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• java class creation dynamically and make it accessible across the network different jvms i.e. serial

  - by inj.rav

  Hi. I have a requirement of creating java classes dynamically and make it accessible different jvms across the network. I tried to use reflection and javassist tool,but nothing worked. Let me explain the scenario we are using Coherence distributed cache. It has a power of doing aggregation/filtering in parallel across the cluster. For example if a class has [dynamic class] has amount variable and getAmount/setAmount methods. Then if we execute COHERENCE queries, it will start process in parallel across the cluster. I tried to create classes at run time by using javassist and reflection. I am able to access it from single JVM, but when I tried to access the same class from other jvm [through coherence cluster]. I am getting exception of class not found [as remote jvm is not having idea of this class].I can over come this by creating same class dynamically on remote jvm also and access the methods. But coherence in built methods/functions are not able to find the class. could some one help me on this matter

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• JPanel.addComponentListener does not work when the listener is a class variable

  - by Coder

  I have a public class which has the following method and instance variable: public void setImagePanel(JPanel value) { imagePanel = value; if (imagePanel != null) { //method 1 : works imagePanel.addComponentListener(new ComponentAdapter() { public void componentResized(ComponentEvent evt) { System.out.println("Here 1"); } }); //method 2 : does not work panelResizeListener = new ResizeListener(); imagePanel.addComponentListener(panelResizeListener); //method 3 : works //ResizeListener listener = new ResizeListener(); //imagePanel.addComponentListener(listener); //method 4 : works //imagePanel.addComponentListener(new ResizeListener()); //method 5 : does not work -- THIS IS THE DESIRED CODE I WANT TO USE imagePanel.addComponentListener(panelResizeListener); } } public class ResizeListener extends ComponentAdapter { @Override public void componentResized(ComponentEvent evt) { System.out.println("RESIZE 3"); } } private ResizeListener panelResizeListener = new ResizeListener(); Each of the methods above correspond the to code immediately below until the next //method comment. What i don't understand is why i can't use the class instance variable and add that to the JPanel as a component listener. What happens in the cases above where i say that the method does not work is that i don't get the "RESIZE 3" log messages. In all cases where i list that it works, then i get the "RESIZE 3" messages. The outer class is public with no other modification except that it implements an interface that i created (which has no methods or variables in common with the methods and variables listed above). If anyone can help me i would greatly appreciate it. This problem makes no sense to me, the code should be identical.

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• AssertionFailure: "null identifier" - FluentNH + SQLServerCE

  - by Stefan

  The code fails at session.Save(employee); with AssertionFailure "null identifier". What am I doing wrong? using FluentNHibernate.Cfg; using FluentNHibernate.Cfg.Db; using FluentNHibernate.Mapping; using NHibernate; using NHibernate.Cfg; using NHibernate.Tool.hbm2ddl; namespace FNHTest { public class Employee { public virtual int Id { get; private set; } public virtual string Name { get; set; } public virtual string Surname { get; set; } } public class EmployeeMap : ClassMap { public EmployeeMap() { Id(e = e.Id); Map(e = e.Name); Map(e = e.Surname); } } public class DB { private static ISessionFactory mySessionFactory = null; private static ISessionFactory SessionFactory { get { if (mySessionFactory == null) { mySessionFactory = Fluently.Configure() .Database(MsSqlCeConfiguration.Standard .ConnectionString("Data Source=MyDB.sdf")) .Mappings(m = m.FluentMappings.AddFromAssemblyOf()) .ExposeConfiguration(BuildSchema) .BuildSessionFactory(); } return mySessionFactory; } } private static void BuildSchema(Configuration configuration) { SchemaExport schemaExport = new SchemaExport(configuration); schemaExport.Execute(false, true, false); } public static ISession OpenSession() { return SessionFactory.OpenSession(); } } public class Program { public static void Main(string[] args) { var employee = new Employee { Name = "John", Surname = "Smith" }; using (ISession session = DB.OpenSession()) { session.Save(employee); } } } }

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• Qt Socket blocking functions required to run in QThread where created. Any way past this?

  - by Alexander Kondratskiy

  The title is very cryptic, so here goes! I am writing a client that behaves in a very synchronous manner. Due to the design of the protocol and the server, everything has to happen sequentially (send request, wait for reply, service reply etc.), so I am using blocking sockets. Here is where Qt comes in. In my application I have a GUI thread, a command processing thread and a scripting engine thread. I create the QTcpSocket in the command processing thread, as part of my Client class. The Client class has various methods that boil down to writing to the socket, reading back a specific number of bytes, and returning a result. The problem comes when I try to directly call Client methods from the scripting engine thread. The Qt sockets randomly time out and when using a debug build of Qt, I get these warnings: QSocketNotifier: socket notifiers cannot be enabled from another thread QSocketNotifier: socket notifiers cannot be disabled from another thread Anytime I call these methods from the command processing thread (where Client was created), I do not get these problems. To simply phrase the situation: Calling blocking functions of QAbstractSocket, like waitForReadyRead(), from a thread other than the one where the socket was created (dynamically allocated), causes random behaviour and debug asserts/warnings. Anyone else experienced this? Ways around it? Thanks in advance.

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• BindingFlags.DeclaredOnly alternative to avoid ambiguous properties of derived classes

  - by JoeBilly

  I'am looking for a solution to access 'flatten' (lowest) properties values of a class and its derived via reflection by property names. ie access either Property1 or Property2 from the ClassB or ClassC type : public class ClassA { public virtual object Property1 { get; set; } public object Property2 { get; set; } } public class ClassB : ClassA { public override object Property1 { get; set; } } public class ClassC : ClassB { } Using simple reflection works until you have virtual properties that are overrired (ie Property1 from ClassB). Then you get a AmbiguousMatchException because the searcher don't know if you want the property of the main class or the derived. Using BindingFlags.DeclaredOnly avoid the AmbiguousMatchException but unoverrided virtual properties or derived classes properties are ommited (ie Property2 from ClassB). Is there an alternative to this poor workaround : // Get the main class property with the specified propertyName PropertyInfo propertyInfo = _type.GetProperty(propertyName, BindingFlags.DeclaredOnly | BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static); // If not found, get the property wherever it is if (propertyInfo == null) propertyInfo = _type.GetProperty(propertyName); Furthermore, this workaround not resolve the reflection of 2nd level properties : getting Property1 from ClassC and AmbiguousMatchException is back. My thoughts : I have no choice except loop... Erk... ?? I'am open to Emit, Lambda (is the Expression.Call can handle this?) even DLR solution. Thanks !

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• Spring - Transaction Readonly

  - by AAK

  Hello Gurus! Just wanted your expert opinions on declarative transaction management for Spring. Here is my setup - A. DAO Layer is Plain old JDBC using jdbcTemplete (No hibernate etc) B. Service Layer is POJO with declarative trasnactions as follows - save*, readonly=false, rollback for Throwable Things work fine with above setup. However when I say get*, readonly=true I see errors in my log file saying - Database connection cannot be marked as readonly. This happens for all get* methods in Service Layer. Now my questions - A. Do I have to say get* as readonly? All my get* methods are pure read DB operations. I do not wish to run them in any transaction context. How serious is the above error? B. When I remove the get* confiiguration, I do not see the errors, morever all my simple get* operations are performed without transactions. Is this the way to go? C. Why would anyone want to have transactional methods where readonly = true? Is there any practical significance of this configuration? Thank you! As always your resposes are much appreciated!

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• How to design Models the correct way: Object-oriented or "Package"-oriented?

  - by ajsie

  I know that in OOP you want every object (from a class) to be a "thing", eg. user, validator etc. I know the basics about MVC, how they different parts interact with each other. However, i wonder if the models in MVC should be designed according to the traditional OOP design, that is to say, should every model be a database/table/row (solution 2)? Or is the intention more like to collect methods that are affecting the same table or a bunch of related tables (solution 1). example for an Address book module in CodeIgniter, where i want be able to "CRUD" a Contact and add/remove it to/from a CRUD-able Contact Group. Models solution 1: bunching all related methods together (not real object, rather a "package") class Contacts extends Model { function create_contact() {) function read_contact() {} function update_contact() {} function delete_contact() {} function add_contact_to_group() {} function delete_contact_from_group() {} function create_group() {} function read_group() {} function update_group() {} function delete_group() {} } Models solution 2: the OOP way (one class per file) class Contact extends Model { private $name = ''; private $id = ''; function create_contact() {) function read_contact() {} function update_contact() {} function delete_contact() {} } class ContactGroup extends Model { private $name = ''; private $id = ''; function add_contact_to_group() {} function delete_contact_from_group() {} function create_group() {} function read_group() {} function update_group() {} function delete_group() {} } i dont know how to think when i want to create the models. and the above examples are my real tasks for creating an Address book. Should i just bunch all functions together in one class. then the class contains different logic (contact and group), so it can not hold properties that are specific for either one of them. the solution 2 works according to the OOP. but i dont know why i should make such a dividing. what would the benefits be to have a Contact object for example. Its surely not a User object, so why should a Contact "live" with its own state (properties and methods). you experienced guys with OOP/MVC, please shed a light on how one should think here in this very concrete task.

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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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• Java method keyword "final" and its use

  - by Lukas Eder

  When I create complex type hierarchies (several levels, several types per level), I like to use the final keyword on methods implementing some interface declaration. An example: interface Garble { int zork(); } interface Gnarf extends Garble { /** * This is the same as calling {@link #zblah(0)} */ int zblah(); int zblah(int defaultZblah); } And then abstract class AbstractGarble implements Garble { @Override public final int zork() { ... } } abstract class AbstractGnarf extends AbstractGarble implements Gnarf { // Here I absolutely want to fix the default behaviour of zblah // No Gnarf shouldn't be allowed to set 1 as the default, for instance @Override public final int zblah() { return zblah(0); } // This method is not implemented here, but in a subclass @Override public abstract int zblah(int defaultZblah); } I do this for several reasons: It helps me develop the type hierarchy. When I add a class to the hierarchy, it is very clear, what methods I have to implement, and what methods I may not override (in case I forgot the details about the hierarchy) I think overriding concrete stuff is bad according to design principles and patterns, such as the template method pattern. I don't want other developers or my users do it. So the final keyword works perfectly for me. My question is: Why is it used so rarely in the wild? Can you show me some examples / reasons where final (in a similar case to mine) would be very bad?

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• Question about effective logging in C#

  - by MartyIX

  I've written a simple class for debugging and I call the method Debugger.WriteLine(...) in my code like this: Debugger.WriteLine("[Draw]", "InProgress", "[x,y] = " + x.ToString("0.00") + ", " + y.ToString("0.00") + "; pos = " + lastPosX.ToString() + "x" + lastPosY.ToString() + " -> " + posX.ToString() + "x" + posY.ToString() + "; SS = " + squareSize.ToString() + "; MST = " + startTime.ToString("0.000") + "; Time = " + time.ToString() + phase.ToString(".0000") + "; progress = " + progress.ToString("0.000") + "; step = " + step.ToString() + "; TimeMovementEnd = " + UI.MovementEndTime.ToString()); The body of the procedure Debugger.WriteLine is compiled only in Debug mode (directives #if, #endif). What makes me worry is that I often need ToString() in Debugger.WriteLine call which is costly because it creates still new strings (for changing number for example). How to solve this problem? A few points/questions about debugging/tracing: I don't want to wrap every Debugger.WriteLine in an IF statement or to use preprocessor directives in order to leave out debugging methods because it would inevitable lead to a not very readable code and it requires too much typing. I don't want to use any framework for tracing/debugging. I want to try to program it myself. Are Trace methods (http://msdn.microsoft.com/en-us/library/system.diagnostics.trace.aspx) left out if compiling in release mode? If it is so is it possible that my methods would behave similarly? http://msdn.microsoft.com/en-us/library/fht0f5be.aspx output = String.Format("You are now {0} years old.", years); Which seems nice. Is it a solution for my problem with ToString()?

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• iPhone SDK allow touches to affect multiple views

  - by Parad0x13

  I have a main view that has has two buttons on it that control methods to display the next image and display the previous image. In this case the 'Image' is a class that inherits from UIImageView and has multiple pictures on it that you can interact with, and I call this class a 'Pane'. The pane itself handles all the user interaction itself while the main view controls the display of next and previous panes with the buttons. Here is my dilemma, because the pane fully covers the main view it wont allow for the user to tap the buttons on the main view! So once a pane pops up you cannot change it via the buttons! Is there a way to allow touches through transparent parts of a view, or if not how in the world do I achieve this?! I cannot pass touchesBegan or any of those methods from the pane to the superview because all of the button touch methods are created in the xib file. I cannot insert the pane under the control panel because then you wouldn't be able to interact with the pane. And as far as I know theres no way to pass touch events to every single pane within the paneHoldingArray that belongs to the main view I cannot add the command buttons inside of the pane because I want to be able to replace the command button's image with a thumbprint render of the next/previous pane. I've been stuck on this for a very long time, please somebody help me out with a fix action or a new way to re-engineer the code so that it will work!

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• What are good strategies for organizing single class per query service layer?

  - by KallDrexx

  Right now my Asp.net MVC application is structured as Controller - Services - Repositories. The services consist of aggregate root classes that contain methods. Each method is a specific operation that gets performed, such as retrieving a list of projects, adding a new project, or searching for a project etc. The problem with this is that my service classes are becoming really fat with a lot of methods. As of right now I am separating methods out into categories separated by #region tags, but this is quickly becoming out of control. I can definitely see it becoming hard to determine what functionality already exists and where modifications need to go. Since each method in the service classes are isolated and don't really interact with each other, they really could be more stand alone. After reading some articles, such as this, I am thinking of following the single query per class model, as it seems like a more organized solution. Instead of trying to figure out what class and method you need to call to perform an operation, you just have to figure out the class. My only reservation with the single query per class method is that I need some way to organize the 50+ classes I will end up with. Does anyone have any suggestions for strategies to best organize this type of pattern?

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• Using recursion to to trim a binary tree based on a given min and max value

  - by Justin

  As the title says, I have to trim a binary tree based on a given min and max value. Each node stores a value, and a left/right node. I may define private helper methods to solve this problem, but otherwise I may not call any other methods of the class nor create any data structures such as arrays, lists, etc. An example would look like this: overallRoot _____[50]____________________ / \ __________[38] _______________[90] / \ / _[14] [42] [54]_____ / \ \ [8] [20] [72] \ / \ [26] [61] [83] trim(52, 65); should return: overallRoot [54] \ [61] My attempted solution has three methods: public void trim(int min, int max) { rootFinder(overallRoot, min, max); } First recursive method finds the new root perfectly. private void rootFinder(IntTreeNode node, int min, int max) { if (node == null) return; if (overallRoot.data < min) { node = overallRoot = node.right; rootFinder(node, min, max); } else if (overallRoot.data > max) { node = overallRoot = node.left; rootFinder(node, min, max); } else cutter(overallRoot, min, max); } This second method should eliminate any further nodes not within the min/max, but it doesn't work as I would hope. private void cutter(IntTreeNode node, int min, int max) { if (node == null) return; if (node.data <= min) { node.left = null; } if (node.data >= max) { node.right = null; } if (node.data < min) { node = node.right; } if (node.data > max) { node = node.left; } cutter(node.left, min, max); cutter(node.right, min, max); } This returns: overallRoot [54]_____ \ [72] / [61] Any help is appreciated. Feel free to ask for further explanation as needed.

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• How do I prevent a C# method from executing using an attribute validator?

  - by Boydski

  I'd like to create an attribute-based validator that goes a few steps beyond what I've seen in examples. It'll basically prevent methods or other functionality from executing. Please be aware that I'm having to use AzMan since I have no availability to Active Directory in this scenario. Here's some pseudo code of what what I'm looking for: // Attribute validator class AttributeUsage is arbitrary at this point and may include other items [AttributeUsage( AttributeTargets.Method | AttributeTargets.Property, AllowMultiple = true, Inherited = true )] public class PermissionsValidatorAttribute : Attribute { public PermissionsValidatorAttribute(PermissionEnumeration permission){...} public bool UserCanCreateAndEdit(){...} public bool UserCanDelete(){...} public bool UserCanUpload(){...} } Here's a sample of a class/member that'll be decorated. The method will not be executed at all if the PermissionValidator.UserCanDelete() doesn't return true from wherever it's executed: public class DoStuffNeedingPermissions { [PermissionValidator(PermissionEnumeration.MustHaveDeletePermission)] public void DeleteSomething(){...} } I know this is a simple, incomplete example. But you should get the gist of what I'm needing. Make the assumption that DeleteSomething() already exists and I'm preferring to NOT modify the code within the method at all. I'm currently looking at things like the Validation Application Block and am messing with custom attribute POC's. But I'd love to hear opinions with code samples from everyone out there. I'm also certainly not opposed to other methods of accomplishing the same thing such as extension methods or whatever may work to accomplish the same thing. Please remember I'm making the attempt to minimize changes to existing DoStuffNeedingPermissions code. Thanks everyone!

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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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• Fluent Nhibernate Mapping Single class on two database tables

  - by nabeelfarid

  Hi guys, I am having problems with Mapping. I have two tables in my database as follows: Employee and EmployeeManagers Employee EmployeeId int Name nvarchar EmployeeManagers EmployeeIdFk int ManagerIdFk int So the employee can have 0 or more Managers. A manager itself is also an Employee. I have the following class to represent the Employee and Managers public class Employee { public virtual int Id { get; set; } public virtual string Name { get; set; } public virtual IList<Employee> Managers { get; protected set; } public Employee() { Managers = new List<Employee>(); } } I don't have any class to represent Manager because I think there is no need for it, as Manager itself is an Employee. I am using autoMapping and I just can't figure out how to map this class to these two tables. I am implementing IAutoMappingOverride for overriding automappings for Employee but I am not sure what to do in it. public class NodeMap : IAutoMappingOverride { public void Override(AutoMapping<Node> mapping) { //mapping.HasMany(x => x.ValidParents).Cascade.All().Table("EmployeeManager"); //mapping.HasManyToMany(x => x.ValidParents).Cascade.All().Table("EmployeeManager"); } } I also want to make sure that an employee can not be assigned the same manager twice. This is something I can verify in my application but I would like to put constraint on the EmployeeManager table (e.g. a composite key) so a same manager can not be assigned to an employee more than once. Could anyone out there help me with this please? Awaiting Nabeel

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• Symfony 1.2 to 2.3 migration

  - by Bonswouar

  I've got a pretty big Symfony 1.2 project to migrate. First, I modified my .htaccess so I can have some pages handled by Symfony 2. What I'd like to do, to make the migration smoother, is to be able to render some SF2 action/templates/methods/... inside SF1. I added the autoloader to the SF1 app, so I can access to twig rendering methods and other stuff. But how can I call a SF2 action ? For example, if I want to migrate only the footer first, I would also need some php methods, not only rendering. That was previously in SF1 component, where should it be now ? If you've got any suggestion about the way of migrating, don't hesitate ! EDIT 1 : Apparently, the only way to do something like that is to render a full twig template, and/or in this template call some other partial twig templates with render(url, params). Here is my SF1 code to be able to render twig templates : public static function getTwig() { require_once __DIR__.'SF2_PATH/vendor/twig/extensions/lib/Twig/Extensions/Autoloader.php'; Twig_Autoloader::register(); $loader = new Twig_Loader_Filesystem( __DIR__.'SF2_PATH/sf2/src/VENDOR/BUNDLE/'); $twig = new Twig_Environment($loader, array( 'cache' => __DIR__.'SF2_PATH/sf2/app/cache/dev/twig', )); return $twig; } And so : $twig->loadTemplate('header.html.twig'); EDIT 2 : That doesn't seem to work, if in a twig template I try to render an other one with {{render(controller('BUNDLE:CONTROLER:ACTION', {})) }} for example Twig_Error : The function "controller" does not exist. And if I try to render the url Unknown tag name "render". I guess Symfony 2 twig functionalities are not loaded, how can I do that ? EDIT 3 : Ok, now I can do it, but I've got the following message... Twig_Error_Runtime An exception has been thrown during the rendering of a template ("Rendering a fragment can only be done when handling a master Request.") in ...

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• Another IE Issue with AJAX

  - by Nik

  Alright, This code works in every browser except IE (again, to be expected). The code is supposed to refresh based on setInterval, and does so normally in all other browsers except IE, which just doesn't refresh. Can you spot the problem? var nick = document.getElementById("chatnick").value; var sessid = document.getElementById("sessid").value; var room = document.getElementById("roomid").value; function user_read() { $.ajax({ type: "GET", url: "methods.php", data: {method: "u", room: room}, dataType: "html", success: function (data, status, xhr) { $("#userwindow").html(data); setTimeout(user_read, 10000); } }); } function ajax_read() { $.ajax({ type: "GET", url: "methods.php", data: {method: "r", room: room}, dataType: "html", success: function (data, status, xhr) { $("#chatwindow").html(data); setTimeout(ajax_read, 400); } }); } function submit_msg() { var msg = document.getElementById("chatmsg").value; $.ajax({ type: "GET", url: "methods.php", data: {method: "w", room: room, m: msg, n: nick, sessid: sessid}, dataType: "html", success: function (data, status, xhr) { } }); document.getElementById("chatmsg").value = ""; } function keyup(arg1) { if (arg1 == 13) submit_msg(); } setTimeout(function(){ajax_read();}, 400); user_read();

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• How to Elegantly convert switch+enum with polymorphism

  - by Kyle

  I'm trying to replace simple enums with type classes.. that is, one class derived from a base for each type. So for example instead of: enum E_BASE { EB_ALPHA, EB_BRAVO }; E_BASE message = someMessage(); switch (message) { case EB_ALPHA: applyAlpha(); case EB_BRAVO: applyBravo(); } I want to do this: Base* message = someMessage(); message->apply(this); // use polymorphism to determine what function to call. I have seen many ways to do this which all seem less elegant even then the basic switch statement. Using dyanimc_pointer_cast, inheriting from a messageHandler class that needs to be updated every time a new message is added, using a container of function pointers, all seem to defeat the purpose of making code easier to maintain by replacing switches with polymorphism. This is as close as I can get: (I use templates to avoid inheriting from an all-knowing handler interface) class Base { public: template<typename T> virtual void apply(T* sandbox) = 0; }; class Alpha : public Base { public: template<typename T> virtual void apply(T* sandbox) { sandbox->applyAlpha(); } }; class Bravo : public Base { public: template<typename T> virtual void apply(T* sandbox) { sandbox->applyBravo(); } }; class Sandbox { public: void run() { Base* alpha = new Alpha; Base* bravo = new Bravo; alpha->apply(this); bravo->apply(this); delete alpha; delete bravo; } void applyAlpha() { // cout << "Applying alpha\n"; } void applyBravo() { // cout << "Applying bravo\n"; } }; Obviously, this doesn't compile but I'm hoping it gets my problem accross.

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• Using Doctrine to abstract CRUD operations

  - by TomWilsonFL

  This has bothered me for quite a while, but now it is necessity that I find the answer. We are working on quite a large project using CodeIgniter plus Doctrine. Our application has a front end and also an admin area for the company to check/change/delete data. When we designed the front end, we simply consumed most of the Doctrine code right in the controller: //In semi-pseudocode function register() { $data = get_post_data(); if (count($data) && isValid($data)) { $U = new User(); $U->fromArray($data); $U->save(); $C = new Customer(); $C->fromArray($data); $C->user_id = $U->id; $C->save(); redirect_to_next_step(); } } Obviously when we went to do the admin views code duplication began and considering we were in a "get it DONE" mode so it now stinks with code bloat. I have moved a lot of functionality (business logic) into the model using model methods, but the basic CRUD does not fit there. I was going to attempt to place the CRUD into static methods, i.e. Customer::save($array) [would perform both insert and update depending on if prikey is present in array], Customer::delete($id), Customer::getObj($id = false) [if false, get all data]. This is going to become painful though for 32 model objects (and growing). Also, at times models need to interact (as the interaction above between user data and customer data), which can't be done in a static method without breaking encapsulation. I envision adding another layer to this (exposing web services), so knowing there are going to be 3 "controllers" at some point I need to encapsulate this CRUD somewhere (obviously), but are static methods the way to go, or is there another road? Your input is much appreciated.

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• Fluent NHibernate Map to private/protected Field that has no exposing Property

  - by Jon Erickson

  I have the following Person and Gender classes (I don't really, but the example is simplified to get my point across), using NHibernate (Fluent NHibernate) I want to map the Database Column "GenderId" [INT] value to the protected int _genderId field in my Person class. How do I do this? FYI, the mappings and the domain objects are in separate assemblies. public class Person : Entity { protected int _genderId; public virtual int Id { get; private set; } public virtual string Name { get; private set; } public virtual Gender Gender { get { return Gender.FromId(_genderId); } } } public class Gender : EnumerationBase<Gender> { public static Gender Male = new Gender(1, "Male"); public static Gender Female = new Gender(2, "Female"); private static readonly Gender[] _genders = new[] { Male, Female }; private Gender(int id, string name) { Id = id; Name = name; } public int Id { get; private set; } public string Name { get; private set; } public static Gender FromId(int id) { return _genders.Where(x => x.Id == id).SingleOrDefault(); } }

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• My Core Animation block isn't working like I'd expect

  - by Alex Reynolds

  I have a UIView called activityView, which contains two subviews activityIndicator and cancelOperationsButton. These views are embedded in a XIB and wired up to my view controller. I have two methods that deal with activating (showing) and deactivating (hiding) these two subviews: - (void) enableActivityIndicator { [activityIndicator startAnimating]; [cancelOperationsButton setHidden:NO]; } - (void) disableActivityIndicator { [activityIndicator stopAnimating]; [cancelOperationsButton setHidden:YES]; } By themselves, these two methods work fine. To give this a bit of polish, I'd like to add an animation that fades these subviews in and out: - (void) enableActivityIndicator { [activityIndicator startAnimating]; [cancelOperationsButton setHidden:NO]; [UIView beginAnimations:@"fadeIn" context:nil]; [UIView setAnimationDelay:0.0f]; [UIView setAnimationDuration:1.0f]; [UIView setAnimationCurve:UIViewAnimationCurveEaseIn]; activityView.alpha = 1.0f; [UIView commitAnimations]; } - (void) disableActivityIndicator { [UIView beginAnimations:@"fadeOut" context:nil]; [UIView setAnimationDelay:0.0f]; [UIView setAnimationDuration:1.0f]; [UIView setAnimationCurve:UIViewAnimationCurveEaseOut]; activityView.alpha = 0.0f; [UIView commitAnimations]; [activityIndicator stopAnimating]; [cancelOperationsButton setHidden:YES]; } But the animations are not working — the subviews just show up or disappear without the parent view's alpha property having an effect on transparency. How should I write these methods to get the fade-in, fade-out effect I am after?

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• Diamond problem in C++

  - by Jack

  I know the diamond problem. I am using gcc compiler. I have some scenarios I need explanation about. 1) class A{ public: virtual void eat(){cout<<"A eat\n";} }; class B:public A{ public: void eat(){ cout<<"B eat\n";}}; class C:public A{ public: void eat(){ cout<<"C eat\n";}}; class D:public B,C{ public: void eat(){ cout<<"D eat\n";}}; int main() { A * a = new D(); a->eat(); getch(); return 0; } Why doesn't this work? 2) class A{ public: void eat(){cout<<"A eat\n";} }; class B:virtual public A{ public: void eat(){ cout<<"B eat\n";}}; class C:virtual public A{ public: void eat(){ cout<<"C eat\n";}}; class D: public B,C{ public: void eat(){ cout<<"D eat\n";}}; int main() { A * a = new D(); a->eat(); getch(); return 0; } When I do this what happens in the background. How does the ambiguity get removed. Is the concept of vtables involved here?

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• Change classes instantiated with loadNibNamed

  - by Nick H247

  I am trying to change the class of objects created with a nib with the iPhone SDK. The reason for this is; i dont know until runtime what the class is that i want the nib object to be (though they will have the same UIView based super class), and i dont want to create a different nib for every eventuality - as the .nib will be the same for each, apart from the class of one object. I have been successful, with a couple of methods, but either have some knock on effects or am unsure of how safe the methods I have used are: Method 1: Override alloc, on the super class and set a c variable to the class I require: + (id) alloc { if (theClassIWant) { id object = [theClassIWant allocWithZone:NSDefaultMallocZone()]; theClassIWant = nil; return object; } return [BaseClass allocWithZone:NSDefaultMallocZone()]; } this works well, and i assume is 'reasonably' safe, though if I alloc a subclass myself (without setting 'theClassIWant') - an object of the base class is created. I also dont really like the idea of overriding alloc... Method 2: use object_setClass(self,theClassIWant) in initWithCoder (before calling initWithCoder on the super class): - (id) initWithCoder:(NSCoder *)aDecoder { if (theClassIWant) { // the framework doesn't like this: //[self release]; //self = [theClassIWant alloc]; // whoa now! object_setClass(self,theClassIWant); theClassIWant = nil; return [self initWithCoder:aDecoder]; } if (self = [super initWithCoder:aDecoder]) { ... this also works well, but not all the subclasses are necessarily going to be the same size as the super class, so this could be very unsafe! To combat this i tried releasing and re-allocing to the correct type within initWithCoder, but i got the following error from the framework: "This coder requires that replaced objects be returned from initWithCoder:" dont quite get what this means! i am replacing an object in initWithCoder... Any comments on the validity of these methods, or suggestions of improvements or alternatives welcome!

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• How to write a Criteria Query when there's an <any> association

  - by Bevan

  I'm having some trouble constructing the correct Criteria to do a particular query - after an afternoon of consultation with Professor Google, I'm hoping that someone can point me in the right direction. I have two entities of interest: OutputTsDef and NamedAttribute What I'm trying to do is to find all OutputTsDef that have a particular NamedAttribute value. I can write a detached Criteria to find all NamedAttributes that have a given name and value: var attributesCriteria = DetachedCriteria.For<INamedAttribute>() .Add(Expression.Eq("Name", "some name")) .Add(Expression.Eq("Value", "some value")); How do I inject this in to a query for OutputTsDef to restrict the results? var criteria = nHibernateSession.CreateCriteria(typeof(IOutputTsDefEntity)); // What do I write here? var results = criteria.List(); NamedAttribute looks like this - note the use of [Any] as we can have NamedAttributes on many kinds of entity. [AttributeIdentifier("DbKey", Name = "Id.Column", Value = "NamedAttributeID")] [Class(Table = "NamedAttributes")] public class NamedAttribute : BusinessEntity, INamedAttribute { [Any(0, Name = "Entity", MetaType = "System.String", IdType = "System.Int32")] [MetaValue(1, Class = "Sample.OutputTsDef, Sample.Entities", Value = "OTD")] [MetaValue(2, Class = "Sample.OutputTimeSeriesAttributesEntity, Sample.Entities", Value = "OTA")] [Column(3, Name = "OwnerType")] [Column(4, Name = "OwnerKey")] public virtual IBusinessEntity Entity { get; set; } [Property(Column = "Name")] public virtual string Name { get; set; } [Property(Column = "Value")] public virtual string Value { get; set; } ... omitted ... } In regular SQL, I'd just include an extra "where" clause like this: where OutputTsDefId in ( select distinct OwnerKey from NamedAttributes where Name = ? and Value = ? and OwnerType = 'OTD' ) What am I missing? (Question also posted to the NHUsers mailing list - I'll copy any useful information from there, here.)

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