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  • How to detect column conflicts with Hibernate?

    - by Slim
    So let's say I have an ArrayList full of Products that need to be committed to the database via Hibernate. There are already a large number of Products in the database. Each product has an ID. Note this is NOT the PK that is autogenerated by Hibernate. My questions is: what is the best way to detect conflicts with this ID? I am looking for a relatively efficient method of obtaining, from the the database, a List of Products that share an ID with any of the Products in my ArrayList. This is all in a single table called Products and the ID attribute is in column ProductID. The way I've done it is grabbing a list of all Products in the database, and compared each one with each entry in my ArrayList - but that is seriously inefficient and I don't think it would work well with a larger database. How should it be done? Thanks. I say "relatively" efficient because efficiency is not the primary concern, but it shouldn't take noticeably long to test against a table of ~1000-5000 rows. Help? EDIT* I'm very new to hibernate and below is the best I've come up with. How does this look? for(long id : idList){ //idList just holds the IDs of each Product in my ArrayList Query query = session.createQuery("select product from Product product where product.id = :id"); query.setLong("id", id); for(int i = 0; i < query.list().size(); i++){ listOfConflictingProducts.add((Product) query.list().get(i)); } }

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  • How to update only certain items in a list when using MVC?

    - by Eugen
    I'm building a GUI that includes a list with quite a lot of items. I allow the user to add/delete/edit those items. Up until now my update method called in the controller implied an entire JList reset (with its obvious performance issues). Now that there are hundreds of items available, updating the entire list is not fezable any longer. Does anyone know of a tutorial or can share an example (I haven't found any to suit my needs so far) in which the JList is updated something like JList.update(startIndex, endIndex);? Thanks for taking the time to answer.

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  • Hibernate custom join clause on association

    - by myso
    I would like to associate 2 entities using hibernate annotations with a custom join clause. The clause is on the usual FK/PK equality, but also where the FK is null. In SQL this would be something like: join b on a.id = b.a_id or b.a_id is null From what I have read I should use the @WhereJoinTable annotation on the owner entity, but I'm puzzled about how I specify this condition...especially the first part of it - referring to the joining entity's id. Does anyone have an example?

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  • In JSF, how to handle repeating over a list that mutates

    - by Jon
    Hello, In a JSF page, I am iterating over a list of items provided by a session-scoped backing bean. The list needs to be kept up-to-date, so it is replaced with a fresh list every X minutes by a thread (in a thread-safe way). On my page, for each item I provide some text inputs and an "Update" button. If the list is refreshed before I hit "Update", the update does not happen (which is my problem). I happen to be using a4j:repeat, but I think this could also apply to other methods of iteration, including using dataTables. Any thoughts on how I can do this in a non-hackish way? Thanks!

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  • JVM performance test suite

    - by pierr
    Hi, I have just ported phoneME to our MIPS platform. I feel it runs not that fast; however, is there any performance test suite I can run against to get some quantitative measurement of the performance? I might need to pick some weak points for optimization. In addition, what are common criterions used to evalute a JVM ?

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  • Starting new transaction in Spring bean

    - by Marcus
    We have: @Transactional(propagation = Propagation.REQUIRED) public class MyClass implementes MyInterface { ... MyInterface has a single method: go(). When go() executes we start a new transaction which commits/rollbacks when the method is complete - this is fine. Now let's say in go() we call a private method in MyClass that has @Transactional(propagation = Propagation.REQUIRES_NEW. It seems that Spring "ignores" the REQUIRES_NEW annotation and does not start a new transaction. I believe this is because Spring AOP operates on the interface level (MyInterface) and does not intercept any calls to MyClass methods. Is this correct? Is there any way to start a new transaction within the go() transaction? Is the only way to call another Spring managed bean that has transactions configured as REQUIRES_NEW? Update: Adding that when clients execute go() they do so via a reference to the interface, not the class: @Autowired MyInterface impl; impl.go();

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  • can't explain NullPointerException

    - by John Pope
    In the following code, i have a method to get a Vector of persons with the same zodiac sign. persoane is a Vector. I keep getting a NullPointerException at the if condition (persoane is definetly not null). I am unable to see why. Any help would be greatly appreciated public Vector<Persoana> cautaDupaZodie(String zodie) { Vector<Persoana> rezultat= new Vector<Persoana>(); for(int i=0; i<persoane.size(); i++) { if(persoane.get(i).getData().getZodie().equals(zodie)) //the exception occurs here { rezultat.add(persoane.get(i)); } } return rezultat; }

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  • AtomicInteger lazySet and set

    - by Yan Cheng CHEOK
    May I know what is the difference among lazySet and set method for AtomicInteger. javadoc doesn't talk much about lazySet : Eventually sets to the given value. It seems that AtomicInteger will not immediately be set to the desired value, but it will be scheduled to be set in some time. But, what is the practical use of this method? Any example?

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  • Using enums or a set of classes when I know I have a finite set of different options?

    - by devoured elysium
    Let's say I have defined the following class: public abstract class Event { public DateTime Time { get; protected set; } protected Event(DateTime time) { Time = time; } } What would you prefer between this: public class AsleepEvent : Event { public AsleepEvent(DateTime time) : base(time) { } } public class AwakeEvent : Event { public AwakeEvent(DateTime time) : base(time) { } } and this: public enum StateEventType { NowAwake, NowAsleep } public class StateEvent : Event { protected StateEventType stateType; public MealEvent(DateTime time, StateEventType stateType) : base(time) { stateType = stateType; } } and why? I am generally more inclined to the first option, but I can't explain why. Is it totally the same or are any advantages in using one instead of the other? Maybe with the first method its easier to add more "states", altough in this case I am 100% sure I will only want two states: now awake, and now asleep (they signal the moments when one awakes and one falls asleep).

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  • Jsp declaration element

    - by Stardust
    <%! class father { static int s = 0; } %> <% father f1 = new father(); father f2 = new father(); f1.s++; out.println(f2.s); // It must print "1" %> When I run the file, I got this error. Can anybody explain? "The field s cannot be declared static; static fields can only be declared in static or top level types"

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  • Overriding a method in statically created objects

    - by I82Much
    All, Due to a bug in a library I'm using, I need to override the dispose() method on all objects extending a certain class and make it a NO-OP. I know that if I'm making new instances of the classes directly, this is easy to do: layerManager = new LayerManagerLayer(wwd) { @Override public void dispose() {} }; The problem is that a lot of the object instances I get are not directly constructed by my client code, but instead are created via static library method calls. // Here I want to override the dispose method, but I cannot. Layer l = ShapefileLoader.makeShapefileLayer(this.getClass().getResource("polylines10.shp")); Is there a way I can inject my dispose method into that statically created object without modifying the original sourcecode?

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  • JPA: what is the proper pattern for iterating over large result sets?

    - by Caffeine Coma
    Let's say I have a table with millions of rows. Using JPA, what's the proper way to iterate over a query against that table, such that I don't have all an in-memory List with millions of objects? I suspect that the following will blow up if the table is large: List<Model> models = entityManager().createQuery("from Model m", Model.class).getResultList(); for (Model model : models) { // do something with model } Is pagination (looping and manually updating setFirstResult()/setMaxResult()) really the best solution?

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  • Strategies for dealing with Circular references caused by JPA relationships?

    - by ams
    I am trying to partition my application into modules by features packaged into separate jars such as feature-a.jar, feature-b.jar, ... etc. Individual feature jars such as feature-a.jar should contain all the code for a feature a including jpa entities, business logic, rest apis, unit tests, integration test ... etc. The problem I am running into is that bi-directional relationships between JPA entities cause circular references between the jar files. For example Customer entity should be in customer.jar and the Order should be in order.jar but Customer references order and order references customer making it hard to split them into separate jars / eclipse projects. Options I see for dealing with the circular dependencies in JPA entities: Option 1: Put all the entities into one jar / one project Option 2: Don't map certain bi-directianl relationships to avoid circular dependencies across projects. Questions: What rules / principles have you used to decide when to do bi-directional mapping vs. not? Have you been able to break jpa entities into their own projects / jar by features if so how did you avoid the circular dependencies issues?

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  • getResourceAsStream returns HttpInputStream not of the entire file

    - by khue
    Hi, I am having a web application with an applet which will copy a file packed witht the applet to the client machine. When I deploy it to webserver and use: InputStream in = getClass().getResourceAsStream("filename") ; The in.available() always return a size of 8192 bytes for every file I tried, which means the file is corrupted when it is copied to the client computer. The InputStream is of type HttpInputStream (sun.net.protocol.http.HttpUrlConnection$httpInputStream). But while I test applet in applet viewer, the files are copied fine, with the InputStream returned is of type BufferedInputStream, which has the file's byte sizes. I guess that when getResourceStream in file system the BufferedInputStream will be used and when at http protocol, HttpInputStream will be used. How will I copy the file completely, is there a size limited for HttpInputStream? Thanks a lot.

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  • Android - How can I upload a txt file to a website?

    - by Donal Rafferty
    I want to upload a txt file to a website, I'll admit I haven't looked into it in any great detail but I have looked at a few examples and would like more experienced opinions on whether I'm going in the right direction. Here is what I have so far: DefaultHttpClient httpClient = new DefaultHttpClient(); HttpContext localContext = new BasicHttpContext(); private String ret; HttpResponse response = null; HttpPost httpPost = null; public String postPage(String url, String data, boolean returnAddr) { ret = null; httpClient.getParams().setParameter(ClientPNames.COOKIE_POLICY, CookiePolicy.RFC_2109); httpPost = new HttpPost(url); response = null; StringEntity tmp = null; try { tmp = new StringEntity(data,"UTF-8"); } catch (UnsupportedEncodingException e) { System.out.println("HTTPHelp : UnsupportedEncodingException : "+e); } httpPost.setEntity(tmp); try { response = httpClient.execute(httpPost,localContext); } catch (ClientProtocolException e) { System.out.println("HTTPHelp : ClientProtocolException : "+e); } catch (IOException e) { System.out.println("HTTPHelp : IOException : "+e); } ret = response.getStatusLine().toString(); return ret; } And I call it as follows: postPage("http://www.testwebsite.com", "data/data/com.testxmlpost.xml/files/logging.txt", true)); I want to be able to upload a file from the device to a website. But when trying this way I get the following response back. HTTP/1.1 405 Method Not Allowed Am I trying the correct way or should I be doing it another way?

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  • Identifying the GeoPoint that trigger an onTap call

    - by Akroy
    I'm developing a Google Maps app on Android. I have a number of GeoPoints that I'm displaying by adding them as OverlayItems to an ItemizedOverlay. This works well for displaying them and bringing up a nice box when I click them, however I'm trying to put info in the box it brings up. Thus, I've extended ItemizedOverlay with my own class, and I'm overriding onTap (final GeoPoint p, final MapView mapView). At first I thought that this would be very simple, as one of the parameters is the GeoPoint, so I would know exactly which GeoPoint was clicked. However, from what I can tell, the GeoPoint argument there is the GeoPoint for where the user actually touched. Given the range the user can touch and still trigger the onTap, that GeoPoint isn't very helpful for knowing precisely which GeoPoint was actually touched. I'm currently checking the parameter GeoPoint against all my existing GeoPoints and seeing which it's closest to. This seems like a super hacky abstraction inversion. Is there a better way to know what was actually tapped?

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  • Arrays not matching correctly

    - by Nick Gibson
    userAnswer[] holds the string of the answer the user types in and is comparing it to answers[] to see if they match up and then spits out correct or wrong. j is equal to the question number. So if j was question 6, answers[j] should refer to answers[6] right? Then userAnswer[6] should compare to answers[6] and match if its correct. But its giving me wrong answers and displaying the answer I typed as correct. int abc, loopCount = 100; int j = quesNum, overValue, forLoop = 100; for (int loop = 1; loop < loopCount; loop++) { aa = r.nextInt(10+1); abc = (int) aa; String[] userAnswer = new String[x]; JOptionPane.showMessageDialog(null,abc); if(abc < x) { userAnswer[j] = JOptionPane.showInputDialog(null,"Question "+quesNum+"\n"+questions[abc]+"\n\nA: "+a[abc]+"\nB: "+b[abc]+"\nC: "+c[abc]+"\nD: "+d[abc]); if(userAnswer[j].equals(answers[j])) { JOptionPane.showMessageDialog(null,"Correct. \nThe Correct Answer is "+answers[abc]); } else { JOptionPane.showMessageDialog(null,"Wrong. \n The Correct Answer is "+answers[abc]); }//else }//if }//for

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  • What are the possible causes of JasperException

    - by CitadelCSCadet
    I have a JSP that takes an Arraylist from the session object and removes the items from it. It seemed to be working fine and then out of nowhere when I navigate to that page, the page is blank. I checked the Tomcat log files and in catalina.out I am receiving a JasperException an it is showing it as being on a line with the following for(int i; i < agentItems.size(); i++) agentItems is the name of the ArrayList I am using. I have been debugging it and can't seem to figure out what the problem might be. I have read that a JasperException is sometiems thrown as a JSP's NullPointerException. Is this true or am I just completely overlooking the problem? I have the web application running on a local machine and a intermediate server for development in which both of them have had no trouble. Why could it be that only on this server it is giving me problems?

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  • Disposing a dialog in touch devices in lwuit

    - by MANISH
    I am displaying a dialog when a user touches the screen and want the dialog to dispose when the user touches anywhere outside the dialog.i have set setDisposeWhenPointerOutOfBounds() to true though by default it is...n hav written the following code in pointerReleased() event but whenever the user touches the screen outside of dialog the dialog disposes but not without executing the code that shud be executed only wen the x,y are within the dialog....plz help me out....ne1... public void pointerReleased(int x, int y) { dispose(); if (contains(x, y)) { actionCommand((cmds[l.getSelectedIndex()])); } }

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  • When calling CRUD check if "parent" exists with read or join?

    - by Trick
    All my entities can not be deleted - only deactivated, so they don't appear in any read methods (SELECT ... WHERE active=TRUE). Now I have some 1:M tables on this entities on which all CRUD operations can be executed. What is more efficient or has better performance? My first solution: To add to all CRUD operations: UPDATE ... JOIN entity e ... WHERE e.active=TRUE My second solution: Before all CRUD operations check if entity is active: if (getEntity(someId) != null) { //do some CRUD } In getEntity there's just SELECT * FROM entity WHERE id=? AND active=TRUE. Or any other solution, recommendation,...?

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  • html:checkbox query

    - by sarah
    Hi All, i have the following code . and in Form is have property called isActive of type char ,how would i get the checked value of it ,i am getting some symbols like 'o' if checked. I am using userform.getIsActive() ,where i am going wrong .I want 'y' or 'n' values

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  • Servlet Security question about j_security_check, j_username and j_password

    - by Nitesh Panchal
    Hello, I used jdbcRealm in my web application and it's working fine. I defined all constraints also in my web.xml. Like all pages of url pattern /Admin/* should be accessed by only admin. I have a login form with uses standard j_security_check, j_username and j_password. Now, when i type Admin/home.jsf it rightly redirects me login.jsf and there when i type the password i am redirected to home.jsf. This works alright but problem comes i directly go to login.jsf and then type password and username. This time it again redirects me to login.jsf. Is there any way through which i can specify which page to go when successful login is there? I need to specify different different pages for different roles. For Admin, it is /Admin/home.jsf for general users it is /General/home.jsf because login form is shared between different type of users. Where do i specify all these things? Secondly, i want to have a remember me checkbox at the end of login form. How do i do this? By default, it is submitted to j_security_check servlet and i have no control over its execution. Please help. This doesn't seem so hard but looks like i am missing something.

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  • How to set a bean property before executing this f:event listener

    - by user
    How to set a bean property from jsf page before executing this f:event listener: <f:event type="preRenderComponent" listener="bean.method}"/> I tried the below code but it does not set the value to the bean property. <f:event type="preRenderComponent" listener="bean.method}"> <f:setPropertyActionListener target="#{bean.howMany}" value="2"/> </f:event> JSF2.1.6 with PF 3.3 EDIT Any issues with this below code? (This works! but I just want to confirm if there are any issues with this!?) <f:event type="preRenderComponent" listener="#{bean.setHowMany(15)}"/> <f:event type="preRenderComponent" listener="#{bean.method}"/>

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  • How to center elements in the BoxLayout using center of the element?

    - by Roman
    I use outputPanel.setLayout(new BoxLayout(outputPanel, BoxLayout.Y_AXIS)); and then I add elements (for example JLabels, JButtons) to the outputPanel. For example: outputPanel.add(submitButton);. I see that all added elements are "centered". It is good, because I do want my elements to be in the center. When I write "center" I mean "equal distance from left and right". But the problem is that the left part of the element is put into the center. And I want to have center of elements to be put into the center. How can I get this behavior?

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  • view is not rendered when returning ModelAndView

    - by adancu
    Hi, I have the following problem. I need to export a PDF in a controller The code below, where I return a View, works as expected. @RequestMapping(method = RequestMethod.GET) public View exportReport( @RequestParam(value = "userName", required = true) String userName, @RequestParam(value = "startDate", required = true) Date startDate, @RequestParam(value = "endDate", required = true) Date endDate) { /////////////////////////////////////////// return new TimeSheetReportPdfView(); } The problem occurs if I change the method to return a ModelAndView: @RequestMapping(method = RequestMethod.GET) public ModelAndView exportReport( @RequestParam(value = "userName", required = true) String userName, @RequestParam(value = "startDate", required = true) Date startDate, @RequestParam(value = "endDate", required = true) Date endDate) { /////////////////////////////////////////// return new ModelAndView(new TimeSheetReportPdfView(), model); } Now, the PDF is not exported, all I get is a blank page and nothing in the logs. Any help appreciated. Thanks.

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