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  • populatin jComBobox with data from a db tbl(table) column

    - by mnmyles
    Hi guyz? I have a JComboBox which i have named "venue_JCB" i want to load details from a tbl column on form load at the initcomponets() i have declared the method "accessDBinit() ;" and after the initComponets() i have implemented the accessDBinit(); method as follows: ================================code============================ void accessDBinit() //Get Student List in the List Box { try { sql = "SELECT classLevel FROM class_session ORDER BY classLevel"; java.lang.Class.forName("com.mysql.jdbc.Driver"); Connection con2=DriverManager.getConnection("jdbc:mysql:///coast","root",""); Statement stmt2 = (Statement)con2.createStatement(); boolean hasResults = stmt2.execute(sql); if(hasResults) { ResultSet rs2 = stmt2.getResultSet(); if(rs2!=null) { displayResultsinit(rs2); } db.stmt.close(); } } catch(Exception e) { System.out.println(e+"Error in connection"); } } void displayResultsinit(ResultSet r) throws SQLException { ResultSetMetaData rmeta = r.getMetaData(); int numColumns=rmeta.getColumnCount(); while(r.next()) { for(int i=1;i<=numColumns;++i) { if(i<=numColumns) { venue_JCB.addItem(r.getString(i)); } } } } ====================================end of code=================================== the method works (Populate the combobox) but at the output bar i get the following on form load and also whenever i select a component from the combobox ======= error===== java.lang.NullPointerExceptionError in connection could some one please tell me where i am going wrong with the method? Thanks in advance regards Malachi

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  • Can I delay the keyup event for jquery?

    - by Paul
    I'm using the rottentomatoes movie API in conjunction with twitter's typeahead plugin using bootstrap 2.0. I've been able to integerate the API but the issue I'm having is that after every keyup event the API gets called. This is all fine and dandy but I would rather make the call after a small pause allowing the user to type in several characters first. Here is my current code that calls the API after a keyup event: var autocomplete = $('#searchinput').typeahead() .on('keyup', function(ev){ ev.stopPropagation(); ev.preventDefault(); //filter out up/down, tab, enter, and escape keys if( $.inArray(ev.keyCode,[40,38,9,13,27]) === -1 ){ var self = $(this); //set typeahead source to empty self.data('typeahead').source = []; //active used so we aren't triggering duplicate keyup events if( !self.data('active') && self.val().length > 0){ self.data('active', true); //Do data request. Insert your own API logic here. $.getJSON("http://api.rottentomatoes.com/api/public/v1.0/movies.json?callback=?&apikey=MY_API_KEY&page_limit=5",{ q: encodeURI($(this).val()) }, function(data) { //set this to true when your callback executes self.data('active',true); //Filter out your own parameters. Populate them into an array, since this is what typeahead's source requires var arr = [], i=0; var movies = data.movies; $.each(movies, function(index, movie) { arr[i] = movie.title i++; }); //set your results into the typehead's source self.data('typeahead').source = arr; //trigger keyup on the typeahead to make it search self.trigger('keyup'); //All done, set to false to prepare for the next remote query. self.data('active', false); }); } } }); Is it possible to set a small delay and avoid calling the API after every keyup?

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  • Designing DAOs around a JSON API for iPhone Development

    - by Bob Spryn
    So I've been trying to design a clean way of grabbing data for my models in iPhone land. All the data for my application is coming from JSON API's. So right now when a VC needs some models, it does the JSON call itself (asynch) and when it receives the data, it builds the models. It works, but I'm trying to think of a cleaner method whereby the DAO's retrieve the information for me and return the models, all in an async manner. My initial thought is build a protocol for my DAOs, such that the VC would instantiate a DAO and make itself the delegate. When you requested data [DAOinstance getAllUsers] the DAO would do all the network request stuff, and then when it had the data, it would call a method on its delegate (the VC) to pass the data. So I think that's a cool solution, but realized that if I needed to use the same DAO for different purposes in the same VC, my delegate method would have to branch logic depending on which DAO instance initiated the request. So my second thought was to be able to pass 'handler' selectors to the DAO object a la typical javascript patterns. So instead of an official protocol, I would say something like [DAOinstance getAllUsersWithSelector:"TheHandlerFunctionOnMyVC:"] Then when the DAO completed its network activities, it would call the passed selector on the VC, and pass the data back. So am I headed in the wrong direction entirely here? Seems like maybe an ok way to go. Any pointers or articles on designing this kind of data layer would be sweet. Thanks! Bob

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  • Entity Framework in layered architecture

    - by Kamyar
    I am using a layered architecture with the Entity Framework. Here's What I came up with till now (All the projects Except UI are class library): Entities: The POCO Entities. Completely persistence ignorant. No Reference to other projects. Generated by Microsoft's ADO.Net POCO Entity Generator. DAL: The EDMX (Entity Model) file with the context class. (t4 generated). References: Entities BLL: Business Logic Layer. Will implement repository pattern on this layer. References: Entities, DAL. This is where the objectcontext gets populated: var ctx=new DAL.MyDBEntities(); UI: The presentation layer: ASP.NET website. References: Entities, BLL + a connection string entry to entities in the config file (question #2). Now my three questions: Is my layer discintion approach correct? In my UI, I access BLL as follows: var customerRep = new BLL.CustomerRepository(); var Customer = customerRep.GetByID(myCustomerID); The problem is that I have to define the entities connection string in my UI's web.config/app.config otherwise I get a runtime exception. IS defining the entities connectionstring in UI spoils the layers' distinction? Or is it accesptible in a muli layered architecture. Should I take any additional steps to perform chage tracking, lazy loading, etc (by etc I mean the features that Entity Framework covers in a conventional, 1 project, non POCO code generation)? Thanks and apologies for the lengthy question.

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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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  • I need a fast runtime expression parser

    - by Chris Lively
    I need to locate a fast, lightweight expression parser. Ideally I want to pass it a list of name/value pairs (e.g. variables) and a string containing the expression to evaluate. All I need back from it is a true/false value. The types of expressions should be along the lines of: varA == "xyz" and varB==123 Basically, just a simple logic engine whose expression is provided at runtime. UPDATE At minimum it needs to support ==, !=, , =, <, <= Regarding speed, I expect roughly 5 expressions to be executed per request. We'll see somewhere in the vicinity of 100/requests a second. Our current pages tend to execute in under 50ms. Usually there will only be 2 or 3 variables involved in any expression. However, I'll need to load approximately 30 into the parser prior to execution. UPDATE 2012/11/5 Update about performance. We implemented nCalc nearly 2 years ago. Since then we've expanded it's use such that we average 40+ expressions covering 300+ variables on post backs. There are now thousands of post backs occurring per second with absolutely zero performance degradation. We've also extended it to include a handful of additional functions, again with no performance loss. In short, nCalc met all of our needs and exceeded our expectations.

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  • SQL - Multiple join conditions using OR?

    - by Brandi
    I have a query that is using multiple joins. The goal is to say "Out of table A, give me all the customer numbers in which you can match table A's EmailAddress with either email_to or email_from of table B. Ignore nulls, internal emails, etc.". It seems like it would be better to use an or condition in the join than multiple joins since it is the same table. When I try to use AND/OR it does not give the behaviour I expect... AND finishes in a reasonable time, but yields no results (I know that there are matches, so it must be some flaw in my logic) and OR never finishes (I have to kill it). Here is example code to illustrate the question: --my original query SELECT DISTINCT a.CustomerNo FROM A a WITH (NOLOCK) LEFT JOIN B e WITH (NOLOCK) ON a.EmailAddress = e.email_from RIGHT JOIN B f WITH (NOLOCK) ON a.EmailAddress = f.email_to WHERE a.EmailAddress NOT LIKE '%@mydomain.___' AND a.EmailAddress IS NOT NULL AND (e.email_from IS NOT NULL OR f.email_to IS NOT NULL) Here is what I tried, (I am attempting logical equivalence): SELECT DISTINCT a.CustomerNo FROM A a WITH (NOLOCK) LEFT JOIN B e WITH (NOLOCK) ON a.EmailAddress = e.email_from OR a.EmailAddress = e.email_to WHERE a.EmailAddress NOT LIKE '%@mydomain.___' AND a.EmailAddress IS NOT NULL AND (e.email_from IS NOT NULL OR e.email_to IS NOT NULL) So my question is two-fold: Why does having AND in the above query work in a few seconds and OR goes for minutes and never completes? What am I missing to make a logically equivalent statement that has only one join?

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  • Java Code for calculating Leap Year, is this code correct ?

    - by Ibn Saeed
    Hello I am following "The Art and Science of Java" book and it shows how to calculate a leap year. The book uses ACM Java Task Force's library. Here is the code the books uses: import acm.program.*; public class LeapYear extends ConsoleProgram { public void run() { println("This program calculates leap year."); int year = readInt("Enter the year: "); boolean isLeapYear = ((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0)); if (isLeapYear) { println(year + " is a leap year."); } else println(year + " is not a leap year."); } } Now, this is how I calculated the leap year. import acm.program.*; public class LeapYear extends ConsoleProgram { public void run() { println("This program calculates leap year."); int year = readInt("Enter the year: "); if ((year % 4 == 0) && year % 100 != 0) { println(year + " is a leap year."); } else if ((year % 4 == 0) && (year % 100 == 0) && (year % 400 == 0)) { println(year + " is a leap year."); } else { println(year + " is not a leap year."); } } } Is there anything wrong with my code or should i use the one provided by the book ? EDIT :: Both of the above code works fine, What i want to ask is which code is the best way to calculate the leap year.

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  • Modularizing web applications

    - by Matt
    Hey all, I was wondering how big companies tend to modularize components on their page. Facebook is a good example: There's a team working on Search that has its own CSS, javascript, html, etc.. There's a team working on the news feed that has its own CSS, javascript, html, etc... ... And the list goes on They cannot all be aware of what everyone is naming their div tags and whatnot, so what's the controller(?) doing to hook all these components in on the final page?? Note: This doesn't just apply to facebook - any company that has separate teams working on separate components has some logic that helps them out. EDIT: Thanks all for the responses, unfortunately I still haven't really found what I'm looking for - when you check out the source code (granted its minified), the divs have UIDs, my guess is that there is a compilation process that runs through and makes each of the components unique, renaming divs and css rules.. any ideas? EDIT 2: Thanks all for contributing your thoughts - the bounty went to the highest upvoted answer. The question was designed to be vague- I think it led to a really interesting discussion. As I improve my build process, I will contribute my own thoughts and experiences. Thanks all! Matt Mueller

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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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  • Web page database query optimization

    - by morpheous
    I am putting together a web page which is quite 'expensive' in terms of database hits. I don't want to start optimizing at this stage - though with me trying to hit a deadline, I may end up not optimizing at all. Currently the page requires 18 (that's right eighteen) hits to the db. I am already using joins, and some of the queries are UNIONed to minimize the trips to the db. My local dev machine can handle this (page is not slow) however, I feel if I release this into the wild, the number of queries will quickly overwhelm my database (MySQL). I could always use memcache or something similar, but I would much rather continue with my other dev work that needs to be completed before the deadline - at least retrieving the page works - its simply a matter of optimization now (if required). My question therefore is - is 18 db queries for a single page retrieval completely outrageous - (i.e. I should put everything on hold and optimize the hell of the retrieval logic), or shall I continue as normal, meet the deadline and release on schedule and see what happens? [Edit] Just to clarify, I have already done the 'obvious' things like using (single and composite) indexes for fields used in the queries. What I haven't yet done is to run a query analyzer to see if my indexes etc are optimal.

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  • NPE annotation scenarios and static-analysis tools for Java

    - by alex2k8
    Here is a number of code snippets that can throw NullPointerException. 01: public void m1(@Nullable String text) { System.out.print(text.toLowerCase()); // <-- expect to be reported. } 02: private boolean _closed = false; public void m1(@Nullable String text) { if(_closed) return; System.out.print(text.toLowerCase()); // <-- expect to be reported. } 03: public void m1(@NotNull String text) { System.out.print(text.toLowerCase()); } public @Nullable String getText() { return "Some text"; } public void m2() { m1(getText()); // <-- expect to be reported. } Different people have access to different static-analysis tools. It would be nice to collect information, what tools are able to detect and report the issues, and what are failing. Also, if you have your own scenarious, please, publish them. Here my results FindBugs (1.3.9): 01: Parameter must be nonnull but is marked as nullable 02: NOT reported 03: NOT reported IntelliJ IDE 9.0.2 (Community edition): 01: Method invocation text.toLowerCase() may produce java.lang.NullPointerException 02: Method invocation text.toLowerCase() may produce java.lang.NullPointerException 03: Argument getText() might be null

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  • Intermittent asp.net mvc exception: “A public action method ABC could not be found on controller XYZ

    - by Chris Schoon
    Hi, I'm getting an intermittent exception saying that asp.net mvc can’t find the action method. Here’s the exception: A public action method 'Fill' could not be found on controller 'Schoon.Form.Web.Controllers.ChrisController'. I think I have the routing set up correctly because this application works most of the time. Here is the controller’s action method. [ActionName("Fill")] [AcceptVerbs(HttpVerbs.Get | HttpVerbs.Post), UserIdFilter, DTOFilter] public ActionResult Fill(int userId, int subscriberId, DisplayMode? mode) { //… } The route: routes.MapRoute( "SchoonForm", "Form/Fill/{subscriberId}", new { controller = "ChrisController", action = "Fill" }, new { subscriberId = @"\d+" } ); And here is the stack: System.Web.HttpException: A public action method 'Fill' could not be found on controller 'Schoon.Form.Web.Controllers.ChrisController'. at System.Web.Mvc.Controller.HandleUnknownAction(String actionName) in C:\dev\ThirdParty\MvcDev\src\SystemWebMvc\Mvc\Controller.cs:line 197 at System.Web.Mvc.Controller.ExecuteCore() in C:\dev\ThirdParty\MvcDev\src\SystemWebMvc\Mvc\Controller.cs:line 164 at System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) in C:\dev\ThirdParty\MvcDev\src\SystemWebMvc\Mvc\ControllerBase.cs:line 76 at System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext) in C:\dev\ThirdParty\MvcDev\src\SystemWebMvc\Mvc\ControllerBase.cs:line 87 at System.Web.Mvc.MvcHandler.ProcessRequest(HttpContextBase httpContext) in C:\dev\ThirdParty\MvcDev\src\SystemWebMvc\Mvc\MvcHandler.cs:line 80 at System.Web.Mvc.MvcHandler.ProcessRequest(HttpContext httpContext) in C:\dev\ThirdParty\MvcDev\src\SystemWebMvc\Mvc\MvcHandler.cs:line 68 at System.Web.Mvc.MvcHandler.System.Web.IHttpHandler.ProcessRequest(HttpContext httpContext) in C:\dev\ThirdParty\MvcDev\src\SystemWebMvc\Mvc\MvcHandler.cs:line 104 at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) Here is an example of my filters they all work the same way: public class UserIdFilter : ActionFilterAttribute { public override void OnActionExecuting(ActionExecutingContext filterContext) { const string Key = "userId"; if (filterContext.ActionParameters.ContainsKey(Key)) { filterContext.ActionParameters[Key] = // get the user id from session or cookie } base.OnActionExecuting(filterContext); } } Thanks, Chris

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  • Java Binary Tree. Priting InOrder traversal

    - by user69514
    I am having some problems printing an inOrder traversal of my binary tree. Even after inserting many items into the tree it's only printing 3 items. public class BinaryTree { private TreeNode root; private int size; public BinaryTree(){ this.size = 0; } public boolean insert(TreeNode node){ if( root == null) root = node; else{ TreeNode parent = null; TreeNode current = root; while( current != null){ if( node.getData().getValue().compareTo(current.getData().getValue()) <0){ parent = current; current = current.getLeft(); } else if( node.getData().getValue().compareTo(current.getData().getValue()) >0){ parent = current; current = current.getRight(); } else return false; if(node.getData().getValue().compareTo(parent.getData().getValue()) < 0) parent.setLeft(node); else parent.setRight(node); } } size++; return true; } /** * */ public void inOrder(){ inOrder(root); } private void inOrder(TreeNode root){ if( root.getLeft() !=null) this.inOrder(root.getLeft()); System.out.println(root.getData().getValue()); if( root.getRight() != null) this.inOrder(root.getRight()); } }

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  • Java - If statement with String comparison fails

    - by Andrea
    I really don't know why the if statement below is not executing: if (s == "/quit") { System.out.println("quitted"); } Below is the whole class. It is probably a really stupid logic problem but I have been pulling my hair out over here not being able to figure this out. Thanks for looking :) class TextParser extends Thread { public void run() { while (true) { for(int i = 0; i < connectionList.size(); i++) { try { System.out.println("reading " + i); Connection c = connectionList.elementAt(i); Thread.sleep(200); System.out.println("reading " + i); String s = ""; if (c.in.ready() == true) { s = c.in.readLine(); //System.out.println(i + "> "+ s); if (s == "/quit") { System.out.println("quitted"); } if(! s.equals("")) { for(int j = 0; j < connectionList.size(); j++) { Connection c2 = connectionList.elementAt(j); c2.out.println(s); } } } } catch(Exception e){ System.out.println("reading error"); } } } } }

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  • Windsor IHandlerSelector in RIA Services Visual Studio 2010 Beta2

    - by Savvas Sopiadis
    Hi everybody! I want to implement multi tenancy using Windsor and i don't know how to handle this situation: i succesfully used this technique in plain ASP.NET MVC projects and thought incorporating in a RIA Services project would be similar. So i used IHandlerSelector, registered some components and wrote an ASP.NET MVC view to verify it works in a plain ASP.NET MVC environment. And it did! Next step was to create a DomainService which got an IRepository injected in the constructor. This service is hosted in the ASP.NET MVC application. And it actually ... works:i can get data out of it to a Silverlight application. Sample snippet: public OrganizationDomainService(IRepository<Culture> cultureRepository) { this.cultureRepository = cultureRepository; } Last step is to see if it works multi-tenant-like: it does not! The weird thing is this: using some line of code and writing debug messages in a log file i verified that the correct handler is selected! BUT this handler seems not to be injected in the DomainService. I ALWAYS get the first handler (that's the logic in my SelectHandler) Can anybody verify this behavior? Is injection not working in RIA Services? Or am i missing something basic?? Development environment: Visual Studio 2010 Beta2 Thanks in advance

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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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  • Game architecture: modeling different steps/types of UI

    - by Sander
    I have not done any large game development projects, only messed around with little toy projects. However, I never found an intuitive answer to a specific design question. Namely, how are different types/states of UI modeled in games? E.g. how is a menu represented? How is it different from a "game world" state (let's use an FPS as an example). How is an overlaid menu on top of a "game world" modeled? Let's imagine the main loop of a game. Where do the game states come into play? It it a simple case-by-case approach? if (menu.IsEnabled) menu.Process(elapsedTime); if (world.IsEnabled) world.Process(elapsedTime); if (menu.IsVisible) menu.Draw(); if (world.IsVisible) world.Draw(); Or are menu and world represented somewhere in a different logic layer and not represented at this level? (E.g. a menu is just another high-level entity like e.g. player input or enemy manager, equal to all others) foreach (var entity in game.HighLevelEntities) entity.Process(elapsedTime); foreach (var entity in game.HighLevelEntities) entity.Draw(elapsedTime); Are there well-known design patterns for this? Come to think of it, I don't know any game-specific design patterns - I assume there are others, as well? Please tell me about them.

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  • Passing filtering functions to Where() in LINQ-to-SQL

    - by Daniel
    I'm trying to write a set of filtering functions that can be chained together to progressively filter a data set. What's tricky about this is that I want to be able to define the filters in a different context from that in which they'll be used. I've gotten as far as being able to pass a very basic function to the Where() clause in a LINQ statement: filters file: Func<item, bool> returnTrue = (i) => true; repository file: public IQueryable<item> getItems() { return DataContext.Items.Where(returnTrue); } This works. However, as soon as I try to use more complicated logic, the trouble begins: filters file: Func<item, bool> isAssignedToUser = (i) => i.assignedUserId == userId; repository file: public IQueryable<item> getItemsAssignedToUser(int userId) { return DataContext.Items.Where(isAssignedToUser); } This won't even build because userId isn't in the same scope as isAssignedToUser(). I've also tried declaring a function that takes the userId as a parameter: Func<item, int, bool> isAssignedToUser = (i, userId) => i.assignedUserId == userId; The problem with this is that it doesn't fit the function signature that Where() is expecting: Func<item, bool> There must be a way to do this, but I'm at a loss for how. I don't feel like I'm explaining this very well, but hopefully you get the gist. Thanks, Daniel

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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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  • 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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  • Calling services from the Orchestrating layer in SOA?

    - by Martin Lee
    The Service Oriented Architecture Principles site says that Service Composition is an important thing in SOA. But Service Loose Coupling is important as well. Does that mean that the "Orchestrating layer" should be the only one that is allowed to make calls to services in the system? As I understand SOA, the "Orchestrating layer" 'glues' all the services together into one software application. I tried to depict that on Fig.A and Fig.B. The difference between the two is that on Fig.A the application is composed of services and all the logic is done in the "Orchestrating layer" (all calls to services are done from the "Orchestrating layer" only). On Fig.B the application is composed from services, but one service calls another service. Does the architecture on Fig.B violate the "Service Loose Coupling" principle of SOA? Can a service call another service in SOA? And more generally, can the architecture on Fig.A be considered superior to the one on Fig.B in terms of service loose coupling, abstraction, reusability, autonomy, etc.? My guess is that the A architecture is much more universal, but it can add some unnecessary data transfers between the "Orchestrating layer" and all the called services.

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  • copy rows before updating them to preserve archive in Postgres

    - by punkish
    I am experimenting with creating a table that keeps a version of every row. The idea is to be able to query for how the rows were at any point in time even if the query has JOINs. Consider a system where the primary resource is books, that is, books are queried for, and author info comes along for the ride CREATE TABLE authors ( author_id INTEGER NOT NULL, version INTEGER NOT NULL CHECK (version > 0), author_name TEXT, is_active BOOLEAN DEFAULT '1', modified_on TIMESTAMP DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY (author_id, version) ) INSERT INTO authors (author_id, version, author_name) VALUES (1, 1, 'John'), (2, 1, 'Jack'), (3, 1, 'Ernest'); I would like to be able to update the above like so UPDATE authors SET author_name = 'Jack K' WHERE author_id = 1; and end up with 2, 1, Jack, t, 2012-03-29 21:35:00 2, 2, Jack K, t, 2012-03-29 21:37:40 which I can then query with SELECT author_name, modified_on FROM authors WHERE author_id = 2 AND modified_on < '2012-03-29 21:37:00' ORDER BY version DESC LIMIT 1; to get 2, 1, Jack, t, 2012-03-29 21:35:00 Something like the following doesn't really work CREATE OR REPLACE FUNCTION archive_authors() RETURNS TRIGGER AS $archive_author$ BEGIN IF (TG_OP = 'UPDATE') THEN -- The following fails because author_id,version PK already exists INSERT INTO authors (author_id, version, author_name) VALUES (OLD.author_id, OLD.version, OLD.author_name); UPDATE authors SET version = OLD.version + 1 WHERE author_id = OLD.author_id AND version = OLD.version; RETURN NEW; END IF; RETURN NULL; -- result is ignored since this is an AFTER trigger END; $archive_author$ LANGUAGE plpgsql; CREATE TRIGGER archive_author AFTER UPDATE OR DELETE ON authors FOR EACH ROW EXECUTE PROCEDURE archive_authors(); How can I achieve the above? Or, is there a better way to accomplish this? Ideally, I would prefer to not create a shadow table to store the archived rows.

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  • Working with extra fields in an Inline form - save_model, save_formset, can't make sense of the diff

    - by magicrebirth
    Suppose I am in the usual situation where there're extra fields in the many2many relationship: class Person(models.Model): name = models.CharField(max_length=128) class Group(models.Model): name = models.CharField(max_length=128) members = models.ManyToManyField(Person, through='Membership') class Membership(models.Model): person = models.ForeignKey(Person) group = models.ForeignKey(Group) date_joined = models.DateField() invite_reason = models.CharField(max_length=64) # other models which are unrelated to the ones above.. class Trip(models.Model): placeVisited = models.ForeignKey(Place) visitor = models.ForeignKey(Person) pleasuretrip = models.Boolean() class Place(models.Model): name = models.CharField(max_length=128) I want to add some extra fields in the Membership form that gets displayed through the Inline. These fields basically are a shortcut to the instantiation of another model (Trip). Trip can have its own admin views, but these shortcuts are needed because when my project partners are entering 'Membership' data in the system they happen to have also the 'Trip' information handy (and also because some of the info in Membership can just be copied over to Trip etc. etc.). So all I want to have is two extra fields in the Membership Inline - placeVisited and pleasuretrip - which together with the Person instance will let me instantiate the Trip model in the background... I found out I can easily add extra fields to the inline view by defining my own form. But once the data have been entered, how and when to reference to them in order to perform the save operations I need to do? class MyForm(forms.ModelForm): place = forms.ModelChoiceField(required=False, queryset=Place.objects.all(), label="place",) pleasuretrip = forms.BooleanField(required=False, label="...") class MembershipInline(admin.TabularInline): model = Membership form = MyForm def save_model(self, request, obj, form, change): place = form.place pleasuretrip = form.pleasuretrip person = form.person .... # now I can create Trip instances with those data .... obj.save() class GroupAdmin(admin.ModelAdmin): model = Group .... inlines = (MembershipInline,) This doesn't seem to work... I'm also a bit puzzled by the save_formset method... maybe is that the one I should be using? Many thanks in advance for the help!!!!

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  • How to manage data access / preloading efficiently using web services in C# ?

    - by Amadeus45
    Hello all, Ok, this is very "generic" question. We currently have a SQL Server database for which we need to develop an application in ASP.NET with will contain all the business logic in C# Web Services. The thing is that, architecturally speaking, I'm not sure how to design the web service and the data management. There are many things to consider : We need have very rapid access to data. Right now, we have over a million "sales" and "purchases" record from which we need to often calculate and load the current stock for a given day according to a serie of parameter. I'm not sure how we should preload the data and keep the data in the Web Service. Doing a stock calculation within a SQL query will be very lengthy. They currently have a stock calculation application that preloads all sales and purchases for the day and afterwards calculate the stock on the code-side. We want to develop powerful reporting tools. We want to implement a "pivot table" but not sure how to implement it and have good performances. For the reasons above, I'm not sure how to design the data model. Anybody can give me any guidelines on how to start, or from their personnal experiences (what have you done in the past ?) I'm not sure if it's possible to make a bounty even though the question is new (I'd put 300 rep on it, since I really need something). If you know how, let me know. Thanks

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