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  • Good programming website like Stack Overflow?

    - by hhafez
    What other good collaborative programming/software development/engineering websites do you know of? I'm not looking for language or platform specific websites. Nor am I looking for something similar to the format of Stack Overflow. My main criteria is that the community is knowledgeable, helpful active friendly I know the question is open ended/subjective but I'd like to know as many places where I can get the help of my peers. The accepted answer will contain links to your recommended sites have a short description be concise be highly voted by your peers

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  • how can we use AsynCallback method of web service in asp.net

    - by sameer
    Hi All, I was going through the proxy class which is generated using wsdl.exe found the asyncmethod like BeginAsynXXX() and EndAsyncXXX(). i understood how to utilize them on Windows application but i was wondering how can we use them in Web Application built using asp.net here is the code for web service client build as windows application.can any tell me how we can do this with web application. using System; using System.Runtime.Remoting.Messaging; using MyFactorize; class TestCallback { public static void Main(){ long factorizableNum = 12345; PrimeFactorizer pf = new PrimeFactorizer(); //Instantiate an AsyncCallback delegate to use as a parameter //in the BeginFactorize method. AsyncCallback cb = new AsyncCallback(TestCallback.FactorizeCallback); // Begin the Async call to Factorize, passing in our // AsyncCalback delegate and a reference // to our instance of PrimeFactorizer. IAsyncResult ar = pf.BeginFactorize(factorizableNum, cb, pf); // Keep track of the time it takes to complete the async call // as the call proceeds. int start = DateTime.Now.Second; int currentSecond = start; while (ar.IsCompleted == false){ if (currentSecond < DateTime.Now.Second) { currentSecond = DateTime.Now.Second; Console.WriteLine("Seconds Elapsed..." + (currentSecond - start).ToString() ); } } // Once the call has completed, you need a method to ensure the // thread executing this Main function // doesn't complete prior to the call-back function completing. Console.Write("Press Enter to quit"); int quitchar = Console.Read(); } // Set up a call-back function that is invoked by the proxy class // when the asynchronous operation completes. public static void FactorizeCallback(IAsyncResult ar) { // You passed in our instance of PrimeFactorizer in the third // parameter to BeginFactorize, which is accessible in the // AsyncState property. PrimeFactorizer pf = (PrimeFactorizer) ar.AsyncState; long[] results; // Get the completed results. results = pf.EndFactorize(ar); //Output the results. Console.Write("12345 factors into: "); int j; for (j = 0; j<results.Length;j++){ if (j == results.Length - 1) Console.WriteLine(results[j]); else Console.Write(results[j] + ", "); } } }

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  • How to initialize a web app?

    - by Gatis
    My Web App will be deployed as a WAR package in a Jetty instance. It needs to perform a lot of caching before serving requests. How do I call the caching method before anything else? is the a static void main() in the web app standard?

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  • One-liner to determine who wins in Rock, Paper, Scissors

    - by asmeurer
    So I am writing a simple Rock, Paper, Scissors game in C (it's for an assignment by the way, though the main thing is to learn sockets. Also, I suspect it will be due before I get a good answer). I have it setup as Rock=0, Paper=1, and Scissors=2. Is there an easy one-liner to determine who wins? I tried playing around with it on paper, but I couldn't figure out any patterns.

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  • Summary of the last decade of garbage collection?

    - by Ben Karel
    I've been reading through the Jones & Lin book on garbage collection, which was published in 1996. Obviously, the computing world has changed dramatically since then: multicore, out-of-order chips with large caches, and even larger main memory in desktops. The world has also more-or-less settled on the x86 and ARM microarchitectures for most consumer-facing systems. How has the field of garbage collection changed since the seminal book was published?

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  • Maze not generating properly. Out of bounds exception. need quick fix

    - by Dan Joseph Porcioncula
    My maze generator seems to have a problem. I am trying to generate something like the maze from http://mazeworks.com/mazegen/mazetut/index.htm . My program displays this http://a1.sphotos.ak.fbcdn.net/hphotos-ak-snc7/s320x320/374060_426350204045347_100000111130260_1880768_1572427285_n.jpg and the error Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1 at Grid.genRand(Grid.java:73) at Grid.main(Grid.java:35) How do I fix my generator program? import java.awt.*; import java.awt.Color; import java.awt.Component; import java.awt.Graphics; import javax.swing.*; import java.util.ArrayList; public class Grid extends Canvas { Cell[][] maze; int size; int pathSize; double width, height; ArrayList<int[]> coordinates = new ArrayList<int[]>(); public Grid(int size, int h, int w) { this.size = size; maze = new Cell[size][size]; for(int i = 0; i<size; i++){ for(int a =0; a<size; a++){ maze[i][a] = new Cell(); } } setPreferredSize(new Dimension(h, w)); } public static void main(String[] args) { JFrame y = new JFrame(); y.setLayout(new BorderLayout()); Grid f = new Grid(25, 400, 400); y.add(f, BorderLayout.CENTER); y.setSize(450, 450); y.setVisible(true); y.setDefaultCloseOperation(y.EXIT_ON_CLOSE); f.genRand(); f.repaint(); } public void push(int[] xy) { coordinates.add(xy); int i = coordinates.size(); coordinates.ensureCapacity(i++); } public int[] pop() { int[] x = coordinates.get((coordinates.size())-1); coordinates.remove((coordinates.size())-1); return x; } public int[] top() { return coordinates.get((coordinates.size())-1); } public void genRand(){ // create a CellStack (LIFO) to hold a list of cell locations [x] // set TotalCells = number of cells in grid int TotalCells = size*size; // choose a cell at random and call it CurrentCell int m = randomInt(size); int n = randomInt(size); Cell curCel = maze[m][n]; // set VisitedCells = 1 int visCel = 1,d=0; int[] q; int h,o = 0,p = 0; // while VisitedCells < TotalCells while( visCel < TotalCells){ // find all neighbors of CurrentCell with all walls intact if(maze[m-1][n].countWalls() == 4){d++;} if(maze[m+1][n].countWalls() == 4){d++;} if(maze[m][n-1].countWalls() == 4){d++;} if(maze[m][n+1].countWalls() == 4){d++;} // if one or more found if(d!=0){ Point[] ls = new Point[4]; ls[0] = new Point(m-1,n); ls[1] = new Point(m+1,n); ls[2] = new Point(m,n-1); ls[3] = new Point(m,n+1); // knock down the wall between it and CurrentCell h = randomInt(3); switch(h){ case 0: o = (int)(ls[0].getX()); p = (int)(ls[0].getY()); curCel.destroyWall(2); maze[o][p].destroyWall(1); break; case 1: o = (int)(ls[1].getX()); p = (int)(ls[1].getY()); curCel.destroyWall(1); maze[o][p].destroyWall(2); break; case 2: o = (int)(ls[2].getX()); p = (int)(ls[2].getY()); curCel.destroyWall(3); maze[o][p].destroyWall(0); break; case 3: o = (int)(ls[3].getX()); p = (int)(ls[3].getY()); curCel.destroyWall(0); maze[o][p].destroyWall(3); break; } // push CurrentCell location on the CellStack push(new int[] {m,n}); // make the new cell CurrentCell m = o; n = p; curCel = maze[m][n]; // add 1 to VisitedCells visCel++; } // else else{ // pop the most recent cell entry off the CellStack q = pop(); m = q[0]; n = q[1]; curCel = maze[m][n]; // make it CurrentCell // endIf } // endWhile } } public int randomInt(int s) { return (int)(s* Math.random());} public void paint(Graphics g) { int k, j; width = getSize().width; height = getSize().height; double htOfRow = height / (size); double wdOfRow = width / (size); //checks verticals - destroys east border of cell for (k = 0; k < size; k++) { for (j = 0; j < size; j++) { if(maze[k][j].checkWall(2)){ g.drawLine((int) (k * wdOfRow), (int) (j * htOfRow), (int) (k * wdOfRow), (int) ((j+1) * htOfRow)); }} } //checks horizontal - destroys north border of cell for (k = 0; k < size; k++) { for (j = 0; j < size; j++) { if(maze[k][j].checkWall(3)){ g.drawLine((int) (k * wdOfRow), (int) (j * htOfRow), (int) ((k+1) * wdOfRow), (int) (j * htOfRow)); }} } } } class Cell { private final static int NORTH = 0; private final static int EAST = 1; private final static int WEST = 2; private final static int SOUTH = 3; private final static int NO = 4; private final static int START = 1; private final static int END = 2; boolean[] wall = new boolean[4]; boolean[] border = new boolean[4]; boolean[] backtrack = new boolean[4]; boolean[] solution = new boolean[4]; private boolean isVisited = false; private int Key = 0; public Cell(){ for(int i=0;i<4;i++){wall[i] = true;} } public int countWalls(){ int i, k =0; for(i=0; i<4; i++) { if (wall[i] == true) {k++;} } return k;} public boolean checkWall(int x){ switch(x){ case 0: return wall[0]; case 1: return wall[1]; case 2: return wall[2]; case 3: return wall[3]; } return true; } public void destroyWall(int x){ switch(x){ case 0: wall[0] = false; break; case 1: wall[1] = false; break; case 2: wall[2] = false; break; case 3: wall[3] = false; break; } } public void setStart(int i){Key = i;} public int getKey(){return Key;} public boolean checkVisit(){return isVisited;} public void visitCell(){isVisited = true;} }

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  • KohanaPHP redirection loop

    - by sorrko
    Hello, I got problem. I'm builing an app with KohanaPHP framework and I got rediretion endless loop. Here's the code I put in constructor oh my main controller: if(empty($this->user->real_name)) { url::redirect('/'); } Any ideas how to solve that issue?

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  • Overridding a:link

    - by cinqoTimo
    In my main CSS file, I have my a:link selector set to display links in White. a:link{ color: white; } However, I want links in another DIV (.menuItem) to be black. I am trying .menuItem a:link{ color: black; } can't seem to get it to work, so it's probably wrong.. Can anyone lend a hand on this one?

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  • Moving MVC2 Helpers to MVC3 razor view engine

    - by Dai Bok
    Hi, In my MVC 2 site, I have an html helper, that I use to add javascripts for my pages. In my master page I have the main javascripts I want to include, and then in the aspx pages, I include page specific javascripts. So for example, my Site.Master has something like this: .... <head> <%=html.renderScripts() %> </head> ... //core scripts for main page <%html.AddScript("/scripts/jquery.js") %> <%html.AddScript("/scripts/myLib.js") %> .... Then in the child aspx page, I may also want to include other scripts. ... //the page specific script I want to use <% html.AddScript("/scripts/register.aspx.js") %> ... So when the full page gets rendered the javascript files are all collected and rendered in the head by sitemaster placeholder function RenderScripts. This works fine. Now with MVC 3 and razor view engine, they layout pages behave differently, because now my page level javascripts are not rendered/included. Now all I see the LayoutMaster contents. How do I get the solution wo workwith MVC 3 and the razor view engine. (The helper has already been re-written to return a HTMLString ;-)) For reference: my MasterLayout looks like this: ... ... <head> @{ Html.AddJavaScript("/Scripts/jQuery.js"); Html.AddJavaScript("/Scripts/myLib.js"); } //Render scripts @html.RenderScripts() </head> .... and the child page looks like this: @{ Layout = "~/Views/Shared/MasterLayout.cshtml"; ViewBag.Title = "Child Page"; Html.AddJavaScript("/Scripts/register.aspx.js"); } .... <div>some html </div> Thanks for your help. Edit = Just to explain, if this question is not clear enough. When producing a "page" I collect all the javascript files the designers want to use, by using the html.addJavascript("filename.js") and store these in a dictionary - (1) stops people adding duplicate js files - then finally when the page is ready to render, I write out all the javascript files neatly in the header. (2) - this helper helps keep JS in one place, and prevents designers from adding javascript files all over the place. This used to work fine with Master/SiteMaster Pages in mvc 2. but how can I achieve this with razor?

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  • C# Simple Event Handler for Setting Alarm

    - by yeeen
    Why does the following line "alarm.AlarmEvent += new AlarmEventHandler(alarm_Sound);" gives me "An object reference is required for the non-static field, method, or property 'AlarmClock.Alarm.alarm_Sound(object, System.EventArgs)'" public static void Main(string[] args) { Alarm alarm = new Alarm(new DateTime(2010, 4, 7, 23, 2, 0)); alarm.Set(); alarm.AlarmEvent += new AlarmEventHandler(alarm_Sound); } Full source code here: Program.cs AlarmEventArgs

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  • Android: how to share code between projects signed with the same certificate

    - by tomash
    In Android documentation concerning code signing we can read: "By signing multiple applications with the same certificate and using signature-based permissions checks, your applications can share code and data in a secure manner." How exactly such code sharing can be done? Is it possible to release main application and multiple exchangeable plugins then discover them at runtime? What does source code looks like and what are advantages over "standard" intents calls from/to different APK packages?

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  • Whats wrong with this code.Runtime error

    - by javacode
    Hi I am writing this application in eclipse I added all the jar files.I am pasting the code and error.Please let me know what changes I should make to run the application properly. import javax.mail.*; import javax.mail.internet.*; import java.util.*; public class SendMail { public static void main(String [] args) { SendMail sm=new SendMail(); try{ sm.postMail(new String[]{"[email protected]"},"hi","hello","[email protected]"); } catch(MessagingException e) { e.printStackTrace(); } } public void postMail( String recipients[ ], String subject, String message , String from) throws MessagingException { boolean debug = false; //Set the host smtp address Properties props = new Properties(); props.put("mail.smtp.starttls.enable","true"); props.put("mail.smtp.host", "smtp.gmail.com"); props.setProperty("mail.smtp.port", "25"); // create some properties and get the default Session Session session = Session.getDefaultInstance(props, null); session.setDebug(debug); // create a message Message msg = new MimeMessage(session); // set the from and to address InternetAddress addressFrom = new InternetAddress(from); msg.setFrom(addressFrom); InternetAddress[] addressTo = new InternetAddress[recipients.length]; for (int i = 0; i < recipients.length; i++) { addressTo[i] = new InternetAddress(recipients[i]); } msg.setRecipients(Message.RecipientType.TO, addressTo); // Optional : You can also set your custom headers in the Email if you Want msg.addHeader("MyHeaderName", "myHeaderValue"); // Setting the Subject and Content Type msg.setSubject(subject); msg.setContent(message, "text/plain"); Transport.send(msg); } } Error: com.sun.mail.smtp.SMTPSendFailedException: 530 5.7.0 Must issue a STARTTLS command first. 13sm646598ewy.13 at com.sun.mail.smtp.SMTPTransport.issueSendCommand(SMTPTransport.java:1829) at com.sun.mail.smtp.SMTPTransport.mailFrom(SMTPTransport.java:1368) at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:886) at javax.mail.Transport.send0(Transport.java:191) at javax.mail.Transport.send(Transport.java:120) at SendMail.postMail(SendMail.java:54) at SendMail.main(SendMail.java:10)

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  • XML validation in Java - why does this fail?

    - by jd
    hi, first time dealing with xml, so please be patient. the code below is probably evil in a million ways (I'd be very happy to hear about all of them), but the main problem is of course that it doesn't work :-) public class Test { private static final String JSDL_SCHEMA_URL = "http://schemas.ggf.org/jsdl/2005/11/jsdl"; private static final String JSDL_POSIX_APPLICATION_SCHEMA_URL = "http://schemas.ggf.org/jsdl/2005/11/jsdl-posix"; public static void main(String[] args) { System.out.println(Test.createJSDLDescription("/bin/echo", "hello world")); } private static String createJSDLDescription(String execName, String args) { Document jsdlJobDefinitionDocument = getJSDLJobDefinitionDocument(); String xmlString = null; // create the elements Element jobDescription = jsdlJobDefinitionDocument.createElement("JobDescription"); Element application = jsdlJobDefinitionDocument.createElement("Application"); Element posixApplication = jsdlJobDefinitionDocument.createElementNS(JSDL_POSIX_APPLICATION_SCHEMA_URL, "POSIXApplication"); Element executable = jsdlJobDefinitionDocument.createElement("Executable"); executable.setTextContent(execName); Element argument = jsdlJobDefinitionDocument.createElement("Argument"); argument.setTextContent(args); //join them into a tree posixApplication.appendChild(executable); posixApplication.appendChild(argument); application.appendChild(posixApplication); jobDescription.appendChild(application); jsdlJobDefinitionDocument.getDocumentElement().appendChild(jobDescription); DOMSource source = new DOMSource(jsdlJobDefinitionDocument); validateXML(source); try { Transformer transformer = TransformerFactory.newInstance().newTransformer(); transformer.setOutputProperty(OutputKeys.INDENT, "yes"); StreamResult result = new StreamResult(new StringWriter()); transformer.transform(source, result); xmlString = result.getWriter().toString(); } catch (Exception e) { e.printStackTrace(); } return xmlString; } private static Document getJSDLJobDefinitionDocument() { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = null; try { builder = factory.newDocumentBuilder(); } catch (Exception e) { e.printStackTrace(); } DOMImplementation domImpl = builder.getDOMImplementation(); Document theDocument = domImpl.createDocument(JSDL_SCHEMA_URL, "JobDefinition", null); return theDocument; } private static void validateXML(DOMSource source) { try { URL schemaFile = new URL(JSDL_SCHEMA_URL); Sche maFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI); Schema schema = schemaFactory.newSchema(schemaFile); Validator validator = schema.newValidator(); DOMResult result = new DOMResult(); validator.validate(source, result); System.out.println("is valid"); } catch (Exception e) { e.printStackTrace(); } } } it spits out a somewhat odd message: org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'JobDescription'. One of '{"http://schemas.ggf.org/jsdl/2005/11/jsdl":JobDescription}' is expected. Where am I going wrong here? Thanks a lot

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  • testing a shellcode...

    - by kmitnick
    hey folks, I have this piece of code to test a shellcode but I don't understand it so can anyone explain it to me??? forget about the assembly shellcode, what i want to understand is the C code char shellcode[] = "..."; int main(int argc, char **argv) { int (*func)(); func = (int (*)()) shellcode; (int)(*func)(); } I mean everything, what is the empty () ,please explain it as if you are explaining it to a beginner thnx all

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  • Error trying to run rails server

    - by David87
    I am trying to get a basic Rails application to run on my Mac OS X 10.6.5. I created a new app called demo (rails new demo), then went into the demo directory and tried to start the app with rails server. Here is the error message I received: "/Users/dpetrovi/.gem/ruby/1.8/gems/sqlite3-ruby-1.3.2/lib/sqlite3/sqlite3_native.bundle: [BUG] Segmentation fault ruby 1.8.7 (2010-12-23 patchlevel 330) [i686-darwin10] Abort trap" I checked bundle install in the demo folder: "Using rake (0.8.7) Using abstract (1.0.0) Using activesupport (3.0.3) Using builder (2.1.2) Using i18n (0.5.0) Using activemodel (3.0.3) Using erubis (2.6.6) Using rack (1.2.1) Using rack-mount (0.6.13) Using rack-test (0.5.6) Using tzinfo (0.3.23) Using actionpack (3.0.3) Using mime-types (1.16) Using polyglot (0.3.1) Using treetop (1.4.9) Using mail (2.2.13) Using actionmailer (3.0.3) Using arel (2.0.6) Using activerecord (3.0.3) Using activeresource (3.0.3) Using bundler (1.0.7) Using thor (0.14.6) Using railties (3.0.3) Using rails (3.0.3) Using sqlite3-ruby (1.3.2) Your bundle is complete! Use bundle show [gemname] to see where a bundled gem is installed." Ruby, RubyGems, and sqlite3 were installed using MacPorts. Then I used gem to try to install the sqlite3-ruby interface. (sudo gem install sqlite3-ruby). Here is where I first noticed something could be off: "Successfully installed sqlite3-ruby-1.3.2 1 gem installed Installing ri documentation for sqlite3-ruby-1.3.2... No definition for libversion Enclosing class/module 'mSqlite3' for class Statement not known Installing RDoc documentation for sqlite3-ruby-1.3.2... No definition for libversion Enclosing class/module 'mSqlite3' for class Statement not known " I had rails running well on my system a few months ago, so I figured maybe I had some duplicates and it was trying to use the wrong one. I ran: "for cmd in ruby irb gem rake; do which $cmd; done" and got: "/opt/local/bin/ruby /opt/local/bin/irb /opt/local/bin/gem /opt/local/bin/rake" Checking where sqlite3 also gets me: "/opt/local/bin/sqlite3" so they all seem to be in the right place. Obviously /opt/local/bin is in my system path. If I check gems server, it shows that I have installed sqlite3-ruby 1.3.2 gem. Not sure what the problem could be? I am using ruby 1.8.7 (2010-12-23 patchlevel 330) [i686-darwin10]. Macports claims this is the latest (although ive seen 1.9.1) One more thing-- in irb, I tried to check which version of sqlite3 my sqlite3-ruby is bound to, but I can only get this far: ":irb(main):001:0 require 'rubygems' = true irb(main):002:0 require 'sqlite3' /Users/dpetrovi/.gem/ruby/1.8/gems/sqlite3-ruby-1.3.2/lib/sqlite3/sqlite3_native.bundle: [BUG] Segmentation fault ruby 1.8.7 (2010-12-23 patchlevel 330) [i686-darwin10] Abort trap" Any suggestions? Im hoping I overlooked something obvious. Thanks

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  • UML interface: URL iframe integration

    - by Bernd
    I have two applications, A and B, both with a web-based user interface. Both applications are integrated via an URL iframe mechanism. A user can click on a link in application A and then gets the UI of application B as am iframe in application A. Now, since both applications have an interface between each other (do they?): Who provides the interface and who requires the interface, in the UML sense? What is the main information flow on this interface?

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  • Redirect the parent page from IFrame.

    - by Waheed
    I am using an IFrame, and from this IFrame I want to redirect to another page. Please tell me how to do this without any JavaScript, ie, no window.location. Response.Redirect shows the page in the IFrame, but I want to show page as a main page.

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  • How to start the web cam by programmatically?

    - by Nitz
    Hello Guys How to start any web cam through programmatically? my main requirement is it should start webcam? and that should be any application - software not a website. we can use any language. So how can start the web cam using programing language? btw... [I am not talking about the power of the webcam][Any web cam means any companies web cam]

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  • invalid header file while using jar for archiving

    - by arshad
    When i use this cmd line : jar cmf arshad.mf ars.jar *.class i get this error : invalid header field name:Manifest-version This is my manifest file : Manifest-Version: 1.0 Main-Class:t i made the manifest file with notepad in UTF-8 encoding - is there any problem with the manifest ?

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  • Clojure program reading its own MANIFEST.MF

    - by Ralph
    How can a Clojure program find its own MANIFEST.MF (assuming it is packaged in a JAR file). I am trying to do this from my "-main" function, but I can't find a class to use in the following code: (.getValue (.. (java.util.jar.Manifest. (.openStream (java.net.URL. (str "jar:" (.. (class **WHAT-GOES-HERE**) getProtectionDomain getCodeSource getLocation) "!/META-INF/MANIFEST.MF")))) getMainAttributes) "Build-number")) Thanks.

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  • Is READ UNCOMMITTED / NOLOCK safe in this situation?

    - by Ben Challenor
    I know that snapshot isolation would fix this problem, but I'm wondering if NOLOCK is safe in this specific case so that I can avoid the overhead. I have a table that looks something like this: drop table Data create table Data ( Id BIGINT NOT NULL, Date BIGINT NOT NULL, Value BIGINT, constraint Cx primary key (Date, Id) ) create nonclustered index Ix on Data (Id, Date) There are no updates to the table, ever. Deletes can occur but they should never contend with the SELECT because they affect the other, older end of the table. Inserts are regular and page splits to the (Id, Date) index are extremely common. I have a deadlock situation between a standard INSERT and a SELECT that looks like this: select top 1 Date, Value from Data where Id = @p0 order by Date desc because the INSERT acquires a lock on Cx (Date, Id; Value) and then Ix (Id, Date), but the SELECT acquires a lock on Ix (Id, Date) and then Cx (Date, Id; Value). This is because the SELECT first seeks on Ix and then joins to a seek on Cx. Swapping the clustered and non-clustered index would break this cycle, but it is not an acceptable solution because it would introduce cycles with other (more complex) SELECTs. If I add NOLOCK to the SELECT, can it go wrong in this case? Can it return: More than one row, even though I asked for TOP 1? No rows, even though one exists and has been committed? Worst of all, a row that doesn't satisfy the WHERE clause? I've done a lot of reading about this online, but the only reproductions of over- or under-count anomalies I've seen (one, two) involve a scan. This involves only seeks. Jeff Atwood has a post about using NOLOCK that generated a good discussion. I was particularly interested in a comment by Rick Townsend: Secondly, if you read dirty data, the risk you run is of reading the entirely wrong row. For example, if your select reads an index to find your row, then the update changes the location of the rows (e.g.: due to a page split or an update to the clustered index), when your select goes to read the actual data row, it's either no longer there, or a different row altogether! Is this possible with inserts only, and no updates? If so, then I guess even my seeks on an insert-only table could be dangerous. Update: I'm trying to figure out how snapshot isolation works. It seems to be row-based, where transactions read the table (with no shared lock!), find the row they are interested in, and then see if they need to get an old version of the row from the version store in tempdb. But in my case, no row will have more than one version, so the version store seems rather pointless. And if the row was found with no shared lock, how is it different to just using NOLOCK?

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  • How do I implement multiple kinds of an object in OOP?

    - by Jeremy Rudd
    I have multiple kinds of an object, say Car for example. Do I have each kind in an inherited class/subclass of Car? Do I place these under a cartype namespace so as not to mess up the main namespace? Then later when I need an array of cars, should I declare it as var currentCars():Car or var currentCars():Object? Would the former support any subclass of Car?

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