem I am trying to solve, (I have simplified the actual problem, but this should give you all the relevant information). I have a hierarchy like so: 1.A 1.B 1.C 2.A 3.D 4.B 5.F (This is hard to illustrate - each number is the parent, each letter is the child). Creating an instance of the 'letter' objects is expensive (IO, database costs, etc), so should only be done once. The hierarchy needs to be easy to navigate. Children in the hierarchy need to have just one parent. Modifying the contents of the letter objects should be possible directly from the objects in the hierarchy. There needs to be a central store containing all of the 'letter' objects (and only those in the hierarchy). 'letter' and 'number' objects need to be possible to create from a constructor (such as Letter(**kwargs) ). It is perfectably acceptable to expect that when a letter changes from the hierarchy, all other letters will respect the same change. Hope this isn't too abstract to illustrate the problem. What would be the best way of solving this? (Then I'll post my solution) Here's an example script: one = Number('one') a = Letter('a') one.addChild(a) two = Number('two') a = Letter('a') two.addChild(a) for child in one: child.method1() for child in two: print '%s' % child.method2()

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  • Set Property Value on Master Page from Content Page

    - by Merk
    Hello, I tried following the advice posted here: http://stackoverflow.com/questions/1071920/set-property-value-on-master-page-from-content-page. Specifically the last post about creating a class. However, visual studio keeps giving me an error on my default.aspx.cs page when i try to set the value: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; public partial class _Default : BasePage { protected override int NavHighlight { get { return new{0} ; } } protected void Page_Load(object sender, EventArgs e) { } } It throws an error on new, the error being: cannot inplicity convert anonymoustype#1 to int Can someone tell me what i might have done wrong here? Here's what my class looks like: using System; using System.Collections.Generic; using System.Linq; using System.Web; /// <summary> /// Summary description for BasePage /// </summary> public abstract class BasePage : System.Web.UI.Page { protected abstract int NavHighlight { get; } protected override void OnLoad(EventArgs e) { base.OnLoad(e); if (this.Master != null) { //value assignment } } public BasePage() { // // TODO: Add constructor logic here // } } Thanks.

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  • image not displaying in midlet

    - by user316843
    Hello all,am new here. i have a slight problem; PLease look at the following code and tell me if am doing something wrong because the image is not displaying. i have made it really small so it should fit but its not displaying. i have images displaying in other screens but this main midlet would not. Here is the code: import java.io.IOException; import javax.microedition.midlet.*; import javax.microedition.lcdui.*; /** * @author jay */ public class WShop extends MIDlet implements CommandListener { /* Declare display variables*/ private Form mainForm; private Display display; private Command OK,Exit,wView, mView, myView; /* */ Categories categories = new Categories(this); Image image; public WShop() { /* initialize Screen and Command buttons that will be used when the application starts in the class constructor*/ mainForm = new Form("Wind Shopper"); OK = new Command("OK", Command.OK, 2); Exit = new Command("Exit", Command.EXIT, 0); wview= new Command("wview", Command.OK, 0); mview= new Command("mview", Command.OK, 0); try { /* retrieving the main image of the application*/ image = Image.createImage("/main.png"); } catch (IOException ex) { ex.printStackTrace(); } mainForm.addCommand(OK); mainForm.addCommand(Exit); mainForm.addCommand(wView); mainForm.addCommand(mView); mainForm.setCommandListener(this); } public void startApp() { /* checks to see if the display is currently empty and then sets it to the current screen */ if (display == null) { display = Display.getDisplay(this); } display.setCurrent(mainForm); } /* paused state of the application*/ public void pauseApp() { } /* Destroy Midlet state*/ public void destroyApp(boolean unconditional) { } Thanks in advance.

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