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  • .NET 1.0 ThreadPool Question

    - by dotnet-practitioner
    I am trying to spawn a thread to take care of DoWork task that should take less than 3 seconds. Inside DoWork its taking 15 seconds. I want to abort DoWork and transfer the control back to main thread. I have copied the code as follows and its not working. Instead of aborting DoWork, it still finishes DoWork and then transfers the control back to main thread. What am I doing wrong? class Class1 { /// <summary> /// The main entry point for the application. /// </summary> /// private static System.Threading.ManualResetEvent[] resetEvents; [STAThread] static void Main(string[] args) { resetEvents = new ManualResetEvent[1]; int i = 0; resetEvents[i] = new ManualResetEvent(false); ThreadPool.QueueUserWorkItem(new WaitCallback(DoWork),(object)i); Thread.CurrentThread.Name = "main thread"; Console.WriteLine("[{0}] waiting in the main method", Thread.CurrentThread.Name); DateTime start = DateTime.Now; DateTime end ; TimeSpan span = DateTime.Now.Subtract(start); //abort dowork method if it takes more than 3 seconds //and transfer control to the main thread. do { if (span.Seconds < 3) WaitHandle.WaitAll(resetEvents); else resetEvents[0].Set(); end = DateTime.Now; span = end.Subtract(start); }while (span.Seconds < 2); Console.WriteLine(span.Seconds); Console.WriteLine("[{0}] all done in the main method",Thread.CurrentThread.Name); Console.ReadLine(); } static void DoWork(object o) { int index = (int)o; Thread.CurrentThread.Name = "do work thread"; //simulate heavy duty work. Thread.Sleep(15000); //work is done.. resetEvents[index].Set(); Console.WriteLine("[{0}] do work finished",Thread.CurrentThread.Name); } }

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  • Error when compiling code with the Protege API

    - by Anto
    I am new to Protege API and I have just created on Eclipse a small application which uses an external OWL file. Also I did import all the necessary libraries. import java.util.Collection; import java.util.Iterator; import edu.stanford.smi.protege.exception.OntologyLoadException; import edu.stanford.smi.protegex.owl.ProtegeOWL; import edu.stanford.smi.protegex.owl.model.*; public class Trial { public static void main(String[] args) throws OntologyLoadException{ String uri = "C:/Documents and Settings/Anto/Desktop/travel.owl"; OWLModel owlModel = ProtegeOWL.createJenaOWLModelFromURI(uri); Collection classes = owlModel.getUserDefinedOWLNamedClasses(); for(Iterator it = classes.iterator(); it.hasNext();){ OWLNamedClass cls = (OWLNamedClass) it.next(); Collection instances = cls.getInstances(false); System.out.println("Class " + cls.getBrowserText()+ " (" + instances.size()+")"); for(Iterator jt = instances.iterator(); jt.hasNext();){ OWLIndividual individual = (OWLIndividual) jt.next(); System.out.println(" - "+ individual.getBrowserText()); } } } } When I do compile however I get the following errors: WARNING: [Local Folder Repository] The specified file must be a directory. (C:\Documents and Settings\Anto\My Documents\Eclipse Workspace\ProtegeTrial\plugins\edu.stanford.smi.protegex.owl) LocalFolderRepository.update() SEVERE: Exception caught -- java.net.URISyntaxException: Illegal character in path at index 12: C:/Documents and Settings/CiuffreA/Desktop/travel.owl at java.net.URI$Parser.fail(URI.java:2809) at java.net.URI$Parser.checkChars(URI.java:2982) at java.net.URI$Parser.parseHierarchical(URI.java:3066) at java.net.URI$Parser.parse(URI.java:3014) at java.net.URI.<init>(URI.java:578) at edu.stanford.smi.protegex.owl.jena.JenaKnowledgeBaseFactory.getFileURI(Unknown Source) at edu.stanford.smi.protegex.owl.jena.JenaKnowledgeBaseFactory.loadKnowledgeBase(Unknown Source) at edu.stanford.smi.protege.model.Project.loadDomainKB(Unknown Source) at edu.stanford.smi.protege.model.Project.createDomainKnowledgeBase(Unknown Source) at edu.stanford.smi.protegex.owl.jena.creator.OwlProjectFromUriCreator.create(Unknown Source) at edu.stanford.smi.protegex.owl.ProtegeOWL.createJenaOWLModelFromURI(Unknown Source) at Trial.main(Trial.java:14) Exception in thread "main" java.lang.NullPointerException at edu.stanford.smi.protegex.owl.jena.JenaKnowledgeBaseFactory.loadKnowledgeBase(Unknown Source) at edu.stanford.smi.protege.model.Project.loadDomainKB(Unknown Source) at edu.stanford.smi.protege.model.Project.createDomainKnowledgeBase(Unknown Source) at edu.stanford.smi.protegex.owl.jena.creator.OwlProjectFromUriCreator.create(Unknown Source) at edu.stanford.smi.protegex.owl.ProtegeOWL.createJenaOWLModelFromURI(Unknown Source) at Trial.main(Trial.java:14) Does anyone have an idea on where the problem should be?

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  • The Collatz Sequence problem

    - by Gandalf StormCrow
    I'm trying to solve this problem, its not a homework question, its just code I'm submitting to uva.onlinejudge.org so I can learn better java trough examples. Here is the problem sample input : 3 100 34 100 75 250 27 2147483647 101 304 101 303 -1 -1 Here is simple output : Case 1: A = 3, limit = 100, number of terms = 8 Case 2: A = 34, limit = 100, number of terms = 14 Case 3: A = 75, limit = 250, number of terms = 3 Case 4: A = 27, limit = 2147483647, number of terms = 112 Case 5: A = 101, limit = 304, number of terms = 26 Case 6: A = 101, limit = 303, number of terms = 1 The thing is this has to execute within 3sec time interval otherwise your question won't be accepted as solution, here is with what I've come up so far, its working as it should just the execution time is not within 3 seconds, here is code : import java.util.Scanner; class Main { public static void main(String[] args) { Scanner stdin = new Scanner(System.in); int start; int limit; int terms; int a = 0; while (stdin.hasNext()) { start = stdin.nextInt(); limit = stdin.nextInt(); if (start > 0) { terms = getLength(start, limit); a++; } else { break; } System.out.println("Case "+a+": A = "+start+", limit = "+limit+", number of terms = "+terms); } } public static int getLength(int x, int y) { int length = 1; while (x != 1) { if (x <= y) { if ( x % 2 == 0) { x = x / 2; length++; }else{ x = x * 3 + 1; length++; } } else { length--; break; } } return length; } } And yes here is how its meant to be solved : An algorithm given by Lothar Collatz produces sequences of integers, and is described as follows: Step 1: Choose an arbitrary positive integer A as the first item in the sequence. Step 2: If A = 1 then stop. Step 3: If A is even, then replace A by A / 2 and go to step 2. Step 4: If A is odd, then replace A by 3 * A + 1 and go to step 2. And yes my question is how can I make it work inside 3 seconds time interval?

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  • Does writing data to server using Java URL class require response from server?

    - by gigadot
    I am trying to upload files using Java URL class and I have found a previous question on stack-overflow which explains very well about the details, so I try to follow it. And below is my code adopted from the sniplet given in the answer. My problem is that if I don't make a call to one of connection.getResponseCode() or connection.getInputStream() or connection.getResponseMessage() or anything which is related to reponse from the server, the request will never be sent to server. Why do I need to do this? Or is there any way to write the data without getting the response? P.S. I have developed a server-side uploading servlet which accepts multipart/form-data and save it to files using FileUpload. It is stable and definitely working without any problem so this is not where my problem is generated. import java.io.Closeable; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.OutputStream; import java.io.PrintWriter; import java.net.HttpURLConnection; import java.net.URL; import org.apache.commons.io.IOUtils; public class URLUploader { public static void closeQuietly(Closeable... objs) { for (Closeable closeable : objs) { IOUtils.closeQuietly(closeable); } } public static void main(String[] args) throws IOException { File textFile = new File("D:\\file.zip"); String boundary = Long.toHexString(System.currentTimeMillis()); // Just generate some unique random value. HttpURLConnection connection = (HttpURLConnection) new URL("http://localhost:8080/upslet/upload").openConnection(); connection.setDoOutput(true); connection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary); OutputStream output = output = connection.getOutputStream(); PrintWriter writer = writer = new PrintWriter(output, true); // Send text file. writer.println("--" + boundary); writer.println("Content-Disposition: form-data; name=\"file1\"; filename=\"" + textFile.getName() + "\""); writer.println("Content-Type: application/octet-stream"); FileInputStream fin = new FileInputStream(textFile); writer.println(); IOUtils.copy(fin, output); writer.println(); // End of multipart/form-data. writer.println("--" + boundary + "--"); output.flush(); closeQuietly(fin, writer, output); // Above request will never be sent if .getInputStream() or .getResponseCode() or .getResponseMessage() does not get called. connection.getResponseCode(); } }

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  • Neural Networks in C# using NeuronDotNet

    - by kingrichard2005
    Hello, I'm testing the NeuronDotNet library for a class assignment using C#. I have a very simple console application that I'm using to test some of the code snippets provided in the manual fro the library, the goal of the assignment is to teach the program how to distinguish between random points in a square which may or may not be within a circle that is also inside the square. So basically, which points inside the square are also inside the circle. Here is what I have so far: namespace _469_A7 { class Program { static void Main(string[] args) { //Initlaize the backpropogation network LinearLayer inputLayer = new LinearLayer(2); SigmoidLayer hiddenLayer = new SigmoidLayer(8); SigmoidLayer outputLayer = new SigmoidLayer(2); new BackpropagationConnector(inputLayer, hiddenLayer); new BackpropagationConnector(hiddenLayer, outputLayer); BackpropagationNetwork network = new BackpropagationNetwork(inputLayer, outputLayer); //Generate a training set for the ANN TrainingSet trainingSet = new TrainingSet(2, 2); //TEST: Generate random set of points and add to training set, //for testing purposes start with 10 samples; Point p; Program program = new Program(); //Used to access randdouble function Random rand = new Random(); for(int i = 0; i < 10; i++) { //These points will be within the circle radius Type A if(rand.NextDouble() > 0.5) { p = new Point(rand.NextDouble(), rand.NextDouble()); trainingSet.Add(new TrainingSample(new double[2] { p.getX(), p.getY() }, new double[2] { 1, 0 })); continue; } //These points will either be on the border or outside the circle Type B p = new Point(program.randdouble(1.0, 4.0), program.randdouble(1.0, 4.0)); trainingSet.Add(new TrainingSample(new double[2] { p.getX(), p.getY() }, new double[2] { 0, 1 })); } //Start network learning network.Learn(trainingSet, 100); //Stop network learning //network.StopLearning(); } //generates a psuedo-random double between min and max public double randdouble(double min, double max) { Random rand = new Random(); if (min > max) { return rand.NextDouble() * (min - max) + max; } else { return rand.NextDouble() * (max - min) + min; } } } //Class defines a point in X/Y coordinates public class Point { private double X; private double Y; public Point(double xVal, double yVal) { this.X = xVal; this.Y = yVal; } public double getX() { return X; } public double getY() { return Y; } } } This is basically all that I need, the only question I have is how to handle output?? More specifically, I need to output the value of the "step size" and the momentum, although it would be nice to output other information as well. Anyone with experience using NeuronDotNet, your input is appreciated.

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  • for my project I have problem in report

    - by pink rose
    public class stack { private int Array[]; private int top = -1; public int size; public stack(int size) { this.size=size; Array = new int[size]; } public void push(int j) { if (top < size) { Array[++top] = j; } } public int pop() { return Array[top--]; } public int top() { return Array[top]; } public boolean isEmpty() { return (top == -1); } } import javax.swing.JOptionPane; public class menu { private static stack s; private static int numbers[]; public static void main(String args[]) { start(); } public static void start() { int i = Integer.parseInt(JOptionPane.showInputDialog("1. size of array\n2. data entry\n3. display content\n4. exit")); switch (i) { case 1: setSize(); break; case 2: addElement(); break; case 3: showElements(); break; case 4: exit(); } } public static void setSize() { int size = Integer.parseInt(JOptionPane.showInputDialog("Please Enter The Size")); s = new stack(size); numbers = new int[10]; start(); } public static void addElement() { for(int x=0;x<s.size;x++) { int e = Integer.parseInt(JOptionPane.showInputDialog("Please Enter The Element")); numbers[e]++; s.push(e); } start(); } public static void showElements() { String result = ""; int temp; while (!s.isEmpty()) { temp = s.pop(); if (numbers[temp] == 1) { result = temp+result; } } JOptionPane.showMessageDialog(null, result); start(); } public static void exit() { System.exit(0); } } This my project I was finished but I have problem in question in my report Conclusion. It should summarize the state of your project and indicate which part of your project is working and which part is not working or with limitations. You may also provide your suggestions and comments to this project what I can answer I didn't have any idea

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  • for my project I have problem in report

    - by pink rose
    public stack(int size) { this.size=size; Array = new int[size]; } public void push(int j) { if (top < size) { Array[++top] = j; } } public int pop() { return Array[top--]; } public int top() { return Array[top]; } public boolean isEmpty() { return (top == -1); } } import javax.swing.JOptionPane; public class menu { private static stack s; private static int numbers[]; public static void main(String args[]) { start(); } public static void start() { int i = Integer.parseInt(JOptionPane.showInputDialog("1. size of array\n2. data entry\n3. display content\n4. exit")); switch (i) { case 1: setSize(); break; case 2: addElement(); break; case 3: showElements(); break; case 4: exit(); } } public static void setSize() { int size = Integer.parseInt(JOptionPane.showInputDialog("Please Enter The Size")); s = new stack(size); numbers = new int[10]; start(); } public static void addElement() { for(int x=0;x<s.size;x++) { int e = Integer.parseInt(JOptionPane.showInputDialog("Please Enter The Element")); numbers[e]++; s.push(e); } start(); } public static void showElements() { String result = ""; int temp; while (!s.isEmpty()) { temp = s.pop(); if (numbers[temp] == 1) { result = temp+result; } } JOptionPane.showMessageDialog(null, result); start(); } public static void exit() { System.exit(0); } } This my project I was finished but I have problem in question in my report Conclusion. It should summarize the state of your project and indicate which part of your project is working and which part is not working or with limitations. You may also provide your suggestions and comments to this project what I can answer I didn't have any idea

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  • How to inherit from DataAnnotations.ValidationAttribute (it appears SecureCritical under Visual Stud

    - by codetuner
    Hi, I have an [AllowPartiallyTrustedCallers] class library containing subtypes of the System.DataAnnotations.ValidationAttribute. The library is used on contract types of WCF services. In .NET 2/3.5, this worked fine. Since .NET 4.0 however, running a client of the service in the Visual Studio debugger results in the exception "Inheritance security rules violated by type: '(my subtype of ValidationAttribute)'. Derived types must either match the security accessibility of the base type or be less accessible." (System.TypeLoadException) The error appears to occure only when all of the following conditions are met: a subclass of ValidationAttribute is in an AllowPartiallyTrustedCallers assembly reflection is used to check for the attribute the Visual Studio hosting process is enabled (checkbox on Project properties, Debug tab) So basically, in Visual Studio.NET 2010: create a new Console project, add a reference to "System.ComponentModel.DataAnnotations" 4.0.0.0, write the following code: . using System; [assembly: System.Security.AllowPartiallyTrustedCallers()] namespace TestingVaidationAttributeSecurity { public class MyValidationAttribute : System.ComponentModel.DataAnnotations.ValidationAttribute { } [MyValidation] public class FooBar { } class Program { static void Main(string[] args) { Console.WriteLine("ValidationAttribute IsCritical: {0}", typeof(System.ComponentModel.DataAnnotations.ValidationAttribute).IsSecurityCritical); FooBar fb = new FooBar(); fb.GetType().GetCustomAttributes(true); Console.WriteLine("Press enter to end."); Console.ReadLine(); } } } Press F5 and you get the exception ! Press Ctrl-F5 (start without debugging), and it all works fine without exception... The strange thing is that the ValidationAttribute will or will not be securitycritical depending on the way you run the program (F5 or Ctrl+F5). As illustrated by the Console.WriteLine in the above code. But then again, this appear to happen with other attributes (and types?) too. Now the questions... Why do I have this behaviour when inheriting from ValidationAttribute, but not when inheriting from System.Attribute ? (Using Reflector I don't find special settings on the ValidationAttribute class or it's assembly) And what can I do to solve this ? How can I keep MyValidationAttribute inheriting from ValidationAttribute in an AllowPartiallyTrustedCallers assembly without marking it SecurityCritical, still using the new .NET 4 level 2 security model and still have it work using the VS.NET debug host (or other hosts) ?? Thanks a lot! Rudi

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  • Opposite method of math power adding numbers

    - by adopilot
    I have method for converting array of Booleans to integer. It looks like this class Program { public static int GivMeInt(bool[] outputs) { int data = 0; for (int i = 0; i < 8; i++) { data += ((outputs[i] == true) ? Convert.ToInt32(Math.Pow(2, i)) : 0); } return data; } static void Main(string[] args) { bool[] outputs = new bool[8]; outputs[0] = false; outputs[1] = true; outputs[2] = false; outputs[3] = true; outputs[4] = false; outputs[5] = false; outputs[6] = false; outputs[7] = false; int data = GivMeInt(outputs); Console.WriteLine(data); Console.ReadKey(); } } Now I want to make opposite method returning array of Booleans values As I am short with knowledge of .NET and C# until now I have only my mind hardcoding of switch statement or if conditions for every possible int value. public static bool[] GiveMeBool(int data) { bool[] outputs = new bool[8]; if (data == 0) { outputs[0] = false; outputs[1] = false; outputs[2] = false; outputs[3] = false; outputs[4] = false; outputs[5] = false; outputs[6] = false; outputs[7] = false; } //After thousand lines of coed if (data == 255) { outputs[0] = true; outputs[1] = true; outputs[2] = true; outputs[3] = true; outputs[4] = true; outputs[5] = true; outputs[6] = true; outputs[7] = true; } return outputs; } I know that there must be easier way.

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  • JavaScript/Dojo Module Pattern - how to debug?

    - by djna
    I'm working with Dojo and using the "Module Pattern" as described in Mastering Dojo. So far as I can see this pattern is a general, and widely used, JavaScript pattern. My question is: How do we debug our modules? So far I've not been able to persuade Firebug to show me the source of my module. Firebug seems to show only the dojo eval statement used to execute the factory method. Hence I'm not able to step through my module source. I've tried putting "debugger" statements in my module code, and Firebug seems to halt correctly, but does not show the source. Contrived example code below. This is just an example of sufficient complexity to make the need for debugging plausible, it's not intended to be useful code. The page <!-- Experiments with Debugging --> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <title>console me</title> <style type="text/css"> @import "../dojoroot/dojo/resources/dojo.css"; @import "../dojoroot/dijit/themes/tundra/tundra.css"; @import "edf.css"; </style> <script type="text/javascript" src="../dojoroot/dojo/dojo.js"> </script> <script type="text/javascript" > dojo.registerModulePath("mytest", "../../mytest"); dojo.require("mytest.example"); dojo.addOnLoad(function(){ mytest.example.greet(); }); </script> </head> <body class="tundra"> <div id="bulletin"> <p>Just Testing</p> </div> </body> </html> <!-- END: snip1 --> The java script I'd like to debug dojo.provide("mytest.example"); dojo.require("dijit.layout.ContentPane"); /** * define module */ (function(){ //define the main program functions... var example= mytest.example; example.greet= function(args) { var bulletin = dojo.byId("bulletin"); console.log("bulletin:" + bulletin); if ( bulletin) { var content = new dijit.layout.ContentPane({ id: "dummy", region: "center" }); content.setContent('Greetings!'); dojo._destroyElement(bulletin); dojo.place(content.domNode, dojo.body(), "first"); console.log("greeting done"); } else { console.error("no bulletin board"); } } })();

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  • Django + FastCGI - randomly raising OperationalError

    - by ibz
    I'm running a Django application. Had it under Apache + mod_python before, and it was all OK. Switched to Lighttpd + FastCGI. Now I randomly get the following exception (neither the place nor the time where it appears seem to be predictable). Since it's random, and it appears only after switching to FastCGI, I assume it has something to do with some settings. Found a few results when googleing, but they seem to be related to setting maxrequests=1. However, I use the default, which is 0. Any ideas where to look for? PS. I'm using PostgreSQL. Might be related to that as well, since the exception appears when making a database query. Thanks. File "/usr/lib/python2.6/site-packages/django/core/handlers/base.py", line 86, in get_response response = callback(request, *callback_args, **callback_kwargs) File "/usr/lib/python2.6/site-packages/django/contrib/admin/sites.py", line 140, in root if not self.has_permission(request): File "/usr/lib/python2.6/site-packages/django/contrib/admin/sites.py", line 99, in has_permission return request.user.is_authenticated() and request.user.is_staff File "/usr/lib/python2.6/site-packages/django/contrib/auth/middleware.py", line 5, in __get__ request._cached_user = get_user(request) File "/usr/lib/python2.6/site-packages/django/contrib/auth/__init__.py", line 83, in get_user user_id = request.session[SESSION_KEY] File "/usr/lib/python2.6/site-packages/django/contrib/sessions/backends/base.py", line 46, in __getitem__ return self._session[key] File "/usr/lib/python2.6/site-packages/django/contrib/sessions/backends/base.py", line 172, in _get_session self._session_cache = self.load() File "/usr/lib/python2.6/site-packages/django/contrib/sessions/backends/db.py", line 16, in load expire_date__gt=datetime.datetime.now() File "/usr/lib/python2.6/site-packages/django/db/models/manager.py", line 93, in get return self.get_query_set().get(*args, **kwargs) File "/usr/lib/python2.6/site-packages/django/db/models/query.py", line 304, in get num = len(clone) File "/usr/lib/python2.6/site-packages/django/db/models/query.py", line 160, in __len__ self._result_cache = list(self.iterator()) File "/usr/lib/python2.6/site-packages/django/db/models/query.py", line 275, in iterator for row in self.query.results_iter(): File "/usr/lib/python2.6/site-packages/django/db/models/sql/query.py", line 206, in results_iter for rows in self.execute_sql(MULTI): File "/usr/lib/python2.6/site-packages/django/db/models/sql/query.py", line 1734, in execute_sql cursor.execute(sql, params) OperationalError: server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request.

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  • WSIT, Maven, and wsimport -- Can They Work Together?

    - by rtperson
    Hi all, I'm working on a small-ish multi-module project in Maven. We've separated the UI from the database layer using Web Services, and thanks to the jaxws-maven-plugin, the creation of the WSDL and WS client are more or less handled for us. (The plugin is essentially a wrapper around wsgen and wsimport.) So far so good. The problem comes when I try to layer WSIT security into the picture. NetBeans allows me to generate the security metadata easily, but wsimport seems completely incapable of dealing with anything beyond a Basic-auth level of security. Here's our current, insecure way of calling wsimport during a Maven build: <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>jaxws-maven-plugin</artifactId> <version>1.10</version> <executions> <execution> <goals> <goal>wsimport</goal> </goals> <configuration> <wsdlUrls> <wsdlUrl>${basedir}/../WebService/target/jaxws/wsgen/wsdl/WebService.wsdl</wsdlUrl> </wsdlUrls> <packageName>com.yourcompany.appname.ws.client</packageName> <sourceDestDir>${basedir}/src/main/java</sourceDestDir> <destDir>${basedir}/target/jaxws</destDir> </configuration> </execution> </executions> </plugin> I have tried playing around with xauthFile, xadditionalHeaders, passing javax.xml.ws.security.auth.username and password through args. I have also tried using wsimport from the command line to point to the Tomcat-generated WSDL, which has the additional security info. Nothing, however, seems to change the composition of the wsimport-generated files at all. So I guess my question here is, to get a WSIT-compliant client, am I stuck abandoning Maven and the jaxws plugin altogether? Is there a way to get a WSIT client to auto-generate? Or will I need to generate the client by hand? Let me know if you need any additional info beyond what I've written here. I'm deploying to Tomcat, although that doesn't seem to be an issue, as Maven seems happy to pull Metro into the deployed WAR file. Thanks in advance!

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  • JNI loses reference to native methods

    - by lhw
    As an example for later use in Android I wrote a simple callback interface. While doing so i ran into the following error or bug or whatever. In C the two commented lines are supposed to be executed resulting in calling the C callback onChange. But instead i get an UnsatisfiedLinkError. Calling the native Method directly in Java works just fine. Calling it directly from C as presented here in the example also produces the UnsatisfiedLinkError. I'm open for any advice concerning this issue or work arounds and so on. The Java Part: import java.util.LinkedList; import java.util.Random; interface Listener { public void onChange(float f); } class Provider { LinkedList<Listener> all; public Provider() { all = new LinkedList<Listener>(); } public void registerChange(Listener lst) { all.add(lst); } public void sendMsg() { Random rnd = new Random(); for(Listener l : all) { try { l.onChange(rnd.nextFloat()); } catch(Exception e) { System.out.println(e); } } } } class Inheritance implements Listener { static public void main(String[] args) { System.load(System.getProperty("user.dir") + "/libinheritance.so"); } public native void onChange(float f); } The C Part: #include "inheritance.h" jint JNI_OnLoad(JavaVM *jvm, void *reserved) { JNIEnv *env; (*jvm)->GetEnv(jvm, (void**)&env, JNI_VERSION_1_4); inheritance = (*env)->FindClass(env, "Inheritance"); o_inheritance = (*env)->NewObject(env, inheritance, (*env)->GetMethodID(env, inheritance, "<init>", "()V")); provider = (*env)->FindClass(env, "Provider"); o_provider = (*env)->NewObject(env, provider, (*env)->GetMethodID(env, provider, "<init>", "()V")); (*env)->CallVoidMethod(env, o_inheritance, (*env)->GetMethodID(env, inheritance, "onChange", "(F)V"), 1.0); //(*env)->CallVoidMethod(env, o_provider, (*env)->GetMethodID(env, provider, "registerChange", "(LListener;)V"), o_inheritance); //(*env)->CallVoidMethod(env, o_provider, (*env)->GetMethodID(env, provider, "sendMsg", "()V")); (*env)->DeleteLocalRef(env, o_inheritance); (*env)->DeleteLocalRef(env, o_provider); return JNI_VERSION_1_4; } JNIEXPORT void JNICALL Java_Inheritance_onChange(JNIEnv *env, jobject self, jfloat f) { printf("[C] %f\n", f); } The header file: #include <jni.h> /* Header for class Inheritance */ #ifndef _Included_Inheritance #define _Included_Inheritance #ifdef __cplusplus extern "C" { #endif jclass inheritance, provider; jobject o_inheritance, o_provider; /* * Class: Inheritance * Method: onChange * Signature: (F)V */ JNIEXPORT void JNICALL Java_Inheritance_onChange(JNIEnv *, jobject, jfloat); jint JNI_OnLoad(JavaVM *, void *); #ifdef __cplusplus } #endif #endif Compilation: gcc -c -fPIC -I /usr/lib/jvm/java-6-openjdk/include -I /usr/lib/jvm/java-6-openjdk/include/linux/inheritance.c inheritance.h gcc -g -o -shared libinheritance.so -shared -Wl,-soname,libinheritance.so -lc inheritance.o

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  • Are there any working implementations of the rolling hash function used in the Rabin-Karp string sea

    - by c14ppy
    I'm looking to use a rolling hash function so I can take hashes of n-grams of a very large string. For example: "stackoverflow", broken up into 5 grams would be: "stack", "tacko", "ackov", "ckove", "kover", "overf", "verfl", "erflo", "rflow" This is ideal for a rolling hash function because after I calculate the first n-gram hash, the following ones are relatively cheap to calculate because I simply have to drop the first letter of the first hash and add the new last letter of the second hash. I know that in general this hash function is generated as: H = c1ak - 1 + c2ak - 2 + c3ak - 3 + ... + cka0 where a is a constant and c1,...,ck are the input characters. If you follow this link on the Rabin-Karp string search algorithm , it states that "a" is usually some large prime. I want my hashes to be stored in 32 bit integers, so how large of a prime should "a" be, such that I don't overflow my integer? Does there exist an existing implementation of this hash function somewhere that I could already use? Here is an implementation I created: public class hash2 { public int prime = 101; public int hash(String text) { int hash = 0; for(int i = 0; i < text.length(); i++) { char c = text.charAt(i); hash += c * (int) (Math.pow(prime, text.length() - 1 - i)); } return hash; } public int rollHash(int previousHash, String previousText, String currentText) { char firstChar = previousText.charAt(0); char lastChar = currentText.charAt(currentText.length() - 1); int firstCharHash = firstChar * (int) (Math.pow(prime, previousText.length() - 1)); int hash = (previousHash - firstCharHash) * prime + lastChar; return hash; } public static void main(String[] args) { hash2 hashify = new hash2(); int firstHash = hashify.hash("mydog"); System.out.println(firstHash); System.out.println(hashify.hash("ydogr")); System.out.println(hashify.rollHash(firstHash, "mydog", "ydogr")); } } I'm using 101 as my prime. Does it matter if my hashes will overflow? I think this is desirable but I'm not sure. Does this seem like the right way to go about this?

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  • exception occured in java compiler

    - by user2892977
    I am a beginner in Java.I have JDK1.7.0 installed on windows 7 OS.I just wrote a sample java file where the file was not getting compiled and throws the below error. Sam.java:5: ';' expected Sample p = New Sample(); An exception has occurred in the compile r (1.7.0-ea). Please file a bug at the Java Developer Connection (http://java.su n.com/webapps/bugreport) after checking the Bug Parade for duplicates. Include your program and the following diagnostic in your report. Thank you. java.lang.StringIndexOutOfBoundsException: String index out of range: 26 at java.lang.String.charAt(String.java:694) at com.sun.tools.javac.util.Log.printErrLine(Log.java:251) at com.sun.tools.javac.util.Log.writeDiagnostic(Log.java:343) at com.sun.tools.javac.util.Log.report(Log.java:315) at com.sun.tools.javac.util.AbstractLog.error(AbstractLog.java:96) at com.sun.tools.javac.parser.Parser.reportSyntaxError(Parser.java:295) at com.sun.tools.javac.parser.Parser.accept(Parser.java:326) at com.sun.tools.javac.parser.Parser.blockStatements(Parser.java:1599) at com.sun.tools.javac.parser.Parser.block(Parser.java:1500) at com.sun.tools.javac.parser.Parser.block(Parser.java:1514) at com.sun.tools.javac.parser.Parser.methodDeclaratorRest(Parser.java:25 69) at com.sun.tools.javac.parser.Parser.classOrInterfaceBodyDeclaration(Par ser.java:2518) at com.sun.tools.javac.parser.Parser.classOrInterfaceBody(Parser.java:24 45) at com.sun.tools.javac.parser.Parser.classDeclaration(Parser.java:2290) at com.sun.tools.javac.parser.Parser.classOrInterfaceOrEnumDeclaration(P arser.java:2228) at com.sun.tools.javac.parser.Parser.typeDeclaration(Parser.java:2217) at com.sun.tools.javac.parser.Parser.compilationUnit(Parser.java:2163) at com.sun.tools.javac.main.JavaCompiler.parse(JavaCompiler.java:530) at com.sun.tools.javac.main.JavaCompiler.parse(JavaCompiler.java:571) at com.sun.tools.javac.main.JavaCompiler.parseFiles(JavaCompiler.java:82 2) at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:748) at com.sun.tools.javac.main.Main.compile(Main.java:386) at com.sun.tools.javac.main.Main.compile(Main.java:312) at com.sun.tools.javac.main.Main.compile(Main.java:303) at com.sun.tools.javac.Main.compile(Main.java:82) at com.sun.tools.javac.Main.main(Main.java:67) Below is the code for Sam.java file class sam { public static void main(String args[]) { Sample p = New Sample(); p.show(); p.display(); } } I researched in google with the various compiler options but that did not help.I would like to understand the below errors. 1 - Sam.java:5: ';' expected 2 - An exception has occurred in the compiler (1.7.0-ea)

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  • Connecting to MSSQL 2008 from Java

    - by Xinus
    I am trying to connect to MSSQL 2008 server from Java here is a program import java.sql.*; public class connectURL { public static void main(String[] args) { // Create a variable for the connection string. String connectionUrl = "jdbc:sqlserver://localhost/SQLEXPRESS/Databases/HelloWorld:1433;";// + //"databaseName=HelloWorld;integratedSecurity=true;"; // Declare the JDBC objects. Connection con = null; Statement stmt = null; ResultSet rs = null; try { // Establish the connection. Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); con = DriverManager.getConnection(connectionUrl); // Create and execute an SQL statement that returns some data. String SQL = "SELECT TOP 10 * FROM Person.Contact"; stmt = con.createStatement(); rs = stmt.executeQuery(SQL); // Iterate through the data in the result set and display it. while (rs.next()) { System.out.println(rs.getString(4) + " " + rs.getString(6)); } } // Handle any errors that may have occurred. catch (Exception e) { e.printStackTrace(); } finally { if (rs != null) try { rs.close(); } catch(Exception e) {} if (stmt != null) try { stmt.close(); } catch(Exception e) {} if (con != null) try { con.close(); } catch(Exception e) {} } } } But it shows error as com.microsoft.sqlserver.jdbc.SQLServerException: The TCP/IP connection to the host localhost/SQLEXPRESS/Databases/HelloWorld, port 1433 has failed. Error: "null. Verify the connection properties, check that an instance of SQL Server is running on the host and accepting TCP/IP connections at the port, and that no firewall is blocking TCP connections to the port.". at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:170) at com.microsoft.sqlserver.jdbc.SQLServerConnection.connectHelper(SQLServerConnection.java:1049) at com.microsoft.sqlserver.jdbc.SQLServerConnection.login(SQLServerConnection.java:833) at com.microsoft.sqlserver.jdbc.SQLServerConnection.connect(SQLServerConnection.java:716) at com.microsoft.sqlserver.jdbc.SQLServerDriver.connect(SQLServerDriver.java:841) at java.sql.DriverManager.getConnection(Unknown Source) at java.sql.DriverManager.getConnection(Unknown Source) at connectURL.main(connectURL.java:43) I have given followed all the instructions as given in http://teamtutorials.com/database-tutorials/configuring-and-creating-a-database-in-ms-sql-2008 What can be the problem ?

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  • Run bat file in Java and wait 2

    - by Savvas Dalkitsis
    This is a followup question to my other question : http://stackoverflow.com/questions/2434125/run-bat-file-in-java-and-wait The reason i am posting this as a separate question is that the one i already asked was answered correctly. From some research i did my problem is unique to my case so i decided to create a new question. Please go read that question before continuing with this one as they are closely related. Running the proposed code blocks the program at the waitFor invocation. After some research i found that the waitFor method blocks if your process has output that needs to be proccessed so you should first empty the output stream and the error stream. I did those things but my method still blocks. I then found a suggestion to simply loop while waiting the exitValue method to return the exit value of the process and handle the exception thrown if it is not, pausing for a brief moment as well so as not to consume all the CPU. I did this: import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; public class Test { public static void main(String[] args) { try { Process p = Runtime.getRuntime().exec( "cmd /k start SQLScriptsToRun.bat" + " -UuserName -Ppassword" + " projectName"); final BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream())); final BufferedReader error = new BufferedReader(new InputStreamReader(p.getErrorStream())); new Thread(new Runnable() { @Override public void run() { try { while (input.readLine()!=null) {} } catch (IOException e) { e.printStackTrace(); } } }).start(); new Thread(new Runnable() { @Override public void run() { try { while (error.readLine()!=null) {} } catch (IOException e) { e.printStackTrace(); } } }).start(); int i = 0; boolean finished = false; while (!finished) { try { i = p.exitValue(); finished = true; } catch (IllegalThreadStateException e) { e.printStackTrace(); try { Thread.sleep(500); } catch (InterruptedException e1) { e1.printStackTrace(); } } } System.out.println(i); } catch (IOException e) { e.printStackTrace(); } } } but my process will not end! I keep getting this error: java.lang.IllegalThreadStateException: process has not exited Any ideas as to why my process will not exit? Or do you have any libraries to suggest that handle executing batch files properly and wait until the execution is finished?

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  • Why does Celery work in Python shell, but not in my Django views? (import problem)

    - by TIMEX
    I installed Celery (latest stable version.) I have a directory called /home/myuser/fable/jobs. Inside this directory, I have a file called tasks.py: from celery.decorators import task from celery.task import Task class Submitter(Task): def run(self, post, **kwargs): return "Yes, it works!!!!!!" Inside this directory, I also have a file called celeryconfig.py: BROKER_HOST = "localhost" BROKER_PORT = 5672 BROKER_USER = "abc" BROKER_PASSWORD = "xyz" BROKER_VHOST = "fablemq" CELERY_RESULT_BACKEND = "amqp" CELERY_IMPORTS = ("tasks", ) In my /etc/profile, I have these set as my PYTHONPATH: PYTHONPATH=/home/myuser/fable:/home/myuser/fable/jobs So I run my Celery worker using the console ($ celeryd --loglevel=INFO), and I try it out. I open the Python console and import the tasks. Then, I run the Submitter. >>> import fable.jobs.tasks as tasks >>> s = tasks.Submitter() >>> s.delay("abc") <AsyncResult: d70d9732-fb07-4cca-82be-d7912124a987> Everything works, as you can see in my console [2011-01-09 17:30:05,766: INFO/MainProcess] Task tasks.Submitter[d70d9732-fb07-4cca-82be-d7912124a987] succeeded in 0.0398268699646s: But when I go into my Django's views.py and run the exact 3 lines of code as above, I get this: [2011-01-09 17:25:20,298: ERROR/MainProcess] Unknown task ignored: "Task of kind 'fable.jobs.tasks.Submitter' is not registered, please make sure it's imported.": {'retries': 0, 'task': 'fable.jobs.tasks.Submitter', 'args': ('abc',), 'expires': None, 'eta': None, 'kwargs': {}, 'id': 'eb5c65b4-f352-45c6-96f1-05d3a5329d53'} Traceback (most recent call last): File "/home/myuser/mysite-env/lib/python2.6/site-packages/celery/worker/listener.py", line 321, in receive_message eventer=self.event_dispatcher) File "/home/myuser/mysite-env/lib/python2.6/site-packages/celery/worker/job.py", line 299, in from_message eta=eta, expires=expires) File "/home/myuser/mysite-env/lib/python2.6/site-packages/celery/worker/job.py", line 243, in __init__ self.task = tasks[self.task_name] File "/home/myuser/mysite-env/lib/python2.6/site-packages/celery/registry.py", line 63, in __getitem__ raise self.NotRegistered(str(exc)) NotRegistered: "Task of kind 'fable.jobs.tasks.Submitter' is not registered, please make sure it's imported." It's weird, because the celeryd client does show that it's registered, when I launch it. [2011-01-09 17:38:27,446: WARNING/MainProcess] Configuration -> . broker -> amqp://GOGOme@localhost:5672/fablemq . queues -> . celery -> exchange:celery (direct) binding:celery . concurrency -> 1 . loader -> celery.loaders.default.Loader . logfile -> [stderr]@INFO . events -> OFF . beat -> OFF . tasks -> . tasks.Decayer . tasks.Submitter Can someone help?

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  • Overriding LINQ extension methods

    - by Ruben Vermeersch
    Is there a way to override extension methods (provide a better implementation), without explicitly having to cast to them? I'm implementing a data type that is able to handle certain operations more efficiently than the default extension methods, but I'd like to keep the generality of IEnumerable. That way any IEnumerable can be passed, but when my class is passed in, it should be more efficient. As a toy example, consider the following: // Compile: dmcs -out:test.exe test.cs using System; namespace Test { public interface IBoat { void Float (); } public class NiceBoat : IBoat { public void Float () { Console.WriteLine ("NiceBoat floating!"); } } public class NicerBoat : IBoat { public void Float () { Console.WriteLine ("NicerBoat floating!"); } public void BlowHorn () { Console.WriteLine ("NicerBoat: TOOOOOT!"); } } public static class BoatExtensions { public static void BlowHorn (this IBoat boat) { Console.WriteLine ("Patched on horn for {0}: TWEET", boat.GetType().Name); } } public class TestApp { static void Main (string [] args) { IBoat niceboat = new NiceBoat (); IBoat nicerboat = new NicerBoat (); Console.WriteLine ("## Both should float:"); niceboat.Float (); nicerboat.Float (); // Output: // NiceBoat floating! // NicerBoat floating! Console.WriteLine (); Console.WriteLine ("## One has an awesome horn:"); niceboat.BlowHorn (); nicerboat.BlowHorn (); // Output: // Patched on horn for NiceBoat: TWEET // Patched on horn for NicerBoat: TWEET Console.WriteLine (); Console.WriteLine ("## That didn't work, but it does when we cast:"); (niceboat as NiceBoat).BlowHorn (); (nicerboat as NicerBoat).BlowHorn (); // Output: // Patched on horn for NiceBoat: TWEET // NicerBoat: TOOOOOT! Console.WriteLine (); Console.WriteLine ("## Problem is: I don't always know the type of the objects."); Console.WriteLine ("## How can I make it use the class objects when the are"); Console.WriteLine ("## implemented and extension methods when they are not,"); Console.WriteLine ("## without having to explicitely cast?"); } } } Is there a way to get the behavior from the second case, without explict casting? Can this problem be avoided?

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  • Parallel.For System.OutOfMemoryException

    - by Martin Neal
    We have a fairly simple program that's used for creating backups. I'm attempting to parallelize it but am getting an OutofMemoryException within an AggregateExcption. Some of the source folders are quite large, and the program doesn't crash for about 40 minutes after it starts. I don't know where to start looking so the below code is a near exact dump of all code the code sans directory structure and Exception logging code. Any advise as to where to start looking? using System; using System.Diagnostics; using System.IO; using System.Threading.Tasks; namespace SelfBackup { class Program { static readonly string[] saSrc = { "\\src\\dir1\\", //... "\\src\\dirN\\", //this folder is over 6 GB }; static readonly string[] saDest = { "\\dest\\dir1\\", //... "\\dest\\dirN\\", }; static void Main(string[] args) { Parallel.For(0, saDest.Length, i => { try { if (Directory.Exists(sDest)) { //Delete directory first so old stuff gets cleaned up Directory.Delete(sDest, true); } //recursive function clsCopyDirectory.copyDirectory(saSrc[i], sDest); } catch (Exception e) { //standard error logging CL.EmailError(); } }); } } /////////////////////////////////////// using System.IO; using System.Threading.Tasks; namespace SelfBackup { static class clsCopyDirectory { static public void copyDirectory(string Src, string Dst) { Directory.CreateDirectory(Dst); /* Copy all the files in the folder If and when .NET 4.0 is installed, change Directory.GetFiles to Directory.Enumerate files for slightly better performance.*/ Parallel.ForEach<string>(Directory.GetFiles(Src), file => { /* An exception thrown here may be arbitrarily deep into this recursive function there's also a good chance that if one copy fails here, so too will other files in the same directory, so we don't want to spam out hundreds of error e-mails but we don't want to abort all together. Instead, the best solution is probably to throw back up to the original caller of copy directory an move on to the next Src/Dst pair by not catching any possible exception here.*/ File.Copy(file, //src Path.Combine(Dst, Path.GetFileName(file)), //dest true);//bool overwrite }); //Call this function again for every directory in the folder. Parallel.ForEach(Directory.GetDirectories(Src), dir => { copyDirectory(dir, Path.Combine(Dst, Path.GetFileName(dir))); }); } }

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  • Piping input to a Java app with Perl

    - by user319479
    I need to write a Perl script that pipes input into a Java program. This is related to this, but that didn't help me. My issue is that the Java app doesn't get the print statements until I close the handle. What I found online was that $| needs to be set to something greater than 0, in which case newline characters will flush the buffer. This still doesn't work. This is the script: #! /usr/bin/perl -w use strict; use File::Basename; $|=1; open(TP, "| java -jar test.jar") or die "fail"; sleep(2); print TP "this is test 1\n"; print TP "this is test 2\n"; print "tests printed, waiting 5s\n"; sleep(5); print "wait over. closing handle...\n"; close TP; print "closed.\n"; print "sleeping for 5s...\n"; sleep(5); print "script finished!\n"; exit And here is a sample Java app: import java.util.Scanner; public class test{ public static void main( String[] args ){ Scanner sc = new Scanner( System.in ); int crashcount = 0; while( true ){ try{ String input = sc.nextLine(); System.out.println( ":: INPUT: " + input ); if( "bananas".equals(input) ){ break; } } catch( Exception e ){ System.out.println( ":: EXCEPTION: " + e.toString() ); crashcount++; if( crashcount == 5 ){ System.out.println( ":: Looks like stdin is broke" ); break; } } } System.out.println( ":: IT'S OVER!" ); return; } } The Java app should respond to receiving the test prints immediately, but it doesn't until the close statement in the Perl script. What am I doing wrong? Note: the fix can only be in the Perl script. The Java app can't be changed. Also, File::Basename is there because I'm using it in the real script.

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  • jQuery CSS plugin that returns computed style of element to pseudo clone that element?

    - by Keith Bentrup
    I'm looking for a way using jQuery to return an object of computed styles for the 1st matched element. I could then pass this object to another call of jQuery's css method. For example, with width, I can do the following to make the 2 divs have the same width: $('#div2').width($('#div1').width()); It would be nice if I could make a text input look like an existing span: $('#input1').css($('#span1').css()); where .css() with no argument returns an object that can be passed to .css(obj). (I can't find a jQuery plugin for this, but it seems like it should exist. If it doesn't exist, I'll turn mine below into a plugin and post it with all the properties that I use.) Basically, I want to pseudo clone certain elements but use a different tag. For example, I have an li element that I want to hide and put an input element over it that looks the same. When the user types, it looks like they are editing the element inline. I'm also open to other approaches for this pseudo cloning problem for editing. Any suggestions? Here's what I currently have. The only problem is just getting all the possible styles. This could be a ridiculously long list. jQuery.fn.css2 = jQuery.fn.css; jQuery.fn.css = function() { if (arguments.length) return jQuery.fn.css2.apply(this, arguments); var attr = ['font-family','font-size','font-weight','font-style','color', 'text-transform','text-decoration','letter-spacing','word-spacing', 'line-height','text-align','vertical-align','direction','background-color', 'background-image','background-repeat','background-position', 'background-attachment','opacity','width','height','top','right','bottom', 'left','margin-top','margin-right','margin-bottom','margin-left', 'padding-top','padding-right','padding-bottom','padding-left', 'border-top-width','border-right-width','border-bottom-width', 'border-left-width','border-top-color','border-right-color', 'border-bottom-color','border-left-color','border-top-style', 'border-right-style','border-bottom-style','border-left-style','position', 'display','visibility','z-index','overflow-x','overflow-y','white-space', 'clip','float','clear','cursor','list-style-image','list-style-position', 'list-style-type','marker-offset']; var len = attr.length, obj = {}; for (var i = 0; i < len; i++) obj[attr[i]] = jQuery.fn.css2.call(this, attr[i]); return obj; } Edit: I've now been using the code above for awhile. It works well and behaves exactly like the original css method with one exception: if 0 args are passed, it returns the computed style object. As you can see, it immediately calls the original css method if that's the case that applies. Otherwise, it gets the computed styles of all the listed properties (gathered from Firebug's computed style list). Although it's getting a long list of values, it's quite fast. Hope it's useful to others.

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  • Maze Navigation in Player Stage with Roomba

    - by Scott
    Here is my code: /* Scott Landau Robot Lab Assignment 1 */ // Standard Java Libs import java.io.*; // Player/Stage Libs import javaclient2.*; import javaclient2.structures.*; import javaclient2.structures.sonar.*; // Begin public class SpinningRobot { public static Position2DInterface pos = null; public static LaserInterface laser = null; public static void main(String[] args) { PlayerClient robot = new PlayerClient("localhost", 6665); laser = robot.requestInterfaceLaser(0, PlayerConstants.PLAYER_OPEN_MODE); pos = robot.requestInterfacePosition2D(0,PlayerConstants.PLAYER_OPEN_MODE); robot.runThreaded (-1, -1); pos.setSpeed(0.5f, -0.25f); // end pos float x, y; x = 46.0f; y = -46.0f; boolean done = false; while( !done ){ if(laser.isDataReady()) { float[] laser_data = laser.getData().getRanges(); System.out.println("== IR Sensor =="); System.out.println("Left Wall Distance: "+laser_data[360]); System.out.println("Right Wall Distance: " +laser_data[0]); // if laser doesn't reach left wall, move to detect it // so we can guide using left wall if ( laser_data[360] < 0.6f ) { while ( laser_data[360] < 0.6f ) { pos.setSpeed(0.5f, -0.5f); } } else if ( laser_data[0] < 0.6f ) { while(laser_data[0<0.6f) { pos.setSpeed(0.5f, 0.5f); } } pos.setSpeed(0.5f, -0.25f); // end pos? done = ( (pos.getX() == x) && (pos.getY() == y) ); } } } } // End I was trying to have the Roomba go continuously at a slight right curve, quickly turning away from each wall it came to close to if it recognized it with it's laser. I can only use laser_data[360] and laser_data[0] for this one robot. I think this would eventually navigate the maze. However, I am using the Player Stage platform, and Stage freezes when the Roomba comes close to a wall using this code, I have no idea why. Also, if you can think of a better maze navigation algorithm, please let me know. Thank you!

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  • Loading a ConfigurationSection with a required child ConfigurationElement with .Net configuration fr

    - by Vadim Rybak
    I have a console application that is trying to load a CustomConfigurationSection from a web.config file. The custom configuration section has a custom configuration element that is required. This means that when I load the config section, I expect to see an exception if that config element is not present in the config. The problem is that the .NET framework seems to be completely ignoring the isRequired attribute. So when I load the config section, I just creates an instance of the custom configuration element and sets it on the config section. My question is, why is this happening? I want the GetSection() method to fire a ConfigurationErrors exception since a required element is missing from the configuration. Here is how my config section looks. public class MyConfigSection : ConfigurationSection { [ConfigurationProperty("MyConfigElement", IsRequired = true)] public MyConfigElement MyElement { get { return (MyConfigElement) this["MyConfigElement"]; } } } public class MyConfigElement : ConfigurationElement { [ConfigurationProperty("MyAttribute", IsRequired = true)] public string MyAttribute { get { return this["MyAttribute"].ToString(); } } } Here is how I load the config section. class Program { public static Configuration OpenConfigFile(string configPath) { var configFile = new FileInfo(configPath); var vdm = new VirtualDirectoryMapping(configFile.DirectoryName, true, configFile.Name); var wcfm = new WebConfigurationFileMap(); wcfm.VirtualDirectories.Add("/", vdm); return WebConfigurationManager.OpenMappedWebConfiguration(wcfm, "/"); } static void Main(string[] args) { try{ string path = @"C:\Users\vrybak\Desktop\Web.config"; var configManager = OpenConfigFile(path); var configSection = configManager.GetSection("MyConfigSection") as MyConfigSection; MyConfigElement elem = configSection.MyElement; } catch (ConfigurationErrorsException ex){ Console.WriteLine(ex.ToString()); } } Here is what my config file looks like. <?xml version="1.0"?> <configuration> <configSections> <section name="MyConfigSection" type="configurationFrameworkTestHarness.MyConfigSection, configurationFrameworkTestHarness" /> </configSections> <MyConfigSection> </MyConfigSection> The wierd part is that if I open the config file and load the section 2 times in a row, I will get the exception that I expect. var configManager = OpenConfigFile(path); var configSection = configManager.GetSection("MyConfigSection") as MyConfigSection; configManager = OpenConfigFile(path); configSection = configManager.GetSection("MyConfigSection") as MyConfigSection; If I use the code above, then the exception will fire and tell me that MyConfigElement is required. The question is Why is it not throwing this exception the first time??

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  • How do I sort an array of Person Objects by using compareto()?

    - by Adam
    Here is my code: > import java.util.Scanner; import java.util.Arrays; /** This class tests the Person class. */ public class PersonDemo { public static void main(String[] args) { int count = 0; Scanner in = new Scanner(System.in); boolean more = false; Person first = null; Person last = null; while (more) { System.out.println( "Please enter the person's name or a blank line to quit"); String name = in.nextLine(); if (name.equals("")) more = false; else { Person p = new Person(name); //new person object created with inputted name Person[] people = new Person[10]; //new array of 10 person objects people[count] = p; //declare person object with index of variable count as the new person object first = people[count]; // I have no idea what to do here. This is where I'm stuck. last = people[count]; // I can't figure out what to do with this either. first.compareTo(p); //call compareTo method on first and new person object last.compareTo(p); //call compareTo method on last and new person object count++; // increase count variable } } System.out.println("First: " + first.toString()); System.out.println("Last: " + last.toString()); } } And the Person class: /** A person with a name. */ public class Person implements Comparable { /** * Constructs a Person with a name. * @param aName the person's name */ public Person(String aName) { name = aName; } public String getName() { return name; } @Override public int compareTo(Object otherObject) { Person other = (Person)otherObject; if (name.compareTo(other.name) < 0) return -1; if (name.compareTo(other.name) > 0) return 1; return 0; } /** Returns a string representation of the object. @return name of Person */ public String toString() { return "[name=" + name + "]"; } private String name; }

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