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  • Swing modal dialog refuses to close - sometimes!

    - by Zarkonnen
    // This is supposed to show a modal dialog and then hide it again. In practice, // this works about 75% of the time, and the other 25% of the time, the dialog // stays visible. // This is on Ubuntu 10.10, running: // OpenJDK Runtime Environment (IcedTea6 1.9) (6b20-1.9-0ubuntu1) // This always prints // setVisible(true) about to happen // setVisible(false) about to happen // setVisible(false) has just happened // even when the dialog stays visible. package modalproblemdemo; import java.awt.Frame; import javax.swing.JDialog; import javax.swing.SwingUtilities; public class Main { public static void main(String[] args) { final Dialogs d = new Dialogs(); new Thread() { @Override public void run() { d.show(); d.hide(); } }.start(); } static class Dialogs { final JDialog dialog; public Dialogs() { dialog = new JDialog((Frame) null, "Hello World", /*modal*/ true); dialog.setSize(400, 200); } public void show() { SwingUtilities.invokeLater(new Runnable() { public void run() { dialog.setLocationRelativeTo(null); System.out.println("setVisible(true) about to happen"); dialog.setVisible(true); }}); } public void hide() { SwingUtilities.invokeLater(new Runnable() { public void run() { System.out.println("setVisible(false) about to happen"); dialog.setVisible(false); System.out.println("setVisible(false) has just happened"); }}); } } }

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  • Android - How can I upload a txt file to a website?

    - by Donal Rafferty
    I want to upload a txt file to a website, I'll admit I haven't looked into it in any great detail but I have looked at a few examples and would like more experienced opinions on whether I'm going in the right direction. Here is what I have so far: DefaultHttpClient httpClient = new DefaultHttpClient(); HttpContext localContext = new BasicHttpContext(); private String ret; HttpResponse response = null; HttpPost httpPost = null; public String postPage(String url, String data, boolean returnAddr) { ret = null; httpClient.getParams().setParameter(ClientPNames.COOKIE_POLICY, CookiePolicy.RFC_2109); httpPost = new HttpPost(url); response = null; StringEntity tmp = null; try { tmp = new StringEntity(data,"UTF-8"); } catch (UnsupportedEncodingException e) { System.out.println("HTTPHelp : UnsupportedEncodingException : "+e); } httpPost.setEntity(tmp); try { response = httpClient.execute(httpPost,localContext); } catch (ClientProtocolException e) { System.out.println("HTTPHelp : ClientProtocolException : "+e); } catch (IOException e) { System.out.println("HTTPHelp : IOException : "+e); } ret = response.getStatusLine().toString(); return ret; } And I call it as follows: postPage("http://www.testwebsite.com", "data/data/com.testxmlpost.xml/files/logging.txt", true)); I want to be able to upload a file from the device to a website. But when trying this way I get the following response back. HTTP/1.1 405 Method Not Allowed Am I trying the correct way or should I be doing it another way?

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  • SWT Problem with MouseTrackListener and Shell

    - by Krt_Malta
    Hi! I'm developing an Eclipse plug-in and I have a problem which is reproduced in this small SWT application: public static void main(String[] args) { Display display = new Display(); Shell shell = new Shell(display); Text text = new Text(shell, SWT.MULTI | SWT.WRAP | SWT.READ_ONLY | SWT.V_SCROLL); text.setText("Hello"); shell.setLayout(new FillLayout()); shell.addMouseTrackListener(new MouseTrackListener() { public void mouseEnter(MouseEvent arg0) { System.out.println("mouseEnter"); } public void mouseExit(MouseEvent arg0) { System.out.println("mouseExit"); } public void mouseHover(MouseEvent arg0) { System.out.println("mouseHover"); } }); // Display the window shell.open(); while (!shell.isDisposed()) { if (!display.readAndDispatch()) { display.sleep(); } } display.dispose(); } As you can see I'm creating a shell and putting a Textbox inside it and putting it all across the shell. Then I attach a MouseTrackListener to the shell. The events don't fire (as in when I hover in the shell "mouseHover" is not printed etc). When I remove the Textbox the events fire. Can anyone tell me where the problem lies please? I don't want to attach a listener to the textbox but to the shell. I'll really appreciate the help because I've been trying to trace it for quite some time now. Thanks and regards, Krt_Malta

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  • repaint problem

    - by user357816
    I have a problem with my repaint in the method move. I dont know what to doo, the code is below import java.awt.*; import java.io.*; import java.text.*; import java.util.*; import javax.sound.sampled.*; import javax.swing.*; import javax.swing.Timer; import java.awt.event.*; import java.lang.*; public class bbb extends JPanel { public Stack<Integer> stacks[]; public JButton auto,jugar,nojugar; public JButton ok,ok2; public JLabel info=new JLabel("Numero de Discos: "); public JLabel instruc=new JLabel("Presiona la base de las torres para mover las fichas"); public JLabel instruc2=new JLabel("No puedes poner una pieza grande sobre una pequenia!"); public JComboBox numeros=new JComboBox(); public JComboBox velocidad=new JComboBox(); public boolean seguir=false,parar=false,primera=true; public int n1,n2,n3; public int click1=0; public int opcion=1,tiempo=50; public int op=1,continuar=0,cont=0; public int piezas=0; public int posx,posy; public int no; public bbb() throws IOException { stacks = new Stack[3]; stacks[0]=new Stack<Integer>(); stacks[1]=new Stack<Integer>(); stacks[2]=new Stack<Integer>(); setPreferredSize(new Dimension(1366,768)); ok=new JButton("OK"); ok.setBounds(new Rectangle(270,50,70,25)); ok.addActionListener(new okiz()); ok2=new JButton("OK"); ok2.setBounds(new Rectangle(270,50,70,25)); ok2.addActionListener(new vel()); add(ok2);ok2.setVisible(false); auto=new JButton("Automatico"); auto.setBounds(new Rectangle(50,80,100,25)); auto.addActionListener(new a()); jugar=new JButton("PLAY"); jugar.setBounds(new Rectangle(100,100,70,25)); jugar.addActionListener(new play()); nojugar=new JButton("PAUSE"); nojugar.setBounds(new Rectangle(100,150,70,25)); nojugar.addActionListener(new stop()); setLayout(null); info.setBounds(new Rectangle(50,50,170,25)); info.setForeground(Color.white); instruc.setBounds(new Rectangle(970,50,570,25)); instruc.setForeground(Color.white); instruc2.setBounds(new Rectangle(970,70,570,25)); instruc2.setForeground(Color.white); add(instruc);add(instruc2); add(jugar);add(nojugar);jugar.setVisible(false);nojugar.setVisible(false); add(info); info.setVisible(false); add(ok); ok.setVisible(false); add(auto); numeros.setBounds(new Rectangle(210,50,50,25)); numeros.addItem(1);numeros.addItem(2);numeros.addItem(3);numeros.addItem(4);numeros.addItem(5); numeros.addItem(6);numeros.addItem(7);numeros.addItem(8);numeros.addItem(9);numeros.addItem(10); add(numeros); numeros.setVisible(false); velocidad.setBounds(new Rectangle(150,50,100,25)); velocidad.addItem("Lenta"); velocidad.addItem("Intermedia"); velocidad.addItem("Rapida"); add(velocidad); velocidad.setVisible(false); } public void Mover(int origen, int destino) { for (int i=0;i<3;i++) { System.out.print("stack "+i+": "); for(int n : stacks[i]) System.out.print(n+";"); System.out.println(""); } System.out.println("de <"+origen+"> a <"+destino+">"); stacks[destino].push(stacks[origen].pop()); System.out.println(""); this.validate(); this.repaint( ); } public void hanoi(int origen, int destino, int cuantas) { while (parar) {} if (cuantas <= 1) Mover(origen,destino); else { hanoi(origen,3 - (origen+destino),cuantas-1); Mover(origen,destino); hanoi(3 - (origen+destino),destino,cuantas-1); } } public void paintComponent(Graphics g) { ImageIcon fondo= new ImageIcon("fondo.jpg"); g.drawImage(fondo.getImage(),0, 0,1366,768,null); g.setColor(new Color((int)(Math.random() * 254), (int)(Math.random() *255), (int)(Math.random() * 255))); g.fillRect(0,0,100,100); g.setColor(Color.white); g.fillRect(150,600,250,25); g.fillRect(550,600,250,25); g.fillRect(950,600,250,25); g.setColor(Color.red); g.fillRect(270,325,10,275); g.fillRect(270+400,325,10,275); g.fillRect(270+800,325,10,275); int x, y,top=0; g.setColor(Color.yellow); x=150;y=580; for(int ii:stacks[0]) { g.fillRect(x+((ii*125)/10),y-(((ii)*250)/10),((10-ii)*250)/10,20);} x=550;y=580; for(int ii:stacks[1]) {g.fillRect(x+((ii*125)/10),y-(((ii)*250)/10),((10-ii)*250)/10,20);} x=950;y=580; for(int ii:stacks[2]) {g.fillRect(x+((ii*125)/10),y-(((ii)*250)/10),((10-ii)*250)/10,20);} System.out.println("ENTRO"); setOpaque(false); } private class play implements ActionListener //manual { public void actionPerformed(ActionEvent algo) { parar=false; if(primera=true) { hanoi(0,2,no); primera=false; } } } private class stop implements ActionListener //manual { public void actionPerformed(ActionEvent algo) { parar=true; } } private class vel implements ActionListener //manual { public void actionPerformed(ActionEvent algo) { if (velocidad.getSelectedItem()=="Lenta") {tiempo=150;} else if (velocidad.getSelectedItem()=="Intermedia") {tiempo=75;} else tiempo=50; ok2.setVisible(false); jugar.setVisible(true); nojugar.setVisible(true); } } private class a implements ActionListener //auto { public void actionPerformed(ActionEvent algo) { auto.setVisible(false); info.setVisible(true); numeros.setVisible(true); ok.setVisible(true); op=3; } } private class okiz implements ActionListener //ok { public void actionPerformed(ActionEvent algo) { no=Integer.parseInt(numeros.getSelectedItem().toString()); piezas=no; if (no>0 && no<11) { info.setVisible(false); numeros.setVisible(false); ok.setVisible(false); for (int i=no;i>0;i--) stacks[0].push(i); opcion=2; if (op==3) { info.setText("Velocidad: ");info.setVisible(true); velocidad.setVisible(true); ok2.setVisible(true); } } else { } repaint(); } } } the code of the other class that calls the one up is below: import java.awt.*; import java.io.*; import java.net.URL; import javax.imageio.*; import javax.swing.*; import javax.swing.border.*; import java.lang.*; import java.awt.event.*; public class aaa extends JPanel { private ImageIcon Background; private JLabel fondo; public static void main(String[] args) throws IOException { JFrame.setDefaultLookAndFeelDecorated(true); final JPanel cp = new JPanel(new BorderLayout()); JFrame frame = new JFrame ("Torres de Hanoi"); frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE); frame.setSize(550,550); frame.setVisible(true); bbb panel = new bbb(); frame.getContentPane().add(panel); frame.pack(); frame.setVisible(true); } }

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  • Is there a more elegant way to act on the first and last items in a foreach enumeration than count++

    - by Edward Tanguay
    Is there a more elegant way to act on the first and last items when iterating through a foreach loop than incrementing a separate counter and checking it each time? For instance, the following code outputs: >>> [line1], [line2], [line3], [line4] <<< which requires knowing when you are acting on the first and last item. Is there a more elegant way to do this now in C# 3 / C# 4? It seems like I could use .Last() or .First() or something like that. using System; using System.Collections.Generic; using System.Text; namespace TestForNext29343 { class Program { static void Main(string[] args) { StringBuilder sb = new StringBuilder(); List<string> lines = new List<string> { "line1", "line2", "line3", "line4" }; int index = 0; foreach (var line in lines) { if (index == 0) sb.Append(">>> "); sb.Append("[" + line + "]"); if (index < lines.Count - 1) sb.Append(", "); else sb.Append(" <<<"); index++; } Console.WriteLine(sb.ToString()); Console.ReadLine(); } } }

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  • 2-Way databinding with Entity Framework and WPF DataGrid , is Possible ?

    - by Panindra
    i am working on POS application using SQL CE , WPF , Entity framework 3.5sp2 and iam trying to use data grid as my Order Entry Control for User to enter Products Order . Iam plannning to bind this to enitiy frmae work model , abd looking for 2 way updating ? private void button1_Click(object sender, RoutedEventArgs e) { using (MasterEntities nwEntities = new MasterEntities()) { var users = from d in nwEntities.Companies select new { d.CompanyId, d.CompanyName, d.Place }; listBox1.DataContext = users; dataGrid1.DataContext = users; // foreach (String c in customers) // { // MessageBox.Show(c.ToString()); // } } } When try to double clikc on the datagrid it through s a error with Caption " Invalid Operation Execption was unhandled " and Message " A TwoWay or OneWayToSource binding cannot work on the read-only property 'CompanyId' of type '<f__AnonymousType0`3[System.Int32,System.String,System.String]'. whats wrong here and my xaml coding goes like this <Grid> <ListBox Name="listBox1" ItemsSource="{Binding}" /> <Button Content="Show " Name="button1" Click="button1_Click" /> <DataGrid AutoGenerateColumns="False" Name="dataGrid1" ItemsSource="{Binding}" > <DataGrid.Columns> <DataGridTextColumn Header=" ID" Binding="{Binding CompanyId}"/> <DataGridTextColumn Header="Company Name" Binding="{Binding CompanyName}"/> <DataGridTextColumn Header="Place" Binding="{Binding Place}" /> </DataGrid.Columns> </DataGrid> </Grid> EDITED : i made the changes shown by @vorrtex, But, then i added another button to save the chages and in button click event i added follwing code , butit showing Updating error private void button2_Click(object sender, RoutedEventArgs e) { nwEntities.SaveChanges(); }

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  • Deployment of SQL Server: installing a second instance?

    - by Workshop Alex
    Simple problem. I'm working on a Delphi 2007/WIN32 application which now uses MS Access as simple data store. I have to modify it to support SQL Server Express, which is easy. These modifications are working so the application can be deployed using either SQL Server or MS Access. (Whatever the user prefers.) I did consider deploying the whole application together with the SQL Compact but this is not practicak. Using SQL Server Express 2008 instead of 2005 is an option, but also has a few nasty side-effects which we don't want to resolve for now. The problem is deploying the whole project. The installation with SQL Server would need a quiet installation so the user won't notice it. SQL Server is mentioned in the documentation so they know it's there. We just don't want to bother them with technical issues. In most cases, such an installation will go just fine. But what if the user already has an SQL Server (2005) installation which is used for something else? Personally, I would prefer to just install a second instance of SQL Server on their system so it won't conflict with the other installation. (Thus, if they uninstall the other app, the SQL instance will just stay installed.) While SQL Server 2005 and 2008 can be installed on the same system simply by using two different names for the instance, I wonder if it's also possible to install SQL Server 2005 twice on a single system to get two instances. And if possible, how?

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  • Loading JNI lib on Mac OS X?

    - by Clinton
    Background So I am attempting to load a jnilib (specifically JOGL) into Java on Mac OS X at runtime. I have been following along the relevant Stack Overflow questions: Maven and the JOGL Library Loading DLL in Java - Eclipse - JNI How to make a jar file that include all jar files The end goal for me is to package platform specific JOGL files into a JAR and unzip them into a temp directory and load them at start-up. I worked my problem back to simply attempting to load JOGL using hard-coded paths: File f = new File("/var/folders/+n/+nfb8NHsHiSpEh6AHMCyvE+++TI/-Tmp-/libjogl.jnilib"); System.load(f.toString()); f = new File ("/var/folders/+n/+nfb8NHsHiSpEh6AHMCyvE+++TI/-Tmp-/libjogl_awt.jnilib"); System.load(f.toString()); I get the following exception when attempting to use the JOGL API: Exception in thread "main" java.lang.UnsatisfiedLinkError: no jogl in java.library.path But when I specify java.library.path by adding the following JVM option: -Djava.library.path="/var/folders/+n/+nfb8NHsHiSpEh6AHMCyvE+++TI/-Tmp-/" Everything works fine. Question Is it possible use System.load (or some other variant) on Mac OS X as a replacement for -Djava.library.path that is invoked at runtime?

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  • C# XML node with colon

    - by Sticky
    Hi, my code attempts to grab data from the RSS feed of a website. It grabs the nodes fine, but when attempting to grab the data from a node with a colon, it crashes and gives the error "Namespace Manager or XsltContext needed. This query has a prefix, variable, or user-defined function." The code is shown below: WebRequest request = WebRequest.Create("http://buypoe.com/external.php?type=RSS2&lastpost=true"); WebResponse response = request.GetResponse(); StringBuilder sb = new StringBuilder(""); System.IO.StreamReader rssStream = new System.IO.StreamReader(response.GetResponseStream(), System.Text.Encoding.GetEncoding("utf-8")); XmlDocument rssDoc = new XmlDocument(); rssDoc.Load(rssStream); XmlNodeList rssItems = rssDoc.SelectNodes("rss/channel/item"); for (int i = 0; i < 5; i++) { XmlNode rssDetail; rssDetail = rssItems.Item(i).SelectSingleNode("dc:creator"); if (rssDetail != null) { user = rssDetail.InnerText; } else { user = ""; } } I understand that I need to define the namespace, but am unsure how to do this. Help would be appreciated.

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  • problem with two key ranges in couchdb

    - by Duasto
    I'm having problem getting the right results in my coordinate system. To explain my system, I have this simple database that have x_axis, y_axis and name columns. I don't need to get all the data, I just need to display some part of it. For example, I have a coordinate system that have 10:10(meaning from x_axis -10 to 10 and from y_axis -10 to 10) and I want to display only 49 coordinates. In sql query I can do it something like this: "select * from coordinate where x_axis = -3 and x_axis <= 3 and y_axis = -3 y_axis <= 3" I tried this function but no success: "by_range": { "map": "function(doc) { emit([doc.x_axis, doc.y_axis], doc) }" } by_range?startkey=[-3,-3]&endkey=[3,3] I got a wrong results of: -3x-3 -3x-2 -3x-1 -3x0 -3x1 -3x2 -3x3 <-- should not display this part -- -3x4 -3x5 -3x6 -3x7 -3x8 -3x9 -3x10 <-- end of should not display this part -- ..... up to 3x3 to give you a better understanding of my project here is the screenshot of that I want to be made: Oops they don't allowed new poster to post an image img96(dot)imageshack(dot)us/img96/5382/coordinates(dot)jpg <<< just change the "(dot)" to "."

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  • How to deploy to multiple redundant production servers with "cap deploy"?

    - by Chad Johnson
    Capistrano is working great to deploy to a single server. However, I have multiple production API servers for my web application. When I deploy, my code needs to get deployed to every API server at once. Specifying each server manually is NOT the solution I am looking for (e.g. I don't want to do "cap api1 deploy; cap api2 deploy"). Is there a way, using Capistrano, to deploy to all servers at once, with just a simple "cap deploy"? I'm wondering what changes I would need to make to a typical deploy.rb file, whether I'd need to create a separate file for each server, and whether and how the Capfile would need to be changed. Also, I need to be able to specify a different deploy_to path for each server. And ideally, I wouldn't have to repeat things in different config files for different servers (eg. wouldn't have to specify :repository, :application, etc. multiple times). I have spent hours searching Google on this and looking through tutorials, but I have found nothing helpful. Here is a snippet from my current deploy.rb file: set :application, "testapplication" set :repository, "ssh://domain.com//srv/hg/#{application}" set :scm, :mercurial set :deploy_to, "/srv/www/#{application}" role :web, "domain.com" role :app, "domain.com" role :db, "domain.com", :primary => true, :norelease => true Should I just use the multistage extension and do this? task :deploy_everything do system "cap api1 deploy" system "cap api2 deploy" system "cap api2 deploy" end That could work, but I feel like this isn't what this extension is meant for...

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  • How can I limit asp.net control actions based on user role?

    - by Duke
    I have several pages or views in my application which are essentially the same for both authenticated users and anonymous users. I'd like to limit the insert/update/delete actions in formviews and gridviews to authenticated users only, and allow read access for both authed and anon users. I'm using the asp.net configuration system for handling authentication and roles. This system limits access based on path so I've been creating duplicate pages for authed and anon paths. The solution that comes to mind immediately is to check roles in the appropriate event handlers, limiting what possible actions are displayed (insert/update/delete buttons) and also limiting what actions are performed (for users that may know how to perform an action in the absence of a button.) However, this solution doesn't eliminate duplication - I'd be duplicating security code on a series of pages rather than duplicating pages and limiting access based on path; the latter would be significantly less complicated. I could always build some controls that offered role-based configuration, but I don't think I have time for that kind of commitment right now. Is there a relatively easy way to do this (do such controls exist?) or should I just stick to path-based access and duplicate pages? Does it even make sense to use two methods of authorization? There are still some pages which are strictly for either role so I'll be making use of path-based authorization anyway. Finally, would using something other than path-based authorization be contrary to typical asp.net design practices, at least in the context of using the asp.net configuration system?

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  • TransactionRequiredException on OptimisticLockException

    - by João Madureira Pires
    Hi there. I have the following class that generates sequencial Card Numbers. I'm trying to recover from OptimisticLockException, by calling recursively the same method. however, i'm getting TransactionRequiredException. Dows anyone knows how to recover from OptimisticLockException in my case? Thanks a lot in advance @Name("simpleAutoIncrementGenerator") public class SimpleAutoIncrementGenerator extends CardNumberGenerator{ private static final long serialVersionUID = 2869548248468809665L; private int numberOfRetries = 0; @Override public String generateNextNumber(CardInstance cardInstance, EntityManager entityManager) { try{ EntityCard card = (EntityCard)entityManager.find(EntityCard.class, cardInstance.getId()); if(card != null){ String nextNumber = ""; String currentNumber = card.getCurrentCardNumber(); if(currentNumber != null && !currentNumber.isEmpty()){ Long numberToInc = Long.parseLong(currentNumber); numberToInc ++; nextNumber = String.valueOf(numberToInc); card.setCurrentCardNumber(nextNumber); // this is just to cause a OptimisticLock Exception try { Thread.sleep(4000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } entityManager.persist(card); entityManager.flush(); return nextNumber; } } }catch (OptimisticLockException oLE) { System.out.println("\n\n\n\n OptimisticLockException \n\n\n\n"); if(numberOfRetries < CentralizedConfig.CARD_NUMBER_GENERATOR_MAX_TRIES){ numberOfRetries ++; return generateNextNumber(cardInstance,entityManager); } }catch (TransactionRequiredException trE) { System.out.println("\n\n\n\n TransactionRequiredException \n\n\n\n"); if(numberOfRetries < CentralizedConfig.CARD_NUMBER_GENERATOR_MAX_TRIES){ numberOfRetries ++; return generateNextNumber(cardInstance,entityManager); } }catch (StaleObjectStateException e) { System.out.println("\n\n\n\n StaleObjectStateException \n\n\n\n"); if(numberOfRetries < CentralizedConfig.CARD_NUMBER_GENERATOR_MAX_TRIES){ numberOfRetries ++; return generateNextNumber(cardInstance,entityManager); } } return null; } }

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  • Patterns / Solutions to complicated Feature Management

    - by yclian
    Hi all, My company develops CDN / Web-Hosting solution. We have a middleware that's served as a business logic layer and exposes web service for the front-end. I would like to seek for a clean solution to feature management - there're uncertainties and ugly workarounds/solutions in the software that the dev would say "when it happens or is broken, we will fix it". For example, here're the following features that a web publisher can have: Sites limit Bandwidth limit SSL feature + SSL configuration per site If we downgrade a web publisher, when he's having 10 sites, down to 5 sites, we can choose not to suspend the rest of the 5 sites, or we shall prompt for suspension before the downgrade. For the case of bandwidth limit, the downgrade is easy, when the bandwidth check happens, if the publisher has it exceeded, then we will suspend his account. For the case of SSL feature. Every SSL configuration is tied to a site, what shall happen to these configuration object when the SSL feature is downgraded from enabled to disabled? So as you can see, there're many different situations and there are different ways of handling it. I can make a system that examines the impacts and prompts the user to make changes before the downgrade/upgrade. Or a system that ignores the impacts and just upgrade/downgrade. Bad. Or a system designed in a way that the client code need to be aware of the complex feature matrix (or I can expose a helper to the client code to check if a feature is not DEFUNCT) There can be many ways that I am still thinking but puzzled. I am wondering, how would you tackle this issue and is there any recommended patterns or books or software that you think I can refer to? Appreciate your help.

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  • what's the performance difference between int and varchar for primary keys

    - by user568576
    I need to create a primary key scheme for a system that will need peer to peer replication. So I'm planning to combine a unique system ID and a sequential number in some way to come up with unique ID's. I want to make sure I'll never run out of ID's, so I'm thinking about using a varchar field, since I could always add another character if I start running out. But I've read that integers are better optimized for this. So I have some questions... 1) Are integers really better optimized? And if they are, how much of a performance difference is there between varchars and integers? I'm going to use firebird for now. But I may switch later. Or possibly support multiple db's. So I'm looking for generalizations, if that's possible. 2) If integers are significantly better optimized, why is that? And is it likely that varchars will catch up in the future, so eventually it won't matter anyway? My varchar keys won't have any meaning, except for the unique system ID part. But I may want to obscure that somehow. Also, I plan to efficiently use all the bits of each character. I don't, for example, plan to code the integer 123 as the character string "123". So I don't think varchars will require more space than integers.

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  • Best way to run multiple queries per second on database, performance wise?

    - by Michael Joell
    I am currently using Java to insert and update data multiple times per second. Never having used databases with Java, I am not sure what is required, and how to get the best performance. I currently have a method for each type of query I need to do (for example, update a row in a database). I also have a method to create the database connection. Below is my simplified code. public static void addOneForUserInChannel(String channel, String username) throws SQLException { Connection dbConnection = null; PreparedStatement ps = null; String updateSQL = "UPDATE " + channel + "_count SET messages = messages + 1 WHERE username = ?"; try { dbConnection = getDBConnection(); ps = dbConnection.prepareStatement(updateSQL); ps.setString(1, username); ps.executeUpdate(); } catch(SQLException e) { System.out.println(e.getMessage()); } finally { if(ps != null) { ps.close(); } if(dbConnection != null) { dbConnection.close(); } } } And my DB connection private static Connection getDBConnection() { Connection dbConnection = null; try { Class.forName(DB_DRIVER); } catch (ClassNotFoundException e) { System.out.println(e.getMessage()); } try { dbConnection = DriverManager.getConnection(DB_CONNECTION, DB_USER,DB_PASSWORD); return dbConnection; } catch (SQLException e) { System.out.println(e.getMessage()); } return dbConnection; } This seems to be working fine for now, with about 1-2 queries per second, but I am worried that once I expand and it is running many more, I might have some issues. My questions: Is there a way to have a persistent database connection throughout the entire run time of the process? If so, should I do this? Are there any other optimizations that I should do to help with performance? Thanks

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  • Determining the popularity of a video with ratings and views

    - by user295825
    I am about to embark on a new project - a video website. Users will be able to register, and vote on videos by clicking "like" or "dislike", or something to that effect. In any event, it will be a 2-option voting system, not a 5-star system. Every X number of days, I will be generating a "chart" of the most popular videos. So my question is: how should I determine the popularity of a given video? If I went the route of tallying up the videos with the most views, this could have the effect of exceptionally bad videos making it to the of the charts (just because they're so bad). If I go the route of a scoring system based on the amount of "like" and "dislike" votes (eg. 100 like votes, and 50 dislike votes equals a score of 2), videos with few views could appear on the top of the charts. So, what I need to do is a combination of the two. Barring, of course, spammy views and votes. What's your guys' thoughts on the subject?

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  • How is timezone handled in the lifecycle of an ADO.NET + SQL Server DateTime column?

    - by stimpy77
    Using SQL Server 2008. This is a really junior question and I could really use some elaborate information, but the information on Google seems to dance around the topic quite a bit and it would be nice if there was some detailed elaboration on how this works... Let's say I have a datetime column and in ADO.NET I set it to DateTime.UtcNow. 1) Does SQL Server store DateTime.UtcNow accordingly, or does it offset it again based on the timezone of where the server is installed, and then return it offset-reversed when queried? I think I know that the answer is "of course it stores it without offsetting it again" but want to be certain. So then I query for it and cast it from, say, an IDataReader column to a DateTime. As far as I know, System.DateTime has metadata that internally tracks whether it is a UTC DateTime or it is an offsetted DateTime, which may or may not cause .ToLocalTime() and .ToUniversalTime() to have different behavior depending on this state. So, 2) Does this casted System.DateTime object already know that it is a UTC DateTime instance, or does it assume that it has been offset? Now let's say I don't use UtcNow, I use DateTime.Now, when performing an ADO.NET INSERT or UPDATE. 3) Does ADO.NET pass the offset to SQL Server and does SQL Server store DateTime.Now with the offset metadata? So then I query for it and cast it from, say, an IDataReader column to a DateTime. 4) Does this casted System.DateTime object already know that it is an offset time, or does it assume that it is UTC?

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  • Sum of even fibonacci numbers

    - by user300484
    This is a Project Euler problem. If you don't want to see candidate solutions don't look here. Hello you all! im developping an application that will find the sum of all even terms of the fibonacci sequence. The last term of this sequence is 4,000,000 . There is something wrong in my code but I cannot find the problem since it makes sense to me. Can you please help me? using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { long[] arr = new long [1000000] ; long i= 2; arr[i-2]=1; arr[i-1]=2; long n= arr[i]; long s=0; for (i=2 ; n <= 4000000; i++) { arr[i] = arr[(i - 1)] + arr[(i - 2)]; } for (long f = 0; f <= arr.Length - 1; f++) { if (arr[f] % 2 == 0) s += arr[f]; } Console.Write(s); Console.Read(); } } }

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  • What are salesforce.com and Apex like as an application development platform?

    - by mhollers
    I have recently discovered that salesforce.com is much more than an online CRM after coming across a Morrison's Case Study in which they develop a works management application. I've been trying it out with a view to recreating our own Works Management system on the platform. My background is in Microsoft and .Net, and the obvious 1st choice would be asp.net. However, there's only really myself with .net experience and my manager with a more legacy Synergy programming background, and I am self taught and am looking at evaluating other RAD options (eg Ironspeed). the nature of the business is in the main 2-5 concurrent construction type contracts that run for 3-5 yrs each, each requiring 15-50 system users. Traditionally we have used our character based Works Mangement system for everything and tweaked it for each contract. The Salesforce licensing model on the face of it suits this sort of flexibilty, but I'm worried about the development flexibilty/learning curve and all the issues that surround lock-in. There doesn't seem to be much neutral sober analysis of the platform on the web that isn't salesforce's own material/blogs Has anyone any experience of developing an application on salesforce as compared to the more 'traditional' .Net route?

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  • Can i change the identity of the logged in user in ASP.net?

    - by Rising Star
    I have an ASP.net application I'm developing authentication for. I am using an existing cookie-based log on system to log users in to the system. The application runs as an anonymous account and then checks the cookie when the user wants to do something restricted. This is working fine. However, there is one caveat: I've been told that for each page that connects to our SQL server, I need to make it so that the user connects using an Active Directory account. because the system I'm using is cookie based, the user isn't logged in to Active Directory. Therefore, I use impersonation to connect to the server as a specific account. However, the powers that be here don't like impersonation; they say that it clutters up the code. I agree, but I've found no way around this. It seems that the only way that a user can be logged in to an ASP.net application is by either connecting with Internet Explorer from a machine where the user is logged in with their Active Directory account or by typing an Active Directory username and password. Neither of these two are workable in my application. I think it would be nice if I could make it so that when a user logs in and receives the cookie (which actually comes from a separate log on application, by the way), there could be some code run which tells the application to perform all network operations as the user's Active Directory account, just as if they had typed an Active Directory username and password. It seems like this ought to be possible somehow, but the solution evades me. How can I make this work?

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  • Writing out sheet to text file using POI event model

    - by Eduardo Dennis
    I am using XLSX2CSV example to parse large sheets from a workbook. Since I only need to output the data for specific sheets I added an if statement in the process method to test for the specific sheets. When the condition is met I continue with the process. public void process() throws IOException, OpenXML4JException, ParserConfigurationException, SAXException { ReadOnlySharedStringsTable strings = new ReadOnlySharedStringsTable(this.xlsxPackage); XSSFReader xssfReader = new XSSFReader(this.xlsxPackage); StylesTable styles = xssfReader.getStylesTable(); XSSFReader.SheetIterator iter = (XSSFReader.SheetIterator) xssfReader.getSheetsData(); while (iter.hasNext()) { InputStream stream = iter.next(); String sheetName = iter.getSheetName(); if (sheetName.equals("SHEET1")||sheetName.equals("SHEET2")||sheetName.equals("SHEET3")||sheetName.equals("SHEET4")||sheetName.equals("SHEET5")){ processSheet(styles, strings, stream); try { System.setOut(new PrintStream( new FileOutputStream("C:\\Users\\edennis.AD\\Desktop\\test\\"+sheetName+".txt"))); } catch (Exception e) { e.printStackTrace(); } stream.close(); } } } But I need to output text file and not sure how to do it. I tried to use the System.set() method to output everything from system.out to text but that's not working I just get blank files.

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  • Use cases of [ordered], the new PowerShell 3.0 feature

    - by Roman Kuzmin
    PowerShell 3.0 CTP1 introduces a new feature [ordered] which is somewhat a shortcut for OrderedDictionary. I cannot imagine practical use cases of it. Why is this feature really useful? Can somebody provide some useful examples? Example: this is, IMHO, rather demo case than practical: $a = [ordered]@{a=1;b=2;d=3;c=4} (I do not mind if it is still useful, then I am just looking for other useful cases). I am not looking for use cases of OrderedDictionary, it is useful, indeed. But we can use it directly in v2.0 (and I do a lot). I am trying to understand why is this new feature [ordered] needed in addition. Collected use cases from answers: $hash = [ordered]@{} is shorter than $hash = New-Object System.Collections.Specialized.OrderedDictionary N.B. ordered is not a real shortcut for the type. New-Object ordered does not work. N.B. 2: But this is still a good shortcut because (I think, cannot try) it creates typical for PowerShell case insensitive dictionary. The equivalent command in v2.0 is too long, indeed: New-Object System.Collections.Specialized.OrderedDictionary]([System.StringComparer]::OrdinalIgnoreCase)

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  • Line End Problem Reading with Scanner Class in Java

    - by dikbas
    I am not an experienced Java programmer and i'm trying to write some text to a file and then read it with Scanner. I know there are lots of ways of doing this, but i want to write records to file with delimiters, then read the pieces. The problem is so small. When I look the output some printing isn't seen(shown in below). I mean the bold line in the Output that is only written "Scanner". I would be appreciated if anyone can answer why "String: " isn't seen there. (Please answer just what i ask) I couldn't understand if it is a simple printing problem or a line end problem with "\r\n". Here is the code and output: import java.io.FileReader; import java.io.FileWriter; import java.io.IOException; import java.util.Scanner; public class Tmp { public static void main(String args[]) throws IOException { int i; boolean b; String str; FileWriter fout = new FileWriter("test.txt"); fout.write("Testing|10|true|two|false\r\n"); fout.write("Scanner|12|one|true|"); fout.close(); FileReader fin = new FileReader("Test.txt"); Scanner src = new Scanner(fin).useDelimiter("[|\\*]"); while (src.hasNext()) { if (src.hasNextInt()) { i = src.nextInt(); System.out.println("int: " + i); } else if (src.hasNextBoolean()) { b = src.nextBoolean(); System.out.println("boolean: " + b); } else { str = src.next(); System.out.println("String: " + str); } } fin.close(); } } Here is the output: String: Testing int: 10 boolean: true String: two String: false Scanner int: 12 String: one boolean: true

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  • GNU C++ how to check when -std=c++0x is in effect?

    - by TerryP
    My system compiler (gcc42) works fine with the TR1 features that I want, but trying to support newer compiler versions other than the systems, trying to accessing TR1 headers an #error demanding the -std=c++0x option because of how it interfaces with library or some hub bub like that. /usr/local/lib/gcc45/include/c++/bits/c++0x_warning.h:31:2: error: #error This file requires compiler and library support for the upcoming ISO C++ standard, C++0x. This support is currently experimental, and must be enabled with the -std=c++0x or -std=gnu++0x compiler options. Having to supply an extra switch is no problem, to support GCC 4.4 and 4.5 under this system (FreeBSD), but obviously it changes the picture! Using my system compiler (g++ 4.2 default dialect): #include <tr1/foo> using std::tr1::foo; Using newer (4.5) versions of the compiler with -std=c++0x: #include <foo> using std::foo; Is there anyway using the pre processor, that I can tell if g++ is running with C++0x features enabled? Something like this is what I'm looking for: #ifdef __CXX0X_MODE__ #endif but I have not found anything in the manual or off the web. At this rate, I'm starting to think that life would just be easier, to use Boost as a dependency, and not worry about a new language standard arriving before TR4... hehe.

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