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  • Saving tree-structures in Databases

    - by Nina Null
    Hello everyone. I use Hibernate/Spring and a MySQL Database for my data management. Currently I display a tree-structure in a JTable. A tree can have several branches, in turn a branch can have several branches (up to nine levels) again, or having leaves. Lately I have performanceproblemes, as soon as I want to create new branches on deeper levels. At this time a branch has a foreign key to its parent. The domainobject has access to its parent by calling getParent(), which returns the parent-branch. The deeper the level, the longer it takes to create a new branch. Microbenchmark results for creating a new branch are like: Level 1: 32 ms. Level 3: 80 ms. Level 9: 232 ms. Obviously the level (which means the number of parents) is responsible for this. So I wanted to ask, if there are any appendages to work around this kind of problem. I don’t understand why Hibernate needs to know about the whole object tree (all parents until the root) while creating a new branch. But as far as I know this can be the only reason for the delay while creating a new branch, because a branch doesn’t have any other relations to any other objects. I would be very thankful for any workarounds or suggestions. greets, jambusa

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  • Maven: add a dependency to a jar by relative path

    - by flybywire
    I have a proprietary jar that I want to add to my pom as a dependency. But I don't want to add it to a repository. The reason is that I want my usual maven commands such as mvn compile, etc, to work out of the box. (Without demanding from the developers a to add it to some repository by themselves). I want the jar to be in a 3rdparty lib in source control, and link to it by relative path from the pom.xml file. Can this be done? How?

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  • is this possible with activex controls ?

    - by Youssef AZARI
    Hello, I'm developping an Activex controller for IE7. I want to check version of flash+svg and install it if missing or old, and also change some settings in IE like setting up the printer to use landscape format.. I'm completly new to activex, so i'm trying to figure out how to do it, can you please post some pointers ? is what i'm trying to do possible with activex controls ? Thanks

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  • Managed bean property value not set to null

    - by Vladimir
    Hi! I'm new to JSF, so this question might be strange. I have an inputText component's value bound to managed bean's property of type Float. I need to set property to null when inputText field is empty, not to 0 value. It's not done by default, so I added converter with the following method implemented: public Object getAsObject(FacesContext arg0, UIComponent arg1, String arg2) throws ConverterException { if (StringUtils.isEmpty(arg2)) { return null; } float result = Float.parseFloat(arg2); if (result == 0) { return null; } return result; } I registered converter, and assigned it to inputText component. I logged arg2 argument, and also logged return value from getAsObject method. By my log I can see that it returns null value. But, I also log setter property on backing bean and argument is 0 value, not null as expected. To be more precise, it is setter property is called twice, once with null argument, second time with 0 value argument. It still sets backing bean value to 0. How can I set value to null? Thanks in advance.

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  • Get the ID of a Child in a cascade="all" relationship, while adding it to a collection, in Hibernate

    - by Marco
    Hi, i have two Entities, "Parent" and "Child", that are linked through a bidirectional one-to-many relationship with the cascade attribute set to "all". When adding a Child object to the Parent children collection using the code below, i can't get the ID of the persisted child until i commit the transaction: Parent p = (Parent) session.load(Parent.class, pid); Child c = new Child(); p.addChild(c); // "c" hasn't an ID (is always zero) However, when i persist a child entity by explicitly calling the session.save() method, the ID is created and set immediately, even if the transaction hasn't been committed: Child c = new Child(); session.save(c); // "c" has an ID Is there a way to get the ID of the child entity immediately without calling the session.save() method? Thanks

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  • Getting 404 when attempting to POST file to Google Cloud Storage from service account

    - by klactose
    I'm wondering if anyone can tell me the proper syntax & formatting for a service account to send a POST Object to bucket request? I'm attempting it programmatically using the HttpComponents library. I manage to get a token from my GoogleCredential, but every time I construct the POST request, I get: HTTP/1.1 403 Forbidden <?xml version='1.0' encoding='UTF-8'?><Error><Code>AccessDenied</Code><Message>Access denied.</Message><Detailsbucket-name</Details></Error The Google documentation that describes the request methods, mentions posting using html forms, but I'm hoping that wasn't suggesting the ONLY way to get the job done. I know that HttpComponents has a way to explicitly create form data by using UrlEncodedFormEntity, but it doesn't support multipart data. Which is why I went with using the MultipartEntity class. My code is below: MultipartEntity entity = new MultipartEntity( HttpMultipartMode.BROWSER_COMPATIBLE ); String token = credential.getAccessToken(); entity.addPart("Authorization", new StringBody("OAuth " + token)); String date = formatDate(new Date()); entity.addPart("Date", new StringBody(date)); entity.addPart("Content-Encoding", new StringBody("UTF-8")); entity.addPart("Content-Type", new StringBody("multipart/form-data")); entity.addPart("bucket", new StringBody(bucket)); entity.addPart("key", new StringBody("fileName")); entity.addPart("success_action_redirect", new StringBody("/storage")); File uploadFile = new File("pathToFile"); FileBody fileBody = new FileBody(uploadFile, "text/xml"); entity.addPart("file", fileBody); httppost.setEntity(entity); System.out.println("Posting URI = "+httppost.toString()); HttpResponse response = client.execute(httppost); HttpEntity resp_entity = response.getEntity(); As I mentioned, I am able to get an actual token, so I'm pretty sure the problem is in how I've formed the request as opposed to not being properly authenticated. Keep in mind: This is being performed by a service account. Which means that it does have Read/Write access Thanks for reading, and I appreciate any help!

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  • Handling multiple exceptions

    - by the-banana-king
    Hi there, I have written a class which loads configuration objects of my application and keeps track of them so that I can easily write out changes or reload the whole configuration at once with a single method call. However, each configuration object might potentially throw an exception when doing IO, yet I do not want those errors to cancel the overall process so that the other objects are still given a chance to reload/write. Therefore I collect all exceptions which are thrown while iterating over the objects and store them in a super-exception, which is thrown after the loop, since each exception must still be handled and someone has to be notified of what exactly went wrong. However, that approach looks a bit odd to me. Someone out there with a cleaner solution? Here is some code of the mentioned class: public synchronized void store() throws MultipleCauseException { MultipleCauseException me = new MultipleCauseException("unable to store some resources"); for(Resource resource : this.resources.values()) { try { resource.store(); } catch(StoreException e) { me.addCause(e); } } if(me.hasCauses()) throw me; }

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  • What if a large number of objects are passed to my SwingWorker.process() method?

    - by Trejkaz
    I just found an interesting situation. Suppose you have some SwingWorker (I've made this one vaguely reminiscent of my own): public class AddressTreeBuildingWorker extends SwingWorker<Void, NodePair> { private DefaultTreeModel model; public AddressTreeBuildingWorker(DefaultTreeModel model) { } @Override protected Void doInBackground() { // Omitted; performs variable processing to build a tree of address nodes. } @Override protected void process(List<NodePair> chunks) { for (NodePair pair : chunks) { // Actually the real thing inserts in order. model.insertNodeInto(parent, child, parent.getChildCount()); } } private static class NodePair { private final DefaultMutableTreeNode parent; private final DefaultMutableTreeNode child; private NodePair(DefaultMutableTreeNode parent, DefaultMutableTreeNode child) { this.parent = parent; this.child = child; } } } If the work done in the background is significant then things work well - process() is called with relatively small lists of objects and everything is happy. Problem is, if the work done in the background is suddenly insignificant for whatever reason, process() receives a huge list of objects (I have seen 1,000,000, for instance) and by the time you process each object, you have spent 20 seconds on the Event Dispatch Thread, exactly what SwingWorker was designed to avoid. In case it isn't clear, both of these occur on the same SwingWorker class for me - it depends on the input data, and the type of processing the caller wanted. Is there a proper way to handle this? Obviously I can intentionally delay or yield the background processing thread so that a smaller number might arrive each time, but this doesn't feel like the right solution to me.

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  • getRequestProperty("Authorization") always returns null

    - by Thilo
    I am trying to read the authorization header for an HTTP request (because I need to add something to it), but I always get null for the header value. Other headers work fine. public void testAuth() throws MalformedURLException, IOException{ URLConnection request = new URL("http://google.com").openConnection(); request.setRequestProperty("Authorization", "MyHeader"); request.setRequestProperty("Stackoverflow", "anotherHeader"); // works fine assertEquals("anotherHeader", request.getRequestProperty("Stackoverflow")); // Auth header returns null assertEquals("MyHeader", request.getRequestProperty("Authorization")); } Am I doing something wrong? Is this a "security" feature? Is there a way to make this work with URLConnection, or do I need to use another HTTP client library?

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  • Inheriting the main method

    - by Eric
    I want to define a base class that defines a main method that instantiates the class, and runs a method. There are a couple of problems though. Here is the base class: public abstract class Strategy { abstract void execute(SoccerRobot robot); public static void main(String args) { Strategy s = new /*Not sure what to put here*/(); s.execute(new SoccerRobot()) } } And here is an example derived class: public class UselessStrategy { void execute(SoccerRobot robot) { System.out.println("I'm useless") } } It defines a simple execute method, which should be called in a main method upon usage as a the main application. However, in order to do so, I need to instantiate the derived class from within the base class's main method. Which doesn't seem to be possible. I'd rather not have to repeat the main method for every derived class, as it feels somewhat unnessary. Is there a right way of doing this?

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  • Hibernate criteria with projection not performing query for @OneToMany mapping

    - by Josh
    I have a domain object, Expense, that has a field called initialFields. It's annotated as so: @OneToMany(fetch = FetchType.EAGER, cascade = { CascadeType.ALL }, orphanRemoval = true) @JoinTable(blah blah) private final List<Field> initialFields; Now I'm trying to use Projections in order to only pull certain fields for performance reasons, but when doing so the initialFields field is always null. It's the only OneToMany field and the only field I am trying to retrieve with the projection that is behaving this way. If I use a regular HQL query initialFields is populated appropriately, but of course I can't limit the fields. Anyone ever seen anything like this?

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  • How to add an element to an array without a modification of the old array or creation a new one?

    - by Roman
    I have the following construction: for (String playerName: players). I would like to make a loop over all players plus one more special player. But I do not want to modify the players array by adding a new element to it. So, what can I do? Can I replace players in the for (String playerName: players) by something containing all elements of the players plus one more element?

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  • Why a EDT violation happens?

    - by Roman
    I started to use CheckThreadViolationRepaintManager to detect EDT violations. It complains about: partner = getParameter("partner",generatePartnerSelectionPanel(),Design.partnerSelectionDuration); Because it does not like generatePartnerSelectionPanel() because it does not like JPanel panel = new JPanel(); in this method. But I cannot find out why there should be a problem around that. In more details, generatePartnerSelectionPanel() generates a JPanel (I do it not in the EDT) but then, in the getParameter I add the JPanel to the main JFrame and I do it in the EDT (using invokeLater). So, why there should be a problem?

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  • JoinColumn name not used in sql

    - by Vladimir
    Hi! I have a problem with mapping many-to-one relationship without exact foreign key constraint set in database. I use OpenJPA implementation with MySql database, but the problem is with generated sql scripts for insert and select statements. I have LegalEntity table which contains RootId column (among others). I also have Address table which has LegalEntityId column which is not nullable, and which should contain values referencing LegalEntity's "RootId" column, but without any database constraint (foreign key) set. Address entity is mapped: @Entity @Table(name="address") public class Address implements Serializable { ... @ManyToOne(fetch=FetchType.LAZY, optional=false) @JoinColumn(referencedColumnName="RootId", name="LegalEntityId", nullable=false, insertable=true, updatable=true, table="LegalEntity") public LegalEntity getLegalEntity() { return this.legalEntity; } } SELECT statement (when fetching LegalEntity's addresses) and INSERT statment are generated: SELECT t0.Id, .., t0.LEGALENTITY_ID FROM address t0 WHERE t0.LEGALENTITY_ID = ? ORDER BY t0.Id DESC [params=(int) 2] INSERT INTO address (..., LEGALENTITY_ID) VALUES (..., ?) [params=..., (int) 2] If I omit table attribute from mentioned statements are generated: SELECT t0.Id, ... FROM address t0 INNER JOIN legalentity t1 ON t0.LegalEntityId = t1.RootId WHERE t1.Id = ? ORDER BY t0.Id DESC [params=(int) 2] INSERT INTO address (...) VALUES (...) [params=...] So, LegalEntityId is not included in any of the statements. Is it possible to have relationship based on such referencing (to column other than primary key, without foreign key in database)? Is there something else missing? Thanks in advance.

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  • App Engine datastore does not support operator OR

    - by JohnIdol
    I am trying to query the google datastore for something like (with pm -- persistanceManager): String filters = "( field == 'value' || field == 'anotherValue' )"; Query query = pm.newQuery(myType.class, filters); When I execute - I am getting back: App Engine datastore does not support operator OR. What's the best approach in people experience for this kind of queries? Any help appreciated!

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  • 64 bits ant.jar

    - by sonic
    I have installed 64 bits RHEL. I have following questions regarding ant.jar for the system. I was not able to find ant.jar build with 64 bit JVM from the apache website. Do I have to build it form the source code, if I intend to run the jar on 64 bit JVM? Would it speed up the build process if I use ant.jar build with 64 bit JVM and run it on 64 bit JVM?

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  • JAXB Customizations and List<Object>

    - by DaUltimateTrooper
    Hi everybody. I used JAXB to create some classes from an XSD. The result was not quite what I expected and most probably it can be customized. It created a generic list instead of 3 different lists. Can this be corrected somehow? @XmlElements({ @XmlElement(name = "M1", type = M1_Type.class), @XmlElement(name = "M2", type = M2_Type.class), @XmlElement(name = "M3", type = M3_Type.class) }) protected List<Object> m1Orm2OrM3; Is there a customization to fix this?

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  • Netbeans Error: "Could not add one or more tag libraries"

    - by JJ4UC
    I am using Netbeans 6.1 and Tomcat 6.0.1.6. I made some very minor changes to a project that had been working and now I am getting the following error: com.sun.rave.web.ui.appbase.ApplicationException: org.apache.jasper.JasperException: Could not add one or more tag libraries. The only change I made was to a backing bean method, no new UI components, jsp, etc. Any direction would be greatly appreciated. Thanks!

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  • JAX-RS --- How to return JSON and HTTP Status code together?

    - by masato-san
    I'm writing REST web app (Netbean6.9, JAX-RS, Toplink-essential) and trying to return JSON and Http status code. I have code ready and working just to return JSON when HTTP GET Method is called from client. Code snippet @Path("get/id") @GET @Produces("application/json") public M_?? getMachineToUpdate(@PathParam("id") String id) { //some code to return JSON . . return myJson But I also want to return HTTP status code (500, 200, 204 etc) along with returning JSON. I tried using HttpServletResponse object, response.sendError("error message", 500); But this made browser to think it's real 500 so output web page was regular Http 500 error page. What I want to is just to return status code so that my Javascript on client side can handle some logic depending on what HTTP status code is returned. (maybe just to display the error code and message on html page.) Is it possible to do so? or should HTTP status code not be used for such thing?

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  • I need data structure for effective handling with dates

    - by ante.sabo
    What I need is something like Hashtable which I will fill with prices that were actual at desired days. For example: I will put two prices: January 1st: 100USD, March 5th: 89USD. If I search my hashtable for price: hashtable.get(February 14th) I need it to give me back actual price which was entered at Jan. 1st because this is the last actual price. Normal hashtable implementation won't give me back anything, since there is nothing put on that dat. I need to see if there is such implementation which can find quickly object based on range of dates.

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  • Download dynaic file with GWT

    - by Maksim
    I have a GWT page where user enter data (start date, end date, etc.), then this data goes to the server via RPC call. On the server I want to generate Excel report with POI and let user save that file on their local machine. This is my test code to stream file back to the client but for some reason it does not know: public class ReportsServiceImpl extends RemoteServiceServlet implements ReportsService { public String myMethod(String s) { File f = new File("/excelTestFile.xls"); String filename = f.getName(); int length = 0; try { HttpServletResponse resp = getThreadLocalResponse(); ServletOutputStream op = resp.getOutputStream(); ServletContext context = getServletConfig().getServletContext(); resp.setContentType("application/octet-stream"); resp.setContentLength((int) f.length()); resp.setHeader("Content-Disposition", "attachment; filename*=\"utf-8''" + filename + ""); byte[] bbuf = new byte[1024]; DataInputStream in = new DataInputStream(new FileInputStream(f)); while ((in != null) && ((length = in.read(bbuf)) != -1)) { op.write(bbuf, 0, length); } in.close(); op.flush(); op.close(); } catch (Exception ex) { ex.printStackTrace(); } return "Server says: " + filename; } } I've red somewhere on internet that you can't do file stream with RPC and I have to use Servlet for that. Is there any example of how to use Servlet and how to call that servlet from ReportsServiceImpl

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