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  • Why do I get a segmentation fault while redirecting sys.stdout to Tkinter.Text widget in Python?

    - by Brent Nash
    I'm in the process of building a GUI-based application with Python/Tkinter that builds on top of the existing Python bdb module. In this application, I want to silence all stdout/stderr from the console and redirect it to my GUI. To accomplish this purpose, I've written a specialized Tkinter.Text object (code at the end of the post). The basic idea is that when something is written to sys.stdout, it shows up as a line in the "Text" with the color black. If something is written to sys.stderr, it shows up as a line in the "Text" with the color red. As soon as something is written, the Text always scrolls down to view the most recent line. I'm using Python 2.6.1 at the moment. On Mac OS X 10.5, this seems to work great. I have had zero problems with it. On RedHat Enterprise Linux 5, however, I pretty reliably get a segmentation fault during the run of a script. The segmentation fault doesn't always occur in the same place, but it pretty much always occurs. If I comment out the sys.stdout= and sys.stderr= lines from my code, the segmentation faults seem to go away. I'm sure there are other ways around this that I will probably have to resort to, but can anyone see anything I'm doing blatantly wrong here that could be causing these segmentation faults? It's driving me nuts. Thanks! PS - I realize redirecting sys.stderr to the GUI might not be a great idea, but I still get segmentation faults even when I only redirect sys.stdout and not sys.stderr. I also realize that I'm allowing the Text to grow indefinitely at the moment. class ConsoleText(tk.Text): '''A Tkinter Text widget that provides a scrolling display of console stderr and stdout.''' class IORedirector(object): '''A general class for redirecting I/O to this Text widget.''' def __init__(self,text_area): self.text_area = text_area class StdoutRedirector(IORedirector): '''A class for redirecting stdout to this Text widget.''' def write(self,str): self.text_area.write(str,False) class StderrRedirector(IORedirector): '''A class for redirecting stderr to this Text widget.''' def write(self,str): self.text_area.write(str,True) def __init__(self, master=None, cnf={}, **kw): '''See the __init__ for Tkinter.Text for most of this stuff.''' tk.Text.__init__(self, master, cnf, **kw) self.started = False self.write_lock = threading.Lock() self.tag_configure('STDOUT',background='white',foreground='black') self.tag_configure('STDERR',background='white',foreground='red') self.config(state=tk.DISABLED) def start(self): if self.started: return self.started = True self.original_stdout = sys.stdout self.original_stderr = sys.stderr stdout_redirector = ConsoleText.StdoutRedirector(self) stderr_redirector = ConsoleText.StderrRedirector(self) sys.stdout = stdout_redirector sys.stderr = stderr_redirector def stop(self): if not self.started: return self.started = False sys.stdout = self.original_stdout sys.stderr = self.original_stderr def write(self,val,is_stderr=False): #Fun Fact: The way Tkinter Text objects work is that if they're disabled, #you can't write into them AT ALL (via the GUI or programatically). Since we want them #disabled for the user, we have to set them to NORMAL (a.k.a. ENABLED), write to them, #then set their state back to DISABLED. self.write_lock.acquire() self.config(state=tk.NORMAL) self.insert('end',val,'STDERR' if is_stderr else 'STDOUT') self.see('end') self.config(state=tk.DISABLED) self.write_lock.release()

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  • 3 matchers expected, 4 recorded.

    - by user564159
    I get this exception during the mock recording time. Searched for a solution in this forum. Made sure that i did not mess up any another parameter. The below mock expection is giving the error. EasyMock.expect(slotManager.addSlotPageletBinding(EasyMock.isA(String.class), EasyMock.isA(String.class), EasyMock.isA(helloWorld.class))).andReturn(true); before this statement i have another mock expection on the same method with TWO parameter(overloaded method).Below is that mock. EasyMock.expect(slotManager.addSlotPageletBinding(EasyMock.isA(String.class),EasyMock.isA(String.class))).andReturn(true).anyTimes(); Could any one guide me on this. Thanks. java.lang.IllegalStateException: 3 matchers expected, 4 recorded. at org.easymock.internal.ExpectedInvocation.createMissingMatchers(ExpectedInvocation.java:56) at org.easymock.internal.ExpectedInvocation.(ExpectedInvocation.java:48) at org.easymock.internal.ExpectedInvocation.(ExpectedInvocation.java:40) at org.easymock.internal.RecordState.invoke(RecordState.java:76) at org.easymock.internal.MockInvocationHandler.invoke(MockInvocationHandler.java:38) at org.easymock.internal.ObjectMethodsFilter.invoke(ObjectMethodsFilter.java:72) at org.easymock.classextension.internal.ClassProxyFactory$1.intercept(ClassProxyFactory.java:79) at com.amazon.inca.application.SlotManager$$EnhancerByCGLIB$$3bf5ac02.addSlotPageletBinding() at com.amazon.iris3.apps.Iris3YourAccountApplicationTest.testBuildIncaViewConfiguration(Iris3YourAccountApplicationTest.java:107) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at junit.framework.TestCase.runTest(TestCase.java:168) at junit.framework.TestCase.runBare(TestCase.java:134) at junit.framework.TestResult$1.protect(TestResult.java:110) at junit.framework.TestResult.runProtected(TestResult.java:128) at junit.framework.TestResult.run(TestResult.java:113) at junit.framework.TestCase.run(TestCase.java:124) at junit.framework.TestSuite.runTest(TestSuite.java:232) at junit.framework.TestSuite.run(TestSuite.java:227) at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:83) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

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  • Is a "factory" method the right pattern?

    - by jdt141
    Hey all - So I'm working to improve an existing implementation. I have a number of polymorphic classes that are all composed into a higher level container class. The problem I'm dealing with at the moment is that the higher level container class, well, sucks. It looks something like this, which I really don't have a problem with (as the polymorphic classes in the container should be public). My real issue is the constructor... /* * class1 and class 2 derive from the same superclass */ class Container { public: boost::shared_ptr<ComposedClass1> class1; boost::shared_ptr<ComposedClass2> class2; private: ... } /* * Constructor - builds the objects that we need in this container. */ Container::Container(some params) { class1.reset(new ComposedClass1(...)); class2.reset(new ComposedClass2(...)); } What I really need is to make this container class more re-usable. By hard-coding up the member objects and instantiating them, it basically isn't and can only be used once. A factory is one way to build what I need (potentially by supplying a list of objects and their specific types to be created?) Other ways to get around this problem? Seems like someone should have solved it before... Thanks!

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  • "Link" against a SWC in Flex

    - by ggambett
    I'm trying to do a very simple app in Flash/Flex, that loads an image embedded in the swf itself and then shows it. The thing is I'm trying to do it using the command line only (mxmlc and compc) and without using @Embed, and failing miserably. I have a very simple Main.as : package { import flash.display.*; import flash.utils.*; public class Main extends Sprite { public function Main () : void { var pDef:Class = getDefinitionByName("icon_big.png") as Class; var _image:BitmapData = new pDef(0, 0); var pSprite:Sprite = new Sprite(); pSprite.graphics.beginBitmapFill(_image); pSprite.graphics.drawRect(0, 0, _image.width, _image.height); pSprite.graphics.endFill(); addChild(pSprite); } } } This works fine if I add icon_big.png to the Library using the Flash IDE, but I can't figure out how to do it from the command line. I'm using compc to put the png inside a swc : compc --include-file icon_big.png icon_big.png -output assets.swc This generates a 17 kb assets.swf, slightly bigger than icon_big.png. Then I try to compile and link Main.as : mxmlc -include-libraries+=assets.swc Main.as This produces a 944 byte Main.swf, which clearly doesn't include the asset, and fails at runtime. According to the mxmlc docs I found, -include-libraries should link with every class, including the ones not directly referenced by code (as is the case here, since I'm getting the class from code), and it unsurprisingly fails at runtime. Note that this same code (or, more precisely, quite equivalent code) works when used within a Flash project - I'm not looking to fix the code, but how to do in the command line whatever Flash does internally. I feel I'm just "not getting" something... any clues?

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  • Unable to use nMock GetProperty routine on a property of an inherited object...

    - by Chris
    I am getting this error when trying to set an expectation on an object I mocked that inherits from MembershipUser: ContactRepositoryTests.UpdateTest : FailedSystem.InvalidProgramException: JIT Compiler encountered an internal limitation. Server stack trace: at MockObjectType1.ToString() Exception rethrown at [0]: at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(ref MessageData msgData, Int32 type) at System.Object.ToString() at NMock2.Internal.ExpectationBuilder.On(Object receiver) Here are the tools I am using... VS2008 (SP1) Framework 3.5 nUnit 2.4.8 nMock 2.0.0.44 Resharper 4.1 I am at a loss as to why this would be happening. Any help would be appreciated. Test Class... [TestFixture] public class AddressRepositoryTests { private Mockery m_Mockery; private Data.IAddress m_MockDataAddress; private IUser m_MockUser; [SetUp] public void Setup() { m_Mockery = new Mockery(); m_MockDataAddress = m_Mockery.NewMock<Data.IAddress>(); m_MockUser = m_Mockery.NewMock<IUser>(); } [TearDown] public void TearDown() { m_Mockery.Dispose(); } [Test] public void CreateTest() { string line1 = "unitTestLine1"; string line2 = "unitTestLine2"; string city = "unitTestCity"; int stateId = 1893; string postalCode = "unitTestPostalCode"; int countryId = 223; bool active = false; int createdById = 1; Expect.Once .On(m_MockUser) .GetProperty("Identity") .Will(Return.Value(createdById)); Expect.Once .On(m_MockDataAddress) .Method("Insert") .With( line1, line2, city, stateId, postalCode, countryId, active, createdById, Is.Anything ) .Will(Return.Value(null)); IAddressRepository addressRepository = new AddressRepository(m_MockDataAddress); IAddress address = addressRepository.Create( line1, line2, city, stateId, postalCode, countryId, active, m_MockUser ); Assert.IsNull(address); } } User Class... public interface IUser { int? Identity { get; set; } int? CreatedBy { get; set; } DateTime CreatedOn { get; set; } int? ModifiedBy { get; set; } DateTime? ModifiedOn { get; set; } string UserName { get; } object ProviderUserKey { get; } string Email { get; set; } string PasswordQuestion { get; } string Comment { get; set; } bool IsApproved { get; set; } bool IsLockedOut { get; } DateTime LastLockoutDate { get; } DateTime CreationDate { get; } DateTime LastLoginDate { get; set; } DateTime LastActivityDate { get; set; } DateTime LastPasswordChangedDate { get; } bool IsOnline { get; } string ProviderName { get; } string ToString(); string GetPassword(); string GetPassword(string passwordAnswer); bool ChangePassword(string oldPassword, string newPassword); bool ChangePasswordQuestionAndAnswer(string password, string newPasswordQuestion, string newPasswordAnswer); string ResetPassword(string passwordAnswer); string ResetPassword(); bool UnlockUser(); } public class User : MembershipUser, IUser { #region Public Properties private int? m_Identity; public int? Identity { get { return m_Identity; } set { if (value <= 0) throw new Exception("Address.Identity must be greater than 0."); m_Identity = value; } } public int? CreatedBy { get; set; } private DateTime m_CreatedOn = DateTime.Now; public DateTime CreatedOn { get { return m_CreatedOn; } set { m_CreatedOn = value; } } public int? ModifiedBy { get; set; } public DateTime? ModifiedOn { get; set; } #endregion Public Properties #region Public Constructors public User() { } #endregion Public Constructors } Address Class... public interface IAddress { int? Identity { get; set; } string Line1 { get; set; } string Line2 { get; set; } string City { get; set; } string PostalCode { get; set; } bool Active { get; set; } int? CreatedBy { get; set; } DateTime CreatedOn { get; set; } int? ModifiedBy { get; set; } DateTime? ModifiedOn { get; set; } } public class Address : IAddress { #region Public Properties private int? m_Identity; public int? Identity { get { return m_Identity; } set { if (value <= 0) throw new Exception("Address.Identity must be greater than 0."); m_Identity = value; } } public string Line1 { get; set; } public string Line2 { get; set; } public string City { get; set; } public string PostalCode { get; set; } public bool Active { get; set; } public int? CreatedBy { get; set; } private DateTime m_CreatedOn = DateTime.Now; public DateTime CreatedOn { get { return m_CreatedOn; } set { m_CreatedOn = value; } } public int? ModifiedBy { get; set; } public DateTime? ModifiedOn { get; set; } #endregion Public Properties } AddressRepository Class... public interface IAddressRepository { IAddress Create(string line1, string line2, string city, int stateId, string postalCode, int countryId, bool active, IUser createdBy); } public class AddressRepository : IAddressRepository { #region Private Properties private Data.IAddress m_DataAddress; private Data.IAddress DataAddress { get { if (m_DataAddress == null) m_DataAddress = new Data.Address(); return m_DataAddress; } set { m_DataAddress = value; } } #endregion Private Properties #region Public Constructor public AddressRepository() { } public AddressRepository(Data.IAddress dataAddress) { DataAddress = dataAddress; } #endregion Public Constructor #region Public Methods public IAddress Create(string line1, string line2, string city, int stateId, string postalCode, int countryId, bool active, IUser createdBy) { if (String.IsNullOrEmpty(line1)) throw new Exception("You must enter a Address Line 1 to register."); if (String.IsNullOrEmpty(city)) throw new Exception("You must enter a City to register."); if (stateId <= 0) throw new Exception("You must select a State to register."); if (String.IsNullOrEmpty(postalCode)) throw new Exception("You must enter a Postal Code to register."); if (countryId <= 0) throw new Exception("You must select a Country to register."); DataSet dataSet = DataAddress.Insert( line1, line2, city, stateId, postalCode, countryId, active, createdBy.Identity, DateTime.Now ); return null; } #endregion Public Methods } DataAddress Class... public interface IAddress { DataSet GetByAddressId (int? AddressId); DataSet Update (int? AddressId, string Address1, string Address2, string City, int? StateId, string PostalCode, int? CountryId, bool? IsActive, Guid? ModifiedBy); DataSet Insert (string Address1, string Address2, string City, int? StateId, string PostalCode, int? CountryId, bool? IsActive, int? CreatedBy, DateTime? CreatedOn); } public class Address : IAddress { public DataSet GetByAddressId (int? AddressId) { Database database = DatabaseFactory.CreateDatabase(); DbCommand dbCommand = database.GetStoredProcCommand("prAddress_GetByAddressId"); DataSet dataSet; try { database.AddInParameter(dbCommand, "AddressId", DbType.Int32, AddressId); dataSet = database.ExecuteDataSet(dbCommand); } catch (SqlException sqlException) { string callMessage = "prAddress_GetByAddressId " + "@AddressId = " + AddressId; throw new Exception(callMessage, sqlException); } return dataSet; } public DataSet Update (int? AddressId, string Address1, string Address2, string City, int? StateId, string PostalCode, int? CountryId, bool? IsActive, Guid? ModifiedBy) { Database database = DatabaseFactory.CreateDatabase(); DbCommand dbCommand = database.GetStoredProcCommand("prAddress_Update"); DataSet dataSet; try { database.AddInParameter(dbCommand, "AddressId", DbType.Int32, AddressId); database.AddInParameter(dbCommand, "Address1", DbType.AnsiString, Address1); database.AddInParameter(dbCommand, "Address2", DbType.AnsiString, Address2); database.AddInParameter(dbCommand, "City", DbType.AnsiString, City); database.AddInParameter(dbCommand, "StateId", DbType.Int32, StateId); database.AddInParameter(dbCommand, "PostalCode", DbType.AnsiString, PostalCode); database.AddInParameter(dbCommand, "CountryId", DbType.Int32, CountryId); database.AddInParameter(dbCommand, "IsActive", DbType.Boolean, IsActive); database.AddInParameter(dbCommand, "ModifiedBy", DbType.Guid, ModifiedBy); dataSet = database.ExecuteDataSet(dbCommand); } catch (SqlException sqlException) { string callMessage = "prAddress_Update " + "@AddressId = " + AddressId + ", @Address1 = " + Address1 + ", @Address2 = " + Address2 + ", @City = " + City + ", @StateId = " + StateId + ", @PostalCode = " + PostalCode + ", @CountryId = " + CountryId + ", @IsActive = " + IsActive + ", @ModifiedBy = " + ModifiedBy; throw new Exception(callMessage, sqlException); } return dataSet; } public DataSet Insert (string Address1, string Address2, string City, int? StateId, string PostalCode, int? CountryId, bool? IsActive, int? CreatedBy, DateTime? CreatedOn) { Database database = DatabaseFactory.CreateDatabase(); DbCommand dbCommand = database.GetStoredProcCommand("prAddress_Insert"); DataSet dataSet; try { database.AddInParameter(dbCommand, "Address1", DbType.AnsiString, Address1); database.AddInParameter(dbCommand, "Address2", DbType.AnsiString, Address2); database.AddInParameter(dbCommand, "City", DbType.AnsiString, City); database.AddInParameter(dbCommand, "StateId", DbType.Int32, StateId); database.AddInParameter(dbCommand, "PostalCode", DbType.AnsiString, PostalCode); database.AddInParameter(dbCommand, "CountryId", DbType.Int32, CountryId); database.AddInParameter(dbCommand, "IsActive", DbType.Boolean, IsActive); database.AddInParameter(dbCommand, "CreatedBy", DbType.Int32, CreatedBy); database.AddInParameter(dbCommand, "CreatedOn", DbType.DateTime, CreatedOn); dataSet = database.ExecuteDataSet(dbCommand); } catch (SqlException sqlException) { string callMessage = "prAddress_Insert " + "@Address1 = " + Address1 + ", @Address2 = " + Address2 + ", @City = " + City + ", @StateId = " + StateId + ", @PostalCode = " + PostalCode + ", @CountryId = " + CountryId + ", @IsActive = " + IsActive + ", @CreatedBy = " + CreatedBy + ", @CreatedOn = " + CreatedOn; throw new Exception(callMessage, sqlException); } return dataSet; } }

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  • jQuery | Click child, hides parent

    - by Jamie
    Hey, I have a list of using ul and li: <span class="important">Show/Hide</span> <div id="important" class="hidden"> <ul class="sub"> <li> Value one </li> <li class="child"> <img src="../img/close.png" /> </li> </ul> </div> $(".important").click(function () { $("#important").slideToggle("fast"); }); When the child (class="child") is clicked on, it should slide up the div (id="important"), however, there are other lists that have different IDs, I want the div to slide up when the child is clicked I did this: $(".child").click(function () { $(".child < div").slideUp("fast"); }); I have no idea how to make it work, I've done other combinations, can't seem to do it.

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  • Java generics SuppressWarnings("unchecked") mystery

    - by Johannes Ernst
    Why does code alternative(1) compile without warnings, and code alternative(2) produce an "unchecked cast" warning? Common for both: class Foo<T> { Foo( T [] arg ) { } } Alternative (1): class Bar<T> extends Foo<T> { protected static final Object [] EMPTY_ARRAY = {}; @SuppressWarnings("unchecked") Bar() { super( (T []) EMPTY_ARRAY ); } } Alternative (2): class Bar<T> extends Foo<T> { @SuppressWarnings("unchecked") Bar() { super( (T []) EMPTY_ARRAY ); } protected static final Object [] EMPTY_ARRAY = {}; } Alternative (2) produces: javac -Xlint:unchecked Foo.java Bar.java Bar.java:4: warning: [unchecked] unchecked cast super( (T []) EMPTY_ARRAY ); ^ required: T[] found: Object[] where T is a type-variable: T extends Object declared in class Bar 1 warning This is: java version "1.7.0_07" Java(TM) SE Runtime Environment (build 1.7.0_07-b10) Java HotSpot(TM) 64-Bit Server VM (build 23.3-b01, mixed mode)

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  • Unrequired property keeps getting data-val-required attribute

    - by frennky
    This is the model with it's validation: [MetadataType(typeof(TagValidation))] public partial class Tag { } public class TagValidation { [Editable(false)] [HiddenInput(DisplayValue = false)] public int TagId { get; set; } [Required] [StringLength(20)] [DataType(DataType.Text)] public string Name { get; set; } //... } Here is the view: <h2>Create</h2> <script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script> @using (Html.BeginForm()) { @Html.ValidationSummary(true) <fieldset> <legend>Tag</legend> <div>@Html.EditorForModel()</div> <p> <input type="submit" value="Create" /> </p> </fieldset> } <div> @Html.ActionLink("Back to List", "Index") </div> And here is what get's renderd: <form action="/Tag/Create" method="post"> <fieldset> <legend>Tag</legend> <div><input data-val="true" data-val-number="The field TagId must be a number." data-val-required="The TagId field is required." id="TagId" name="TagId" type="hidden" value="" /> <div class="editor-label"><label for="Name">Name</label></div> <div class="editor-field"><input class="text-box single-line" data-val="true" data-val-length="The field Name must be a string with a maximum length of 20." data-val-length-max="20" data-val-required="The Name field is required." id="Name" name="Name" type="text" value="" /> <span class="field-validation-valid" data-valmsg-for="Name" data-valmsg-replace="true"></span></div> ... </fieldset> </form> The problem is that TagId validation gets generated althoug thare is no Required attribute set on TagId property. Because of that I can't even pass the client-side validation in order to create new Tag in db. What am I missing?

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  • MEF GetExports<T, TMetaDataView> returning nothing with AllowMultiple = True

    - by sohum
    I don't understand MEF very well, so hopefully this is a simple fix of how I think it works. I'm trying to use MEF to get some information about a class and how it should be used. I'm using the Metadata options to try to achieve this. My interfaces and attribute looks like this: public interface IMyInterface { } public interface IMyInterfaceInfo { Type SomeProperty1 { get; } double SomeProperty2 { get; } string SomeProperty3 { get; } } [MetadataAttribute] [AttributeUsage(AttributeTargets.Class, AllowMultiple = true)] public class ExportMyInterfaceAttribute : ExportAttribute, IMyInterfaceInfo { public ExportMyInterfaceAttribute(Type someProperty1, double someProperty2, string someProperty3) : base(typeof(IMyInterface)) { SomeProperty1 = someProperty1; SomeProperty2 = someProperty2; SomeProperty3 = someProperty3; } public Type SomeProperty1 { get; set; } public double SomeProperty2 { get; set; } public string SomeProperty3 { get; set; } } The class that is decorated with the attribute looks like this: [ExportMyInterface(typeof(string), 0.1, "whoo data!")] [ExportMyInterface(typeof(int), 0.4, "asdfasdf!!")] public class DecoratedClass : IMyInterface { } The method that is trying to use the import looks like this: private void SomeFunction() { // CompositionContainer is an instance of CompositionContainer var myExports = CompositionContainer.GetExports<IMyInterface, IMyInterfaceInfo>(); } In my case myExports is always empty. In my CompositionContainer, I have a Part in my catalog that has two ExportDefinitions, both with the following ContractName: "MyNamespace.IMyInterface". The Metadata is also loaded correctly per my exports. If I remove the AllowMultiple setter and only include one exported attribute, the myExports variable now has the single export with its loaded metadata. What am I doing wrong?

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  • Returning the same type the function was passed

    - by Ken Bloom
    I have the following code implementation of Breadth-First search. trait State{ def successors:Seq[State] def isSuccess:Boolean = false def admissableHeuristic:Double } def breadthFirstSearch(initial:State):Option[List[State]] = { val open= new scala.collection.mutable.Queue[List[State]] val closed = new scala.collection.mutable.HashSet[State] open.enqueue(initial::Nil) while (!open.isEmpty){ val path:List[State]=open.dequeue() if(path.head.isSuccess) return Some(path.reverse) closed += path.head for (x <- path.head.successors) if (!closed.contains(x)) open.enqueue(x::path) } return None } If I define a subtype of State for my particular problem class CannibalsState extends State { //... } What's the best way to make breadthFirstSearch return the same subtype as it was passed? Supposing I change this so that there are 3 different state classes for my particular problem and they share a common supertype: abstract class CannibalsState extends State { //... } class LeftSideOfRiver extends CannibalsState { //... } class InTransit extends CannibalsState { //... } class RightSideOfRiver extends CannibalsState { //... } How can I make the types work out so that breadthFirstSearch infers that the correct return type is CannibalsState when it's passed an instance of LeftSideOfRiver? Can this be done with an abstract type member, or must it be done with generics?

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  • Does Delphi really handle dynamic classes better than static?

    - by John
    Hello, I was told more than once that Delphi handles dynamic classes better than static.Thereby using the following: type Tsomeclass=class(TObject) private procedure proc1; public someint:integer; procedure proc2; end; var someclass:TSomeclass; implementation ... initialization someclass:=TSomeclass.Create; finalization someclass.Free; rather than type Tsomeclass=class private class procedure proc1; public var someint:integer; class procedure proc2; end; 90% of the classes in the project I'm working on have and need only one instance.Do I really have to use the first way for using those classes? Is it better optimized,handled by Delphi? Sorry,I have no arguments to backup this hypothesis,but I want an expert's opinion. Thanks in advance!

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  • Performance tuning of a Hibernate+Spring+MySQL project operation that stores images uploaded by user

    - by Umar
    Hi I am working on a web project that is Spring+Hibernate+MySQL based. I am stuck at a point where I have to store images uploaded by a user into the database. Although I have written some code that works well for now, but I believe that things will mess up when the project would go live. Here's my domain class that carries the image bytes: @Entity public class Picture implements java.io.Serializable{ long id; byte[] data; ... // getters and setters } And here's my controller that saves the file on submit: public class PictureUploadFormController extends AbstractBaseFormController{ ... protected ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) throws Exception{ MutlipartFile file; // getting MultipartFile from the command object ... // beginning hibernate transaction ... Picture p=new Picture(); p.setData(file.getBytes()); pictureDAO.makePersistent(p); // this method simply calls getSession().saveOrUpdate(p) // committing hiernate transaction ... } ... } Obviously a bad piece of code. Is there anyway I could use InputStream or Blob to save the data, instead of first loading all the bytes from the user into the memory and then pushing them into the database? I did some research on hibernate's support for Blob, and found this in Hibernate In Action book: java.sql.Blob and java.sql.Clob are the most efficient way to handle large objects in Java. Unfortunately, an instance of Blob or Clob is only useable until the JDBC transaction completes. So if your persistent class defines a property of java.sql.Clob or java.sql.Blob (not a good idea anyway), you’ll be restricted in how instances of the class may be used. In particular, you won’t be able to use instances of that class as detached objects. Furthermore, many JDBC drivers don’t feature working support for java.sql.Blob and java.sql.Clob. Therefore, it makes more sense to map large objects using the binary or text mapping type, assuming retrieval of the entire large object into memory isn’t a performance killer. Note you can find up-to-date design patterns and tips for large object usage on the Hibernate website, with tricks for particular platforms. Now apparently the Blob cannot be used, as it is not a good idea anyway, what else could be used to improve the performance? I couldn't find any up-to-date design pattern or any useful information on Hibernate website. So any help/recommendations from stackoverflowers will be much appreciated. Thanks

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  • How can I make the C# compiler infer these type parameters automatically?

    - by John Feminella
    I have some code that looks like the following. First I have some domain classes and some special comparators for them. public class Fruit { public int Calories { get; set; } public string Name { get; set; } } public class FruitEqualityComparer : IEqualityComparer<Fruit> { // ... } public class BasketEqualityComparer : IEqualityComparer<IEnumerable<Fruit>> { // ... } Next, I have a helper class called ConstraintChecker. It has a simple BaseEquals method that makes sure some simple base cases are considered: public static class ConstraintChecker { public static bool BaseEquals(T lhs, T rhs) { bool sameObject = l == r; bool leftNull = l == null; bool rightNull = r == null; return sameObject && !leftNull && !rightNull; } There's also a SemanticEquals method which is just a BaseEquals check and a comparator function that you specify. public static bool SemanticEquals<T>(T lhs, T rhs, Func<T, T, bool> f) { return BaseEquals(lhs, rhs) && f(lhs, rhs); } And finally there's a SemanticSequenceEquals method which accepts two IEnumerable<T> instances to compare, and an IEqualityComparer instance that will get called on each pair of elements in the list via Enumerable.SequenceEquals. public static bool SemanticSequenceEquals<T, U, V>(U lhs, U rhs, V comparator) where U : IEnumerable<T> where V : IEqualityComparer<T> { return SemanticEquals(lhs, rhs, (l, r) => lhs.SequenceEqual(rhs, comparator)); } } // end of ConstraintChecker The point of SemanticSequenceEquals is that you don't have to define two comparators whenever you want to compare both IEnumerable<T> and T instances; now you can just specify an IEqualityComparer<T> and it will also handle lists when you invoke SemanticSequenceEquals. So I could get rid of the BasketEqualityComparer class, which would be nice. But there's a problem. The C# compiler can't figure out the types involved when you invoke SemanticSequenceEquals: return ConstraintChecker.SemanticSequenceEquals(lhs, rhs, new FruitEqualityComparer()); If I specify them explicitly, it works: return ConstraintChecker.SemanticSequenceEquals< Fruit, IEnumerable<Fruit>, IEqualityComparer<Fruit> > (lhs, rhs, new FruitEqualityComparer()); What can I change here so that I don't have to write the type parameters explicitly?

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  • How do I use Google's Gson API to deserialize JSON properly?

    - by FK82
    Hi, In short, this is a sketch of the JSON object I want to parse in JAVA: { object1: { item1: //[String | Array | Object] , item2: // ... //<> more items object2: { // } //<> more objects } These are the POJO s I created for parsing (I'll leave out the import statements for brevity's sake): (1) The representation of the complete JSON object public class JObjectContainer { private List<JObject> jObjects ; public JObjectContainer() { // } //get & set methods } (2) The representation of the nested objects: public class JObject { private String id ; private List<JNode> jObjects ; public JObject() { // } //get & set methods } (3) The representation of the items: public class JNode { private JsonElement item1 ; private JsonElement item2 ; //<> more item fields public JNode() { // } //get & set methods } Now, creating a Gson instance (FileReader for importing the jsonFile), Gson gson = new Gson() ; JObjectContainer joc = gson(jsonFile,JObjectContainer.class) ; I get a NullPointerException whenever I try to access the parseable object (e.g. through a ListIterator). Gson does however create an object of the class I specified and does not throw any subsequent errors. I know that this has been done before. So, what am I missing? TIA

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  • Assigning a vector of one type to a vector of another type

    - by deworde
    Hi, I have an "Event" class. Due to the way dates are handled, we need to wrap this class in a "UIEvent" class, which holds the Event, and the date of the Event in another format. What is the best way of allowing conversion from Event to UIEvent and back? I thought overloading the assignment or copy constructor of UIEvent to accept Events (and vice versa)might be best.

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  • How to hide editor-label for public property when calling EditorFor(...)?

    - by FreshCode
    When calling Html.EditorFor(m => m), where m is a public class with public properties, a hidden input and a label are displayed for properties with the [HiddenInput] attribute. How can I hide the label without making it private or creating an editor template? Example public class User { [HiddenInput] public Guid ID { get; set; } // should not be displayed in editor template public string Name { get; set; } // should be editable } Undesired result for ID property by EditorFor(...) with label <div class="editor-label"> <label for="ID">ID</label> <!-- Why is this here? --> </div> <div class="editor-field"> <input id="ID" name="ID" type="hidden" value=""> </div>

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  • Mac OS X: java.lang.ClassNotFoundException: com.sun.java.browser.plugin2.DOM

    - by Thilo
    I am trying to use the new LiveConnect features introduced in Java 6 Update 10. Code looks like this (copied from the applet tutorial): Class<?> c = Class.forName("com.sun.java.browser.plugin2.DOM"); Method m = c.getMethod("getDocument", java.applet.Applet.class); Document document = (Document) m.invoke(null, this); But all I am getting is a ClassNotFoundException for the entry-point class. This on the Mac, 10.6, with both Firefox and Safari. Java Plug-in 1.6.0_22 Using JRE version 1.6.0_22-b04-307-10M3261 Java HotSpot(TM) 64-Bit Server VM Is this not implemented on the Mac? Or do I need to configure something? All I need to do is get and set the value of form elements on the page, so I would be fine with an older (pre-6u10) API if that works better.

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  • [Java] Cannot find symbol

    - by m00st
    I've created a class called Entity this is the superclass. Actor has successfully extended Entity; now trying to do the same with Item results in the Cannot find symbol error. Here is example code: public class Actor extends Entity { Actor(String filename, int x, int y) { super(filename, x, y); } } works just fine but this doesn't: public class Item extends Entity { }

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  • How do I prevent JAXB from binding superclass methods of the @XmlRootElement when marshalling?

    - by Matt Fisher
    I have a class that is annotated as the @XmlRootElement with @XmlAccessorType(XmlAccessType.NONE). The problem that I am having is that the superclass's methods are being bound, when I do not want them to be bound, and cannot update the class. I am hoping there is an annotation that I can put on the root element class to prevent this from happening. Example: @XmlRootElement @XmlAccessorType(XmlAccessType.NONE) public class Person extends NamedObject { @XmlElement public String getId() { ... } } I would expect that only the methods annotated @XmlElement on Person would be bound and marshalled, but the superclass's methods are all being bound, as well. The resulting XML then has too much information. How do I prevent the superclass's methods from being bound without having to annotate the superclass, itself?

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  • ASP.NET MVC security: how to check if a controller method is allowed to execute under current user's

    - by Gart
    Given an ASP.NET MVC Controller class declaration: public class ItemController : Controller { public ActionResult Index() { // ... } public ActionResult Details() { // ... } [Authorize(Roles="Admin, Editor")] public ActionResult Edit() { // ... } [Authorized(Roles="Admin")] public ActionResult Delete() { // .. } } I need to reflect a list of methods in this class which may be invoked with the current user's permissions. Please share some ideas of what could be done in this case.

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  • Persist collection of interface using Hibernate

    - by Olvagor
    I want to persist my litte zoo with Hibernate: @Entity @Table(name = "zoo") public class Zoo { @OneToMany private Set<Animal> animals = new HashSet<Animal>(); } // Just a marker interface public interface Animal { } @Entity @Table(name = "dog") public class Dog implements Animal { // ID and other properties } @Entity @Table(name = "cat") public class Cat implements Animal { // ID and other properties } When I try to persist the zoo, Hibernate complains: Use of @OneToMany or @ManyToMany targeting an unmapped class: blubb.Zoo.animals[blubb.Animal] I know about the targetEntity-property of @OneToMany but that would mean, only Dogs OR Cats can live in my zoo. Is there any way to persist a collection of an interface, which has several implementations, with Hibernate?

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  • UML Modelling in C++Builder 2010 Professional

    - by Gordon Brandly
    I'd like to do some basic class diagram UML models in the Pro version of C++Builder 2010. Embarcadero has a C++Builder Features Matrix document, one line of which says "UML Code Visualization – at any time, get a UML model view of your source code" and has a check in the "Professional" column of that table -- I assume this means it should be available to me. Yet, when I open an existing project and do a View | Model View, there's nothing in the Model View window. The only diagram I can find is on the Graph tab of the C++ Class Explorer. I wouldn't call that a UML diagram myself -- is that what Embarcadero is referring to? Embarcadero's table shows that many UML diagrams are not available in Pro, but it looks to me like Class Diagrams should be available. Other lines in that same table indicate that both "Full two-way class diagrams with synchronization between code and diagrams" and "Diagram hyper-linking and annotations" are also supposed to be available in Pro. The Class Explorer graph is one-way only as far as I can tell, so I hope they're referring to something else I haven't been able to find so far. Thanks for any insight into this.

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  • Extending Java Enums

    - by CaseyB
    Here's what I am looking to accomplish, I have a class that has an enum of some values and I want to subclass that and add more values to the enum. This is a bad example, but: public class Digits { public enum Digit { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 } } public class HexDigits extends Digits { public enum Digit { A, B, C, D, E, F } } so that HexDigits.Digit contains all Hex Digits. Is that possible?

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  • Documenting PHP multiple inheritance with PhpDoc

    - by Sam Dark
    I have multiple inheritance like this one: http://stackoverflow.com/questions/356128/can-i-extend-a-class-using-more-than-1-class-in-php (let's not discuss this approach itself please) and want my IDE to know about inherited class methods and properties. Is there a way to do it with PhpDoc?

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