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  • Partial overriding in Java (or dynamic overriding while overloading)

    - by Lie Ryan
    If I have a parent-child that defines some method .foo() like this: class Parent { public void foo(Parent arg) { System.out.println("foo in Function"); } } class Child extends Parent { public void foo(Child arg) { System.out.println("foo in ChildFunction"); } } When I called them like this: Child f = new Child(); Parent g = f; f.foo(new Parent()); f.foo(new Child()); g.foo(new Parent()); g.foo(new Child()); the output is: foo in Parent foo in Child foo in Parent foo in Parent But, I want this output: foo in Parent foo in Child foo in Parent foo in Child I have a Child class that extends Parent class. In the Child class, I want to "partially override" the Parent's foo(), that is, if the argument arg's type is Child then Child's foo() is called instead of Parent's foo(). That works Ok when I called f.foo(...) as a Child; but if I refer to it from its Parent alias like in g.foo(...) then the Parent's foo(..) get called irrespective of the type of arg. As I understand it, what I'm expecting doesn't happen because method overloading in Java is early binding (i.e. resolved statically at compile time) while method overriding is late binding (i.e. resolved dynamically at compile time) and since I defined a function with a technically different argument type, I'm technically overloading the Parent's class definition with a distinct definition, not overriding it. But what I want to do is conceptually "partially overriding" when .foo()'s argument is a subclass of the parent's foo()'s argument. I know I can define a bucket override foo(Parent arg) in Child that checks whether arg's actual type is Parent or Child and pass it properly, but if I have twenty Child, that would be lots of duplication of type-unsafe code. In my actual code, Parent is an abstract class named "Function" that simply throws NotImplementedException(). The children includes "Polynomial", "Logarithmic", etc and .foo() includes things like Child.add(Child), Child.intersectionsWith(Child), etc. Not all combination of Child.foo(OtherChild) are solvable and in fact not even all Child.foo(Child) is solvable. So I'm best left with defining everything undefined (i.e. throwing NotImplementedException) then defines only those that can be defined. So the question is: Is there any way to override only part the parent's foo()? Or is there a better way to do what I want to do?

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  • JPopupMenu returning a null?

    - by Zenzen
    Ok so I'm working on an Eclipse plugin based on the JGraph example. The problem is I can't really get the "save" method to work, here's how the program works in short: - I have a DiagramEditor class with an init() method, where I create a GraphEditor object and call the createFrame() methord of that object. - GraphEditor extends the BasicGraphEditor (which extends JPanel), the createFrame() method returns a JFrame and has a line "frame.setJMenuBar(menuBar)" - the "menuBar" is an object variable, which is initialized in the BasicGraphEditor. Till here everything is cool, the problem is with the action listener which is supposed to save a file. To get the graph I need to get the GraphEditor component, so I do a Component component = (Component) e.getSource() whitch is the ActionEvent passed to that action listener and at that stage is the JMenuItem "save", then I get the parent which is the JPopupMenu, then I want to get that JPopupMenu's parent which should be the GraphEdiotor, but instead I get a null. Any idea why? Here's some source code: DiagramEditor.java: @Override public void init(IEditorSite site, IEditorInput input) throws PartInitException { setSite(site); setInput(input); this.diagram = ((DiagramEditorInput)input).getDiagram(); setPartName(this.diagram.getName()); gEditor = new GraphEditor(); gEditor.createFrame().setVisible(true); } BasicGraphEditor.java: public JFrame createFrame() { JFrame frame = new JFrame(); frame.getContentPane().add(this); frame.setJMenuBar(menuBar); //frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(870, 640); return frame; } In the constructor: menuBar = new JMenuBar(); menu = new JMenu("File"); menu.setMnemonic(KeyEvent.VK_F); menuBar.add(menu); JMenuItem openMenuItem = new JMenuItem("Open", KeyEvent.VK_O); // ADD FILE OPENING //openMenuItem.addActionListener(menuListener); menu.add(openMenuItem); JMenuItem saveMenuItem = new JMenuItem("Save", new ImageIcon("/images/save.gif")); saveMenuItem.setMnemonic(KeyEvent.VK_S); saveMenuItem.addActionListener( new SaveAction(false) ); menu.add(saveMenuItem); // menu.add(new SaveAction(false)); JMenuItem saveMenuItemAs = new JMenuItem("SaveAs", new ImageIcon("/images/saveas.gif")); //saveMenuItemAs.setMnemonic(KeyEvent.VK_S); saveMenuItemAs.addActionListener( new SaveAction(true) ); menu.add(saveMenuItemAs); //menu.add(new SaveAction(true)); JMenuItem closeMenuItem = new JMenuItem("Close", KeyEvent.VK_C); closeMenuItem.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent e) { System.exit(0); } } ); menu.add(closeMenuItem);

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  • WCF Custom WSDL XmlSerializerOperationBehavior

    - by Jeff
    Hi, I have code that builds a custom WCF wsdl on the fly. In one particular scenario, the WSDL exported should use the XmlSerializerOperationBehavior as the IWsdlExportExtension as opposed to the default DataContractSerializerOperationBehavior IWsdlExportExtension. However, every time I try this from the WSDL generation code, I get a null reference exception from the ExportBody method of the XmlSerializerMessageContractExporter (which is used internally in System.ServiceModel by the XmlSerializerOperationBehavior ExportContract method). I've reflector'd it and I can't see anything obviously wrong. For some reason, .NET also doesn't want to work with source stepping in this scenario... Simply, the most basic way I can reproduce this is var c = ContractDescription.GetContract(typeof(IMyService)); foreach (var op in c.Operations) { op.Behaviors.Remove(typeof(DataContractSerializerOperationBehavior)); op.Behaviors.Insert(0, new XmlSerializerOperationBehavior(op)); } new WsdlExporter().ExportContract(c); // throws NullReferenceException Does anyone have any ideas on this? Thanks very much.

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  • How can i use ClearCanvas in remote database?

    - by programmerist
    How can i get data from REMOTE database using OnStart method? protected override int OnStart(StudyLoaderArgs studyLoaderArgs) { ApplicationEntity ae = studyLoaderArgs.Server as ApplicationEntity; _ae = ae; EventResult result = EventResult.Success; AuditedInstances loadedInstances = new AuditedInstances(); try { XmlDocument doc = RetrieveHeaderXml(studyLoaderArgs); StudyXml studyXml = new StudyXml(); studyXml.SetMemento(doc); _instances = GetInstances(studyXml).GetEnumerator(); loadedInstances.AddInstance(studyXml.PatientId, studyXml.PatientsName, studyXml.StudyInstanceUid); return studyXml.NumberOfStudyRelatedInstances; } finally { AuditHelper.LogOpenStudies(new string[] { ae.AETitle }, loadedInstances, EventSource.CurrentUser, result); } } i need to use OnStart in main project. How cn i use or call OnStart method

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  • [Rais] OAuth with Digg API

    - by Karl
    I'm attempting to get Rails to play nice with the Digg API's OAuth. I'm using the oauth gem (ruby one, not the rails one). My code looks approximately like this: @consumer = OAuth::Consumer.new(API_KEY, API_SECRET, :scheme => :header, :http_method => :post, :oauth_callback => "http://locahost:3000", :request_token_url => 'http://services.digg.com/1.0/endpoint?method=oauth.getRequestToken', :access_token_url => 'http://services.digg.com/1.0/endpoint?method=oauth.getAccessToken', :authorize_url => 'http://digg.com/oauth/authorize') @request_token = @consumer.get_request_token session[:request_token] = @request_token.token session[:request_token_secret] = @request_token.secret redirect_to @request_token.authorize_url Which is by-the-book in terms of what the gem documentation gave me. However, Digg spits a "400 Bad Request" error back at me when @consumer.get_request_token is called. I can't figure out what I'm doing wrong. Any ideas?

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  • Reading Binary data from a Serial Port.

    - by rross
    I previously have been reading NMEA data from a GPS via a serial port using C#. Now I'm doing something similar, but instead of GPS from a serial. I'm attempting to read a KISS Statement from a TNC. I'm using this event handler. comport.DataReceived += new SerialDataReceivedEventHandler(port_DataReceived); Here is port_DataReceived. private void port_DataReceived(object sender, SerialDataReceivedEventArgs e) { string data = comport.ReadExisting(); sBuffer = data; try { this.Invoke(new EventHandler(delegate { ProcessBuffer(sBuffer); })); } catch { } } The problem I'm having is that the method is being called several times per statement. So the ProcessBuffer method is being called with only a partial statment. How can I read the whole statement?

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  • Expression Blend doesn't recognize comand objects declared in code behind file

    - by Brian Ensink
    I have a WPF UserControl. The code behind file declares some RoutedUICommand objects which are referenced in the XAML. The application builds and runs just fine. However Expression Blend 3 cannot load the XAML in the designer and gives errors like this one: The member "ResetCameraComand" is not recognized or accessible. The class and the member are both public. Building and rebuilding the project in Blend and restarting Blend hasn't helped. Any ideas what the problem is? Here are fragments of my XAML ... <UserControl x:Class="CAP.Visual.CameraAndLightingControl" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:CAP.Visual;assembly=VisualApp" Height="100" Width="700"> <UserControl.CommandBindings> <CommandBinding Command="local:CameraAndLightingControl.ResetCameraCommand" Executed="ResetCamera_Executed" CanExecute="ResetCamera_CanExecute"/> </UserControl.CommandBindings> .... ... and the code behind C# namespace CAP.Visual { public partial class CameraAndLightingControl : UserControl { public readonly static RoutedUICommand ResetCameraCommand; static CameraAndLightingControl() { ResetCameraCommand = new RoutedUICommand("Reset Camera", "ResetCamera", typeof(CameraAndLightingControl)); }

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  • how to find maximum frequent item sets from large transactional data file

    - by ANIL MANE
    Hi, I have the input file contains large amount of transactions like Transaction ID Items T1 Bread, milk, coffee, juice T2 Juice, milk, coffee T3 Bread, juice T4 Coffee, milk T5 Bread, Milk T6 Coffee, Bread T7 Coffee, Bread, Juice T8 Bread, Milk, Juice T9 Milk, Bread, Coffee, T10 Bread T11 Milk T12 Milk, Coffee, Bread, Juice i want the occurrence of every unique item like Item Name Count Bread 9 Milk 8 Coffee 7 Juice 6 and from that i want an a fp-tree now by traversing this tree i want the maximal frequent itemsets as follows The basic idea of method is to dispose nodes in each “layer” from bottom to up. The concept of “layer” is different to the common concept of layer in a tree. Nodes in a “layer” mean the nodes correspond to the same item and be in a linked list from the “Head Table”. For nodes in a “layer” NBN method will be used to dispose the nodes from left to right along the linked list. To use NBN method, two extra fields will be added to each node in the ordered FP-Tree. The field tag of node N stores the information of whether N is maximal frequent itemset, and the field count’ stores the support count information in the nodes at left. In Figure, the first node to be disposed is “juice: 2”. If the min_sup is equal to or less than 2 then “bread, milk, coffee, juice” is a maximal frequent itemset. Firstly output juice:2 and set the field tag of “coffee:3” as “false” (the field tag of each node is “true” initially ). Next check whether the right four itemsets juice:1 be the subset of juice:2. If the itemset one node “juice:1” corresponding to is the subset of juice:2 set the field tag of the node “false”. In the following process when the field tag of the disposed node is FALSE we can omit the node after the same tagging. If the min_sup is more than 2 then check whether the right four juice:1 is the subset of juice:2. If the itemset one node “juice:1” corresponding to is the subset of juice:2 then set the field count’ of the node with the sum of the former count’ and 2 After all the nodes “juice” disposed ,begin to dispose the node “coffee:3”. Any suggestions or available source code, welcome. thanks in advance

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  • Dynamic adding of usercontrols not showing control on page

    - by Phil
    I am trying to insert a user control dynamically into my default.aspx page via the following method in the page_init: Dim control As UserControl = LoadControl("~\Modules\Content.ascx") Controls.Add(control) When I run the page there is no sign of the usercontrol. Am I using the correct code to insert the usercontrol? Is there an alternative method of insertion available? Does the fact that the usercontrol has a page_load make a difference? Do I need to register the control in my aspx page at design time? Thanks in advance for any assistance you can offer.

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  • Should methods containing LINQ expressions be tested / mocked?

    - by Phil.Wheeler
    Assuming I have a class with a method that takes a System.Linq.Expressions.Expression as a parameter, how much value is there in unit testing it? public void IEnumerable<T> Find(Expression expression) { return someCollection.Where(expression).ToList(); } Unit testing or mocking these sorts of methods has been a mind-frying experience for me and I'm now at the point where I have to wonder whether it's all just not worth it. How would I unit test this method using some arbitrary expression like List<Animal> = myAnimalRepository.Find(x => x.Species == "Cat");

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  • Monitor file selection in explorer (like clipboard monitoring) in C#

    - by Christian
    Hi, I am trying to create a little helper application, one scenario is "file duplication finder". What I want to do is this: I start my C# .NET app, it gives me an empty list. Start the normal windows explorer, select a file in some folder The C# app tells me stuff about this file (e.g. duplicates) How can I monitor the currently selected file in the "normal" windows explorer instance. Do I have to start the instance using .NET to have a handle of the process. Do I need a handle, or is there some "global hook" I can monitor inside C#. Its a little bit like monitoring the clipboard, but not exactly the same... Any help is appreciated (if you don't have code, just point me to the right interops, dlls or help pages :-) Thanks, Chris EDIT 1 (current source, thanks to Mattias) using SHDocVw; using Shell32; public static void ListExplorerWindows() { foreach (InternetExplorer ie in new ShellWindowsClass()) DebugExplorerInstance(ie); } public static void DebugExplorerInstance(InternetExplorer instance) { Debug.WriteLine("DebugExplorerInstance ".PadRight(30, '=')); Debug.WriteLine("FullName " + instance.FullName); Debug.WriteLine("AdressBar " + instance.AddressBar); var doc = instance.Document as IShellFolderViewDual ; if (doc != null) { Debug.WriteLine(doc.Folder.Title); foreach (FolderItem item in doc.SelectedItems()) { Debug.WriteLine(item.Path); } } }

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  • How can I render a Batik SVG Java object in the view portion of a Spring MVC application?

    - by mattblang
    I am creating and manipulating a SVGOMDocument object in a controller method. How can I render this object in a JSP view? I get very close with the following controller method and <object> tag. @RequestMapping(value = "/seal") public ResponseEntity<SVGDocument> createSeal() throws IOException { InputStream file = new ClassPathResource("seal.svg").getInputStream(); String parser = XMLResourceDescriptor.getXMLParserClassName(); SAXSVGDocumentFactory factory = new SAXSVGDocumentFactory(parser); SVGDocument svg = (SVGDocument) factory.createDocument("http://www.w3.org/2000/svg", file); svg.getElementById("name").getFirstChild().setNodeValue("a test name"); return new ResponseEntity<SVGDocument>(svg, HttpStatus.OK); } <object data="/seal" type="image/svg+xml"></object> This displays a string of XML that is a SVG. The string is in quotes with every XML quote escaped.

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  • Sendkeys problem from .NET program

    - by user203123
    THe code below I copied from MSDN with a bit of modification: [DllImport("user32.dll", CharSet = CharSet.Unicode)] public static extern IntPtr FindWindow(string lpClassName,string lpWindowName); DllImport("User32")] public static extern bool SetForegroundWindow(IntPtr hWnd); int cnt = 0; private void button1_Click(object sender, EventArgs e) { IntPtr calculatorHandle = FindWindow("Notepad", "Untitled - Notepad"); if (calculatorHandle == IntPtr.Zero) { MessageBox.Show("Calculator is not running."); return; } SetForegroundWindow(calculatorHandle); SendKeys.SendWait(cnt.ToString()); SendKeys.SendWait("{ENTER}"); cnt++; SendKeys.Flush(); System.Threading.Thread.Sleep(1000); } The problem is the number sequence in Notepad is not continuously. The first click always results 0 (as expected). but from the second click, the result is unpredictable (but the sequence is still in order, e.g. 3, 4, 5, 10, 14, 15, ....) If I click the button fast enough, I was able to get the result in continuous order (0,1,2,3,4,....) but sometimes it produces more than 2 same numbers (e.g. 0,1,2,3,3,3,4,5,6,6,6,7,8,9,...)

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  • storing data at remote server using php

    - by VIPUL GOYAL
    I want to send data to php file and execute insert query in it to store data in database. When i execute this code, it executes but database does not get updated. Code of PHP file Java code------------------------------Remote.java------------------------------ public class Remote extends Activity { EditText name; Button s; String r; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); name= (EditText)findViewById(R.id.editText1); s=(Button)findViewById(R.id.button1); s.setOnClickListener(new OnClickListener() { public void onClick(View v) { try { r = name.getText().toString(); ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>(); postParameters.add(new BasicNameValuePair("username", r)); CustomHttpClient.executeHttpPost("http://vipul.eu5.org/abc.php", postParameters); //Enetr Your remote PHP,ASP, Servlet file link } catch (Exception e) { e.printStackTrace(); } } }); } } -----------------------------CustomHttpClient.java---------------------------- public class CustomHttpClient { private static HttpClient getHttpClient() { if (mHttpClient == null) { mHttpClient = new DefaultHttpClient(); final HttpParams params = mHttpClient.getParams(); HttpConnectionParams.setConnectionTimeout(params, HTTP_TIMEOUT); HttpConnectionParams.setSoTimeout(params, HTTP_TIMEOUT); ConnManagerParams.setTimeout(params, HTTP_TIMEOUT); } return mHttpClient; } /** * Performs an HTTP Post request to the specified url with the * specified parameters. * * @param url The web address to post the request to * @param postParameters The parameters to send via the request * @return The result of the request * @throws Exception */ public static void executeHttpPost(String url, ArrayList postParameters) throws Exception { try { HttpClient client = getHttpClient(); HttpPost request = new HttpPost(url); UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(postParameters); request.setEntity(formEntity); HttpResponse response = client.execute(request); } catch(Exception e) { } } }

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  • What are the basics of dealing with user input events in Android?

    - by user279112
    Hello. I thought I had understood this question, but something is quite wrong here. When the user (me, so far) tries to press keys, nothing really happens, and I am having a lot of trouble understanding what it is that I've missed. Consider this before I present some code to help clarify my problem: I am using Android's Lunar Lander example to make my first "real" Android program. In that example, of course, there exist a class LunarView, and class nested therein LunarThread. In my code the equivalents of these classes are Graphics and GraphicsThread, respectively. Also I can make sprite animations in 2D just fine on Android. I have a Player class, and let's say GraphicsThread has a Player member referred to as "player". This class has four coordinates - x1, y1, x2, and y2 - and they define a rectangle in which the sprite is to be drawn. I've worked it out so that I can handle that perfectly. Whenever the doDraw(Canvas canvas) method is invoked, it'll just look at the values of those coordinates and draw the sprite accordingly. Now let's say - and this isn't really what I'm trying to do with the program - I'm trying to make the program where all it does is display the Player sprite at one location of the screen UNTIL the FIRST time the user presses the Dpad's left button. Then the location will be changed to another set position on the screen, and the sprite will be drawn at that position for the rest of the program invariably. Also note that the GraphicsThread member in Graphics is called "thread", and that the SurfaceHolder member in GraphicsThread is called "mSurfaceHolder". So consider this method in class Graphics: @Override public boolean onKeyDown(int keyCode, KeyEvent msg) { return thread.keyDownHandler(keyCode, msg); } Also please consider this method in class GraphicsThread: boolean keyDownHandler(int keyCode, KeyEvent msg) { synchronized (mSurfaceHolder) { if (keyCode == KeyEvent.KEYCODE_DPAD_LEFT) { player.x1 = 100; player.y1 = 100; player.x2 = 120; player.y2 = 150; } } return true; } Now then assuming that player's coordinates start off as (200, 200, 220, 250), why won't he do anything different when I press Dpad: Left? Thanks!

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  • By-Name-Parameters for Constructors

    - by hotzen
    Hello, coming from my other question is there a way to get by-name-parameters for constructors working? I need a way to provide a code-block which is executed on-demand/lazy/by-name inside an object and this code-block must be able to access the class-methods as if the code-block were part of the class. Following Testcase fails: package test class ByNameCons(code: => Unit) { def exec() = { println("pre-code") code println("post-code") } def meth() = println("method") def exec2(code2: => Unit) = { println("pre-code") code2 println("post-code") } } object ByNameCons { def main(args: Array[String]): Unit = { val tst = new ByNameCons { println("foo") meth() // knows meth() as code is part of ByNameCons } tst.exec() // ByName fails (executed right as constructor) println("--------") tst.exec2 { // ByName works println("foo") //meth() // does not know meth() as code is NOT part of ByNameCons } } } Output: foo method pre-code post-code -------- pre-code foo post-code

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  • IAuthenticationRequest.RedirectToProvider is not supposed to return, yet it does

    - by ripper234
    The method DotNetOpenAuth.OpenId.RelyingParty.IAuthenticationRequest.RedirectToProvider() is documented never to return: Redirects the user agent to the provider for authentication. Execution of the current page terminates after this call. However, it does return under the latest implementation (3.4.3). I'm using the following code: using (var relayingParty = new OpenIdRelyingParty()) { var response = relayingParty.GetResponse(); if (response == null) { // Stage 2: user submitting Identifier var openId = Request.Form["openId"]; relayingParty.CreateRequest(openId).RedirectToProvider(); throw new Exception("Never gets here"); } ... } (The line with "Never gets here" is reached). I need to return an ActionResult from this method ... Is this a known bug? Is there a aorkaround? Should I return EmptyResult? As far as I understand this is a bug - I submitted it in the project issue tracker.

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  • Java 2D Resize

    - by jon077
    I have some old Java 2D code I want to reuse, but was wondering, is this the best way to get the highest quality images? public static BufferedImage getScaled(BufferedImage imgSrc, Dimension dim) { // This code ensures that all the pixels in the image are loaded. Image scaled = imgSrc.getScaledInstance( dim.width, dim.height, Image.SCALE_SMOOTH); // This code ensures that all the pixels in the image are loaded. Image temp = new ImageIcon(scaled).getImage(); // Create the buffered image. BufferedImage bufferedImage = new BufferedImage(temp.getWidth(null), temp.getHeight(null), BufferedImage.TYPE_INT_RGB); // Copy image to buffered image. Graphics g = bufferedImage.createGraphics(); // Clear background and paint the image. g.setColor(Color.white); g.fillRect(0, 0, temp.getWidth(null),temp.getHeight(null)); g.drawImage(temp, 0, 0, null); g.dispose(); // j2d's image scaling quality is rather poor, especially when // scaling down an image to a much smaller size. We'll post filter // our images using a trick found at // http://blogs.cocoondev.org/mpo/archives/003584.html // to increase the perceived quality.... float origArea = imgSrc.getWidth() * imgSrc.getHeight(); float newArea = dim.width * dim.height; if (newArea <= (origArea / 2.)) { bufferedImage = blurImg(bufferedImage); } return bufferedImage; } public static BufferedImage blurImg(BufferedImage src) { // soften factor - increase to increase blur strength float softenFactor = 0.010f; // convolution kernel (blur) float[] softenArray = { 0, softenFactor, 0, softenFactor, 1-(softenFactor*4), softenFactor, 0, softenFactor, 0}; Kernel kernel = new Kernel(3, 3, softenArray); ConvolveOp cOp = new ConvolveOp(kernel, ConvolveOp.EDGE_NO_OP, null); return cOp.filter(src, null); }

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  • Is 1/0 a legal Java expression?

    - by polygenelubricants
    The following compiles fine in my Eclipse: final int j = 1/0; // compiles fine!!! // throws ArithmeticException: / by zero at run-time Java prevents many "dumb code" from even compiling in the first place (e.g. "Five" instanceof Number doesn't compile!), so the fact this didn't even generate as much as a warning was very surprising to me. The intrigue deepens when you consider the fact that constant expressions are allowed to be optimized at compile time: public class Div0 { public static void main(String[] args) { final int i = 2+3; final int j = 1/0; final int k = 9/2; } } Compiled in Eclipse, the above snippet generates the following bytecode (javap -c Div0) Compiled from "Div0.java" public class Div0 extends java.lang.Object{ public Div0(); Code: 0: aload_0 1: invokespecial #8; //Method java/lang/Object."<init>":()V 4: return public static void main(java.lang.String[]); Code: 0: iconst_5 1: istore_1 // "i = 5;" 2: iconst_1 3: iconst_0 4: idiv 5: istore_2 // "j = 1/0;" 6: iconst_4 7: istore_3 // "k = 4;" 8: return } As you can see, the i and k assignments are optimized as compile-time constants, but the division by 0 (which must've been detectable at compile-time) is simply compiled as is. javac 1.6.0_17 behaves even more strangely, compiling silently but excising the assignments to i and k completely out of the bytecode (probably because it determined that they're not used anywhere) but leaving the 1/0 intact (since removing it would cause an entirely different program semantics). So the questions are: Is 1/0 actually a legal Java expression that should compile anytime anywhere? What does JLS say about it? If this is legal, is there a good reason for it? What good could this possibly serve?

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  • Passing Activity to non-activity object properly

    - by rayman
    In my app ive got a non-activity object which it's role is being a manager class. many times i need to pass "source activity" to methods as parameter to that manager class in order to make some operations on that activity. for exaple let's assume we have MyActivity which gotta do some toast. so i have this manager class called MyManager, and i have this method in it raiseToast(Activity sourceActivity) { Toast.makeText(sourceActivity, demo, Toast.LENGTH_LONG).show(); } and from Myactivity class we calling that method this way: MyManager manager=new MyManager(); manager.raitetoast(MyActivity.this); it works fine. what I'm asking here, is this a proper way to pass an Activity as parameter to a non-activity object? I'm having a memory leaks on real device(not the emulator), I wonder if this could also causing any reason for that? Thanks Idan.

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  • Parameter for BPEL process

    - by Hubidubi
    Hi I use OpenESB + BPEL. I would like to use some parameter to set system specific settings (path, string constants, etc.). I tried to use a properties file that a simple java class should read up and use with this method (http://wiki.open-esb.java.net/Wiki.jsp?page=BPELSEHowToCallJavaMethods). The problem is that I can't create properties file in BPEL project (not supported). So I created a file by hand. But this file is not included in the deployed app. Is there any working solution for including property file or is there any other method to set parameters on BPEL process? Thanks, Hubidubi

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  • How to print non-ASCII characters in Python

    - by Roman
    I have a problem when I'm printing (or writing to a file) the non-ASCII characters in Python. I've resolved it by overriding the str method in my own objects, and making "x.encode('utf-8')" inside it, where x is a property inside the object. But, if I receive a third-party object, and I make "str(object)", and this object has a non-ASCII character inside, it will fail. So the question is: is there any way to tell the str method that the object has an UTF-8 codification, generically? I'm working with Python 2.5.4.

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  • How to render a Partial from a Model in Rails 2.3.5

    - by empire29
    I have a Rails 2.3.5 application and Im trying to render several Partials from within a Model (i know, i know -- im not supposed to). The reason im doing this is im integrating a Comet server (APE) into my Rails app and need to push updates out based on the Model's events (ex. after_create). I have tried doing this: ActionView::Base.new(Rails::Configuration.new.view_path).render(:partial => "pages/show", :locals => {:page => self}) Which allows me to render simple partials that don't user helpers, however if I try to user a link_to in my partial, i receive an error stating: undefined method `url_for' for nil:NilClass I've made sure that the object being passed into the "project_path(project)" is not nil. I've also tried including: include ActionView::Helpers::UrlHelper include ActionController::UrlWriter in the Module that contains the method that makes the above "render" call. Does anyone know how to work around this? Thanks

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  • Generate n-dimensional random numbers in Python

    - by Magsol
    I'm trying to generate random numbers from a gaussian distribution. Python has the very useful random.gauss() method, but this is only a one-dimensional random variable. How could I programmatically generate random numbers from this distribution in n-dimensions? For example, in two dimensions, the return value of this method is essentially distance from the mean, so I would still need (x,y) coordinates to determine an actual data point. I suppose I could generate two more random numbers, but I'm not sure how to set up the constraints. I appreciate any insights. Thanks!

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