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  • ResultSet and aggregation

    - by kachanov
    Ok, I admit my situation is special There is a data system that supports SQL-92 and JDBC interface However the SQL requets are pretty expensive, and in my application I need to retreive the same data multiple times and aggregate it ("group by") on different fields to show different dimensions of the same data. For example on one screen I have three tables that show the same set or records but aggregated by City (1st grid), by Population (2nd grid), by number of babies (3rd grid) This amounts to 3 SQL queries (which is very slow), UNLESS anyone of you can suggest any idea any library from apache commons or from google code, so that I can select all records into ResultSet and get 3 arrays of data group by different fields from this single ResultSet. Am I'm missing some obvious and unexpected solution to this problem?

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  • log4j rootLogger seems to inherit log level of other logger. Why?

    - by AndrewR
    I've got a log4J setup in which the root logger is supposed to log ERROR level messages and above to the console and another logger logs everything to syslog. log4j.properties is: # Root logger option log4j.rootLogger=ERROR,R log4j.appender.R=org.apache.log4j.ConsoleAppender log4j.appender.R.layout=org.apache.log4j.PatternLayout log4j.appender.R.layout.ConversionPattern=%d %p %t %c - %m%n log4j.logger.SGSearch=DEBUG,SGSearch log4j.appender.SGSearch=org.apache.log4j.net.SyslogAppender log4j.appender.SGSearch.SyslogHost=localhost log4j.appender.SGSearch.Facility=LOCAL6 log4j.appender.SGSearch.layout=org.apache.log4j.PatternLayout log4j.appender.SGSearch.layout.ConversionPattern=[%-5p] %m%n In code I do private static final Logger logger = Logger.getLogger("SGSearch"); . . . logger.info("Commencing snapshot index [" + args[1] + " -> " + args[2] + "]"); What is happening is that I get the console logging for all logging levels. What seems to be happening is that the level for SGSearch overrides the level set for the root logger somehow. I can't figure it out. I have confirmed that Log4J is reading then properties file I think it is, and no other (via the -Dlog4j.debug option)

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  • Advantages of using a Dynamic Client with JAX-WS

    - by jconlin
    What are the advantages of using a dynamic client with JAX-WS services as opposed to just using generated client classes? What are the disadvantages? **For my particular case I am using Apache CXF, I'm not sure what other libraries allow "dynamic" clients. -I thought I didn't need to add this, but... I'm looking for non-obvious(I know...subjective) advantages. I don't need someone else to tell me that an advantage of not using generated classes is that I don't need to generate classes.

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  • javax.persistence.NoResultException: getSingleResult() did not retrieve any entities

    - by apple1988
    Hello, i have created a namedquery with ejb to check if the username is used. When the singleResult is null, then i get the following Exception : javax.persistence.NoResultException: getSingleResult() did not retrieve any entities But this exception is the result that i want when the username is free. ^^ Here is the code: public User getUserByUsername(String username) throws DAOException{ try{ Query q = em.createNamedQuery(User.getUserByUsername); q.setParameter("username", username); return (User) q.getSingleResult(); }catch(Exception e){ throwException(username, e); return null; } } Does anybody know what the problem is. :( I will return null andy don`t get an Exception. Thank you very much

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  • Which use cases make temporary JMS queues a better choice than persistent queues?

    - by Stephen Harmon
    When you are designing a JMS application, which use cases make you pick temporary queues over persistent queues? We use temporary queues for response messages. We're having some issues maintaining connections to the temp queues, though, so I am testing persistent response queues, instead. One clear disadvantage of persistent queues is that your application has to "know" about them beforehand. If that's not a big deal, though, are there use cases where temp queues are the obvious choice?

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  • Using switch and enumerations as substitute for named methods

    - by MatthewMartin
    This pattern pops up a lot. It looks like a very verbose way to move what would otherwise be separate named methods into a single method and then distinguished by a parameter. Is there any good reason to have this pattern over just having two methods Method1() and Method2() ? The real kicker is that this pattern tends to be invoked only with constants at runtime-- i.e. the arguments are all known before compiling is done. public enum Commands { Method1, Method2 } public void ClientCode() { //Always invoked with constants! Never user input. RunCommands(Commands.Method1); RunCommands(Commands.Method2); } public void RunCommands(Commands currentCommand) { switch (currentCommand) { case Commands.Method1: // Stuff happens break; case Commands.Method2: // Other stuff happens break; default: throw new ArgumentOutOfRangeException("currentCommand"); } }

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  • Tomcat Http and Https on the same port

    - by Ofri Dagan
    Hi, I have a web-service endpoint and a http connector on port X. At some point this endpoint needs to switch to https, but on the same port! (I know this is not the normal way of doing things, but this is what my clients expect from an old server they are using...) Is there a way to do it in tomcat?

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  • stop thread that does not get interrupted

    - by prmatta
    I have a thread that sits and reads objects off of an ObjectInputStream: public void run() { try { ois = new ObjectInputStream(clientSocket.getInputStream()); Object o; while ((o = ois.readObject()) != null) { //do something with object } } catch (Exception ex) { //Log exception } } readObject does not throw InterruptedException and as far as I can tell, no exception is thrown when this thread is interrupted. How do I stop this thread?

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  • Problem with button addition when double clicking a command label

    - by mistique
    Hy, I got an intersting problem which I stumbled upon. When I double click a label in a JLabel I want to add another button in a JPanel, its a shorter way to make a dragg and drop. The problem is that the button doesn't appears only if i'll position the mouse on the area the button should appear. Why does it happens this way? Anyone got a clue? Are there some thread related issues involved? Thanks in advance

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  • Format attribute of <bean:write> tag in Struts

    - by Sushant Taneja
    Hello All, I am developing a web application using Struts 1.2.7 I want to print a list of integers using the tag. I searched and found that the format attribute is used to print the desired result but was unsuccessful. What should I pass as the value in format to print 3 digit integers/floating point numbers. The code sample is as follows: <logic:iterate name="intList" id="integer" > <bean:write name="integer" /> <logic:iterate /> Here intList is a List of int(s) passed as a request attribute to the jsp page under consideration.

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  • Method with throws Exception: Where is it actually handled?

    - by Esq
    Here is an example code, I am throwing an exception here, it works perfectly fine without the try/catch block of code for some reason. Do I have to handle this inside this method "EntryDelete" or Do I have to handle this where the method is called from? If so can I see an example, what do I have to import in there? What is the acceptable syntax or method to do this? public boolean EntryDelete(int entryId) throws SQLException{ this.open(); kDatabase.delete(kENTRY_TABLE, kENTRY_ENTRY_ID + "=" + entryId, null); this.close(); return true; } Thanks

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  • Ref to map vs. map to refs vs. multiple refs

    - by mikera
    I'm working on a GUI application in Swing+Clojure that requires various mutable pieces of data (e.g. scroll position, user data, filename, selected tool options etc.). I can see at least three different ways of handling this set of data: Create a ref to a map of all the data: (def data (ref { :filename "filename.xml" :scroll [0 0] })) Create a map of refs to the individual data elements: (def datamap { :filename (ref "filename.xml") :scroll (ref [0 0]) })) Create a separate ref for each in the namespace: (def scroll (ref [0 0])) (def filename (ref "filename.xml")) Note: This data will be accessed concurrently, e.g. by background processing threads or the Swing event handling thread. However there probably isn't a need for consistent transactional updates of multiple elements. What would be your recommended approach and why?

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  • Spring MVC: should service layer be returning operation specific DTO's ?

    - by arrages
    In my Spring MVC application I am using DTO in the presentation layer in order to encapsulate the domain model in the service layer. The DTO's are being used as the spring form backing objects. hence my services look something like this: userService.storeUser(NewUserRequestDTO req); The service layer will translate DTO - Domain object and do the rest of the work. Now my problem is that when I want to retrieve a DTO from the service to perform say an Update or Display I can't seem to find a better way to do it then to have multiple methods for the lookup that return different DTO's like... EditUserRequestDTO userService.loadUserForEdit(int id); DisplayUserDTO userService.loadUserForDisplay(int id); but something does not feel right about this approach. The reason do have separate DTO's is that DisplayUserDTO is strongly typed to be read only and also there are many properties of user that are entities from a lookup table in the db (like city and state) so the DisplayUserDTO would have the string description of the properties while the EditUserRequestDTO will have the id's that will back the select drop down lists in the forms. What do you think? thanks

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  • JavaMe Bluetooth service registration

    - by NoGlue
    Hello, I am trying to develope an application that offers a service via bluetooth. Everything works fine in the emulator but as soon I install it on a real device (6120/X6 Nokia) the service cannot be found. If I search for already registered services such as OBEX they are found. So I think it has something to do with the registration. This is how I register the service, all of this happens in its own thread. try { LocalDevice.getLocalDevice().setDiscoverable(DiscoveryAgent.GIAC); } catch (BluetoothStateException e) { } try { notifier = (StreamConnectionNotifier) Connector.open(m_url); ServiceRecord sr = local.getRecord(notifier); StreamConnection conn = notifier.acceptAndOpen(); } catch (IOException e) { } And this is what m_url looks like: "btspp://localhost:" + 0x1116 + ";name=BlueMatch"; Thanks for your time. Best regards

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  • How to detect Out Of Memory condition?

    - by Jaromir Hamala
    I have an application running on Websphere Application Server 6.0 and it crashes nearly every day because of Out-Of-Memory. From verbose GC is certain there are the memory leaks(many of them) Unfortunately the application is provided by external vendor and getting things fixed is slow & painful process. As part of the process I need to gather the logs and heapdumps each time the OOM occurs. Now I'm looking for some way how to automate it. Fundamental problem is how to detect OOM condition. One way would be to create shell script which will periodically search for new heapdumps. This approach seems me a kinda dirty. Another approach might be to leverage the JMX somehow. But I have little or no experience in this area and don't have much idea how to do it. Or is in WAS some kind of trigger/hooks for this? Thank you very much for every advice!

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  • ExecutorSerrvice memory leak on exception

    - by TofuBeer
    I am having a hard time tracking this down since the profiler keeps crashing (hotspot error). Before I go too deep into figuring it out I'd like to know if I really have a problem or not :-) I have a few thread pools created via: Executors.newFixedThreadPool(10); The threads connect to different web sites and, on occasion, I get connection refused and wind up throwing an exception. When I later on call Future.get() to get the result it will then catch the ExecutionException that wraps the exception that was thrown when the connection could not be made. The program uses a fairly constant amount of memory up until the point in time that the exceptions get thrown (they tend to happen in batches when a particular site is overloaded). After that point the memory again remains constant but at a higher level. So my question is along the lines of is the memory behaviour (reported by "top" on Unix) expected because the exceptions just triggered something or do I probably have an actual leak that I'll need to track down? Additionally when Future.get() throws an exception is there anything else I need to do besides catch the exception (such as call Future.cancel() on it)?

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  • Using exponential smoothing with NaN values

    - by Eric
    I have a sample of some kind that can create somewhat noisy output. The sample is the result of some image processing from a camera, which indicates the heading of a blob of a certain color. It is an angle from around -45° to +45°, or a NaN, which means that the blob is not actually in view. In order to combat the noisy data, I felt that exponential smoothing would do the trick. However, I'm not sure how to handle the NaN values. On the one hand, involving them in the math would result in a NaN average, which would then prevent any meaningful results. On the other hand, ignoring NaN values completely would mean that a "no-detection" scenario would never be reported. And just to complicate things, the data is also noisy in that it can get false NaN value, which ideally would be smoothed somehow to prevent random noise. Any ideas about how I could implement such an exponential smoother?

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  • Formatting my String

    - by pringlesinn
    I need to write currency values like $35.40 (thirty five dollars and forty cents) and after that, i want to write some "****" so at the end it will be: thirty five dollars and forty cents********* in a maximun of 100 characters I've asked a question about something very likely but I couldn't understand the main command. String format = String.format("%%-%ds", 100); String valorPorExtenso = String.format(format, new Extenso(tituloTO.getValor()).toString()); What do I need to change on format to put *** at the end of my sentence? The way it is now it puts spaces.

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  • Revalidate JPanel's parent frame

    - by Tom Brito
    I need show/hide some fields of my panel, and I want the panel to fit the frame. How could I notify to the parent frame to revalidate? I think in pass the frame to my panel's constructor, but I think may have a way this is already done. I remember that there was a protected attribute in JPanel, but there isn't.. maybe i remembering the wrong component.

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