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  • can i know the Thread runnable class attributes in java?

    - by dori naji
    probability this question have been asked before but i cant find anything in my searching mechanism. I am trying to create a multiple threads, in an array list but i want to retrieve them from an arraylist and filter them by the attribute of w1 i used in my code. any ideas ? w1 = new FirstWorker(ProductsList, OrdersList, s); FirstWorkerThread = new Thread(w1); ThreadArrayList.add(FirstWorkerThread); //I know i cant do the code below but i want to do that how ? for(Thread x : ThreadArrayList){ x.ProductsList } this is FirstWorker class import java.lang.String; import java.util.HashMap; /* * To change this template, choose Tools | Templates and open the template in * the editor. */ /** * * @author Dimitris */ public class FirstWorker extends Thread implements Runnable { private OrderList orderlist; private ProductList productlist; private String Worker; boolean Stop; private int speed = 1000; public FirstWorker(ProductList productlist, OrderList orderlist, String Worker) { this.productlist = productlist; this.orderlist = orderlist; this.Worker = Worker; this.Stop = true; } public void run() { if (Stop == true) { try { Thread.sleep(100); } catch (InterruptedException e) { } while (orderlist.returnLengthofOrder() != 0) { if (Thread.interrupted()) { System.out.println("I am in the thread inturrupt"); // We've been interrupted: no more crunching. return; } if (orderlist.getDone() == true) { } else if (orderlist.getDone() == false) { orderlist.setDoneTrue(); orderlist.Purchased(Worker); orderlist.setDoneFalse(); try { Thread.sleep(this.speed); } catch (InterruptedException e) { return; } } } } } public void setWork() { Stop = false; } public void setSpeed(int speed) { this.speed = speed; } }

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  • Java OO design confusion: how to handle actions modified by states modified by actions...

    - by Arvanem
    Hi folks, Given an entity, whose action is potentially modified by states (of the entity and other entities) in turn potentially modified by other actions (of the entity and other entities) , what is the best way to code or design to handle the potential existence of the modifiers? Speaking metaphorically, I am coding a Java application representing a piano. As you know a piano has keys (which, when pressed, emit sound) and pedals (which, when pressed, modify the keys' sounds). My base class structure is as follows: Entity (for keys and pedals) State (this holds each entity's states, e.g. name such as "soft pedal", and boolean "Pressed"), Action (this holds each entity's actions, e.g. play sound when pressed, or modify others sounds). By composition, the Entity class has a copy of each of State and Action inside it. e.g.: public class Entity { State entityState = new State(); Action entityAction = new Action(); Thus I have coded a "C-Sharp" key Entity. When I "press" that entity (set its "Pressed" state to true), its action plays a "C-Sharp" sound and then sets its "Pressed" state to false. At the same time, if the "C-Sharp" key entity is not "tuned", its sound deviates from "C-Sharp". Meanwhile I have coded a "soft pedal" Entity. When that entity is "pressed", no sound plays but its action is to make softer the sound of the "C-Sharp" and other key entities. I have also coded a "sustain pedal" Entity. When that entity is "pressed", no sound plays but its action is to enable reverberation of the sound of the "C-Sharp" and other key entities. Both the "soft" and "sustain pedals" can be pressed at the same time with the result that keys entities become both softened and reverberating. In short, I do not understand how to make this simultaneous series of states and actions modify each other in a sensible OO way. I am wary of coding a massive series of "if" statements or "switches". Thanks in advance for any help or links you can offer.

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  • simple image upload in aspnet mvc

    - by FosterZ
    hi,i'm building a simple school portal, i have stucked at uploading an image into my application, i.e a user should upload school image to my server, i have directory for images as ./Content/Images -- all uploading images should be uploaded to this directory. i have following code input type="file" id="SchoolImageUrl" name="SchoolImageUrl" class="required" using this m'getting a browse button, i have no idea how to upload that image to server and how would be my action controller ? i have following controller for creating school public ActionResult SchoolCreate(_ASI_School schoolToCreate, FormCollection collection) { if (!ModelState.IsValid) return View(); try { // TODO: Add insert logic here schoolToCreate.SchoolId = Guid.NewGuid().ToString(); schoolToCreate.UserId = new Guid(Request.Form["currentUser"]); schoolToCreate.SchoolAddedBy = User.Identity.Name; HttpPostedFileBase file = Request.Files["SchoolImageUrl"]; file.SaveAs(file.FileName); //schoolToCreate.SchoolImageUrl = Reuseable.ImageUpload(Request.Files["SchoolImageUrl"], Server.MapPath("../Content")); //schoolToCreate.SchoolImageUrl = Path.GetFullPath(Request.Files[0].FileName); schoolToCreate.SchoolImageUrl = collection["SchoolImageUrl"]; UpdateModel(schoolToCreate); _schoolRepository.CreateSchool(schoolToCreate); //_schoolRepository.SaveToDb(); return RedirectToAction("DepartmentCreate", "Department", new { userId = schoolToCreate.UserId, schoolId = schoolToCreate.SchoolId }); } catch { return View("CreationFailed"); } } here im geting object referece error

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  • Is there a way to programmatically tell if particular block of memory was not freed by FastMM?

    - by Wodzu
    I am trying to detect if a block of memory was not freed. Of course, the manager tells me that by dialog box or log file, but what if I would like to store results in a database? For example I would like to have in a database table a names of routines which allocated given blocks. After reading a documentation of FastMM I know that since version 4.98 we have a possibility to be notified by manager about memory allocations, frees and reallocations as they occur. For example OnDebugFreeMemFinish event is passing to us a PFullDebugBlockHeader which contains useful informations. There is one thing that PFullDebugBlockHeader is missing - the information if the given block was freed by the application. Unless OnDebugFreeMemFinish is called only for not freed blocks? This is which I do not know and would like to find out. The problem is that even hooking into OnDebugFreeMemFinish event I was unable to find out if the block was freed or not. Here is an example: program MemLeakTest; {$APPTYPE CONSOLE} uses FastMM4, ExceptionLog, SysUtils; procedure MemFreeEvent(APHeaderFreedBlock: PFullDebugBlockHeader; AResult: Integer); begin //This is executed at the end, but how should I know that this block should be freed //by application? Unless this is executed ONLY for not freed blocks. end; procedure Leak; var MyObject: TObject; begin MyObject := TObject.Create; end; begin OnDebugFreeMemFinish := MemFreeEvent; Leak; end. What I am missing is the callback like: procedure OnMemoryLeak(APointer: PFullDebugBlockHeader); After browsing the source of FastMM I saw that there is a procedure: procedure LogMemoryLeakOrAllocatedBlock(APointer: PFullDebugBlockHeader; IsALeak: Boolean); which could be overriden, but maybe there is an easier way?

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  • Java Process.waitFor() and IO streams

    - by lynks
    I have the following code; String[] cmd = { "bash", "-c", "~/path/to/script.sh" }; Process p = Runtime.getRuntime().exec(cmd); PipeThread a = new PipeThread(p.getInputStream(), System.out); PipeThread b = new PipeThread(p.getErrorStream(), System.err); p.waitFor(); a.die(); b.die(); The PipeThread class is quite simple so I will include it in full; public class PipeThread implements Runnable { private BufferedInputStream in; private BufferedOutputStream out; public Thread thread; private boolean die = false; public PipeThread(InputStream i, OutputStream o) { in = new BufferedInputStream(i); out = new BufferedOutputStream(o); thread = new Thread(this); thread.start(); } public void die() { die = true; } public void run() { try { byte[] b = new byte[1024]; while(!die) { int x = in.read(b, 0, 1024); if(x > 0) out.write(b, 0, x); else die(); out.flush(); } } catch(Exception e) { e.printStackTrace(); } try { in.close(); out.close(); } catch(Exception e) { } } } My problem is this; p.waitFor() blocks endlessly, even after the subprocess has terminated. If I do not create the pair of PipeThread instances, then p.waitFor() works perfectly. What is it about the piping of io streams that is causing p.waitFor() to continue blocking? I'm confused as I thought the IO streams would be passive, unable to keep a process alive, or to make Java think the process is still alive.

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  • Gui problem after rewriting to MVC

    - by trevor_nise
    I'm practicing MVC style programming. I have a Mastermind game in a single file, working with no problems (maybe apart of the fact that "Check" button is invisible at start). http://paste.pocoo.org/show/226726/ But when I've rewritten it to model, view, controller files - when I click on empty Pin (that should be updated, and repainted with new color) - noting happens. Can anybody see any problems here ? I've tried placing repaint() in different places, but it simply does not work at all :/ Main : public class Main { public static void main(String[] args){ Model model = new Model(); View view = new View("Mastermind", 400, 590, model); Controller controller = new Controller(model, view); view.setVisible(true); } } Model : import java.util.Random; public class Model{ static final int LINE = 5, SCORE = 10, OPTIONS = 20; Pin pins[][] = new Pin[21][LINE]; int combination[] = new int[LINE]; int curPin = 0; int turn = 1; Random generator = new Random(); int repaintPin; boolean pinsRepaint=false; int pinsToRepaint; boolean isUpdate = true, isPlaying = true, isRowFull = false; static final int HIT_X[] = {270,290,310,290,310}, HIT_Y[] = {506,496,496,516,516}; public Model(){ for ( int i=0; i < SCORE; i++ ){ for ( int j = 0; j < LINE; j++ ){ pins[i][j] = new Pin(20,0); pins[i][j].setPosition(j*50+30,510-i*50); pins[i+SCORE][j] = new Pin(8,0); pins[i+SCORE][j].setPosition(HIT_X[j],HIT_Y[j]-i*50); } } for ( int i=0; i < LINE; i++ ){ pins[OPTIONS][i] = new Pin( 20, i+2 ); pins[OPTIONS][i].setPosition( 370,i * 50 + 56); } } void fillHole(int color) { pins[turn-1][curPin].setColor(color+1); pinsRepaint = true; pinsToRepaint = turn; curPin = (curPin+1) % LINE; if (curPin == 0){ isRowFull = true; } pinsRepaint = false; pinsToRepaint = 0; } void check() { int junkPins[] = new int[LINE], junkCode[] = new int[LINE]; int pinCount = 0, pico = 0; for ( int i = 0; i < LINE; i++ ) { junkPins[i] = pins[turn-1][i].getColor(); junkCode[i] = combination[i]; } for ( int i = 0; i < LINE; i++ ){ if (junkPins[i]==junkCode[i]) { pins[turn+SCORE][pinCount].setColor(1); pinCount++; pico++; junkPins[i] = 98; junkCode[i] = 99; } } for ( int i = 0; i < LINE; i++ ){ for ( int j = 0; j < LINE; j++ ) if (junkPins[i]==junkCode[j]) { pins[turn+SCORE][pinCount].setColor(2); pinCount++; junkPins[i] = 98; junkCode[j] = 99; j = LINE; } } pinsRepaint = true; pinsToRepaint = turn + SCORE; pinsRepaint = false; pinsToRepaint=0; if ( pico == LINE ){ isPlaying = false; } else if ( turn >= 10 ){ isPlaying = false; } else{ curPin = 0; isRowFull = false; turn++; } } void combination() { for ( int i = 0; i < LINE; i++ ){ combination[i] = generator.nextInt(6) + 1; } } } class Pin{ private int color, X, Y, radius; public Pin(){ X = 0; Y = 0; radius = 0; color = 0; } public Pin( int r,int c ){ X = 0; Y = 0; radius = r; color = c; } public int getX(){ return X; } public int getY(){ return Y; } public int getRadius(){ return radius; } public void setRadius(int r){ radius = r; } public void setPosition( int x,int y ){ this.X = x ; this.Y = y ; } public void setColor( int c ){ color = c; } public int getColor() { return color; } } View: import java.awt.*; import javax.swing.*; public class View extends Frame{ Model model; JButton checkAnswer; private JPanel button; private static final Color COLORS[] = {Color.black, Color.white, Color.red, Color.yellow, Color.green, Color.blue, new Color(7, 254, 250)}; public View(String name, int w, int h, Model m){ model = m; setTitle( name ); setSize( w,h ); setResizable( false ); this.setLayout(new BorderLayout()); button = new JPanel(); button.setSize( new Dimension(400, 100)); button.setVisible(true); checkAnswer = new JButton("Check"); checkAnswer.setSize( new Dimension(200, 30)); button.add( checkAnswer ); this.add( button, BorderLayout.SOUTH); button.setVisible(true); } @Override public void paint( Graphics g ) { g.setColor( new Color(238, 238, 238)); g.fillRect( 0,0,400,590); for ( int i=0; i < model.pins.length; i++ ) { paintPins(model.pins[i][0],g); paintPins(model.pins[i][1],g); paintPins(model.pins[i][2],g); paintPins(model.pins[i][3],g); paintPins(model.pins[i][4],g); } } @Override public void update( Graphics g ) { if ( model.isUpdate ) { paint(g); } else { model.isUpdate = true; paintPins(model.pins[model.repaintPin-1][0],g); paintPins(model.pins[model.repaintPin-1][1],g); paintPins(model.pins[model.repaintPin-1][2],g); paintPins(model.pins[model.repaintPin-1][3],g); paintPins(model.pins[model.repaintPin-1][4],g); } } void repaintPins( int pin ) { model.repaintPin = pin; model.isUpdate = false; repaint(); } public void paintPins(Pin p, Graphics g ){ int X = p.getX(); int Y = p.getY(); int color = p.getColor(); int radius = p.getRadius(); int x = X-radius; int y = Y-radius; if (color > 0){ g.setColor( COLORS[color]); g.fillOval( x,y,2*radius,2*radius ); } else{ g.setColor( new Color(238, 238, 238) ); g.drawOval( x,y,2*radius-1,2*radius-1 ); } g.setColor( Color.black ); g.drawOval( x,y,2*radius,2*radius ); } } Controller: import java.awt.*; import java.awt.event.*; public class Controller implements MouseListener, ActionListener { private Model model; private View view; public Controller(Model m, View v){ model = m; view = v; view.addWindowListener( new WindowAdapter(){ public void windowClosing(WindowEvent e){ System.exit(0); } }); view.addMouseListener(this); view.checkAnswer.addActionListener(this); model.combination(); } public void actionPerformed( ActionEvent e ) { if(e.getSource() == view.checkAnswer){ if(model.isRowFull){ model.check(); } } } public void mousePressed(MouseEvent e) { Point mouse = new Point(); mouse = e.getPoint(); if (model.isPlaying){ if (mouse.x > 350) { int button = 1 + (int)((mouse.y - 32) / 50); if ((button >= 1) && (button <= 5)){ model.fillHole(button); if(model.pinsRepaint){ view.repaintPins( model.pinsToRepaint ); } } } } } public void mouseClicked(MouseEvent e) {} public void mouseReleased(MouseEvent e){} public void mouseEntered(MouseEvent e) {} public void mouseExited(MouseEvent e) {} }

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  • rename an html page according to an image within it

    - by Jake
    Hi, firstly I'll give some background regarding the situation. I have a website containing approximately 56k pages each page contain a mapped sketch of a machine part. this machine part is made out of smaller parts which are outlined in the image and hold a certain number. when you hover over the numbers a box with the part item code shows up. I order parts according to this item codes but recently a lot of the items codes have changed, therefore I am looking for a solution. now I own a database with data on all the 56k parts and I want to link the relevant webpage to each record according to the name of the part(a column in my database), the problem is that the webpages names has no logic name that could connect with the part name in any way but the image that is displayed in the page has the exact name of the part. I want to rename all the html files I has according to the Images displayed within them. how can I achieve that without renaming all the 56k pages manually? additionally how can I add the links to all the 56k pages automatically to my database after all the above is done? Thank you for your patience I know it was long.

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  • Trouble bringing a Blackberry App to Foreground

    - by Luis Armando
    I have an app that is listening in background and when the user clicks "send" it displays a dialogue. However I need to bring my app to foreground so the user answers some questions before letting the message go. but I haven't been able to do this, this is the code in my SendListener: SendListener sl = new SendListener(){ public boolean sendMessage(Message msg){ Dialog myDialog = new Dialog(Dialog.D_OK, "message from within SendListener", Dialog.OK,Bitmap.getPredefinedBitmap(Bitmap.EXCLAMATION), Dialog.GLOBAL_STATUS) { //Override inHolster to prevent the Dialog from being dismissed //when a user holsters their BlackBerry. This can //cause a deadlock situation as the Messages //application tries to save a draft of the message //while the SendListener is waiting for the user to //dismiss the Dialog. public void inHolster() { } }; //Obtain the application triggering the SendListener. Application currentApp = Application.getApplication(); //Detect if the application is a UiApplication (has a GUI). if( currentApp instanceof UiApplication ) { //The sendMessage method is being triggered from //within a UiApplication. //Display the dialog using is show method. myDialog.show(); App.requestForeground(); } else { //The sendMessage method is being triggered from // within an application (background application). Ui.getUiEngine().pushGlobalScreen( myDialog, 1, UiEngine.GLOBAL_MODAL ); } return true; } }; store.addSendListener(sl); App is an object I created above: Application App = Application.getApplication(); I have also tried to invoke the App to foreground using its processID but so far no luck.

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  • Data Annotations on ViewModels or Domain Objects

    - by Ahmad
    Where would data annotations be more suitable: ViewModels or Domain Objects or Both I am struggling to decide where these will be more suited. I have not as yet fully utilized them but this question came to mind. From most of the examples I have seen, they are generally placed on Models and simply use the required attributes for validation using ModelState.IsValid. I have also seen another question on SO where the use of data annotations alone is not sufficient and advocate. Option 1 - I will still need to validate again in my service layer. ( I think that my service layer should be complete and this include validation, since its planned to be used elsewhere) Option 2 - How will I then get the benefits of the built in validation both client and server side. Option 3 - there will be a repetition of validation logic, however I was wondering if one could use a MetaData class approach that can be used for both ViewModels and Domain Objects. ( This is completely of the top of my head, so it may be nonsensical) I wonder if this question even makes sense. If not, can someone please help in understanding this better. Have I completely misunderstood the use of data annotations?

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  • javascript equivalent of ASP preInit event

    - by Pankaj Kumar
    Hi guys, searching for this has yielded no resuts.. i have a middle page that has an iframe and all the pages open in that iframe...i have to implement a chat system just like in Google and so to ensure that the chat windows did not close whwn the page would postback i am opening all pages in iframe.... this is a social networking site and user can have themes which have background images per theme now when i visit a friends profile the backgrounf image of the middle page should change... i have this code to find parent of iframe and change background image $(document).ready(function(){ var theme=document.getElementById("ctl00_decideFooterH").value; var t= parent.document.getElementsByTagName("body"); if(theme=='basicTheme'){ t[0].className="basic"; } else if(theme=='Tranquility') { t[0].className="Tranquility"; } else if(theme=='AbstractPink') { t[0].className="abstractPink"; } }); and this code is the master page that all child pages that would open in iframe would access..the trouble is that there is a lag between the theme application on server side(which happens at PreInit) and the background image change which is done by this document.ready that gets executed after the iframe has loaded.. so essentially i need a javascript function that would either execute parallel to PreInit or some other logic....so guys plz help its urgent

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  • Delphi : Handling the fact that Strings are not Objects

    - by awmross
    I am trying to write a function that takes any TList and returns a String representation of all the elements of the TList. I tried a function like so function ListToString(list:TList<TObject>):String; This works fine, except you can't pass a TList to it. E2010 Incompatible types: 'TList<System.TObject>' and 'TList<System.string>' In Delphi, a String is not an Object. To solve this, I've written a second function: function StringListToString(list:TList<string>):String; Is this the only solution? Are there other ways to treat a String as more 'object-like'? In a similar vein, I also wanted to write an 'equals' function to compare two TLists. Again I run into the same problem function AreListsEqual(list1:TList<TObject>; list2:TList<TObject>):boolean; Is there any way to write this function (perhaps using generics?) so it can also handle a TList? Are there any other tricks or 'best practises' I should know about when trying to create code that handles both Strings and Objects? Or do I just create two versions of every function? Can generics help? I am from a Java background but now work in Delphi. It seems they are lately adding a lot of things to Delphi from the Java world (or perhaps the C# world, which copied them from Java). Like adding equals() and hashcode() to TObject, and creating a generic Collections framework etc. I'm wondering if these additions are very practical if you can't use Strings with them.

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  • Cannot access Class methods from previous windows form - C#

    - by George
    I am writing an app, still, where I need to test some devices every minute for 30 minutes. It made sense to use a timer set to kick off every 60 secs and do whats required in the event handler. However, I need the app to wait for the 30 mins until I have finished with the timer since the following code alters the state of the devices I am trying to monitor. I obviously don't want to use any form of loop to do this. I thought of using another windows form, since I also display the progress, which will simply kick off the timer and wait until its complete. The problem I am having with this is that I use a device Class and cant seem to get access to the methods in the device class from the 2nd (3rd actually - see below) windows form. I have an initial windows form where I get input from the user, then call the 2nd windows form where it work out which tests need to be done and which device classes need to be used, and then I want to call the 3rd windows form to handle the timer. I will have up to 6-7 device classes and so wanted to only instantiate them when actually requiring them, from the 2nd form. Should I have put this logic into the 1st windows form (program class ??) ? Would I not still have the problem of not being able to access device class methods from there too ? Anyway, perhaps someone knows of a better way to do the checks every minute without the rest of the code executing (and changing the status of the devices) or how I should be accessing the methods in the app ?? Well that's the problem, I cant get that part of it to work correctly. Here is the definition for the calling form including the device class - namespace NdtStart { public partial class fclsNDTCalib : Form { NDTClass NDT = new NDTClass(); public fclsNDTCalib() (new fclsNDTTicker(NDT)).ShowDialog(); Here is the class def for the called form - namespace NdtStart { public partial class fclsNDTTicker : Form { public fclsNDTTicker() I tried lots but couldn't get the arguments to work.

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  • Servlet Mapping Help - Possible to Avoid Referencing Context Name?

    - by AJ
    Hi all, I am working on a Spring application and trying to get my URL mapping correct. What I would like to have work is the following: http://localhost:8080/idptest -> doesn't work But instead, I have to reference the context name in my URL in order to resolve the mapping: http://localhost:8080/<context_name>/idptest -> works How can I avoid the requirement of referencing the context name in my URL without using a rewrite/proxy engine e.g. Apache? Here is the servlet definition and mapping from my web.xml: <servlet> <servlet-name>idptest</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/conf/idptest.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>idptest</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> Here's the outline of my controller (showing annotations for request mappings): @Controller @RequestMapping("/idptest") public class MyController { @RequestMapping(method=RequestMethod.GET) public String setupForm(Model model){ MyObject someObject = new MyObject(); model.addAttribute("someObject", someObject); return "myform"; } @RequestMapping(method = RequestMethod.POST) public String processSubmit(@ModelAttribute("someObject") MyObject someObject) throws Exception { // POST logic... } } Thanks!

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  • c# delegate and abstract class

    - by BeraCim
    Hi all: I currently have 2 concrete methods in 2 abstract classes. One class contains the current method, while the other contains the legacy method. E.g. // Class #1 public abstract class ClassCurrent<T> : BaseClass<T> where T : BaseNode, new() { public List<T> GetAllRootNodes(int i) { //some code } } // Class #2 public abstract class MyClassLegacy<T> : BaseClass<T> where T : BaseNode, new() { public List<T> GetAllLeafNodes(int j) { //some code } } I want the corresponding method to run in their relative scenarios in the app. I'm planning to write a delegate to handle this. The idea is that I can just call the delegate and write logic in it to handle which method to call depending on which class/project it is called from (at least thats what I think delegates are for and how they are used). However, I have some questions on that topic (after some googling): 1) Is it possible to have a delegate that knows the 2 (or more) methods that reside in different classes? 2) Is it possible to make a delegate that spawns off abstract classes (like from the above code)? (My guess is a no, since delegates create concrete implementation of the passed-in classes) 3) I tried to write a delegate for the above code. But I'm being technically challenged: public delegate List GetAllNodesDelegate(int k); GetAllNodesDelegate del = new GetAllNodesDelegate(ClassCurrent.GetAllRootNodes); I got the following error: An object reference is required for the non-static field, method, property ClassCurrent<BaseNode>.GetAllRootNodes(int) I might have misunderstood something... but if I have to manually declare a delegate at the calling class, AND to pass in the function manually as above, then I'm starting to question whether delegate is a good way to handle my problem. Thanks.

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  • How to get a Class literal from a generically specific Class

    - by h2g2java
    There are methods like these which require Class literals as argument. Collection<EmpInfo> emps = SomeSqlUtil.select( EmpInfo.class, "select * from emps"); or GWT.create(Razmataz.class); The problem presents itself when I need to supply generic specific classes like EmpInfo<String> Razmataz<Integer> The following would be wrong syntax Collection<EmpInfo<String>> emps = SomeSqlUtil.select( EmpInfo<String>.class, "select * from emps"); or GWT.create(Razmataz<Integer>.class); Because you cannot do syntax like Razmataz<Integer>.class So, how would I be able to squeeze a class literal out of EmpInfo<String> Razmataz<Integer> so that I could feed them as arguments to methods requiring Class literals? Further info Okay, I confess that I am asking this primarily for GWT. I have a pair of GWT RPC interface Razmataz. (FYI, GWT RPC interface has to be defined in server-client pairs). I plan to use the same interface pair for communicating whether it be String, Integer, Boolean, etc. GWT.create(Razmataz) for Razmataz<T> complains that, since I did not specify T, GWT compiler treated it as Object. Then GWT compiler would not accept Object class. It needs to be more specific than being an Object. So, it seems there is no way for me to tell GWT.create what T is because a Class literal is a runtime concept while generics is a compile time concept, Right?

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  • substitution cypher with different alphabet length

    - by seanizer
    I would like to implement a simple substitution cypher to mask private ids in URLs I know how my IDs will look like (combination of upperchase ascii, digits and underscore), and they will be rather long, as they are composed keys. I would like to use a longer alphabet to shorten the resulting codes (I'd like to use upper and lower case ascii letters, digits and nothing else). So my incoming alphabet would be [A-Z0-9_] (37 chars) and my outgoing alphabet would be [A-Za-z0-9] (62 chars) so a compression of almost 50% would be available. let's say my URLs look like this: /my/page/GFZHFFFZFZTFZTF_24_F34 and I want them to look like this instead: /my/page/Ft32zfegZFV5 Obviously both arrays would be shuffled to bring some random order in. This does not have to be secure. if someone figures it out: fine, but I don't want the scheme to be obvious. My desired solution would be to convert the string to an integer representation of radix 37, convert the radix to 62 and use the second alphabet to write out that number. is there any sample code available that does something similar? Integer.parseInt ( http://java.sun.com/javase/6/docs/api/java/lang/Integer.html#parseInt%28java.lang.String,%20int%29 ) has some similar logic, but it is hard-coded to use standard digit behavior Any hints? I am using java to implement this but code or pseudo-code in any other language is of course also helpful

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  • Rails form with a better URL

    - by Sam
    Wow, switching to REST is a different paradigm for sure and is mainly a headache right now. view <% form_tag (businesses_path, :method => "get") do %> <%= select_tag :business_category_id, options_for_select(@business_categories.collect {|bc| [bc.name, bc.id ]}.insert(0, ["All Containers", 0]), which_business_category(@business_category) ), { :onchange => "this.form.submit();"} %> <% end %> controller def index @business_categories = BusinessCategory.find(:all) if params[:business_category_id].to_i != 0 @business_category = BusinessCategory.find(params[:business_category_id]) @businesses = @business_category.businesses else @businesses = Business.all end respond_to do |format| format.html # index.html.erb format.xml { render :xml => @businesses } end end routes map.resources What I want to to is get a better URL than what this form is presenting which is the following: http://localhost:3000/businesses?business_category_id=1 Without REST I would have do something like http://localhost:3000/business/view/bbq bbq as permalink or I would have done http://localhost:300/business_categories/view/bbq and get the business that are associated with the category but I don't really know the best way of doing this. So the two questions are what is the best logic of finding a business by its categories using the latter form and number two how to get that in a pretty URL all through RESTful routes in Rails.

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  • Extending the .NET type system so the compiler enforces semantic meaning of primitive values in cert

    - by Drew Noakes
    I'm working with geometry a bit at the moment and am converting a lot between degrees and radians. Unfortunately, both of these are represented by double, so there's compile time warning/error if I try to pass a value in degrees where radians are expected. I believe F# has a compile-time solution for this (called units of measure.) I'd like to do something similar in C#. As another example, imagine a SQL library that accepts various query parameters as strings. It'd be good to have a way of enforcing that only clean strings were allowed to be passed in at runtime, and the only way to get a clean string was to pass through some SQL injection attack preventing logic. The obvious solution is to wrap the double/string/whatever in a new type to give it the type information the compiler needs. I'm curious if anyone has an alternative solution. If you do think wrapping is the only/best way, then please go into some of the downsides of the pattern (and any upsides I haven't mentioned too.) I'm especially concerned about the performance of abstracted primitive numeric types on my calculations at runtime.

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  • heterogeneous comparisons in python3

    - by Matt Anderson
    I'm 99+% still using python 2.x, but I'm trying to think ahead to the day when I switch. So, I know that using comparison operators (less/greater than, or equal to) on heterogeneous types that don't have a natural ordering is no longer supported in python3.x -- instead of some consistent (but arbitrary) result we raise TypeError instead. I see the logic in that, and even mostly think its a good thing. Consistency and refusing to guess is a virtue. But what if you essentially want the python2.x behavior? What's the best way to go about getting it? For fun (more or less) I was recently implementing a Skip List, a data structure that keeps its elements sorted. I wanted to use heterogeneous types as keys in the data structure, and I've got to compare keys to one another as I walk the data structure. The python2.x way of comparing makes this really convenient -- you get an understandable ordering amongst elements that have a natural ordering, and some ordering amongst those that don't. Consistently using a sort/comparison key like (type(obj).__name__, obj) has the disadvantage of not interleaving the objects that do have a natural ordering; you get all your floats clustered together before your ints, and your str-derived class separates from your strs. I came up with the following: import operator def hetero_sort_key(obj): cls = type(obj) return (cls.__name__+'_'+cls.__module__, obj) def make_hetero_comparitor(fn): def comparator(a, b): try: return fn(a, b) except TypeError: return fn(hetero_sort_key(a), hetero_sort_key(b)) return comparator hetero_lt = make_hetero_comparitor(operator.lt) hetero_gt = make_hetero_comparitor(operator.gt) hetero_le = make_hetero_comparitor(operator.le) hetero_ge = make_hetero_comparitor(operator.gt) Is there a better way? I suspect one could construct a corner case that this would screw up -- a situation where you can compare type A to B and type A to C, but where B and C raise TypeError when compared, and you can end up with something illogical like a > b, a < c, and yet b > c (because of how their class names sorted). I don't know how likely it is that you'd run into this in practice.

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  • Adding figures using contextual menu - Eclipse GEF

    - by darkie15
    All, I am creating a palette less eclipse plugin where am adding figures to the custom editor through the contextual menu, but am not finding a way to do it. Can anyone please guide me as to how to go about adding figures to editor dynamically through context menu i.e. adding actions/commands. Since Eclipse GEF plugin development finds so less examples to look at, I am adding my solution so others find it useful. This code helps to render a node to the editor. Source code for Action class to render figures to the editor: public class AddNodeAction extends EditorPartAction { public static final String ADD_NODE = "ADDNODE"; public AddNodeAction(IEditorPart editor) { super(editor); setText("Add a Node"); setId(ADD_NODE); // Important to set ID } public void run() { <ParentModelClass> parent= (<ParentModelClass>)getEditorPart().getAdapter(<ParentModelClass>.class); if (parent== null) return; CommandStack command = (CommandStack)getEditorPart().getAdapter(CommandStack.class); if (command != null) { CompoundCommand totalCmd = new CompoundCommand(); <ChildModelToRenderFigureCommand>cmd = new <ChildModelToRenderFigureCommand>(parent); cmd.setParent(parent); <ChildModelClass> newNode = new <ChildModelClass>(); cmd.setNode(newNode); cmd.setLocation(getLocation()); // Any location you wish to set to totalCmd.add(cmd); command.execute(totalCmd); } } @Override protected boolean calculateEnabled() { return true; } }

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  • Adding and removing elements efficiently from Collection object

    - by user569125
    Hi, Below coding is the working sample,but still i am not happy with this code with related to performancewise.Please have a look and let me know if any better approach is there.Thanks in advance. Adding items to the arraylist object String resultItems[] = paging.getMoveLeftArray().split(","); String fields[]={"id","name","name1"}; leftObj=new ArrayList(); for(int i=0;i<resultItems.length;i++){ //below line mea TestVO bean=new TestVO(); String resultItem = resultItems[i]; String idANDname[] = resultItem.split("@"); String id = idANDname[0]; // name or id should not contain "-" String name[] = idANDname[1].split("-"); //values and fileds are always having same length for(int j=0;j<name.length;j++) { PropertyUtils.setProperty(bean, fields[j], name[j]); } leftObj.add(bean); } Removing items from the arraylist object:availableList contains all the TestVO objects: String []removeArray=paging.getMoveRightArray().split(","); tempList=new CopyOnWriteArrayList(); newTempList=new CopyOnWriteArrayList(); for(int i=0;i<availableList.size();i++){ boolean flag = false; TestVO tempObj = (TestVO )availableList.get(i); int id =(Integer)tempObj.getId(); // System.out.println("id value"+id); // availableList.get(i).getClass().getField(name); for(int j=0;j<removeArray.length;j++){ String resultItem = removeArray[j]; String idandname[] = resultItem.split("@"); for(int k=0;k<idandname.length;k++){ String ids[]=idandname[0].split("-"); if(id==Integer.parseInt(ids[0])){ flag = true; break; } } } if(flag){ tempList.add(tempObj); } else{ newTempList.add(tempObj); }

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  • Returning the same type the function was passed

    - by Ken Bloom
    I have the following code implementation of Breadth-First search. trait State{ def successors:Seq[State] def isSuccess:Boolean = false def admissableHeuristic:Double } def breadthFirstSearch(initial:State):Option[List[State]] = { val open= new scala.collection.mutable.Queue[List[State]] val closed = new scala.collection.mutable.HashSet[State] open.enqueue(initial::Nil) while (!open.isEmpty){ val path:List[State]=open.dequeue() if(path.head.isSuccess) return Some(path.reverse) closed += path.head for (x <- path.head.successors) if (!closed.contains(x)) open.enqueue(x::path) } return None } If I define a subtype of State for my particular problem class CannibalsState extends State { //... } What's the best way to make breadthFirstSearch return the same subtype as it was passed? Supposing I change this so that there are 3 different state classes for my particular problem and they share a common supertype: abstract class CannibalsState extends State { //... } class LeftSideOfRiver extends CannibalsState { //... } class InTransit extends CannibalsState { //... } class RightSideOfRiver extends CannibalsState { //... } How can I make the types work out so that breadthFirstSearch infers that the correct return type is CannibalsState when it's passed an instance of LeftSideOfRiver? Can this be done with an abstract type member, or must it be done with generics?

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  • Private Java class properties mysteriously reset between method calls....

    - by Michael Jones
    I have a very odd problem. A class property is mysteriously reset between method calls. The following code is executed so the constructor is called, then the parseConfiguration method is called. Finally, processData is called. The parseConfiguration method sets the "recursive" property to "true". However, as soon as it enters "processData", "recursive" becomes "false". This problem isn't isolated to a single class -- I have several examples of this in my code. How can this possibly be happening? I've tried initialising properties when they're declared outside any methods, I've tried initialising them in constructors... nothing works. The only complication I can think of here is that this class is invoked by an object that runs in a thread -- but here is one instance per thread, so surely no chance that threads are interfering. I've tried setting both methods to "synchronized", but this still happens. Please help! /** * This class or its superclasses are NOT threaded and don't extend Thread */ public class DirectoryAcquirer extends Manipulator { /** * @var Whether to recursively scan directories */ private boolean recursive = false; /** * Constructor */ public DirectoryAcquirer() { } /** * Constructor that initialises the configuration * * @param config * @throws InvalidConfigurationException */ public DirectoryAcquirer(HierarchicalConfiguration config) throws InvalidConfigurationException { super(config); } @Override protected void parseConfiguration() throws InvalidConfigurationException { // set whether to recurse into directories or not if (this.config.containsKey("recursive")) { // this.recursive gets set to "true" here this.recursive = this.config.getBoolean("recursive"); } } @Override public EntityCollection processData(EntityCollection data) { // here this.recursive is "false" this.logger.debug("processData: Entered method"); } }

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  • Summation loop program in Pascal

    - by user2526598
    I am having a bit of an issue with this problem. I am taking a Pascal programming class and this problem was in my logic book. I am required to have the user enter a series of (+) numbers and once he/she enters a (-) number, the program should find the sum of all the (+) numbers. I accomplished this, but now I am attempting part two of this problem, which requires me to utilize a nested loop to run the program x amount of times based on the user's input. The following code is what I have so far and honestly I am stumped: program summation; //Define main program's variables var num, sum, numRun : integer; //Design procedure that will promt user for number of runs procedure numRunLoop ( var numRun : integer ); begin writeln('How many times shall I run this program?'); readln(numRun); end; //Design procedure that will sum a series of numbers //based on user input procedure numPromptLoop( numRun : integer; var num : integer ); var count : integer; begin //Utilize for to establish run limit for count := 1 to numRun do begin //Use repeat to prompt user for numbers repeat writeln('Enter a number: '); readln(num); //Tells program when to sum if num >= 0 then sum := sum + num; until num < 0; end; end; //Design procedure that will display procedure addItion( sum : integer ); begin writeln('The sum is; ', sum); end; begin numRunLoop(numRun); numPromptloop(numRun, num); addItion(sum); readln(); end.

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  • Mutex example / tutorial ?

    - by Nav
    I've noticed that asking questions for the sake of creating a reference list etc. is encouraged in SO. This is one such question, so that anyone Googling for a mutex tutorial will find a good one here. I'm new to multithreading, and was trying to understand how mutexes work. Did a lot of Googling and this is the only decent tutorial I found, but it still left some doubts of how it works because I created my own program and the locking didn't work. One absolutely non-intuitive syntax of the mutex is pthread_mutex_lock( &mutex1 );, where it looks like the mutex is being locked, when what I really want to lock is some other variable. Does this syntax mean that locking a mutex locks a region of code until the mutex is unlocked? Then how do threads know that the region is locked? And isn't such a phenomenon supposed to be called critical section? In short, could you please help with the simplest possible mutex example program and the simplest possible explanation on the logic of how it works? I'm sure this will help plenty of other newbies.

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