Search Results

Search found 32968 results on 1319 pages for 'java roadtrip'.

Page 238/1319 | < Previous Page | 234 235 236 237 238 239 240 241 242 243 244 245  | Next Page >

  • improving data extraction from text file in Java

    - by owca
    I have CSV file with sample data in this form : 220 30 255 0 0 Javascript 200 20 0 255 128 Thinking in java , where the first column is height, second thickness, next three are rgb values for color and last one is title. All need to be treated as separate variables. I have already written my own solution for this, but I'm wondering if there are no better/easier/shorter ways of doing this. Extracted data will then be used to create Book object, throw every Book into array of books and print it with swing. Here's the code : private static Book[] addBook(Book b, Book[] bookTab){ Book[] tmp = bookTab; bookTab = new Book[tmp.length+1]; for(int i = 0; i < tmp.length; i++){ bookTab[i] = tmp[i]; } bookTab[tmp.length] = b; return bookTab; } public static void main(String[] args) { Book[] books = new Book[0]; try { BufferedReader file = new BufferedReader(new FileReader("K:\\books.txt")); String s; while ((s = file.readLine()) != null) { int hei, thick, R, G, B; String tit; hei = Integer.parseInt(s.substring(0, 3).replaceAll(" ", "")); thick = Integer.parseInt(s.substring(4, 6).replaceAll(" ", "")); R = Integer.parseInt(s.substring(10, 13).replaceAll(" ", "")); G = Integer.parseInt(s.substring(14, 17).replaceAll(" ", "")); B = Integer.parseInt(s.substring(18, 21).replaceAll(" ", "")); tit = s.substring(26); System.out.println(tyt+wys+grb+R+G+B); books = addBook(new Book(wys, grb, R, G, B, tyt),books); } file.close(); } catch (IOException e) { //do nothing } }

    Read the article

  • Fun things you can do by mutating Java strings

    - by polygenelubricants
    So I've come around since I asked how to limit setAccessible to only “legitimate” uses and have come to embrace its power for fun. Enabled by its power, of course, is string mutation. import java.lang.reflect.Field; public class Mutator { static void mutate(Object obj, String field, Object newValue) { try { Field f = obj.getClass().getDeclaredField(field); f.setAccessible(true); f.set(obj, newValue); } catch (Exception e) { } } public static void mutate(String from, String to) { mutate(from, "value", to.toCharArray()); mutate(from, "count", to.length()); } public static void main(String args[]) { Mutator.mutate(System.getProperty("line.separator"), "<br/>\n"); System.out.println("Hello world!"); Mutator.mutate(Integer.toString(Integer.MIN_VALUE), "OMG!"); System.out.println(-2147483648); Mutator.mutate(String.valueOf((Object) null), "LOL!"); System.out.println(Arrays.toString(new int[3][])); Mutator.mutate(Arrays.toString(new int[0]), ":("); System.out.println(Arrays.toString(new byte[0])); } } Output (if no exception is thrown): Hello world!<br/> OMG!<br/> [LOL!, LOL!, LOL!]<br/> :(<br/> Let's see what other fun things we can come up with.

    Read the article

  • Can't select data from MySQL database: java.lang.NullPointerException

    - by Devel
    Hi, I'm trying to select data from database using this code: //DATABASE ResultSet rs; String polecenie; Statement st; String[] subj; public void polacz() { try { Class.forName("com.mysql.jdbc.Driver"); Connection pol=DriverManager.getConnection("jdbc:mysql://localhost:3306/testgenerator", "root", "pospaz"); st = pol.createStatement(); lblPolaczonoZBaza.setText("Polaczono z baza danych testgenerator"); } catch (Exception ek) { statusMessageLabel.setText("Can't connect to d: "+ek); } polecenie = "select * from subjects"; try { rs = st.executeQuery(polecenie); int i=0; while (rs.next()){ subj[i] = rs.getString("name"); i++; } st.close(); } catch (Exception ek) { statusMessageLabel.setText("Can't select data: "+ek); } } The second catch shows exception: java.lang.NullPointerException I looked everywhere and I can't find the solution. I'd be grateful for any help.

    Read the article

  • Java and dynamic variables

    - by Arvanem
    Hi folks, I am wondering whether it is possible to make dynamic variables in Java. In other words, variables that change depending on my instructions. FYI, I am making a trading program. A given merchant will have an array of items for sale for various prices. The dynamism I am calling for comes in because each category of items for sale has its own properties. For example, a book item has two properties: int pages, and boolean hardCover. In contrast, a bookmark item has one property, String pattern. Here are skeleton snippets of code so you can see what I am trying to do: public class Merchants extends /* certain parent class */ { // only 10 items for sale to begin with Stock[] itemsForSale = new Stock[10]; // Array holding Merchants public static Merchants[] merchantsArray = new Merchants[maxArrayLength]; // method to fill array of stock goes here } and public class Stock { int stockPrice; int stockQuantity; String stockType; // e.g. book and bookmark // Dynamic variables here, but they should only be invoked depending on stockType int pages; boolean hardCover; String pattern; }

    Read the article

  • Java 2D Resize

    - by jon077
    I have some old Java 2D code I want to reuse, but was wondering, is this the best way to get the highest quality images? public static BufferedImage getScaled(BufferedImage imgSrc, Dimension dim) { // This code ensures that all the pixels in the image are loaded. Image scaled = imgSrc.getScaledInstance( dim.width, dim.height, Image.SCALE_SMOOTH); // This code ensures that all the pixels in the image are loaded. Image temp = new ImageIcon(scaled).getImage(); // Create the buffered image. BufferedImage bufferedImage = new BufferedImage(temp.getWidth(null), temp.getHeight(null), BufferedImage.TYPE_INT_RGB); // Copy image to buffered image. Graphics g = bufferedImage.createGraphics(); // Clear background and paint the image. g.setColor(Color.white); g.fillRect(0, 0, temp.getWidth(null),temp.getHeight(null)); g.drawImage(temp, 0, 0, null); g.dispose(); // j2d's image scaling quality is rather poor, especially when // scaling down an image to a much smaller size. We'll post filter // our images using a trick found at // http://blogs.cocoondev.org/mpo/archives/003584.html // to increase the perceived quality.... float origArea = imgSrc.getWidth() * imgSrc.getHeight(); float newArea = dim.width * dim.height; if (newArea <= (origArea / 2.)) { bufferedImage = blurImg(bufferedImage); } return bufferedImage; } public static BufferedImage blurImg(BufferedImage src) { // soften factor - increase to increase blur strength float softenFactor = 0.010f; // convolution kernel (blur) float[] softenArray = { 0, softenFactor, 0, softenFactor, 1-(softenFactor*4), softenFactor, 0, softenFactor, 0}; Kernel kernel = new Kernel(3, 3, softenArray); ConvolveOp cOp = new ConvolveOp(kernel, ConvolveOp.EDGE_NO_OP, null); return cOp.filter(src, null); }

    Read the article

  • Cleaning a string consisting of html/server-side tags in Java

    - by Denzil
    I have a text like: I've got a date with this fellow tomorrow. Well me and thousands of others. <br /><br /><img src="http://www.newwest.net/images/thumbnails_feature/barack_obama_westerners.jpg"><br /><br />Tomorrow morning I will be getting up at stupid o'clock and driving up to Manchester, NH to see Barak Obama speak. <br /><br />You all should come too!<br /><br /><a href="http://nh.barackobama.com/manchesterchange">RSVP for the event</a> I would want to like to clean it too : I've got a date with this fellow tomorrow. Well me and thousands of others http://www.newwest.net/images/thumbnails_feature/barack_obama_westerners.jpg Tomorrow morning I will be getting up at stupid o'clock and driving up to Manchester, NH to see Barak Obama speak.You all should come too! h**p://nh.barackobama.com/manchesterchange RSVP for the event I would like to write a JAVA program for the same. Any pointers/suggestions would be appreciated.The tags aren't limited to the above post. This was just an example. Thanks! PS: Replace *'s by t's in the second hyperlink as Stack Overflow doesn't allow me to post more than one link.

    Read the article

  • C# client to Java web service

    - by tomislavg
    I have received wsdl file from outside company. I'm using VS2005 c#. With wsdl.exe I have created class containing methods and types for the given web service. To connect to the service outside company requires that certificate from the smart card is inputed in the header. I think i have achieved this with service.ClientCertificates.Add("Path to exported cert" - at least for now, after probably later i will take it from Certificate Store When service is called there are three steps that are taken and visible by the Fidller(Web Debugging Proxy)). service is called on the url http://test.company.com/webservice.wsdl service redirects the request to certificate server and pin needs to be inputed to get cookie for the server service is again redirected to url http://test.company.com/webservice.wsdl At point 1. I can see that my request send to the server contains .... but at point 3. i can not see request` just a empty string. The exception is thrown Msg: Possible SOAP version mismatch: Envelope namespace http://schemas.xmlsoap.org/wsdl/ was unexpected. Expecting http://schemas.xmlsoap.org/soap/envelope/. Does somebody have an example how to connect to java web service with certificate and AlowRedirect enabled for the web service? Any ideas what i am doing wrong are more that welcome.

    Read the article

  • Provisioning Api using java

    - by user268515
    Hi i'm working in java and tried to retrieve all the user in the domain for that i used Provisionin api............ Its working good But my idea is to Use 2-legged OAuth to retrieve the users from the domain Is it Possible? I dont how to specify the URL please Help me And i triede the following the program final String CONSUMER_KEY = "xxxxxxxxxx.com"; final String CONSUMER_SECRET = "12345678122154154df9"; final String DOMAIN = "xxxxxxxxxx.com"; GoogleOAuthParameters oauthParameters = new GoogleOAuthParameters(); oauthParameters.setOAuthConsumerKey(CONSUMER_KEY); oauthParameters.setOAuthConsumerSecret(CONSUMER_SECRET); oauthParameters.setOAuthType(OAuthType.TWO_LEGGED_OAUTH); OAuthHmacSha1Signer signer = new OAuthHmacSha1Signer(); URL feedUrl = new URL("https://apps-apis.google.com/a/feeds/" + DOMAIN + "/user/2.0/[email protected]"); userService = new UserService("Myapplication"); userService.setOAuthCredentials(oauthParameters, signer); userService.useSsl(); UserFeed allUsers = new UserFeed(); UserFeed allpage; Link nextLink; do { allpage = userService.getFeed(feedUrl, UserFeed.class); allUsers.getEntries().addAll(allpage.getEntries()); nextLink = allpage.getLink(Link.Rel.NEXT, Link.Type.ATOM); if (nextLink != null) { feedUrl = new URL(nextLink.getHref()); } }while (nextLink != null); return allUsers; } Its returing the error as com.google.gdata.util.AuthenticationException: Unknown authorization header

    Read the article

  • [Java] Cluster Shared Cache

    - by GuiSim
    Hi everyone. I am searching for a java framework that would allow me to share a cache between multiple JVMs. What I would need is something like Hazelcast but without the "distributed" part. I want to be able to add an item in the cache and have it automatically synced to the other "group member" cache. If possible, I'd like the cache to be sync'd via a reliable multicast (or something similar). I've looked at Shoal but sadly the "Distributed State Cache" seems like an insufficient implementation for my needs. I've looked at JBoss Cache but it seems a little overkill for what I need to do. I've looked at JGroups, which seems to be the most promising tool for what I need to do. Does anyone have experiences with JGroups ? Preferably if it was used as a shared cache ? Any other suggestions ? Thanks ! EDIT : We're starting tests to help us decide between Hazelcast and Infinispan, I'll accept an answer soon. EDIT : Due to a sudden requirements changes, we don't need a distributed map anymore. We'll be using JGroups for a low level signaling framework. Thanks everyone for you help.

    Read the article

  • Printing a sideways triangle in java

    - by Will
    I'm trying to print a sideways triangle in java. If the user enters 5, the output should be: * *** ***** *** * If the user enters 6, the output should be: * *** ***** ***** *** * I've gotten it to work for the case when the user enters 5, 3, or 1 but my code seems to work for those three cases only. I was wondering if anyone could help me get my code working for more cases. Here it is: public void printArrow( int n ) { int asterisks = 1; for ( int i = 0; i <= n/2; i++ ) { for ( int j = i; j < asterisks; j++ ) { System.out.print( "*" ); } asterisks += 3; System.out.println(); } asterisks = asterisks / 2 - 2; for ( int i = 0; i < n/2; i++ ) { for ( int k = i; k < asterisks; k++ ) { System.out.print( "*" ); } if ( i == 1 ) { System.out.print( "*" ); } asterisks -= 2; System.out.println(); } }

    Read the article

  • Java Bucket Sort on Strings

    - by Michael
    I can't figure out what would be the best way to use Bucket Sort to sort a list of strings that will always be the same length. An algorithm would look like this: For the last character position down to the first: For each word in the list: Place the word into the appropriate bucket by current character For each of the 26 buckets(arraylists) Copy every word back to the list I'm writing in java and I'm using an arraylist for the main list that stores the unsorted strings. The strings will be five characters long each. This is what I started. It just abrubdly stops within the second for loop because I don't know what to do next or if I did the first part right. ArrayList<String> count = new ArrayList<String>(26); for (int i = wordlen; i > 0; i--) { for (int j = 0; i < myList.size(); i++) myList.get(j).charAt(i) } Thanks in advanced.

    Read the article

  • Writing catch block with cleanup operations in Java ...

    - by kedarmhaswade
    I was not able to find any advise on catch blocks in Java that involve some cleanup operations which themselves could throw exceptions. The classic example is that of stream.close() which we usually call in the finally clause and if that throws an exception, we either ignore it by calling it in a try-catch block or declare it to be rethrown. But in general, how do I handle cases like: public void doIt() throws ApiException { //ApiException is my "higher level" exception try { doLower(); } catch(Exception le) { doCleanup(); //this throws exception too which I can't communicate to caller throw new ApiException(le); } } I could do: catch(Exception le) { try { doCleanup(); } catch(Exception e) { //ignore? //log? } throw new ApiException(le); //I must throw le } But that means I will have to do some log analysis to understand why cleanup failed. If I did: catch(Exception le) { try { doCleanup(); } catch(Exception e) { throw new ApiException(e); } It results in losing the le that got me here in the catch block in the fist place. What are some of the idioms people use here? Declare the lower level exceptions in throws clause? Ignore the exceptions during cleanup operation?

    Read the article

  • Java performance issue

    - by Colby77
    Hi, I've got a question related to java performance and method execution. In my app there are a lot of place where I have to validate some parameter, so I've written a Validator class and put all the validation methods into it. Here is an example: public class NumberValidator { public static short shortValidator(String s) throws ValidationException{ try{ short sh = Short.parseShort(s); if(sh < 1){ throw new ValidationException(); } return sh; }catch (Exception e) { throw new ValidationException("The parameter is wrong!"); } } ... But I'm thinking about that. Is this OK? It's OO and modularized, but - considering performance - is it a good idea? What if I had awful lot of invocation at the same time? The snippet above is short and fast, but there are some methods that take more time. What happens when there are a lot of calling to a static method or an instance method in the same class and the method is not synchronized? All the calling methods have to fall in line and the JVM executes them sequentially? Is it a good idea to have some class that are identical to the above-mentioned and randomly call their identical methods? I think it is not, because "Don't repeat yourself " and "Duplication is Evil" etc. But what about performance? Thanks is advance.

    Read the article

  • converting a Tree to newick format. java

    - by Esmond
    I'm having problems converting a binary rooted tree to newick format. The full explanation for such a format can be found: http://code.google.com/p/mrsrf/wiki/NewickTree An example of a newick format would be as follows: for a tree T such as http://www.cs.mcgill.ca/~cs251/OldCourses/1997/topic8/images/completetreetwo.gif the newick representation would be: (((8,9),(10,11)),((12,13),(14,15))) the internal node will become the commas while the leaves will be retained. such trees have internal nodes which will always have 2 children. I have a problem using recursion to come out with this newick format. The output contains far too many nodes and braces. Any comments to resolve this problem is appreciated or even an iterative algorithm would be welcomed import java.util.Stack; public class Tree { .... public String inOrderNewick(Node root, String output) throws ItemNotFoundException { if (root.hasChild()) { output += "("; output += inOrderNewick(root.child1, output); output += ","; output += inOrderNewick(root.child2, output); output += ")"; return output; } else { output += root.getSeq(); return output; } } }

    Read the article

  • How do i write this jpql query? java

    - by Nitesh Panchal
    Hello, Say i have 5 tables, tblBlogs tblBlogPosts tblBlogPostComment tblUser tblBlogMember BlogId BlogPostsId BlogPostCommentId UserId BlogMemberId BlogTitle BlogId CommentText FirstName UserId PostTitle BlogPostsId BlogId BlogMemberId Now i want to retrieve only those blogs and posts for which blogMember has actually commented. So in short, how do i write this plain old sql :- Select b.BlogTitle, bp.PostTitle, bpc.CommentText from tblBlogs b Inner join tblBlogPosts bp on b.BlogId = bp.BlogId Inner Join tblBlogPostComment bpc on bp.BlogPostsId = bpc.BlogPostsId Inner Join tblBlogMember bm On bpc.BlogMemberId = bm.BlogMemberId Where bm.UserId = 1; As you can see, everything is Inner join, so only that row will be retrieved for which the user has commented on some post of some blog. So, suppose he has joined 3 blogs whose ids are 1,2,3 (The blogs which user has joined are in tblBlogMembers) but the user has only commented in blog 2 (of say BlogPostId = 1). So that row will be retrieved and 1,3 won't as it is Inner Join. How do i write this kind of query in jpql? In jpql, we can only write simple queries like say :- Select bm.blogId from tblBlogMember Where bm.UserId = objUser; Where objUser is supplied using :- em.find(User.class,1); Thus once we get all blogs(Here blogId represents a blog object) which user has joined, we can loop through and do all fancy things. But i don't want to fall in this looping business and write all this things in my java code. Instead, i want to leave that for database engine to do. So, how do i write the above plain sql into jpql? and what type of object the jpql query will return? because i am only selecting few fields from all table. In which class should i typecast the result to? I think i posted my requirement correctly, if i am not clear please let me know. Thanks in advance :).

    Read the article

  • Unable to access Java-created file -- sometimes

    - by BlairHippo
    In Java, I'm working with code running under WinXP that creates a file like this: public synchronized void store(Properties props, byte[] data) { try { File file = filenameBasedOnProperties(props); if ( file.exists() ) { return; } File temp = File.createTempFile("tempfile", null); FileOutputStream out = new FileOutputStream(temp); out.write(data); out.flush(); out.close(); file.getParentFile().mkdirs(); temp.renameTo(file); } catch (IOException ex) { // Complain and whine and stuff } } Sometimes, when a file is created this way, it's just about totally inaccessible from outside the code (though the code responsible for opening and reading the file has no problem), even when the application isn't running. When accessed via Windows Explorer, I can't move, rename, delete, or even open the file. Under Cygwin, I get the following when I ls -l the directory: ls: cannot access [big-honkin-filename] total 0 ?????????? ? ? ? ? ? [big-honkin-filename] As implied, the filenames are big, but under the 260-character max for XP (though they are slightly over 200 characters). To further add to the sense the my computer just wants me to feel stupid, sometimes the files created by this code are perfectly normal. The only pattern I've spotted is that once one file in the directory "locks", the rest are screwed. Anybody ever run into something like this before, or have any insights into what's going on here?

    Read the article

  • Capture data read from file into string stream Java

    - by halluc1nati0n
    I'm coming from a C++ background, so be kind on my n00bish queries... I'd like to read data from an input file and store it in a stringstream. I can accomplish this in an easy way in C++ using stringstreams. I'm a bit lost trying to do the same in Java. Following is a crude code/way I've developed where I'm storing the data read line-by-line in a string array. I need to use a string stream to capture my data into (rather than use a string array).. Any help? char dataCharArray[] = new char[2]; int marker=0; String inputLine; String temp_to_write_data[] = new String[100]; // Now, read from output_x into stringstream FileInputStream fstream = new FileInputStream("output_" + dataCharArray[0]); // Convert our input stream to a BufferedReader BufferedReader in = new BufferedReader (new InputStreamReader(fstream)); // Continue to read lines while there are still some left to read while ((inputLine = in.readLine()) != null ) { // Print file line to screen // System.out.println (inputLine); temp_to_write_data[marker] = inputLine; marker++; }

    Read the article

  • Ant: How to force java compilation if classpath jars have changed but sources have not

    - by Ittai
    Hi, I have the following usecase: I have a java project (myProj) which uses a common.jar from a different project(common). I want the javac ant task to work even if the sources of myProj have not changed if the common.jar has changed (as the sources of myProj depend of it and might be invalid now). I have a task which copies the common.jar from a central location to the myProj lib if it has changed and I can use it to set a property whether or not to "force" compilation so that end is taken care of. I'm not sure how (or if) I can tell the javac task to try and compile anyway? I don't want to change myProj's sources (or timestamps) so that the task will start. Excerpt from the ant build.xml file: <path id="project.class.path"> <pathelement location... /> ... <fileset dir="lib" includes="**/*.jar" /> </path> <target name="copyLibs" > <copy file="${central.loc}/common.jar" todir="lib" /> ... </target> <target name="javac" > <javac srcdir="src" includes="**" excludes=... > <classpath refid="project.class.path"/> </javac> </target> Thanks in advance, Ittai

    Read the article

  • Sending a file over web service from java to .net

    - by Goran
    Hello, I have built .NET 1.1 Web Service which should accept files and save them. Here is the code of the webmethod: [WebMethod] public bool SaveDocument(Byte[] docbinaryarray, string docname) { string dirPath = @"C:\Temp\WSTEST\"; if(!Directory.Exists(dirPath)) { Directory.CreateDirectory(dirPath); } string filePath = dirPath + docname; FileStream objfilestream = new FileStream(filePath, FileMode.Create, FileAccess.ReadWrite); objfilestream.Write(docbinaryarray, 0, docbinaryarray.Length); objfilestream.Close(); return true; } When I make a client in .NET with reference to this Web service everything goes great, but when a college of mine tries to send me a file from a JAVA client I don't get the actuall file. All I get is byte array with only one element. Definition of byte array for file, in WSDL looks like this: <s:element minOccurs="0" maxOccurs="1" name="docbinaryarray" type="s:base64Binary" /> He sends me base64binary and fails every time. All I get is Byte array with only one element inside.

    Read the article

  • Finding a picture in a picture with java?

    - by tarrasch
    what i want to to is analyse input from screen in form of pictures. I want to be able to identify a part of an image in a bigger image and get its coordinates within the bigger picture. Example: would have to be located in And the result would be the upper right corner of the picture in the big picture and the lower left of the part in the big picture. As you can see, the white part of the picture is irrelevant, what i basically need is just the green frame. Is there a library that can do something like this for me? Runtime is not really an issue. What i want to do with this is just generating a few random pixel coordinates and recognize the color in the big picture at that position, to recognize the green box fast later. And how would it decrease performance, if the white box in the middle is transparent? The question has been asked several times on SO as it seems without a single answer. I found i found a solution at http://werner.yellowcouch.org/Papers/subimg/index.html . Unfortunately its in C++ and i do not understand a thing. Would be nice to have a Java implementation on SO.

    Read the article

  • Can't get recursive function to work in Java

    - by Ahmed Salah
    I read docs about java recorsion and I thought I have understood it, but when I try to use it in the following example, it does not work as expected. I a class account, which has amount and can have forther subAccount. I would have implemented one method getSum, which has to return the summ of the amount of the account and amount of all of its subaccount. In the following code, the call of the method getSumm() should return 550, but it behaves strange. can somebody help please? public class Balance{ ArrayList<Balance> subAccounts = new ArrayList<Balance>(); String accountID = null; Double amount = null; double result=0; public double getSum(ArrayList<Balance> subAccounts){ if(subAccounts !=null && subAccounts.size()>0){ for (int i = 0; i < subAccounts.size(); i++) { result = result + getSum(subAccounts.get(i).subAccounts); } } else { return amount; } return result; } public static void main(String[] args) { Balance bs1 = new Balance(); Balance bs2 = new Balance(); Balance bs3 = new Balance(); bs1.amount=100.0; bs2.amount=150.0; bs3.amount=300.0; ArrayList<Balance> subAccounts1 = new ArrayList<Balance>(); bs2.subAccounts=null; bs3.subAccounts=null; subAccounts1.add(bs2); subAccounts1.add(bs3); bs1.subAccounts=subAccounts1; double sum= bs1.getSum(subAccounts1); System.out.println(sum); } }

    Read the article

  • Divide a path into N sections using Java or PostgreSQL/PostGIS

    - by Guido
    Imagine a GPS tracking system that is following the position of several objects. The points are stored in a database (PostgreSQL + PostGIS). Each path is composed by a different number of points. That is the reason why, in order to compare a pair of paths, I need to divide every path in a set of 100 points. Do you know any PostGIS function that already implement this algorithm? I've not been able to find it. If not, I'd like to solve it using Java. In this case I'd like to know an efficient and easy to implement algorithm to divide a path into N points. The most simple example could be to divide this path into three points: position 1 : x=1, y=2 position 2 : x=1, y=3 And the result should be: position 1 : x=1, y=2 (starting point) position 2 : x=5, y=2.5 position 3 : x=9, y=3 (end point) Edit: By 'compare a pair of paths' I mean to calculate the distance between two paths. I plan to divide each path in 100 points, and sum the euclidean distance between each one of these points as the distance between the two paths.

    Read the article

  • Java assignment issues - Is this atomic?

    - by Bob
    Hi, I've got some questions about Java's assigment. Strings I've got a class: public class Test { private String s; public synchronized void setS(String str){ s = s + " - " + str; } public String getS(){ return s; } } I'm using "synchronized" in my setter, and avoiding it in my getter, because in my app, there are a tons of data gettings, and very few settings. Settings must be synchronized to avoid inconsistency. My question is: is getting and setting a variable atomic? I mean, in a multithreaded environment, Thread1 is about to set variable s, while Thread2 is about to get "s". Is there any way the getter method could get something different than the s's old value or the s's new value (suppose we've got only two threads)? In my app it is not a problem to get the new value, and it is not a problem to get the old one. But could I get something else? What about HashMap's getting and putting? considering this: public class Test { private Map<Integer, String> map = Collections.synchronizedMap(new HashMap<Integer, String>()); public synchronized void setMapElement(Integer key, String value){ map.put(key, value); } public String getValue(Integer key){ return map.get(key); } } Is putting and getting atomic? How does HashMap handle putting an element into it? Does it first remove the old value and put the now one? Could I get other than the old value or the new value? Thanks in advance!

    Read the article

  • Query Level 2 Caching throwing ClassCastException

    - by Sameer Malhotra
    Hi, I am using JPA and Hibernate for the database. I have configured (EHCacache) second level cache and query level cache, but just to make sure that caching is working I was trying to get the statistics which is throwing class cast exception.Any help will be highly appreciated. My main goal is to see all the objects which have been cached to make sure that the caching is working properly. Here is the code: public List<CodeValue> findByCodetype(String propertyName) { try { final String queryString = "select model from CodeValue model where model.codetype" + "= :propertyValue" + " order by model.code"; Query query = em.createQuery(queryString); query.setHint("org.hibernate.cacheable", true); query.setHint("org.hibernate.cacheRegion", "query.findByCodetype"); query.setParameter("propertyValue", propertyName); List resultList = query.getResultList(); org.hibernate.Session session = (Session) em.getDelegate(); SessionFactory sessionFactory = session.getSessionFactory(); Map cacheEntries = sessionFactory.getStatistics() .getSecondLevelCacheStatistics("query.findByCodetype") .getEntries(); logger.info("The statistics are: " + cacheEntries); return resultList; } catch (RuntimeException re) { logger.error("findByCodetype failed in trauma patient", re); throw re; } } The error is existing right when I am trying to print the statistics. Below is exception: [6/7/10 19:23:17:059 GMT] 00000034 SystemOut O java.lang.ClassCastException: org.hibernate.cache.QueryKey incompatible with org.hibernate.cache.CacheKey at org.hibernate.stat.SecondLevelCacheStatistics.getEntries(SecondLevelCacheStatistics.java:51) at com.idph.trauma.registry.service.TraumaPatientDAO.findByCodetype(TraumaPatientDAO.java:439) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:615) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204) at $Proxy209.findByCodetype(Unknown Source) Do you know what's going on?

    Read the article

  • Java - SwingWorker - problem

    - by Yatendra Goel
    I am developing a Java Desktop Application. This app executes the same task public class MyTask implements Callable<MyObject> { in multiple thread simultaneously. Now, when a user clicks on a "start" button, I have created a SwingWorker myWorker and have executed it. Now, this myWorker creates multiple instances of MyTask and submits them to an ExecutorService. Each MyTask instance has a loop and generates an intermediate result at every iteration. Now, I want to collect these intermediate results from each MyTask instances as soon as they are generated. Then after collecting these intermediate results from every MyTask instance, I want to publish it through SwingWorker.publish(MyObject) so that the progress is shown on the EDT. Q1. How can I implement this? Should I make MyTask subclass of SwingWorker instead of Callable to get intermediate results also, because I think that Callable only returns final result. Q2. If the answer of Q1. is yes, then can you give me a small example to show how can I get those intermediate results and aggregate them and then publish them from main SwingWorker? Q3. If I can't use SwingWorker in this situation, then how can I implement this?

    Read the article

< Previous Page | 234 235 236 237 238 239 240 241 242 243 244 245  | Next Page >