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  • How to introduce multi-column constraint with JPA annotations?

    - by plouh
    I am trying to introduce a multi-key constraint on a JPA-mapped entity: public class InventoryItem { @Id private Long id; @Version private Long version; @ManyToOne @JoinColumn("productId") private Product product; @Column(nullable=false); private long serial; } Basically (product, serial) pair should be unique, but I only found a way to say that serial should be unique. This obviously isn't a good idea since different products might have same serial numbers. Is there a way to generate this constraint via JPA or am I forced to manually create it to DB?

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  • Is there some way to assume @Nullable as default? (using FindBugs or any other free tool).

    - by alex2k8
    Consider such code public void m1(String text) { if(text == null) text = "<empty>"; System.out.println(text.toLowerCase()); } And this is a buggy version: public void m1(String text) { System.out.println(text.toLowerCase()); } If null value passed, the NullPointerException may be thrown. I would like the static-analysis tool (e.g. FindBugs) to report this issue. Unsuccessfully the FindBugs (at least by default) requires me to specify @Nullable annotation explicitly. public void m1(@Nullable String text) { System.out.println(text.toLowerCase()); // FindBugs: text must be nonnull but is marked as nullable } The problem is that if I forget to annotate it, the bug will be missed!!! How can I make the FindBugs (or any other free tool) to assume @Nullable by default?

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  • Project works in eclipse but not when exported

    - by Mike
    I wrote an application that uses GraphViz to generate some graphs as .gif's according to the DOT syntax. When I run from Eclipse the images are generated fine but when I export it as a jar the images are created but there is no data in them. When I view them in Microsoft Picture Viewer its just the red X. It was working as an exported jar until I put the picture generation in its own thread. I can't seem to figure out whats going on here. Are there any problems exporting multi-threaded projects? Any one have any ideas? Thanks

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  • Good article about File- and Folder Permissions on production server?

    - by Camran
    I have a classifieds website, and users may post classifieds, add images, remove classifieds etc etc... I have no idea what to set the permissions to on folders. For instance, a php script which I have uploads a file to a directory. What would you have set the directory permissions to? Nobody need access to the directory, only the php script... Just wonder if anybody has a good (brief) article about setting the "right" permissions? Thanks

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  • Date or String declaration in a javabean

    - by Jeff
    Should I declare an attribute in a javabean that holds a date value a user types in on an HTML form as a String or Date? I feel I should declare as a Date, however, since I do server validation on all form data, if the date doesn't validate, when I pass the form bean back to the jsp view for correcting, I lose the date value that the user tried to type in. If I declare as a String, if the date doesn't validate, I'm able to set the string value in the bean and pass the bean back to the view and the user can see what they incorrectly typed. But with a String declaration for Date inputs I forsee problems down the road with my DAO. I want to be able to use a DAO utility which generates a prepare statement using setObject. In my html form I request dates to be mm/dd/yyyy and in DAO i'm using Oracle Date. I can not use hibernate or such, since this is a corporate intranet. What is the best practice "pattern" I should be following??

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  • dynamically changing setRequired to false

    - by E Shindler
    Hi, I'm new to wicket, can someone please tell me how to dynamically setRequired to false. Here is my code: AjaxButton cancel=new AjaxButton("cancel"){ public void onSubmit(AjaxRequestTarget target, Form form){ passwrd.setRequired(false); nameField.setRequired(false); usernameField.setRequired(false); LecturerPage lecturer=new LecturerPage(); setResponsePage(lecturer); } }; addstud.add(cancel); Tomcat is telling me that my feedback panel is being left unrendered(my ok button makes use of a feedback panel). Thank you!

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  • calling a service layer method to my presentation layer

    - by Josepth Vodary
    Ok I feel really dumb asking this but I seem to be missing something really simple here. I have the following code in a class in my service layer - public Items getItems(String category, float amount, String color, String type) The code reads from a database and returns the results - I plan on placing it in a jframe. Nice and simple. But no matter how I call it from the jframe I get errors in eclipse that the code is wrong - either that their are illegal modifiers or such. So obviously I am calling it completely wrong, so my stupid question is how do you call that method into a jframe? For example - if I try to call it this way: public Items getItems(); I get told that getItems is an illegal parameter. If I call this.. Items getItems(); I am told its undefined

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  • Swing: Programmatically select a text

    - by HH
    Hey everyone, I have a very simple Swing GUI with just a JTetxtArea. I am trying to programmatically select a part of text using: textArea.select(startSelection,endSelection); This work. However as soon as I add some other components to the GUI I do not see selection anymore frame.getContentPane().add(button); frame.getContentPane().add(textArea); textArea.select(startSelection,endSelection); I suspect that during layouting the gui, some event causes the text to be deselected. Am I right? And could anybody suggest a solution? My goal is to have a program which displays a text, and allows the user to input start and end selection position, and a selection appears between these two position. Thank you.

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  • proper way to use list to array?

    - by cometta
    public class TestClass{ private String divisions[] ={}; public void doAction(){ Collection testArray = new ArrayList(); // put testArray will data divisions = (String [] ) testArray.toArray(division); //should i use this divisions = (String [] ) testArray.toArray(new String [] {}); //should i use this? } } if i use case 1, and i call doaction multiple time, the division, something will show wrong records if i use case2, divisions will always show the correct records. is my assumption should use case 2?

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  • Android: Referring to a string resource when defining a log name

    - by spookypeanut
    In my Android app, I want to use a single variable for the log name in multiple files. At the moment, I'm specifying it separately in each file, e.g. public final String LOG_NAME = "LogName"; Log.d(LOG_NAME, "Logged output); I've tried this: public final String LOG_NAME = (String) getText(R.string.app_name_nospaces); And while this works in generally most of my files, Eclipse complains about one of them: The method getText(int) is undefined for the type DatabaseManager I've made sure I'm definitely importing android.content.Context in that file. If I tell it exactly where to find getText: Multiple markers at this line - Cannot make a static reference to the non-static method getText(int) from the type Context - The method getText(int) is undefined for the type DatabaseManager I'm sure I've committed a glaringly obvious n00b error, but I just can't see it! Thanks for all help: if any other code snippets would help, let me know.

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  • Exception handling pattern

    - by treefrog
    It is a common pattern I see where the error codes associated with an exception are stored as Static final ints. when the exception is created to be thrown, it is constructed with one of these codes along with an error message. This results in the method that is going to catch it having to look at the code and then decide on a course of action. The alternative seems to be- declare a class for EVERY exception error case Is there a middle ground ? what is the recommended method ?

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  • Sorting an ArrayList of Contacts

    - by Sameera0
    Ok so I have a been making an addressbook application and have pretty much finished all the key features but I am looking to implement a sort feature in the program. I want to sort an Arraylist which is of a type called Contact (contactArray) which is a separate class which contains four fields; name, home number, mobile number and address. So I was looking into using the collection sort yet am not sure how i'd implement this. Is this the right sort I should be using / is it possible to use or should I look into making a custom sort?

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  • How do I manipulate a tree of immutable objects?

    - by Frederik
    I'm building an entire application out of immutable objects so that multi-threading and undo become easier to implement. I'm using the Google Collections Library which provides immutable versions of Map, List, and Set. My application model looks like a tree: Scene is a top-level object that contains a reference to a root Node. Each Node can contain child Nodes and Ports. An object graph might look like this: Scene | +-- Node | +-- Node | +- Port +-- Node | +- Port +- Port If all of these objects are immutable, controlled by a top-level SceneController object: What is the best way to construct this hierarchy? How would I replace an object that is arbitrarily deep in the object tree? Is there a way to support back-links, e.g. a Node having a "parent" attribute?

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  • How to start an activity that is defined in other Android projects?

    - by qichuan
    I have defined some common Activities in a library project and want to reuse these activity in my working project. I declared my library project as Android library, use the fully-qualified name of the Activities and declare them in the AndroidManifest.xml of the new project. However, I get 'Unable to find explicit activity class' error when launching the application. Any other configurations shall I do in order to start the Activities?

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  • Hibernate - Persisting polymorphic joins

    - by Marty Pitt
    Hi I'm trying to understand how to best implement a polymorphic one-to-many in hibernate. Eg: @MappedSuperclass public class BaseEntity { Integer id; // etc... } @Entity public class Author extends BaseEntity {} @Entity public class Post extends BaseEntity {} @Entity public class Comment extends BaseEntity {} And now, I'd like to also persist audit information, with the following class: @Entity public class AuditEvent { @ManyToOne // ? BaseEntity entity; } What is the appropriate mapping for auditEvent.entity? Also, how will Hibernate actually persist this? Would a series of join tables be generated (AuditEvent_Author , AuditEvent_Post, AuditEvent_Comment), or is there a better way? Note, I'd rather not have my other entity classes expose the other side of the join (eg., List<AuditEvent> events on BaseEntity) - but if that's the cleanest way to implement, then it will suffice.

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  • Please explain how Trial Division works for Primality Test

    - by mister_dani
    I came across this algorithm for testing primality through trial division I fully understand this algorithm static boolean isPrime(int N) { if (N < 2) return false; for (int i = 2; i <= Math.sqrt(N); i++) if (N % i == 0) return false; return true; } It works just fine. But then I came across this other one which works just as good but I do not fully understand the logic behind it. static boolean isPrime(int N) { if (N < 2) return false; for (int i = 2; i * i<N; i++) if (N % i == 0) return false; return true; } It seems like i *i < N behaves like i <= Math.sqrt(N). If so, why?

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  • Two forms but only 1 jsp file

    - by joshft91
    Here's what I've got going on. I have one .jsp file. However, I have two forms with multiple inputs inside those forms. What is the best way to detect that one form was submitted but not the other? Here's an example: I have this form: <form name = "login" action="index.jsp" method="get"> Username: <input id="username" name="username" type="text"/><br/> Password: <input id="password" name="password" type="password"/> <input type="submit" Value="Login" ></input> </form> If that button is clicked, I'd like to run this code: String username = request.getParameter("username"); String password = request.getParameter("password"); if((username!= null && !username.trim().equals("")) && (password != null && !username.trim().equals(""))) { DBentry DBentry=new DBentry(); boolean flag = DBentry.isTaken(username); if(flag) {%><script type="text/javascript">alert("Login Successful!");</script><% } else { %><script type="text/javascript">alert("Unrecognized username. Please register!");</script><% } } else { %><script type="text/javascript">alert("Please enter both a username and password!");</script><% } Further down I would have something exactly like it but submitting a different form. Thanks!

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  • Major inconsistencies in Zend Framework

    - by John Nall
    Okay first of all let me just say Zend Framework is the greatest tool I have ever used in 30+ years of programming (well, for web development, Qt wins the desktop market). However, through my use I have noticed some glaring and annoying inconsistencies. For instance, Zend_Form_Element's have a setAttrib() method. Now why the hell is this the only method in that API which is abbrev.? Why then am I using setRequired() instead of setReq()? I have more examples, I am extremely nerd raged about this. It is completely ruining what could have been God's gift to web development. FOR FUTURE REFERENCE NEVER ABBREV. THINGS WHEN MAKING AN API. also always filter data before storing it i m o Who do we talk to about this, where something will actually get done about it?

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  • How to execute query with IN clause in spring?

    - by GK
    I have following code : try { MapSqlParameterSource parameters = new MapSqlParameterSource(); parameters.addValue("ids", year); return this.template.getJdbcOperations().query( "SELECT * FROM INCOME WHERE PROVNUM=? AND FISCALDATE IN ( :ids )", this.rowMapper, parameters); }catch (EmptyResultDataAccessException ex) { return null; } But i am not able to send the value for PROVNUM. how to do that? need help, thanks.

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  • red5: how can i extend ISharedObject ?

    - by ufk
    Hiya. Red5 uses ISharedObject interface to create shared objects and to operate them. because ISharedObject is an interface I'm having issues extending it. I would like to extend the getAttribute, setAttribute, get{Int/String/Map}Attribute so the values will be checked before entered or pulled out. how is it possible to do so ? thanks

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