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  • JPA getSingleResult() or null

    - by Eugene Ramirez
    Hi. I have an insertOrUpdate method which inserts an Entity when it doesn't exist or update it if it does. To enable this, I have to findByIdAndForeignKey, if it returned null insert if not then update. The problem is how do I check if it exists? So I tried getSingleResult. But it throws an exception if the public Profile findByUserNameAndPropertyName(String userName, String propertyName) { String namedQuery = Profile.class.getSimpleName() + ".findByUserNameAndPropertyName"; Query query = entityManager.createNamedQuery(namedQuery); query.setParameter("name", userName); query.setParameter("propName", propertyName); Object result = query.getSingleResult(); if(result==null)return null; return (Profile)result; } but "getSingleResult" throws an exception. Thanks

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  • Best practices retrieving XML/stream from HTTP in Android

    - by Jeffrey
    Hello everyone, what are the best practices parsing XML from an HTTP resource in Android? I've been using HttpURLConnection to retrieve an InputStream, wrapping it with a BufferedInputStream, and then using SAX to parse the buffered stream. For the most part it works, though I do receive error reports of SocketTimeoutException: The operation timed out or general parsing error. I believe it's due to the InputStream. Would using HttpClient instead of HttpURLConnection help? If yes, why? Should the stream be output to a file, having the file parsed instead of the stream? Any input or direction would be greatly appreciated. Thanks for your time.

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  • How to handle large dataset with JPA (or at least with Hibernate)?

    - by Roman
    I need to make my web-app work with really huge datasets. At the moment I get either OutOfMemoryException or output which is being generated 1-2 minutes. Let's put it simple and suppose that we have 2 tables in DB: Worker and WorkLog with about 1000 rows in the first one and 10 000 000 rows in the second one. Latter table has several fields including 'workerId' and 'hoursWorked' fields among others. What we need is: count total hours worked by each user; list of work periods for each user. The most straightforward approach (IMO) for each task in plain SQL is: 1) select Worker.name, sum(hoursWorked) from Worker, WorkLog where Worker.id = WorkLog.workerId group by Worker.name; //results of this query should be transformed to Multimap<Worker, Long> 2) select Worker.name, WorkLog.start, WorkLog.hoursWorked from Worker, WorkLog where Worker.id = WorkLog.workerId; //results of this query should be transformed to Multimap<Worker, Period> //if it was JDBC then it would be vitally //to set resultSet.setFetchSize (someSmallNumber), ~100 So, I have two questions: how to implement each of my approaches with JPA (or at least with Hibernate); how would you handle this problem (with JPA or Hibernate of course)?

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  • How do I add a library in Eclipse?

    - by jul
    hi, I downloaded the Gson library from http://code.google.com/p/google-gson/. The archive contains the following jar files: google-gson-1.3/gson-1.3-javadoc.jar google-gson-1.3/gson-1.3.jar google-gson-1.3/gson-1.3-sources.jar How do I set my Eclipse to be able to use the package in my projects? Where do I put the documentation? Thanks jul

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  • How can I find out if two arguments are instances of the same, but unknown class?

    - by Ingmar
    Let us say we have a method which accepts two arguments o1 and o2 of type Object and returns a boolean value. I want this method to return true only when the arguments are instances of the same class, e.g.: foo(new Integer(4),new Integer(5)); Should return true, however: foo(new SomeClass(), new SubtypeSomeClass()); should return false and also: foo(new Integer(3),"zoo"); should return false. I believe one way is to compare the fully qualified class names: public boolean foo(Object o1, Object o2){ Class<? extends Object> c1 = o1.getClass(); Class<? extends Object> c2 = o2.getClass(); if(c1.getName().equals(c2.getName()){ return true;} return false; } An alternative conditional statement would be : if (c1.isAssignableFrom(c2) && c2.isAssignableFrom(c1)){ return true; } The latter alternative is rather slow. Are there other alternatives to this problem?

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  • Why does my JButton look differently of different computers?

    - by Roman
    I use JButtons in my application. They need to have different colors. First I used that btn.setBackground(col);. It works on my computer and on another computer my button just gray (not red, as it's supposed to be). Trying to solve this problem I decided to use images. I do it in the following way: tmp = new JButton(newIcon); Again, it works fine on my computer and on another computer I see just gray buttons. Does anybody have any ideas what can be the reason of the problem and how it can be solved? I heard it can be related to "look-and-feel of the native system". But I do not know what it means and what should I do if it is the case? Can anybody pleas, help me with that?

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  • How to get fan list of Facebook page or can overwrite facebook social plugin css?

    - by Vaibhav Bhalke
    Hi, We are trying it with facebook social plugin. The HTML code for it as follow: <iframe border='0' src='http://www.facebook.com/plugins/likebox.php?id=1185611481&width=243&height=400&connections=15&stream=false&header=false' scrolling='yes' frameborder='0' allowTransparency='false' style='border:0px; overflow:hidden; width:243px; height:300px; background-color: #03869E; color: white;'> <iframe> As it replace inner HTML of frame on load. We want our own CSS to apply to this HTML. But as it replace whole HTML and it have its own CSS we are unable to set our CSS. We are doing this in GWT. Is there any way we can get the list of fans so we can display it as we want and can apply css? Or check given user is fan of page?

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  • Android file-creation fails.

    - by Alxandr
    I use the following code to create a folder "mymir" and a file ".nomedia" (in the mymir-folder) on the sdcard of an android unit. However, somehow it fails with the exception that the folder the ".nomedia"-file is to be placed in dosn't exist. Here's the code: private String EnsureRootDir() throws IOException { File sdcard = Environment.getExternalStorageDirectory(); File mymirFolder = new File(sdcard.getAbsolutePath() + "/mymir/"); if(!mymirFolder.exists()) { File noMedia = new File(mymirFolder.getAbsolutePath() + "/.nomedia"); noMedia.mkdirs(); noMedia.createNewFile(); } return mymirFolder.getAbsolutePath(); }

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  • Which view will be resolved, code from spring's docs

    - by Blankman
    So when you go to /appointments the get() action is called, so then would the view be get.jsp (assuming you are using .jsp, and assuming you are mapping action names to views)? And what about the getnewform? It seems to be returning an object? Is that basically passed into the view? @Controller @RequestMapping("/appointments") public class AppointmentsController { private final AppointmentBook appointmentBook; @Autowired public AppointmentsController(AppointmentBook appointmentBook) { this.appointmentBook = appointmentBook; } @RequestMapping(method = RequestMethod.GET) public Map<String, Appointment> get() { return appointmentBook.getAppointmentsForToday(); } @RequestMapping(value="/{day}", method = RequestMethod.GET) public Map<String, Appointment> getForDay(@PathVariable @DateTimeFormat(iso=ISO.DATE) Date day, Model model) { return appointmentBook.getAppointmentsForDay(day); } @RequestMapping(value="/new", method = RequestMethod.GET) public AppointmentForm getNewForm() { return new AppointmentForm(); } @RequestMapping(method = RequestMethod.POST) public String add(@Valid AppointmentForm appointment, BindingResult result) { if (result.hasErrors()) { return "appointments/new"; } appointmentBook.addAppointment(appointment); return "redirect:/appointments"; } } In the example, the @RequestMapping is used in a number of places. The first usage is on the type (class) level, which indicates that all handling methods on this controller are relative to the /appointments path. The get() method has a further @RequestMapping refinement: it only accepts GET requests, meaning that an HTTP GET for /appointments invokes this method. The post() has a similar refinement, and the getNewForm() combines the definition of HTTP method and path into one, so that GET requests for appointments/new are handled by that method.

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  • invalid header file while using jar for archiving

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

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  • What does this do and why does it require a transaction?

    - by S. Palin
    What does the following code example do and why does it require a transaction? // PersistenceManager pm = ...; Transaction tx = pm.currentTransaction(); User user = userService.currentUser(); List<Account> accounts = new ArrayList<Account>(); try { tx.begin(); Query query = pm.newQuery("select from Customer " + "where user == userParam " + "parameters User userParam"); List<Customer> customers = (List<Customer>) query.execute(user); query = pm.newQuery("select from Account " + "where parent-pk == keyParam " + "parameters Key keyParam"); for (Customer customer : customers) { accounts.addAll((List<Account>) query.execute(customer.key)); } } finally { if (tx.isActive()) { tx.rollback(); } }

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  • chat website in jsp/servlet

    - by akshay
    I want to devlelop a chat website using JSP/Servlets and Tomcat. I have following questions: Can the website handle load (1000 people at one time) without slowing down? Will it cause the website to slow down? What is the ideal server configuration for this kind of website? Note that I don't have a huge budget to host. How can I implement server push? Will PHP or JSP be ideal for such website?

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  • Why might RvdProxy.getServices() incorrectly return an empty Array?

    - by butterchicken
    The following code snippet attempts to create a Tib DaemonManager connecting to a particular rvd, and then query for that rvd's services. public static void main(String[] args) throws RuntimeException { DaemonManager daemonManager = new DaemonManager("http://foo.com:7580"); if(daemonManager.getDaemonType() == DaemonManager.RVD) { DaemonProxy daemonProxy = daemonManager.getDaemonProxy(); final RvdProxy rvdProxy = (RvdProxy) daemonProxy; Service[] services = rvdProxy.getServices(); System.out.println(services.length); //prints 0 for (Service service : services) { System.out.println(service.getNetwork()); } } } This prints zero, even though the web interface for this rvd lists multiple available services. Why might this happen? The daemon I am connecting to is running v 7.5.1 of the software, and the rvconfig.jar that I am using is from v 7.5.1 as well. Is there a gotcha when using Tibco's DaemonManager that is causing me to come unstuck?

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  • How to store some of the entity's values in another table using hibernate?

    - by nimcap
    Hi guys, is there a simple way to persist some of the fields in another class and table using hibernate. For example, I have a Person class with name, surname, email, address1, address2, city, country fields. I want my classes to be: public class Person { private String name; private String surname; private String email; private Address address; // .. } public class Address { private Person person; // to whom this belongs private String address1; private String address2; private String city; private Address country; // .. } and I want to store Address in another table. What is the best way to achieve this? Edit: I am using annotations. It does not have to be the way I described, I am looking for best practices. PS. If there is a way to make Address immutable (to use as a value object) that is even better, or maybe not because I thought everything from wrong perspective :)

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  • JDT: How to retrieve the correct IJavaElement to a corresponding RefactoringDescriptor?

    - by Chris
    I implement the IRefactoringExecutionListener interface in an Eclipse plug-in to get notified when the user refactors his code, so I can update a visual editor displaying corresponding UML Boxes accordingly. Now I have a RefactoringDescriptor and cannot manage to map it's information (project name as String, new name as String and resource path as IPath) to my model. My model is basically a Hashmap in which fully qualified names (String) of types are mapped instances of IJavaElement, or more precisely: IType. How can I "convert" between the two representations so I can update my model? Regards, Chris

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  • String operations

    - by NEO
    I am trying to find the most repeated word in a string. My code is as follows: public class Word { private String toWord; private int Count; public Word(int count, String word){ toWord = word; Count = count; } public static void main(String args[]){ String str="my name is neo and my other name is also neo because I am neo"; String []str1=str.split(" "); Word w1=new Word(0,str1[0]); LinkedList<Word> list = new LinkedList<Word>(); list.add(w1); ListIterator itr = list.listIterator(); for(int i=1;i<str1.length;i++){ while(itr.hasNext()){ if(str1[i].equalsTO(????)); else list.add(new Word(0,str1[i])); } How do I compare the string from string array str1 to the string stored in the linked list and then how do i increase the respective count. I will then print the string with the highest count, I dont know how to do that either.

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  • How do I sort an ArrayList lexicographically?

    - by Jake
    I am trying to sort an ArrayList of Strings that represent card values. So, some cards contain letters ("King") and some contain Strings containing only a number ("7"). I know to use Collections.sort, but it only sorts Strings that contain letters. How do I get the ArrayList to be sorted by number as well as alphabetically?

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  • What is the best practice of using return keyword?

    - by Artic
    What is the best practice of using return keyword? If i need to return something from method which pattern is better to use? public boolean method(){ if (case1){ return true; } if (case 2){ return false; } return false; } or public boolean method(){ boolean result = false; if (case1){ result = true; } if (case 2){ result = false; } return result; }

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  • Declare two classes from eachother.

    - by tumba25
    I'm writing a app in NetBeans. I have two classes MyApp_View and MyApp_Functions. The MyApp_View class starts like this public class MyApp_View extends FrameView { MyApp_Functions My_functions = new MyApp_Functions(); public MyApp_View(SingleFrameApplication app) { super(app); In MyApp_Functions I have MyApp_View my_view = new MyApp_View(null); I want to access the public variables in MyApp_View from MyApp_Functions and the public methods in functions from view, but have no success with this. Is this doable? And how?

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  • ResultSet in JTable

    - by Merin Treesa Joseph
    Sir, How display ResultSet in JTable. i using this code /*String [] record= new String[ColCount]; for (i=0; i } cell[i] = rset1.getString("loginname"); cell[i] = rset1.getString( "role"); System.out.println(cell[i][0]); //ItemGroup = rset1.getString( "Status"); } System.out.println(ItemCode); JTable jt = new JTable( cell[i], headers);*/ but i get only one row that lastly inserted to database.

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  • Variable length Blob in hibernate?

    - by Seth
    I have a byte[] member in one of my persistable classes. Normally, I'd just annotate it with @Lob and @Column(name="foo", size=). In this particular case, however, the length of the byte[] can vary a lot (from ~10KB all the way up to ~100MB). If I annotate the column with a size of 128MB, I feel like I'll be wasting a lot of space for the small and mid-sized objects. Is there a variable length blob type I can use? Will hibernate take care of all of this for me behind the scenes without wasting space? What's the best way to go about this? Thanks!

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  • Get HTTP Get parameters from Restlet Request

    - by Holograham
    I am trying to figure out how to get the parameters from a Restlet request object. my request comes in as /customer?userId=1 and I want to grab the parameter to pass to my DAO for the query. @Get("xml") public Representation toXml() throws ResourceException, Exception { try { //get param from request //call DAO with parameter } catch(Exception e) { throw e; } }

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