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  • Error with Property Validation in Form Submission in ASP.NET MVC

    - by Maxim Z.
    I have a simple form on an ASP.NET MVC site that I'm building. This form is submitted, and then I validate that the form fields aren't null, empty, or improperly formatted. However, when I use ModelState.AddModelError() to indicate validation errors from my controller code, I get an error when my view is re-rendered. In Visual Studio, I get that the following line is highlighted as being the location of the error: <%=Html.TextBox("Email")%> The error is the following: NullReferenceException was unhandled by user code - object reference not set to an instance of an object. My complete code for that textbox is the following: <p> <label for="Email">Your Email:</label> <%=Html.TextBox("Email")%> <%=Html.ValidationMessage("Email", "*") %> </p> Here's how I'm doing that validation in my controller: try { System.Net.Mail.MailAddress address = new System.Net.Mail.MailAddress(email); } catch { ModelState.AddModelError("Email", "Should not be empty or invalid"); } return View(); Note: this applies to all of my fields, not just my Email field, as long as they are invalid.

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  • How to use SQLErrorCodeSQLExceptionTranslator and DAO class with @Repository in Spring?

    - by GuidoMB
    I'm using Spring 3.0.2 and I have a class called MovieDAO that uses JDBC to handle the db. I have set the @Repository annotations and I want to convert the SQLException to the Spring's DataAccessException I have the following example: @Repository public class JDBCCommentDAO implements CommentDAO { static JDBCCommentDAO instance; ConnectionManager connectionManager; private JDBCCommentDAO() { connectionManager = new ConnectionManager("org.postgresql.Driver", "postgres", "postgres"); } static public synchronized JDBCCommentDAO getInstance() { if (instance == null) instance = new JDBCCommentDAO(); return instance; } @Override public Collection<Comment> getComments(User user) throws DAOException { Collection<Comment> comments = new ArrayList<Comment>(); try { String query = "SELECT * FROM Comments WHERE Comments.userId = ?"; Connection conn = connectionManager.getConnection(); PreparedStatement stmt = conn.prepareStatement(query); stmt = conn.prepareStatement(query); stmt.setInt(1, user.getId()); ResultSet result = stmt.executeQuery(); while (result.next()) { Movie movie = JDBCMovieDAO.getInstance().getLightMovie(result.getInt("movie")); comments.add(new Comment(result.getString("text"), result.getInt("score"), user, result.getDate("date"), movie)); } connectionManager.closeConnection(conn); } catch (SQLException e) { e.printStackTrace(); //CONVERT TO DATAACCESSEXCEPTION } return comments; } } I Don't know how to get the Translator and I don't want to extends any Spring class, because that is why I'm using the @Repository annotation

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  • Creating a draft version of the page before publishing in Drupal 6?

    - by Marco
    I've been looking for a good way to handle revisions in Drupal, but I am yet to succeed. For some reason there is no built in way to save a draft (that I've found so far), and the modules I've tried so far do not seem to fully work. First I tried save_as_draft, which seemed to do almost what I wanted, and if I'm not mistaken, also handles CCK fields. Sadly it seems to be broken somehow, so I can't edit a page once I've saved it as a draft.. maybe I could fix it by going through the code, but that would not be my preferred solution. The other module I tried is aptly named draft, but from what I can tell, this module only handles the title and body fields, and does this in a way that appear odd to me. Is there some common practice to solve this? I couldn't imagine that nobody had to solve this before, but I haven't found any good solution to it yet. Clarification I need this functionality for already existing content, that is, I want to be able to create and edit a draft version of an already published page, while the "old" version would still be available to anonymous users.

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  • Should I remove all inheritance from my model in order to work with ria services?

    - by TimothyP
    I've posted some questions on this before, but it's different. So consider a small portion of our model: Person Customer Employee Spouse Person is the base class which has 3 classes that inherit from it. These 4 are very central in our design and link to many other entities. I could solve all the problems I'm experiencing with ria-services by removing the inheritance but that would really increase the complexety of the model. The first problem I experienced was that I couldn't query for Customers, Employees or Spouses, but someone gave me a solution, which was to add something like this to the DomainService: public IQueryable<Employee> GetEmployees() { return this.ObjectContext.People.OfType<Employee>(); } public IQueryable<Customer> GetCustomers() { return this.ObjectContext.People.OfType<Customer>(); } public IQueryable<Spouse> GetSpouses() { return this.ObjectContext.People.OfType<Spouse>(); } Next I tried something that seemed very normal to me: var employee = new Employee() { //.... left out to reduce the length of this question }; var spouse = new Spouse() { //.... left out to reduce the length of this questions }; employee.Spouse = spouse; context.People.Add(spouse); context.People.Add(employee); context.SubmitChanges(); Then I get the following exception: Cannot retrieve an entity set for the derived entity type 'Spouse'. Use EntityContainer.GetEntitySet(Type) to get the entity set for the base entity type 'Person'. Even when the spouse is already in the database, and I retreive it first I get similar exceptions. Also note that for some reason in some places "Persons" is used instead of "People"... So how do I solve this problem, what am I doing wrong and will I keep running into walls when using ria services with inheritance? I found some references on the web, all saying it works and then some DomainService code in which they suposedly changed something but no details... I'm using VS2010 RC1 + Silveright 4

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  • BN_hex2bn magically segfaults in openSSL

    - by xunil154
    Greetings, this is my first post on stackoverflow, and i'm sorry if its a bit long. I'm trying to build a handshake protocol for my own project and am having issues with the server converting the clients RSA's public key to a Bignum. It works in my clent code, but the server segfaults when attempting to convert the hex value of the clients public RSA to a bignum. I have already checked that there is no garbidge before or after the RSA data, and have looked online, but i'm stuck. header segment: typedef struct KEYS { RSA *serv; char* serv_pub; int pub_size; RSA *clnt; } KEYS; KEYS keys; Initializing function: // Generates and validates the servers key /* code for generating server RSA left out, it's working */ //Set client exponent keys.clnt = 0; keys.clnt = RSA_new(); BN_dec2bn(&keys.clnt->e, RSA_E_S); // RSA_E_S contains the public exponent Problem code (in Network::server_handshake): // *Recieved an encrypted message from the network and decrypt into 'buffer' (1024 byte long)* cout << "Assigning clients RSA" << endl; // I have verified that 'buffer' contains the proper key if (BN_hex2bn(&keys.clnt->n, buffer) < 0) { Error("ERROR reading server RSA"); } cout << "clients RSA has been assigned" << endl; The program segfaults at BN_hex2bn(&keys.clnt->n, buffer) with the error (valgrind output) Invalid read of size 8 at 0x50DBF9F: BN_hex2bn (in /usr/lib/libcrypto.so.0.9.8) by 0x40F23E: Network::server_handshake() (Network.cpp:177) by 0x40EF42: Network::startNet() (Network.cpp:126) by 0x403C38: main (server.cpp:51) Address 0x20 is not stack'd, malloc'd or (recently) free'd Process terminating with default action of signal 11 (SIGSEGV) Access not within mapped region at address 0x20 at 0x50DBF9F: BN_hex2bn (in /usr/lib/libcrypto.so.0.9.8) And I don't know why it is, Im using the exact same code in the client program, and it works just fine. Any input is greatly appriciated!

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  • Did the Unity Team fix that "generics handling" bug back in 2008?

    - by rasx
    At my level of experience with Unity it might be faster to ask whether the "generics handling" bug acknowledged by ctavares back in 2008 was fixed in a public release. Here was the problem (which might be my problem today): Hi, I get an exception when using .... container.RegisterType(typeof(IDictionary<,), typeof(Dictionary<,)); The exception is... "Resolution of the dependency failed, type = \"IDictionary2\", name = \"\". Exception message is: The current build operation (build key Build Key[System.Collections.Generic.Dictionary2[System.String,System.String], null]) failed: The current build operation (build key Build Key[System.Collections.Generic.Dictionary2[System.String,System.String], null]) failed: The type Dictionary2 has multiple constructors of length 2. Unable to disambiguate. When I attempt... IDictionary myExampleDictionary = container.Resolve(); Here was the moderated response: There are no books that'll help, Unity is a little too new for publishers to have caught up yet. Unfortunately, you've run into a bug in our generics handling. This is currently fixed in our internal version, but it'll be a little while before we can get the bits out. In the meantime, as a workaround you could do something like this instead: public class WorkaroundDictionary : Dictionary { public WorkaroundDictionary() { } } container.RegisterType(typeof(IDictionary<,),typeof(WorkaroundDictionary<,)); The WorkaroundDictionary only has the default constructor so it'll inject no problem. Since the rest of your app is written in terms of IDictionary, when we get the fixed version done you can just replace the registration with the real Dictionary class, throw out the workaround, and everything will still just work. Sorry about the bug, it'll be fixed soon!

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  • Runtime Exception when using Custom Healthmonitoring event in medium trust

    - by Elementenfresser
    Hi, I'm using custom healthmonitoring events in ASP.NET We recently moved to a new server with default High Trust Permissions. Literature says that healthmonitoring and custom events should work under Medium or higher trust (http://msdn.microsoft.com/en-us/library/bb398933.aspx). Problem is it doesn't. In less than high trust I get a SecurityException saying The application attempted to perform an operation not allowed by the security policy It works in Full trust or when I remove the inheritance of System.Web.Management.WebErrorEvent. Any suggestions anyone? Here is the super simple code behind with a custom event defined: public partial class Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { try { CallCustomEvent(); } catch (Exception ex) { Response.Write(ex.Message); throw ex; } } /// <summary> /// this metho is never called due to lacking permissions... /// </summary> private void CallCustomEvent() { try { //do something useful here } catch (Exception) { //code to instantiate the forbidden inheritance... WebBaseEvent.Raise(new CustomEvent()); } } } /// <summary> /// custom error inheriting WebErrorEvent which is not allowed in high trust? can't believe that... /// </summary> public class CustomEvent : WebErrorEvent { public CustomEvent() : base("test", HttpContext.Current.Request, 100001, new ApplicationException("dummy")) { } } and the Web Config excerpt for high trust: <system.web> <trust level="High" originUrl="" />

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  • LOAD DATA INFILE with variables

    - by Hasitha
    I was tring to use the LOAD DATA INFILE as a sotred procedure but it seems it cannot be done. Then i tried the usual way of embedding the code to the application itself like so, conn = new MySqlConnection(connStr); conn.Open(); MySqlCommand cmd = new MySqlCommand(); cmd = conn.CreateCommand(); string tableName = getTableName(serverName); string query = "LOAD DATA INFILE '" + fileName + "'INTO TABLE "+ tableName +" FIELDS TERMINATED BY '"+colSep+"' ENCLOSED BY '"+colEncap+"' ESCAPED BY '"+colEncap+"'LINES TERMINATED BY '"+colNewLine+"' ("+colUpFormat+");"; cmd.CommandText = query; cmd.ExecuteNonQuery(); conn.Close(); The generated query that gets saved in the string variable query is, LOAD DATA INFILE 'data_file.csv'INTO TABLE tbl_shadowserver_bot_geo FIELDS TERMINATED BY ',' ENCLOSED BY '"' ESCAPED BY '"'LINES TERMINATED BY '\n' (timestamp,ip,port,asn,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy,url,agent,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy,@dummy); But now when i run the program it gives an error saying, MySQLException(0x80004005) Parameter @dummy must be defined first. I dont know how to get around this, but when i use the same query on mysql itself directly it works fine. PLEASE help me..thank you very much :)

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  • PostMessage does not seem to be working.

    - by Vaccano
    I am trying to use PostMessage to send a tab key. Here is my code: // This class allows us to send a tab key when the the enter key // is pressed for the mooseworks mask control. public class MaskKeyControl : MaskedEdit { // [DllImport("coredll.dll", SetLastError = true, CharSet = CharSet.Auto)] // static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, Int32 wParam, Int32 lParam); [return: MarshalAs(UnmanagedType.Bool)] // I am calling this on a Windows Mobile device so the dll is coredll.dll [DllImport("coredll.dll", SetLastError = true)] static extern bool PostMessage(IntPtr hWnd, uint Msg, Int32 wParam, Int32 lParam); public const Int32 VK_TAB = 0x09; public const Int32 WM_KEYDOWN = 0x100; protected override void OnKeyDown(KeyEventArgs e) { if (e.KeyData == Keys.Enter) { PostMessage(this.Handle, WM_KEYDOWN, VK_TAB, 0); return; } base.OnKeyDown(e); } protected override void OnKeyPress(KeyPressEventArgs e) { if (e.KeyChar == '\r') e.Handled = true; base.OnKeyPress(e); } } When I press enter the code gets called, but nothing happens. Then I press TAB and it works fine. (So there is something wrong with my sending of the Tab Message.)

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  • Uninitialized array offset

    - by kimmothy16
    Hey everyone, I am using PHP to create a form with an array of fields. Basically you can add an unlimited number of 'people' to the form and each person has a first name, last name, and phone number. The form requires that you add a phone number for the first person only. If you leave the phone number field blank on any others, the handler file is supposed to be programmed to use the phone number from the first person. So, my fields are: person[] - a hidden field with a value that is this person's primary key. fname[] - an input field lname[] - an input field phone[] - an input field My form handler looks like this: $people = $_POST['person'] $counter = 0; foreach($people as $person): if($phone[$counter] == '') { // use $phone[0]'s phone number } else { // use $phone[$counter] number } $counter = $counter + 1; endforeach; PHP doesn't like this though, it is throwing me an Notice: Uninitialized string offset error. I debugged it by running the is_array function on people, fname, lname, and phone and it returns true to being an array. I can also manually echo out $phone[2], etc. and get the correct value. I've also ran is_int on the $counter variable and it returned true, so I'm unsure why this isn't working as intended? Any help would be great!

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  • How do I apply a "template" or "skeleton" of code in C# here?

    - by Scott Stafford
    In my business layer, I need many, many methods that follow the pattern: public BusinessClass PropertyName { get { if (this.m_LocallyCachedValue == null) { if (this.Record == null) { this.m_LocallyCachedValue = new BusinessClass( this.Database, this.PropertyId); } else { this.m_LocallyCachedValue = new BusinessClass( this.Database, this.Record.ForeignKeyName); } } return this.m_LocallyCachedValue; } } I am still learning C#, and I'm trying to figure out the best way to write this pattern once and add methods to each business layer class that follow this pattern with the proper types and variable names substituted. BusinessClass is a typename that must be substituted, and PropertyName, PropertyId, ForeignKeyName, and m_LocallyCachedValue are all variables that should be substituted for. Are attributes usable here? Do I need reflection? How do I write the skeleton I provided in one place and then just write a line or two containing the substitution parameters and get the pattern to propagate itself? EDIT: Modified my misleading title -- I am hoping to find a solution that doesn't involve code generation or copy/paste techniques, and rather to be able to write the skeleton of the code once in a base class in some form and have it be "instantiated" into lots of subclasses as the accessor for various properties. EDIT: Here is my solution, as suggested but left unimplemented by the chosen answerer. // I'll write many of these... public BusinessClass PropertyName { get { return GetSingleRelation(ref this.m_LocallyCachedValue, this.PropertyId, "ForeignKeyName"); } } // That all call this. public TBusinessClass GetSingleRelation<TBusinessClass>( ref TBusinessClass cachedField, int fieldId, string contextFieldName) { if (cachedField == null) { if (this.Record == null) { ConstructorInfo ci = typeof(TBusinessClass).GetConstructor( new Type[] { this.Database.GetType(), typeof(int) }); cachedField = (TBusinessClass)ci.Invoke( new object[] { this.Database, fieldId }); } else { var obj = this.Record.GetType().GetProperty(objName).GetValue( this.Record, null); ConstructorInfo ci = typeof(TBusinessClass).GetConstructor( new Type[] { this.Database.GetType(), obj.GetType()}); cachedField = (TBusinessClass)ci.Invoke( new object[] { this.Database, obj }); } } return cachedField; }

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  • Why aren't my coordinates matching my JFrame size?

    - by AsLanFromNarnia
    I want to do some drawing in a JPanel but the enclosing JFrame size doesn't seem to match where I've asked the coordinates to be drawn. In my example code, the JFrame size is set to (700, 700) and the last point is drawn at (600, 600). I would expect this point to be drawn 100 pixels away from the right and bottom edges but it isn't (please see screenshot). Here's the code I'm using: import java.awt.Graphics; import javax.swing.JFrame; import javax.swing.JPanel; public class Scratch extends JPanel { static int frameWidth = 700; static int frameHeight = 700; public static void main(String[] args) { JFrame frame = new JFrame(); frame.setSize(frameWidth, frameHeight); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Scratch scratch = new Scratch(); frame.getContentPane().add(scratch); frame.setVisible(true); } @Override public void paintComponent(Graphics g) { g.drawRect(100, 100, 1, 1); g.drawString("100", 100, 100); g.drawRect(200, 200, 1, 1); g.drawString("200", 200, 200); g.drawRect(300, 300, 1, 1); g.drawString("300", 300, 300); g.drawRect(400, 400, 1, 1); g.drawString("400", 400, 400); g.drawRect(500, 500, 1, 1); g.drawString("500", 500, 500); g.drawRect(600, 600, 1, 1); g.drawString("600", 600, 600); } }

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  • Why do pure virtual base classes get direct access to static data members while derived instances do

    - by Shamster
    I've created a simple pair of classes. One is pure virtual with a static data member, and the other is derived from the base, as follows: #include <iostream> template <class T> class Base { public: Base (const T _member) { member = _member; } static T member; virtual void Print () const = 0; }; template <class T> T Base<T>::member; template <class T> void Base<T>::Print () const { std::cout << "Base: " << member << std::endl; } template <class T> class Derived : public Base<T> { public: Derived (const T _member) : Base<T>(_member) { } virtual void Print () const { std::cout << "Derived: " << this->member << std::endl; } }; I've found from this relationship that when I need access to the static data member in the base class, I can call it with direct access as if it were a regular, non-static class member. i.e. - the Base::Print() method does not require a this- modifier. However, the derived class does require the this-member indirect access syntax. I don't understand why this is. Both class methods are accessing the same static data, so why does the derived class need further specification? A simple call to test it is: int main () { Derived<double> dd (7.0); dd.Print(); return 0; } which prints the expected "Derived: 7"

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  • Set Property Value on Master Page from Content Page

    - by Merk
    Hello, I tried following the advice posted here: http://stackoverflow.com/questions/1071920/set-property-value-on-master-page-from-content-page. Specifically the last post about creating a class. However, visual studio keeps giving me an error on my default.aspx.cs page when i try to set the value: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; public partial class _Default : BasePage { protected override int NavHighlight { get { return new{0} ; } } protected void Page_Load(object sender, EventArgs e) { } } It throws an error on new, the error being: cannot inplicity convert anonymoustype#1 to int Can someone tell me what i might have done wrong here? Here's what my class looks like: using System; using System.Collections.Generic; using System.Linq; using System.Web; /// <summary> /// Summary description for BasePage /// </summary> public abstract class BasePage : System.Web.UI.Page { protected abstract int NavHighlight { get; } protected override void OnLoad(EventArgs e) { base.OnLoad(e); if (this.Master != null) { //value assignment } } public BasePage() { // // TODO: Add constructor logic here // } } Thanks.

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  • jqGrid : "All in One" approach width jqGridEdit Class > how to set a composite primary key ?

    - by Qualliarys
    Hello, How to set a composite primary key for a "All in One" approach (grid defined in JS file, and data using jqGridEdit Class in php file) ? Please, for me a composite primary key of a table T, is a elementary primary key that is defined with some fields belong to this table T ! Here is my test, but i get no data and cannot use the CRUD operations : In my JS file i have this lines code: ... colModel":[ {"name":"index","index":"index","label":"index"}, // <= THAT'S JUST THE INDEX OF MY TABLE {"name":"user","index":"user","label":"user","key":true}, // <= A PART OF MY COMPOSITE PRIMARY KEY {"name":"pwd","index":"pwd","label":"pwd","key":true}, // <= A PART OF MY COMPOSITE PRIMARY KEY {"name":"state","index":"state","label":"state","key":true}, // <= A PART OF MY COMPOSITE PRIMARY KEY ... <= AND SO ON "url":"mygrid_crud.php", "datatype":"json", "jsonReader":{repeatitems:false}, "editurl": "mygrid_crud.php", "prmNames":{"id":"index"} // <= WHAT I NEED TO WRITE HERE ??? ... In my php file (mygrid_crud.php) : ... $grid = new jqGridEdit($conn); $query = "SELECT * FROM mytable WHERE user='$user' and pwd='$pwd' and state='$state'..."; // <= SELECT * it's ok or i need to specify all fields i need ? $grid->SelectCommand = $query; $grid->dataType = "json"; $grid->table = 'mytable'; $grid->setPrimaryKeyId('index'); // <= WHAT I NEED TO WRITE HERE ??? ... $grid->editGrid(); Please, say me what is wrong, and how to do to set a composite primary key in this approach !? Thank you so much for tour responses.

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  • How to find the first declaring method for a reference method

    - by Oliver Gierke
    Suppose you have a generic interface and an implementation: public interface MyInterface<T> { void foo(T param); } public class MyImplementation<T> implements MyInterface<T> { void foo(T param) { } } These two types are frework types. In the next step I want allow users to extend that interface as well as redeclare foo(T param) to maybe equip it with further annotations. public interface MyExtendedInterface extends MyInterface<Bar> { @Override void foo(Bar param); // Further declared methods } I create an AOP proxy for the extended interface and intercept especially the calls to furtherly declared methods. As foo(…) is no redeclared in MyExtendedInterface I cannot execute it by simply invoking MethodInvocation.proceed() as the instance of MyImplementation only implements MyInterface.foo(…) and not MyExtendedInterface.foo(…). So is there a way to get access to the method that declared a method initially? Regarding this example is there a way to find out that foo(Bar param) was declared in MyInterface originally and get access to the accoriding Method instance? I already tried to scan base class methods to match by name and parameter types but that doesn't work out as generics pop in and MyImplementation.getMethod("foo", Bar.class) obviously throws a NoSuchMethodException. I already know that MyExtendedInterface types MyInterface to Bar. So If I could create some kind of "typed view" on MyImplementation my math algorithm could work out actually.

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  • Why I do not see a static variable in a loop?

    - by Roman
    I have a static method which sets a variable: static String[] playersNames; public static void setParameters(String[] players) { playersNames = players; } Then I have a static block: static { JRadioButton option; ButtonGroup group = new ButtonGroup(); // Wright a short explanation of what the user should do. partnerSelectionPanel.add(new JLabel("Pleas select a partner:")); // Generate radio-buttons corresponding to the options available to the player. // Bellow is the problematic line causing the null pointer exception: for (String playerName: playersNames) { final String pn = playerName; option = new JRadioButton(playerName, false); option.addActionListener(new ActionListener(){ @Override public void actionPerformed(ActionEvent evt) { partner = pn; } }); partnerSelectionPanel.add(option); group.add(option); } partnerSelectionPanel.add(label); // Add the "Submit" button to the end of the "form". JButton submitButton = new JButton("Submit"); submitButton.addActionListener(new ActionListener(){ @Override public void actionPerformed(ActionEvent evt) { partnerSelected(); } }); partnerSelectionPanel.add(submitButton); } Compiler does not complain about anything but when I try to execute the code I get problems. In this place SelectPartnerGUI.setParameters(players); I have: Exception in thread "main" java.lang.ExceptionInitializerError. and it is cause by java.lang.NullpointerException at this place for (String playerName: playersNames). Does my program do not see the palyersNames?

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  • proper use of volatile keyword

    - by luke
    I think i have a pretty good idea about the volatile keyword in java, but i'm thinking about re-factoring some code and i thought it would be a good idea to use it. i have a class that is basically working as a DB Cache. it holds a bunch of objects that it has read from a database, serves requests for those objects, and then occasionally refreshes the database (based on a timeout). Heres the skeleton public class Cache { private HashMap mappings =....; private long last_update_time; private void loadMappingsFromDB() { //.... } private void checkLoad() { if(System.currentTimeMillis() - last_update_time > TIMEOUT) loadMappingsFromDB(); } public Data get(ID id) { checkLoad(); //.. look it up } } So the concern is that loadMappingsFromDB could be a high latency operation and thats not acceptable, So initially i thought that i could spin up a thread on cache startup and then just have it sleep and then update the cache in the background. But then i would need to synchronize my class (or the map). and then i would just be trading an occasional big pause for making every cache access slower. Then i thought why not use volatile i could define the map reference as volatile private volatile HashMap mappings =....; and then in get (or anywhere else that uses the mappings variable) i would just make a local copy of the reference: public Data get(ID id) { HashMap local = mappings; //.. look it up using local } and then the background thread would just load into a temp table and then swap the references in the class HashMap tmp; //load tmp from DB mappings = tmp;//swap variables forcing write barrier Does this approach make sense? and is it actually thread-safe?

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  • How do I update blackberry UI items from a thread?

    - by Andrei T. Ursan
    public class PlayText extends Thread { private int duration; private String text; private PlayerScreen playerscrn; public PlayText(String text, int duration) { this.duration = duration; this.text = text; this.playerscrn = (PlayerScreen)UiApplication.getUiApplication().getActiveScreen(); } public void run() { synchronized(UiApplication.getEventLock()) { try{ RichTextField text1player = new RichTextField(this.text, Field.NON_FOCUSABLE); playerscrn.add(text1player); playerscrn.invalidate(); Thread.sleep(this.duration); RichTextField text2player = new RichTextField("hahhaha", Field.NON_FOCUSABLE); playerscrn.add(text2player); playerscrn.invalidate(); Thread.sleep(1000); RichTextField text3player = new RichTextField("Done", Field.NON_FOCUSABLE); playerscrn.add(text3player); playerscrn.invalidate(); }catch(Exception e){ System.out.println("I HAVE AN ERROR"); } } } } With the above code I'm trying to create a small text player. Instead to get all the text labels one by one, something like display text1player wait this.duration milliseconds display text2player wait 1000 milliseconds display text3player thread done. The screens waits this.duration + 1000 milliseconds and displays all the labels at once. I tried with a runnable and calling .invokeLater or .invokeAndWait but I still get the same behavior, and even if I get dirty like above using synchronized it still doesn't work. Does anyone know how I can display each label at a time? Thank you!

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  • reddit style voting with django

    - by dotty
    Hay i need to hand implemeneting a voting system into a model. I've had a huge helping hand from Mike DeSimone making this work in the first place, but i need to expand upon his work. Here is my current code View def show_game(request): game = Game.objects.get(pk=1) discussions = game.gamediscussion_set.filter(reply_to=None) d = { 'game':game, 'discussions':discussions } return render_to_response('show_game', d) Template <ul> {% for discussion in discussions %} {{ discussion.html }} {% endfor %} </ul> Model class GameDiscussion(models.Model): game = models.ForeignKey(Game) message = models.TextField() reply_to = models.ForeignKey('self', related_name='replies', null=True, blank=True) created_on = models.DateTimeField(blank=True, auto_now_add=True) userUpVotes = models.ManyToManyField(User, blank=True, related_name='threadUpVotes') userDownVotes = models.ManyToManyField(User, blank=True, related_name='threadDownVotes') def html(self): DiscussionTemplate = loader.get_template("inclusions/discussionTemplate") return DiscussionTemplate.render(Context({ 'discussion': self, 'replies': [reply.html() for reply in self.replies.all()] })) DiscussionTemplate <li> {{ discussion.message }} {% if replies %} <ul> {% for reply in replies %} {{ reply }} {% endfor %} </ul> {% endif %} </li> As you can see we have 2 fields userUpVotes and userDownVotes on the model, these will calculate how to order the discussions and replies. How would i implement these 2 fields to order the replies and discussions based on votes? Any help would be great!

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  • C#/LINQ: How to define generically a keySelector for a templated class before calling OrderBy

    - by PierrOz
    Hi Folks, I have the following class defined in C# class myClass<T,U> { public T PropertyOne { get; set; } public U PropertyTwo { get; set; } } I need to write a function that reorder a list of myClass objects and takes two other parameters which define how I do this reorder: does my reordering depend on PropertyOne or PropertyTwo and is it ascending or descending. Let's say this two parameters are boolean. With my current knowledge in LINQ, I would write: public IList<myClass<T,U>> ReOrder(IList<myClass<T,U>> myList, bool usePropertyOne, bool ascending) { if (usePropertyOne) { if (ascending) { return myList.OrderBy(o => o.PropertyOne).ToList(); } else { return myList.OrderByDescending(o => o.PropertyOne).ToList(); } } else { if (ascending) { return myList.OrderBy(o => o.PropertyTwo).ToList(); } else { return myList.OrderByDescending(o => o.PropertyTwo).ToList(); } } } What could be a more efficient/elegant way to do that ? How can I declare the Func,TResult keySelector object to reuse when I call either OrderBy or OrderByDescending? I'm interesting in the answer since in my real life, I can have more than two properties.

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  • django class with an array of "parent" foreignkeys issue

    - by user298032
    Let's say I have a class called Fruit with child classes of the different kinds of Fruit with their own specific attributes, and I want to collect them in a FruitBasket: class Fruit(models.Model):     type = models.CharField(max_length=120,default='banana',choices=FRUIT_TYPES)     ... class Banana(Fruit):     """banana (fruit type)"""     length = models.IntegerField(blank=True, null=True)     ... class Orange(Fruit):     """orange (fruit type)"""     diameter = models.IntegerField(blank=True, null=True)     ... class FruitBasket(models.Model):     fruits = models.ManyToManyField(Fruit)     ... The problem I seem to be having is when I retrieve and inspect the Fruits in a FruitBasket, I only retrieve the Fruit base class and can't get at the Fruit child class attributes. I think I understand what is happening--when the array is retrieved from the database, the only fields that are retrieved are the Fruit base class fields. But is there some way to get the child class attributes as well without multiple expensive database transactions? (For example, I could get the array, then retrieve the child Fruit classes by the id of each array element). thanks in advance, Chuck

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  • What do I name this class whose sole purpose is to report failure?

    - by Blair Holloway
    In our system, we have a number of classes whose construction must happen asynchronously. We wrap the construction process in another class that derives from an IConstructor class: class IConstructor { public: virtual void Update() = 0; virtual Status GetStatus() = 0; virtual int GetLastError() = 0; }; There's an issue with the design of the current system - the functions that create the IConstructor-derived classes are often doing additional work which can also fail. At that point, instead of getting a constructor which can be queried for an error, a NULL pointer is returned. Restructuring the code to avoid this is possible, but time-consuming. In the meantime, I decided to create a constructor class which we create and return in case of error, instead of a NULL pointer: class FailedConstructor : public IConstructor public: virtual void Update() {} virtual Status GetStatus() { return STATUS_ERROR; } virtual int GetLastError() { return m_errorCode; } private: int m_errorCode; }; All of the above this the setup for a mundane question: what do I name the FailedConstructor class? In our current system, FailedConstructor would indicate "a class which constructs an instance of Failed", not "a class which represents a failed attempt to construct another class". I feel like it should be named for one of the design patterns, like Proxy or Adapter, but I'm not sure which.

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  • Django - how to write users and profiles handling in best way?

    - by SpankMe
    Hey, I am writing simple site that requires users and profiles to be handled. The first initial thought is to use django's build in user handling, but then the user model is too narrow and does not contain fields that I need. The documentation mentions user profiles, but user profiles section has been removed from djangobook covering django 1.0 (ideally, the solution should work with django 1.2), and the Internet is full of different solutions, not making the choice easier (like user model inheritance, user profiles and django signals, and so on). I would like to know, how to write this in good, modern, fast and secure way. Should I try to extend django builtin user model, or maybe should I create my own user model wide enough to keep all the information I need? Below you may find some specifications and expectations from the working solution: users should be able to register and authenticate every user should have profile (or model with all required fields) users dont need django builtin admin panel, but they need to edit their profiles/models via simple web form Please, let me know how do you solve those issues in your applications, and what is the best current way to handle users with django. Any links to articles/blogs or code examples are highly appreciated!

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  • How to use sessions in PDO?

    - by Byakugan
    I am still redoing and getting rid of old mysql_* commands in my code. I tried to transfer my session login form old code and this is what I got so far: public function login($user, $password) { if (!empty($user) && !empty($password)) { $password = $web->doHash($user, $password); // in this function is (return sha1(strtoupper($user).':'.strtoupper($password)) $stmt = $db_login->prepare("SELECT * FROM account WHERE username=:user AND pass_hash=:password"); $stmt->bindValue(':user', $user, PDO::PARAM_STR); $stmt->bindValue(':password', $password, PDO::PARAM_STR); $stmt->execute(); $rows = $stmt->rowCount(); if ($rows > 0) { $results_login = $stmt->fetch(PDO::FETCH_ASSOC); $_SESSION['user_name'] = $results_login['username']; $_SESSION['user_id'] = $results_login['id']; return true; } else { return false; } } else { return false; } } After that I am using checks if user logged on site: public function isLogged() { return (!empty($_SESSION['user_id']) && !empty($_SESSION['user_name'])); } But it seems - this function returns always empty because $_SESSION does not exists in PDO? And of course logout is used in this form on my sites: public function logout() { unset($_SESSION['user_id']); unset($_SESSION['user_name']); } But I think PDO has different way of handling session? I did not find any so what is it can i somehow add $_SESSION in PDO withou changing code much? I am using variables $_SESSION['user_name'] and $_SESSION['user_id'] in all over my web project. Summary: 1) How to use sessions in PDO correctly? 2) What is difference between using $stmt->fetch(PDO::FETCH_ASSOC); and $stmt->fetchAll(); Thank you.

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