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• Help decoding MSDN Dynamic Data Article

  - by davemackey

  I'm trying to run through this msdn article: http://msdn.microsoft.com/en-us/library/dd723645.aspx One of the steps is: In the class file for the page, change the base class from UserControl to EntityTemplateUserControl. Nowhere is it made clear what page is being referenced. Can someone help me? I don't see any relevant class in the pages I have, so I assumed maybe they were talking about the ascx and didn't really mean page, but I'm not seeing an option there either.

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• How to pass data to a C++0x lambda function that will run in a different thread?

  - by Dimitri C.

  In our company we've written a library function to call a function asynchronously in a separate thread. It works using a combination of inheritance and template magic. The client code looks as follows: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, &DemoThread::SomeFunction, stringToPassByValue); Since the introduction of lambda functions I'd like to use it in combination with lambda functions. I'd like to write the following client code: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, [=]() { const std::string someCopy = stringToPassByValue; }); Now, with the Visual C++ 2010 this code doesn't work. What happens is that the stringToPassByValue is not copied. Instead the "capture by value" feature passes the data by reference. The result is that if the function is executed after stringToPassByValue has gone out of scope, the application crashes as its destructor is called already. So I wonder: is it possible to pass data to a lambda function as a copy? Note: One possible solution would be to modify our framework to pass the data in the lambda parameter declaration list, as follows: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, [=](const std::string stringPassedByValue) { const std::string someCopy = stringPassedByValue; } , stringToPassByValue); However, this solution is so verbose that our original function pointer solution is both shorter and easier to read. Update: The full implementation of AsyncCall is too big to post here. In short, what happens is that the AsyncCall template function instantiates a template class holding the lambda function. This class is derived from a base class that contains a virtual Execute() function, and upon an AsyncCall() call, the function call class is put on a call queue. A different thread then executes the queued calls by calling the virtual Execute() function, which is polymorphically dispatched to the template class which then executes the lambda function.

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• Example of contravariance

  - by Misha

  I am thinking of the following example to illustrate why contravariance is useful. Let's consider a GUI framework with Widgets, Events, and Event Listeners. abstract class Event; class KeyEvent extends Event class MouseEvent extends Event trait EventListener[-Event] { def listen(e:Event) } Let Widgets define the following methods: def addKeyEventListener(listener:EventListener[KeyEvent]) def addMouseEventListener(listener:EventListener[MouseEvent]) These methods accept only "specific" event listeners, which is fine. However I would like to define also "kitchen-sink" listeners, which listen to all events, and pass such listeners to the "add listener" methods above. For instance, I would like to define LogEventListener to log all incoming events class LogEventListener extends EventListener[Event] { def listen(e:Event) { log(event) } } Since the trait EventListener is contravariant in Event we can pass LogEventListener to all those "add listener" methods without losing their type safety. Does it make sense ?

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• JPA - Real primary key generated ID for references

  - by Val

  I have ~10 classes, each of them, have composite key, consist of 2-4 values. 1 of the classes is a main one (let's call it "Center") and related to other as one-to-one or one-to-many. Thinking about correct way of describing this in JPA I think I need to describe all the primary keys using @Embedded / @PrimaryKey annotations. Question #1: My concern is - does it mean that on the database level I will have # of additional columns in each table referring to the "Center" equal to number of column in "Center" PK? If yes, is it possible to avoid it by using some artificial unique key for references? Could you please give an idea how real PK and the artificial one needs to be described in this case? Note: The reason why I would like to keep the real PK and not just use the unique id as PK is - my application have some data loading functionality from external data sources and sometimes they may return records which I already have in local database. If unique ID will be used as PK - for new records I won't be able to do data update, since the unique ID will not be available for just downloaded ones. At the same time it is normal case scenario for application and it just need to update of insert new records depends on if the real composite primary key matches. Question #2: All of the 10 classes have common field "date" which I described in an abstract class which each of them extends. The "date" itself is never a key, but it always a part of composite key for each class. Composite key is different for each class. To be able to use this field as a part of PK should I describe it in each class or is there any way to use it as is? I experimented with @Embedded and @PrimaryKey annotations and always got an error that eclipselink can't find field described in an abstract class. Thank you in advance! PS. I'm using latest version of eclipselink & H2 database.

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• Using Rails and Rspec, how do you test that the database is not touched by a method

  - by Will Tomlins

  So I'm writing a test for a method which for performance reasons should achieve what it needs to achieve without using SQL queries. I'm thinking all I need to know is what to stub: describe SomeModel do describe 'a_getter_method' do it 'should not touch the database' do thing = SomeModel.create something_inside_rails.should_not_receive(:a_method_querying_the_database) thing.a_getter_method end end end EDIT: to provide a more specific example: class Publication << ActiveRecord::Base end class Book << Publication end class Magazine << Publication end class Student << ActiveRecord::Base has_many :publications def publications_of_type(type) #this is the method I am trying to test. #The test should show that when I do the following, the database is queried. self.publications.find_all_by_type(type) end end describe Student do describe "publications_of_type" do it 'should not touch the database' do Student.create() student = Student.first(:include => :publications) #the publications relationship is already loaded, so no need to touch the DB lambda { student.publications_of_type(:magazine) }.should_not touch_the_database end end end So the test should fail in this example, because the rails 'find_all_by' method relies on SQL.

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• Hibernate NamingStrategy implementation that maintains state between calls

  - by Robert Petermeier

  Hi, I'm working on a project where we use Hibernate and JBoss 5.1. We need our entity classes to be mapped to Oracle tables that follow a certain naming convention. I'd like to avoid having to specify each table and column name in annotations. Therefore, I'm currently considering implementing a custom implementation of org.hibernate.cfg.NamingStrategy. The SQL naming conventions require the name of columns to have a suffix that is equivalent to a prefix of the table name. If there is a table "T100_RESOURCE", the ID column would have to be named "RES_ID_T100". In order to implement this in a NamingStrategy, the implementation would have to maintain state, i.e. the current class name it is creating the mappings for. It would rely on Hibernate to always call classToTableName() before propertyToColumnName() and to determine all column names by calling propertyToColumnName() before the next call to classToTableName() Is it safe to do that or are there situations where Hibernate will mix things up? I am not thinking of problems through multiple threads here (which can be solved by keeping the last class name in a ThreadLocal) but also of Hibernate deliberately calling this out of order in certain circumstances. For example Hibernate asking for mappings of three properties of class A, then one of class B, then again more attributes of class A.

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• Load iframe in html, only with jquery

  - by phpExe

  In this jquery code: $(document).ready(function(){ $list = $(".channeList li"); $list.click(function(){ var $this = $(this); var $mainDesc = $(".ply"); var iframe = $("a", $this).attr("rel"); $("iframe", $mainDesc).attr("src", iframe); } ); } ); There is a list o channels in left that iframe loads from a rel's. I want to load first iframe in <div class="ply"></div> In html, I dont want insert the first item. Can we do this without load first item in html and do this only with jquery? The php function channel() { if (is_numeric($_GET['kanalID'])) { $kanalID = $_GET['kanalID']; } if ($_GET['kanalID'] == "") { $kanalID = 1;} $channel = '<ul class="channeList">'; foreach ($tv as $id => $kanal) { $class = $kanalID == $id ? $class = "currentt": ''; $channel .= '<li> <a href="#" rel="http://mysite.com/index.php?id='.$id.'&w=500&h=320" >'.$kanal.'</a></li>'; } $channel .= '</ul>'; $channel .= '<div class="ply"><iframe frameborder=0 width="500" height="320"></iframe></div>'; return $channel; } Thanks in advance

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• Catch a PHP Object Instantiation Error

  - by Rob Wilkerson

  It's really irking me that PHP considers the failure to instantiate an object a Fatal Error (which can't be caught) for the application as a whole. I have set of classes that aren't strictly necessary for my application to function--they're really a convenience. I have a factory object that attempts to instantiate the class variant that's indicated in a config file. This mechanism is being deployed for message storage and will support multiple store types: DatabaseMessageStore FileMessageStore MemcachedMessageStore etc. A MessageStoreFactory class will read the application's preference from a config file, instantiate and return an instance of the appropriate class. It might be easy enough to slap a conditional around the instantiation to ensure that class_exists(), but MemcachedMessageStore extends PHP's Memcached class. As a result, the class_exists() test will succeed--though instantiation will fail--if the memcached bindings for PHP aren't installed. Is there any other way to test whether a class can be instantiated properly? If it can't, all I need to do is tell the user which features won't be available to them, but let them continue one with the application. Thanks.

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• Java: using generic wildcards with subclassing

  - by gibberish

  Say I have a class Foo, a class A and some subclass B of A. Foo accepts A and its sublclasses as the generic type. A and B both require a Foo instance in their constructor. I want A's Foo to be of type A , and B's Foo to be of type B or a superclass of B. So in effect, So I only want this: Foo<X> bar = new Foo<X>; new B(bar); to be possible if X is either A, B, or a both subclass of A and superclass of B. So far this is what I have: class Foo<? extends A>{ //construct } class A(Foo<A> bar){ //construct } class B(Foo<? super B> bar){ super(bar); //construct } The call to super(...) doesn't work, because <A> is stricter than <? super B>. Is it somehow possible to use the constructor (or avoid code duplication by another means) while enforcing these types? Edit: Foo keeps a collection of elements of the generic parameter type, and these elements and Foo have a bidirectional link. It should therefore not be possible to link an A to a Foo.

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• CultureManager issue

  - by Serge

  I have a bug I don't understand. While the following works fine: Resources.Classes.AFieldFormula.DirectFieldFormula this one throws an exception: new ResourceManager(typeof(Resources.Classes.AFieldFormula)).GetString("DirectFieldFormula"); Could not find any resources appropriate for the specified culture or the neutral culture. Make sure \"Resources.Classes.AFieldFormula.resources\" was correctly embedded or linked into assembly \"MygLogWeb\" at compile time, or that all the satellite assemblies required are loadable and fully signed. How comes? Resource designer.cs file: //------------------------------------------------------------------------------ // <auto-generated> // This code was generated by a tool. // Runtime Version:4.0.30319.18408 // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // </auto-generated> //------------------------------------------------------------------------------ namespace Resources.Classes { using System; /// <summary> /// A strongly-typed resource class, for looking up localized strings, etc. /// </summary> // This class was auto-generated by the StronglyTypedResourceBuilder // class via a tool like ResGen or Visual Studio. // To add or remove a member, edit your .ResX file then rerun ResGen // with the /str option, or rebuild your VS project. [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "4.0.0.0")] [global::System.Diagnostics.DebuggerNonUserCodeAttribute()] [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()] public class AFieldFormula { private static global::System.Resources.ResourceManager resourceMan; private static global::System.Globalization.CultureInfo resourceCulture; [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")] internal AFieldFormula() { } /// <summary> /// Returns the cached ResourceManager instance used by this class. /// </summary> [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)] public static global::System.Resources.ResourceManager ResourceManager { get { if (object.ReferenceEquals(resourceMan, null)) { global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("MygLogWeb.Classes.AFieldFormula", typeof(AFieldFormula).Assembly); resourceMan = temp; } return resourceMan; } } /// <summary> /// Overrides the current thread's CurrentUICulture property for all /// resource lookups using this strongly typed resource class. /// </summary> [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)] public static global::System.Globalization.CultureInfo Culture { get { return resourceCulture; } set { resourceCulture = value; } } /// <summary> /// Looks up a localized string similar to Direct field. /// </summary> public static string DirectFieldFormula { get { return ResourceManager.GetString("DirectFieldFormula", resourceCulture); } } } }

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• Converting string to a simple type

  - by zespri

  .Net framework contains a great class named Convert that allows conversion between simple types, DateTime type and String type. Also the class support conversion of the types implementing IConvertible interface. The class has been implemented in the very first version of .Net framework. There were a few things in the first .Net framework that were not done quite right. For example .Parse methods on simple types would throw an exception if the string couldn't be parsed and there would be no way to check if exception is going to be thrown in advance. A future version of .Net Framework removed this deficiency by introducing the TryParse method that resolved this problem. The Convert class dates back to time of the old Parse method, so the ChangeType method on this class in implemented old style - if conversion can't be performed an exception is thrown. Take a look at the following code: public static T ConvertString<T>(string s, T @default) { try { return (T)Convert.ChangeType(s, typeof(T), CultureInfo.InvariantCulture); } catch (Exception) { return @default; } } This code basically does what I want. However I would pretty much like to avoid the ugly try/catch here. I'm sure, that similar to TryParse, there is a modern method of rewriting this code without the catch-all. Could you suggest one?

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• How do I get 2-way data binding to work for nested asp.net Repeater controls

  - by jimblanchard

  I have the following (trimmed) markup: <asp:Repeater ID="CostCategoryRepeater" runat="server"> <ItemTemplate> <div class="costCategory"> <asp:Repeater ID="CostRepeater" runat="server" DataSource='<%# Eval("Costs")%>'> <ItemTemplate> <tr class="oddCostRows"> <td class="costItemTextRight"><span><%# Eval("Variance", "{0:c0}")%></span></td> <td class="costItemTextRight"><input id="SupplementAmount" class="costEntryRight" type="text" value='<%# Bind("SupplementAmount")%>' runat="server" /></td> </tr> </ItemTemplate> </asp:Repeater> </div> </ItemTemplate> </asp:Repeater> The outer repeater's DataSource is set in the code-beside. I've snipped them, but there are Eval statements that wire up to the properties in the outer Repeater. Anyway, one of the fields in the inner Repeater needs to be a Bind instead of an Eval, as I want to get the values that the user types in. The SupplementAmount input element correctly receives it's value when the page loads, but on the other side, when I inspect the contents of the Costs List when the form posts back, the changes the user made aren't present. Thanks.

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• jQuery validate plugin radio with optional text

  - by timborden

  I'm trying to figure out how to validate a form element with a mix of radio inputs and a text input: <label>Question?</label> <input type="radio" class="mandatory" name="questions[1][]" value="1" />answer 1<br/> <input type="radio" class="mandatory" name="questions[1][]" value="2" />answer 2<br/> <input class="ignore" type="radio" id="questions[1][]" />Other (please specify)<br/> <input class="optional mandatory" type="text" name="questions[1][]" value="" /> I've figured out how to get the form to behave as expected (select and unselect) with the following code: $("input.optional").focus(function () { var this_name = $(this).attr("name"); $("input:radio").filter(function() {return $(this).attr('name') == this_name; }).attr('checked', false); $("input").filter(function() {return $(this).attr('id') == this_name; }).attr('checked', true); }); $(':radio').click(function () { var this_name = $(this).attr("name"); $("input").filter(function() {return $(this).attr('id') == this_name; }).attr('checked', false); $("input.optional").filter(function() {return $(this).attr('name') == this_name; }).val(''); }); I was hoping I could use the class "mandatory" to validate the mix of radio and text inputs: $("form .manditory").each(function () { $(this).rules("add", {required: true}); }); But it's not working as expected. With the radio (id="questions[1][]") selected, and the text input containing content, the form element is still flagged as invalid. Suggestions...maybe a better approach? Thanks in advance. UPDATE Sorry, I should have clarified that I'm using the validate plugin: $("form").validate({ ... });

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• C++ app fails to initialize (0xc0000005), when using C# dll

  - by Simon

  Hi, I have a C# DLL, which I call from a native C++ programm. As I use Qt and /clr compiler option did not work I followed this tutorial for a bridge. So I have a VS2008 project (compiled with /clr), which links to the C# DLL and contains the bridge class and the native class, which exposes interfaces to my C++ programm. Another VS2008 project (no .net stuff) calls the native class (statically linked). I had some issues, but now the programm at least compiles. However, if I try to run this programm, I get a (0xc0000005) error on initialization, when I try to use the native class. As this happens on initialization, I don't even see, which DLLs fail to initialize. All DLLs should be in the right place. Any hints? Thank you.

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• How to get selenium to click on an object other than by ID

  - by Zombies

  So here is a little challenge. I have an image. It has 2 attributes: a random ID - not helpful an image url - but it is a button, and other buttons use the same image url, not helpful a CSS class - also used by too many other things to be helpful a style - neither helpful nor unique This image is however inside of an anchor tag, but the anchor tab isn't to a page, it just runs some javascript. Bellow is the html in question: <a id="template:j_id__ctru168pc2" title="Click for the Manual Class LOV" class="xei" style="text-decoration: none;" onclick="return false;" href="#"> <img id="template:j_id__ctru169pc2" class="xgs" style="border: 0pt none;" src="images/lov_ena.png"> </a> How can I click this image without using the ID?

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• What reasons are there to place member functions before member variables or vice/versa?

  - by Cory Klein

  Given a class, what reasoning is there for either of the two following code styles? Style A: class Foo { private: doWork(); int bar; } Style B: class Foo { private: int bar; doWork(); } For me, they are a tie. I like Style A because the member variables feel more fine-grained, and thus would appear past the more general member functions. However, I also like Style B, because the member variables seem to determine, in a OOP-style way, what the class is representing. Are there other things worth considering when choosing between these two styles?

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• Toggle jQuery-UI widgets

  - by cf_PhillipSenn

  I have: <div class="ui-widget"> <div class="ui-widget-header"> <span class="ui-icon ui-icon-circle-triangle-n">My Menu</span> </div> <ul class="ui-widget-content"> <li>Menu Item 1</li> <li>Menu Item 2</li> <li>Menu Item 3</li> </ul> </div> My jQuery is: $('.ui-widget-header').click(function() { $('.ui-widget-header+ul').toggle('slow'); }); Q: How do I toggle classes between ui-icon-circle-triangle-n and ui-icon-circle-triangle-s as the user clicks on .ui-widget-header?

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• Store request.headers in a serialized model attribute

  - by Horace Loeb

  Here's my model: class Comment < ActiveRecord::Base serialize :request_headers end But when I try to do @comment.request_headers = request.headers I get a TypeError (can't dump anonymous class Class) exception. Another way to ask my question: how can I convert request.headers into a Hash? It uses a Hash under the covers so this should be easy, no?

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• Is there a way to have the equivalent of multiple :before and :after pseudo-elements in CSS?

  - by Sergey Basharov

  Currently I have this markup that represents an icon container and some elements styled with CSS inside it that in the end show as graphic icon. <div class="icon"> <div class="icon-element1"></div> <div class="icon-element2"></div> <div class="icon-element3"></div> </div> The number of the child elements can be different depending on the complexity of the icon. What I want is to somehow move as much as possible to CSS stylesheet, so that ideally I would have only <div class="icon"></div> and the rest would just render from CSS styles, something close in concept to :before/:after, a kind of virtual divs. I don't want to use JavaScript to add the elements dynamically. It would be possible to do this if we had multiple :before/:after. Here is an example of an icon I get by using the markup from above: As you can see, there are 3 child elements representing gray case, white screen and turquoise button. Please advise, how I can simplify this markup so that not to have to put all the divs each time I want this icon to be shown.

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• Calling different functions depending on the template parameter c++

  - by Noman Javed

  I want to have something like that class A { public: Array& operator()() { . . . } }; class B { public: Element& operator[](int i) { ... } }; template<class T> class execute { public: output_type = operator()(T& t) { if(T == A) Array out = T()(); else { Array res; for(int i=0 ; i < length; ++i) a[i] = t[i]; } } }; There are two issues here 1. Meta-function replacing if-else in the execute operator() 2. Return type of execute operator() Thanks in anticipation Noman

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• How to synchronize static method in java.

  - by Summer_More_More_Tea

  Hi there: I come up with this question when implementing singleton pattern in Java. Even though the example listed blow is not my real code, yet very similar to the original one. public class ConnectionFactory{ private static ConnectionFactory instance; public static synchronized ConnectionFactory getInstance(){ if( instance == null ){ instance = new ConnectionFactory(); } return instance; } private ConnectionFactory(){ // private constructor implementation } } Because I'm not quite sure about the behavior of a static synchronized method, I get some suggestion from google -- do not have (or as less as possible) multiple static synchronized methods in the same class. I guess when implementing static synchronized method, a lock belongs to Class object is used so that multiple static synchronized methods may degrade performance of the system. Am I right? or JVM use other mechanism to implement static synchronized method? What's the best practice if I have to implement multiple static synchronized methods in a class? Thank you all! Kind regards!

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• iPhone - AES256 Encryption Using Built In Library

  - by Robert

  Hey all, I am using http://pastie.org/966473 as a reference as all I need to do is encrypt something using AES256 encrypting. I created a class and put the implementation in the pastie on top of the implementation for my class. @implementation //pastie code @end @implementation //my class code @end In my class code I create a NSMutableData and try to call the EncryptAES method and I get a warning saying it might not respond to that. What am I doing wrong here? do I need to implement the pastie code elsewhere? Thanks for any help.

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• How do i use 'auto' in C++ (C++0x) ?

  - by LoudNPossiblyRight

  What do i have to do to this code to make it compile, it's braking around this line: auto val = what.getObject(); #include<iostream> using namespace std; class CUP{ public: void whatsHappening(){} }; class MUG{ public: void whatsHappening(){} }; class CupThrower{ public: CUP cp; CUP getObject(){ return cp;} }; class MugThrower{ public: MUG mg; MUG getObject(){return mg;} }; template <typename T> void whatsHappening(T what){ auto val = what.getObject(); //DOES NOT COMPILE val.whatsHappening(); } int main(){ CupThrower ct; MugThrower mt; whatsHappening(ct); whatsHappening(mt); return 0; } i am using VS2008 to compile.

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• How to override the attr_protected?

  - by KandadaBoggu

  I have STI implementation as follows: class Automobile < ActiveRecord::Base end class Car < Automobile end class Truck < Automobile end class User < ActiveRecord::Base has_many :automobiles accepts_nested_attributes_for :automobiles end I am creating a list of automobiles for a user. For each automobile, the UI sets the type field and the properties associated with the automobile.While form submission, the type field is ignored as it is a protected attribute. How do I work around this issue? Is there a declarative way to unprotect a protected attribute?

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• NSXMLParser 's delegate and memory leak

  - by dizzy_fingers

  Hello, I am using a NSXMLParser class in my program and I assign a delegate to it. This delegate, though, gets retained by the setDelegate: method resulting to a minor, yet annoying :-), memory leak. I cannot release the delegate class after the setDelegate: because the program will crash. Here is my code: self.parserDelegate = [[ParserDelegate alloc] init]; //retainCount:1 self.xmlParser = [[NSXMLParser alloc] initWithData:self.xmlData]; [self.xmlParser setDelegate:self.parserDelegate]; //retainCount:2 [self.xmlParser parse]; [self.xmlParser release]; ParserDelegate is the delegate class. Of course if I set 'self' as the delegate, I will have no problem but I would like to know if there is a way to use a different class as delegate with no leaks. Thank you in advance.

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