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  • Looking for detailed explanation of Hibernate UserType methods for mutable objects

    - by Tom
    I am creating a custom UserType class in Hibernate. The specific case is for an HL7v3 clinical document (I work in health IT). It is a mutable object and most of the documentation around the Hibernate UserType interface seems to center around immutable types. I want a better understanding of how and when the interface methods are used, specifically: assemble - why two parameters (one Serializable, one Object)? What is the use case for this method? disassemble - should I just implement this method to return a serializable form (e.g. String representation)? When and how is this method invoked? equals - is this for update? read? contention? dirty reads? What are the consequences of simply returning false in most cases? replace - I really don't understand where the three Object parameters come from, when this method is invoked, and what Hibernate expects to return, or how that return value is used. Any pointers would be appreciated. I've searched and read all I can find on the subject, but have not found much documentation at all explaining how these methods are used for mutable objects.

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  • Recommend JSP Quiz Tutorials

    - by Sandeep Bansal
    Hi Everyone, I need to make a quiz that uses JSP and servlets but I can't find any tutorials online which can help me create my own one. If there are any can someone recommend me some, I have tried Google and nothing reasonable has come up. Thanks.

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  • do I need to close an audio Clip?

    - by Michael
    have an application that processes real-time data and is supposed to beep when a certain event occurs. The triggering event can occur multiple times per second, and if the beep is already playing when another event triggers the code is just supposed to ignore it (as opposed to interrupting the current beep and starting a new one). Here is the basic code: Clip clickClip public void prepareProcess() { super.prepareProcess(); clickClip = null; try { clipFile = new File("C:/WINDOWS/Media/CHIMES.wav"); ais = AudioSystem.getAudioInputStream(clipFile); clickClip = AudioSystem.getClip(); clickClip.open(ais); fileIsLoaded = true; } catch (Exception ex) { clickClip = null; fileIsLoaded = false; } } public void playSound() { if (fileIsLoaded) { if ((clickClip==null) || (!clickClip.isRunning())) { try { clickClip.setFramePosition(0); clickClip.start(); } catch (Exception ex) { System.out.println("Cannot play click noise"); ex.printStackTrace(); } } } The prepareProcess method gets run once in the beginning, and the playSound method is called every time a triggering event occurs. My question is: do I need to close the clickClip object? I know I could add an actionListener to monitor for a Stop event, but since the event occurs so frequently I'm worried the extra processing is going to slow down the real-time data collection. The code seems to run fine, but my worry is memory leaks. The code above is based on an example I found while searching the net, but the example used an actionListener to close the Clip specifically "to eliminate memory leaks that would occur when the stop method wasn't implemented". My program is intended to run for hours so any memory leaks I have will cause problems. I'll be honest: I have no idea how to verify whether or not I've got a problem. I'm using Netbeans, and running the memory profiler just gave me a huge list of things that I don't know how to read. This is supposed to be the simple part of the program, and I'm spending hours on it. Any help would be greatly appreciated! Michael

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  • Netty options for real-time distribution of small messages to a large number of clients?

    - by user439407
    I am designing a (near) real-time Netty server to distribute a large number of very small messages to a large number of clients across the internet. In internal, go as fast as you can testing, I found that I could do 10k clients no sweat, but now that we are trying to go across the internet, where the latency, bandwidth etc varies pretty wildly we are running into the dreaded outOfMemory issues, even with 2 gigs of RAM. I have tried various workarounds(setting the socket stack sizes smaller, setting high and low water marks, cancelling things that are too old), and they help a little, but they seem to only help a little bit. What would some good ways to optimize Netty for sending large #s of small messages without significant delays? Also, the bulk of the message only consists of one kind of message that I don't particularly care if it doesn't arrive. I would use UDP but because we don't control the client, thats not really a possibility. Is it possible to set a separate timeout solely for this kind of message without affecting the other messages? Any insight you could offer would be greatly appreciated.

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  • JUnit - stop it from exiting on finish?

    - by waitinforatrain
    Hi guys, Quick JUnit question. I'm running some unit tests that involve starting up the GUI and doing a load of stuff. I would like to see the results after the test to confirm it visually. However, it gets to the end of the code and exits, as it should. If I want to override this, I put a breakpoint on the last line of the test. This is pretty awkward though. Is there some option to stop it from exiting?

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  • Hibernate: Check if object exists/changed

    - by swalkner
    Assuming I have an object Person with long id String firstName String lastName String address Then I'm generating a Person-object somewhere in my application. Now I'd like to check if the person exists in the database (= firstname/lastname-combination is in the database). If not = insert it. If yes, check, if the address is the same. If not = update the address. Of course, I can do some requests (first, try to load object with firstname/lastname), then (if existing), compare the address. But isn't there a simpler, cleaner approach? If got several different classes and do not like to have so many queries. I'd like to use annotations as if to say: firstname/lastname = they're the primary key. Check for them if the object exists. address is the parameter you have to compare if it stayed the same or not. Does Hibernate/JPA (or another framework) support something like that? pseude-code: if (database.containsObject(person)) { //containing according to compound keys if (database.containsChangedObject(person)) { database.updateObject(person); } } else { database.insertObject(person); }

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  • Can I use JPA/EJB3 on a table that was created at runtime?

    - by tieTYT
    This is weird and probably not possible but I'll ask anyway. I'm making this app that reads in a meta file and creates some tables then populates them with data. I was wondering if I could somehow use JPA to populate those tables. Obviously, there's no way I could have an entity with annotations on it since the table didn't exist at compile time. But perhaps JPA or the entity manager has a way to load data into a nameless table? If possible, I'd expect a method like entityManager.update("myTableName", hashMapOfColumnNamesAndColumnDataValues);

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  • Setting a value into a object using reflection

    - by marionmaiden
    Hello I have an object that has a lot of attributes, each one with it's getter and setter. Each attribute has a non primitive type, that I don't know at runtime. For example, what I have is this: public class a{ private typeA attr1; private typeB attr2; public typeA getAttr1(){ return attr1; } public typeB getAttr2(){ return attr2; } public void setAttr1(typeA at){ attr1 = at; } public void setAttr2(typeB at){ attr2 = at; } } public class typeA{ public typeA(){ // doesn't matter } } public class typeB{ public typeB(){ // doesn't matter } } So, using reflection, I obtained the setter method for an attribute. Setting a value in the standard way is something like this: a test = new a(); a.setAttr1(new typeA()); But how can I do this using reflection? I already got the setAttr1() method using reflection, but I don't know how to create a new typeA object to be inserted in the setter.

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  • Eclipse antRunner command line build has wrong dependency build order

    - by Sam Jones
    My team's Eclipse RCP app builds fine from the Eclipse IDE. When I try to build it from the command line, using the antRunner application, it builds the plugins out of order -- a plugin builds before it's dependencies are built, and so can't resolve some of the needed classes. Where should I look to fix this? As far as I can tell, the dependencies are set up correctly (a feature that depends on a plugin that depends on another plugin). I have my build.properties and folder structure set up as specified here. Is there anything else I should look at?

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  • Collections of generics

    - by Luis Sep
    According to what I've read, I think this can't be done, but I'd like to be sure. I have a class OpDTO and several other *DTO extends OpDTO. Then, I want to have a method to extract just certain elements from lists of these child DTOs, and return the extracted elements in another list: public List<? extends OpDTO> getLastOp (List<? extends OpDTO> listDTOs) { List<? extends OpDTO> last = new ArrayList<? extends OpDTO>(); //compile error: Cannot instantiate the type ArrayList<? extends OpDTO> //processing return last; } I want ult to be a list of elements of the same kind as elements in listDTOs, and use only OpDTO's methods, but it produces a compile error: Cannot instantiate the type ArrayList<? extends OpDTO> I also tried doing something like: public <T> List<T> getLastOp (List<T> listDTOs) { List<T> last = new ArrayList<T>(); //processing return last; } But then I can't enforce elements in listDTOs to be a subclass of OpDTO, and can't instantiate T. Any idea?

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  • Locating multiple nested If statements using regular expressions

    - by TERACytE
    Is there a way to search for multiple nested if statements in code using a regular expression? For example, an expression that would locate an instance of if statements three or more layers deep with different styles (if, if/else, if/elseif/else): if (...) { <code> if (...) { <code> if (...) <code> } else if (...) { <code> } else { <code> } } else { <code> }

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  • How to get equivalent of ResultSetMetaData without ResultSet

    - by javanix
    Hey Guys - I need to resolve a bunch of column names to column indexes (so as to use some of the nice ResultSetMetaData methods). However, the only way that I know how to get a ResultSetMetaData object is by calling getMetaData() on some ResultSet. The problem I have with that is that grabbing a ResultSet takes up uneccesary resources in my mind - I don't really need to query the data in the table, I just want some information about the table. Does anyone know of any way to get a RSMD object without getting a ResultSet (from a potentially huge table) first? Thanks!

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  • Updating to Spring 2.5.5 causes a javax.servlet.UnavailableException: org.springframework.web.struts

    - by Averroes
    I have been told to update some application from Spring 2.0.8 to Spring 2.5.5. This application is using Struts 1.2.7. Once I change the Spring.jar I get the following exception while loading in JBoss 4.0.5: 10:14:57,579 ERROR [[/PortalRRHH]] Servlet /PortalRRHH threw load() exception javax.servlet.UnavailableException: org.springframework.web.struts.DelegatingTilesRequestProcessor This is defined in the struts-config.xml this way: <controller locale="true"> <set-property property="processorClass" value="org.springframework.web.struts.DelegatingTilesRequestProcessor"/> </controller> I have no clue of what is happening since it works with the old version of Spring and the DelegatingTilesRequestProcessor is still available in Spring 2.5.5. I have no previous experience with Struts so if you need anything else to figure what the problem is please ask and I will update the question. Thanks.

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  • Eclipse and Cassandra

    - by H2oNinja
    I've searched various websites for instructions on how to link 'Cassandra' and 'Eclipse' and followed directions to the last detail in several sites. For some reason, while using Git Bash, I cant get through the 'ant build', via instruction in said mentioned locations across the web. In some location's its easy, just make sure you have; 1. Apache Cassandra source 2. Apache Ant 3. Git So, yeah I've downloaded all the above, tried the same directory, different directories, etc., although still unable to get past the middle step of 'ant build'. Here are a few websites I've used to muddle through setting up the Src code for both utilities, 'Eclipse' and 'Cassandra'. http://uisurumadushanka89.blogspot.com/2012/02/apache-cassandra-how-to-setup-source.html and http://wiki.apache.org/cassandra/RunningCassandraInEclipse both resulting in an immediate halt at the 'ant build'. any insights are information is greatly appreciated. Thank-you, Ryan

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  • problem with JMF !

    - by Razan
    Hi.. I have windows vista OS.. I Installed JMF to work with it.. but it seems I'm having some conflicts between Sound and JMF.. because after I installed JMF my projects that use Sound.. midi.. sequences.. are giving exceptions that they don't have some sound classes and so.. and when I removed JMF every thing went OK !! so what I'm gonna do?

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  • How can I disable all images for an JFace menu but leave them enabled in the toolbar

    - by David
    If I create a set of actions to be used in a JFace application and I assign images to those actions, those images show up in both the toolbar (where I want them) and in the menus (where I don't want them). Other than supplying two completely separate sets of actions (which eliminates part of the point of actions in the first place), how can I arrange to have those images displayed ONLY in the toolbar, and have the menus display only text?

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  • Replacing ORM schema without dropping the entire data

    - by Udi
    Hey, I'm using OpenJPA as a JPA provider. Is there a way in which I can recreate the database tables (When an entity changes) without dropping the entire data? When an entity changes, I drop and create every table in the store, and obviously lose the data within. Is there a tool or product to keep the data somehow? Thanks, Udi

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  • How can i underline a text in JDK5, NOT JDK6

    - by Serkan Kasapbasi
    when i search internet i have found a way to underline font like this, Font f=jLabel1.getFont(); Map<TextAttribute,Object> map = new Hashtable<TextAttribute,Object>(); map.put(TextAttribute.UNDERLINE,TextAttribute.UNDERLINE_ON); f=f.deriveFont(map); jLabel1.setFont(f); it works well on jdk6, however it doesnt work on jdk5, and it doesnt warn about anything. first, how can i get same effect on jdk5? second, why is there a TextAttribute.UNDERLINE constant, if it doesnt work?

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  • Accessing property file through batch script

    - by Farid
    Hi everyone, I'm trying to write a batch script, this script is responsible to launch a jar with one parameters. This parameter indicate to my jar wich property file to use in order to setup some configuration. Then the script will zip the results produced by the jar and send them to a location. But in order to set the name of the zip file I would need to be able to read the property file directly from the batch, is there a way to do so ? Thanks and regards, F

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  • System.out.println() does not operate in Akka actor

    - by faisal abdulai
    I am kind of baffled by this encointer. I am working an akka project that was created as a maven projecct and imported into eclipse using the mvn eclipse:eclipse command. the akka actor has the system println method just to make it easy to do read the functions and methods invoked. However any time I run the akka system, the println command does not print any thing to the eclipse console but I do not get any error messages. does any one have any idea about this. below is a code snippet. public class MasterActor extends UntypedActor { /** * */ ActorSystem system = ActorSystem.create("container"); ActorRef worker1; //public MasterActor(){} @Override public void onReceive(Object message) throws Exception { System.out.println(" Master Actor 5"); if(message instanceof GesturePoints) { //GesturePoints gp = (GesturePoints) message; System.out.println(" Master Actor 1"); try { worker1.tell(message, getSelf()); System.out.println(" Master Actor 2"); } catch (Exception e) { getSender().tell(new akka.actor.Status.Failure(e), getSelf()); throw e; } } else{ unhandled(message);} } public void preStart() { worker1 = getContext().actorFor("akka://[email protected]:2553/user/workerActor"); } } don't know whether it is a bug in eclipse. thank you.

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