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  • Auto-implemented getters and setters vs. public fields

    - by tclem
    I see a lot of example code for C# classes that does this: public class Point { public int x { get; set; } public int y { get; set; } } Or, in older code, the same with an explicit private backing value and without the new auto-implemented properties: public class Point { private int _x; private int _y; public int x { get { return _x; } set { _x = value; } } public int y { get { return _y; } set { _y = value; } } } My question is why. Is there any functional difference between doing the above and just making these members public fields, like below? public class Point { public int x; public int y; } To be clear, I understand the value of getters and setters when you need to do some translation of the underlying data. But in cases where you're just passing the values through, it seems needlessly verbose.

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  • capture delete key in CListCtrl and do soem processing

    - by user333422
    Hi, I have a class which inherits from CListCtrl class, say class list. I have another class dlg, which inherits from CDialog. Class dlg contains an instance of class list. I have got a delete button in class dlg, on which I delete the selected item in listCtrl and do lots of other processing. I want the same functionality on delete key. I added OnKeyDown() fn is my class list, where I can capture VK_DELETE key. But my problem is that, how do I do otehr processing that I need to do in dialog class. All that processing is dlg class based not list class based. I have many such dlg classes with different data and in every dlg class processing is different. I tried capturing VK_DELETE in dialog class, but it doesn't capture it if focus is on list class. I am totally stuck and have no idea, how to do this. Please give me some idea how i can do this. Thanks, SG

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  • Delete element from Set

    - by Blitzkr1eg
    Hi. I have 2 classes Tema(Homework) and Disciplina (course), where a Course has a Set of homeworks. In Hibernate i have mapped this to a one-to-many associations like this: <class name="model.Disciplina" table="devgar_scoala.discipline" > <id name="id" > <generator class="increment"/> </id> <set name="listaTeme" table="devgar_scoala.teme"> <key column="Discipline_id" not-null="true" ></key> <one-to-many class="model.Tema" ></one-to-many> </set> </class> <class name="model.Tema" table="devgar_scoala.teme" > <id name="id"> <generator class="increment" /> </id> <property name="titlu" type="string" /> <property name="cerinta" type="binary"> <column name="cerinta" sql-type="blob" /> </property> </class> The problem is that it will add (insert rows in the table 'Teme') but it won't delete any rows and i get no exceptions thrown. Im using the merge() method.

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  • .Net Entity Framework & POCO ... querying full table problem

    - by Chris Klepeis
    I'm attempting to implement a repository pattern with my poco objects auto generated from my edmx. In my repository class, I have: IObjectSet<E> _objectSet; private IObjectSet<E> objectSet { get { if (_objectSet == null) { _objectSet = this._context.CreateObjectSet<E>(); } return _objectSet; } } public IQueryable<E> GetQuery(Func<E, bool> where) { return objectSet.Where(where).AsQueryable<E>(); } public IList<E> SelectAll(Func<E, bool> where) { return GetQuery(where).ToList(); } Where E is the one of my POCO classes. When I trace the database and run this: IList<Contact> c = contactRepository.SelectAll(r => r.emailAddress == "[email protected]"); It shows up in the sql trace as a select for everything in my Contact table. Where am I going wrong here? Is there a better way to do this? Does an objectset not lazy load... so it omitted the where clause? This is the article I read which said to use objectSet's... since with POCO, I do not have EntityObject's to pass into "E" http://devtalk.dk/CommentView,guid,b5d9cad2-e155-423b-b66f-7ec287c5cb06.aspx

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  • Exporting WPF DataGrid to a text file in a nice looking format. Text file must be easy to read.

    - by Andrew
    Hi, Is there a simple way to export a WPF DataGrid to a text file and a .csv file? I've done some searching and can't see that there is a simple DataGrid method to do so. I have got something working (barely) by making use of the ItemsSource of the DataGrid. In my case, this is an array of structs. I do something with StreamWriters and StringBuilders (details available) and basically have: StringBuilder destination = new StringBuilder(); destination.Append(row.CreationDate); destination.Append(seperator); // seperator is '\t' or ',' for csv file destination.Append(row.ProcId); destination.Append(seperator); destination.Append(row.PartNumber); destination.Append(seperator); I do this for each struct in the array (in a loop). This works fine. The problem is that it's not easy to read the text file. The data can be of different lengths within the same column. I'd like to see something like: 2007-03-03 234238423823 823829923 2007-03-03 66 99 And of course, I get something like: 2007-03-03 234238423823 823829923 2007-03-03 66 99 It's not surprising giving that I'm using Tab delimiters, but I hope to do better. It certainly is easy to read in the DataGrid! I could of course have some logic to pad short values with spaces, but that seems quite messy. I thought there might be a better way. I also have a feeling that this is a common problem and one that has probably been solved before (hopefully within the .NET classes themselves). Thanks.

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  • What are Code Smells? What is the best way to correct them?

    - by Rob Cooper
    OK, so I know what a code smell is, and the Wikipedia Article is pretty clear in its definition: In computer programming, code smell is any symptom in the source code of a computer program that indicates something may be wrong. It generally indicates that the code should be refactored or the overall design should be reexamined. The term appears to have been coined by Kent Beck on WardsWiki. Usage of the term increased after it was featured in Refactoring. Improving the Design of Existing Code. I know it also provides a list of common code smells. But I thought it would be great if we could get clear list of not only what code smells there are, but also how to correct them. Some Rules Now, this is going to be a little subjective in that there are differences to languages, programming style etc. So lets lay down some ground rules: ** ONE SMELL PER ANSWER PLEASE! & ADVISE ON HOW TO CORRECT! ** See this answer for a good display of what this thread should be! DO NOT downmod if a smell doesn't apply to your language or development methodology We are all different. DO NOT just quickly smash in as many as you can think of Think about the smells you want to list and get a good idea down on how to work around. DO downmod answers that just look rushed For example "dupe code - remove dupe code". Let's makes it useful (e.g. Duplicate Code - Refactor into separate methods or even classes, use these links for help on these common.. etc. etc.). DO upmod answers that you would add yourself If you wish to expand, then answer with your thoughts linking to the original answer (if it's detailed) or comment if its a minor point. DO format your answers! Help others to be able to read it, use code snippets, headings and markup to make key points stand out!

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  • Some web pages (especially Apple documentation) cause heavy CPU usage in Windows IE8

    - by Mark Lutton
    Maybe this belongs in Server Fault instead, but some of you may have noticed this issue (particularly those developing on Mac, using a Windows machine to read the reference material). I posted the same question on a Microsoft forum and got one answer from someone who reproduced the problem, so it's not just my machine. No solution yet. Ever since this month's security updates, I find that many web pages cause the CPU to run at maximum for as long as the web page is visible. This happens in both IE7 and IE8 on at least three different computers (two with Windows XP, one with Vista). Here is one of the pages, running on XP with IE 8: http://learning2code.blogspot.com/2007/11/update-using-subversion-with-xcode-3.html Here is one that does it in Vista with IE8: http://developer.apple.com/iphone/library/documentation/Cocoa/Reference/Foundation/Classes/NSString_Class/Reference/NSString.html You can leave the page open for hours and the CPU is still at high usage. This doesn't happen every time. It is not always reproduceable. Sometimes it is OK the second or third time it loads. In IE7 the high usage is in ieframe.dll, version 7.0.6000.16890. In IE8 the high usage is in iertutil.dll, version 8.0.6001.18806.

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  • Problems with rails and saving to the database.

    - by Grantismo
    I've been having some difficulty in understanding the source of a problem. Below is a listing of the model classes. Essentially the goal is to have the ability to add sentences to the end of the story, or to add stories to an existing sentence_block. Right now, I'm only attempting to allow users to add sentences, and automatically create a new sentence_block for the new sentence. class Story < ActiveRecord::Base has_many :sentence_blocks, :dependent => :destroy has_many :sentences, :through => :sentence_blocks accepts_nested_attributes_for :sentence_blocks end class SentenceBlock < ActiveRecord::Base belongs_to :story has_many :sentences, :dependent => :destroy end class Sentence < ActiveRecord::Base belongs_to :sentence_block def story @sentence_block = SentenceBlock.find(self.sentence_block_id) Story.find(@sentence_block.story_id) end end The problem is occurring when using the show method of the Story. The Story method is as follows, and the associated show method for a sentence is also included. Sentence.show def show @sentence = Sentence.find(params[:id]) respond_to do |format| format.html {redirect_to(@sentence.story)} format.xml { render :xml => @sentence } end end Story.show def show @story = Story.find(params[:id]) @sentence_block = @story.sentence_blocks.build @new_sentence = @sentence_block.sentences.build(params[:sentence]) respond_to do |format| if @new_sentence.content != nil and @new_sentence.sentence_block_id != nil and @sentence_block.save and @new_sentence.save flash[:notice] = 'Sentence was successfully added.' format.html # new.html.erb format.xml { render :xml => @story } else @sentence_block.destroy format.html format.xml { render :xml => @story } end end end I'm getting a "couldn't find Sentence_block without and id" error. So I'm assuming that for some reason the sentence_block isn't getting saved to the database. Can anyone help me with my understanding of the behavior and why I'm getting the error? I'm trying to ensure that every time the view depicts show for a story, an unnecessary sentence_block and sentence isn't created, unless someone submits the form, I'm not really sure how to accomplish this. Any help would be appreciated.

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  • get html content of a page with Silverlight

    - by Yustme
    Hi, I'm trying to get the html content of a page using silverlight. Webresponse and request classes don't work in silverlight. I did some googling and I found something. This is what i tried: public partial class MainPage : UserControl { string result; WebClient client; public MainPage() { InitializeComponent(); this.result = string.Empty; this.client = new WebClient(); this.client.DownloadStringCompleted += ClientDownloadStringCompleted; } private void btn1_Click(object sender, RoutedEventArgs e) { string url = "http://www.nu.nl/feeds/rss/algemeen.rss"; this.client.DownloadStringAsync(new Uri(url, UriKind.Absolute)); if (this.result != string.Empty && this.result != null) { this.txbSummery.Text = this.result; } } private void ClientDownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e) { this.result = e.Result; //handle the response. } } It gives me a runtime error after pressing the button: Microsoft JScript runtime error: Unhandled Error in Silverlight Application An exception occurred during the operation, making the result invalid. Check InnerException for exception details. at System.ComponentModel.AsyncCompletedEventArgs.RaiseExceptionIfNecessary() at System.Net.DownloadStringCompletedEventArgs.get_Result() at JWTG.MainPage.ClientDownloadStringCompleted(Object sender, DownloadStringCompletedEventArgs e) at System.Net.WebClient.OnDownloadStringCompleted(DownloadStringCompletedEventArgs e) at System.Net.WebClient.DownloadStringOperationCompleted(Object arg) I've tried numerous things but all failed. What am i missing? Or does anyone know how i could achieve this in a different way? Thanks in advance!

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  • Creating a Ruby method that pads an Array

    - by CJ Johnson
    I'm working on creating a method that pads an array, and accepts 1. a desired value and 2. an optional string/integer value. Desired_size reflects the desired number of elements in the array. If a string/integer is passed in as the second value, this value is used to pad the array with extra elements. I understand there is a 'fill' method that can shortcut this - but that would be cheating for the homework I'm doing. The issue: no matter what I do, only the original array is returned. I started here: class Array def pad(desired_size, value = nil) desired_size >= self.length ? return self : (desired_size - self.length).times.do { |x| self << value } end end test_array = [1, 2, 3] test_array.pad(5) From what I researched the issue seemed to be around trying to alter self's array, so I learned about .inject and gave that a whirl: class Array def pad(desired_size, value = nil) if desired_size >= self.length return self else (desired_size - self.length).times.inject { |array, x| array << value } return array end end end test_array = [1, 2, 3] test_array.pad(5) The interwebs tell me the problem might be with any reference to self so I wiped that out altogether: class Array def pad(desired_size, value = nil) array = [] self.each { |x| array << x } if desired_size >= array.length return array else (desired_size - array.length).times.inject { |array, x| array << value } return array end end end test_array = [1, 2, 3] test_array.pad(5) I'm very new to classes and still trying to learn about them. Maybe I'm not even testing them the right way with my test_array? Otherwise, I think the issue is I get the method to recognize the desired_size value that's being passed in. I don't know where to go next. Any advice would be appreciated. Thanks in advance for your time.

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  • JSF - Creating an overlay for popup panels.

    - by Ben
    Hi, I've created an overlay that will popup whenever someone wants to upload a file to the system. The Gui looks like this (when the overlay is up) I have two problems with this: I attached a a4j:support object that, onclick, makes the overlay disappear. The problem with this is that when I click the upload button on the upload component, support catches the click event and closes the overlay with the upload component before I have the chance to finish the operation. I chose two different style classes. One for the overlay and one for the upload panel. But the styling of the overlay takes over the upload component and it becomes transparent as well. The implementation looks something like this: <h:panelgroup layout="block" styleClass="overlayClass"> <rich:fileUpload styleClass="uploadStyleClass"... /> <a4j:support event="onclick" action="#{mrBean.switchOverlayState}" reRender="..."/> </h:panelGroup> The CSS: .overlayClass { Opacity: 0.5; position: fixed; left: 0; right: 0; top: 0; bottom: 0; background: #000; } .uploadStyleClass { opacity: 1.0; ... } Thanks for the help!

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  • Hibernate noob fetch join problem

    - by Bruce
    Hi all I have two classes, Test2 and Test3. Test2 has an attribute test3 that is an instance of Test3. In other words, I have a unidirectional OneToOne association, with test2 having a reference to test3. When I select Test2 from the db, I can see that a separate select is being made to get the details of the associated test3 class. This is the famous 1+N selects problem. To fix this to use a single select, I am trying to use the fetch=join annotation, which I understand to be @Fetch(FetchMode.JOIN) However, with fetch set to join, I still see separate selects. Here are the relevant portions of my setup.. hibernate.cfg.xml: <property name="max_fetch_depth">2</property> Test2: public class Test2 { @OneToOne (cascade=CascadeType.ALL , fetch=FetchType.EAGER) @JoinColumn (name="test3_id") @Fetch(FetchMode.JOIN) public Test3 getTest3() { return test3; } NB I set the FetchType to EAGER out of desperation, even though it defaults to EAGER anyway for OneToOne mappings, but it made no difference. Thanks for any help! Edit: I've pretty much given up on trying to use FetchMode.JOIN - can anyone confirm that they have got it to work ie produce a left outer join? In the docs I see that "Usually, the mapping document is not used to customize fetching. Instead, we keep the default behavior, and override it for a particular transaction, using left join fetch in HQL" If I do a left join fetch instead: query = session.createQuery("from Test2 t2 left join fetch t2.test3"); then I do indeed get the results I want - ie a left outer join in the query.

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  • Set scaleX property on a Sprite without altering the child inside

    - by grammar
    Is this possible? My site is set up with next and prev buttons on the right and left sides respectively, and as you roll over either of the hit areas around the buttons a Sprite fades in which contains a TextField that describes the next page. Said Sprite calls the StartDrag() method, so it follows the mouse within the bounds, which is all fine and dandy on the left side of the page. Adobe, however, seems to have forgotten to put a way to dynamically alter the registration point of a Sprite, MC, whatever else, so when you roll over the right side of the page, the sprite is displayed from the top left and is mostly off the stage. Trying to hack this problem I have tried numerous things ( classes written by others, other hacks) and the best that I have found is to use the scaleX method on the Sprite, changing the scale to -1. This, of course, makes the Sprite seem like it's reflected from its normal point, which means all its children show up backwards. Is there anyway I can use this hack without it altering the text? OR Does anyone know a different way to go about displaying a Sprite from another corner? Any way to make a Sprite fade in and follow the mouse on the LEFT HAND side of the mouse pointer? Thank you very much in advance. Here is a snippet to give an idea of what's happening: naxtPage.labelBG.scaleX = -1; nextPage.labelBG.startDrag( true, nextHitRect ); nextPage.labelBG.x = nextPage.labelBG.parent.mouseX; nextPage.labelBG.y = nextPage.labelBG.parent.mouseY; Cheers

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  • How to get a Class literal from a generically specific Class

    - by h2g2java
    There are methods like these which require Class literals as argument. Collection<EmpInfo> emps = SomeSqlUtil.select( EmpInfo.class, "select * from emps"); or GWT.create(Razmataz.class); The problem presents itself when I need to supply generic specific classes like EmpInfo<String> Razmataz<Integer> The following would be wrong syntax Collection<EmpInfo<String>> emps = SomeSqlUtil.select( EmpInfo<String>.class, "select * from emps"); or GWT.create(Razmataz<Integer>.class); Because you cannot do syntax like Razmataz<Integer>.class So, how would I be able to squeeze a class literal out of EmpInfo<String> Razmataz<Integer> so that I could feed them as arguments to methods requiring Class literals? Further info Okay, I confess that I am asking this primarily for GWT. I have a pair of GWT RPC interface Razmataz. (FYI, GWT RPC interface has to be defined in server-client pairs). I plan to use the same interface pair for communicating whether it be String, Integer, Boolean, etc. GWT.create(Razmataz) for Razmataz<T> complains that, since I did not specify T, GWT compiler treated it as Object. Then GWT compiler would not accept Object class. It needs to be more specific than being an Object. So, it seems there is no way for me to tell GWT.create what T is because a Class literal is a runtime concept while generics is a compile time concept, Right?

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  • The new operator in C# isn't overriding base class member

    - by Dominic Zukiewicz
    I am confused as to why the new operator isn't working as I expected it to. Note: All classes below are defined in the same namespace, and in the same file. This class allows you to prefix any content written to the console with some provided text. public class ConsoleWriter { private string prefix; public ConsoleWriter(string prefix) { this.prefix = prefix; } public void Write(string text) { Console.WriteLine(String.Concat(prefix,text)); } } Here is a base class: public class BaseClass { protected static ConsoleWriter consoleWriter = new ConsoleWriter(""); public static void Write(string text) { consoleWriter.Write(text); } } Here is an implemented class: public class NewClass : BaseClass { protected new static ConsoleWriter consoleWriter = new ConsoleWriter("> "); } Now here's the code to execute this: class Program { static void Main(string[] args) { BaseClass.Write("Hello World!"); NewClass.Write("Hello World!"); Console.Read(); } } So I would expect the output to be Hello World! > Hello World! But the output is Hello World Hello World I do not understand why this is happening. Here is my thought process as to what is happening: The CLR calls the BaseClass.Write() method The CLR initialises the BaseClass.consoleWriter member. The method is called and executed with the BaseClass.consoleWriter variable Then The CLR calls the NewClass.Write() The CLR initialises the NewClass.consoleWriter object. The CLR sees that the implementation lies in BaseClass, but the method is inherited through The CLR executes the method locally (in NewClass) using the NewClass.consoleWriter variable I thought this is how the inheritance structure works? Please can someone help me understand why this is not working?

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  • problem with running Servlet on Tomcat: InvocationTargetException

    - by Fahim
    Hi, I am new to Tomcat, and trying to run a simple HelloWorld servlet. I have installed Tomcat 6, and Jdk1.6 on Mandriva Linux, set CLASSPATH and JAVA_HOME. I have the following files and directories: $CATALINA_HOME/webapps/MyApp/WEB_INF/classes/TestServlet.class $CATALINA_HOME/webapps/MyApp/WEB_INF/web.xml My web.xml file contains the following: http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5" <description>ZibJana Localization</description> <display-name>ZibJana Localization</display-name> <!-- Define the servlets for this application--> <servlet> <servlet-name>ZibJana</servlet-name> <servlet-class>TestServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>ZibJana</servlet-name> <url-pattern>*</url-pattern> </servlet-mapping> But when I try to invoke my servlet with url http://localhost:8080/MyApp, tomcat fails to launch launch the servlet. I checked in the $CATALINA_HOME/logs/catalina.out log-file and found the following error, which occurs every time I start tomcat service. INFO: Deploying web application directory MyApp 16-Mar-2010 12:05:38 AM org.apache.tomcat.util.digester.Digester endElement SEVERE: End event threw exception java.lang.reflect.InvocationTargetException at sun.reflect.GeneratedMethodAccessor18.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) Please let me know where my mistake is. Thanks in advance.

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  • UIActivityIndicatorView in a class without a view

    - by Structurer
    Hi I have defined a class that does a lengthy task and I call it from several other classes. Now I want to show an Activity Indicator while this task is doing it's thing, and then remove it once it's done. Since this is just a boring background task, this class doesn't have a view, and I guess that is where I run into my problem. I can't get this thing to show. This is what I have done in my class: UIActivityIndicatorView *activityIndicator = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 32.0f, 32.0f)]; [activityIndicator setCenter:CGPointMake(160.0f, 208.0f)]; activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhite; UIView *contentView = [[UIView alloc]initWithFrame:[[UIScreen mainScreen] applicationFrame]]; [contentView addSubview:activityIndicator]; [activityIndicator startAnimating]; // Do the class lengthy task that takes several seconds..... [contentView release]; [activityIndicator release]; I guess I do something wrong when I get the contentView, but how should I get it properly? Thanks for any advices...

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  • Sorting out POCO, Repository Pattern, Unit of Work, and ORM

    - by CoffeeAddict
    I'm reading a crapload on all these subjects: POCO Repository Pattern Unit of work Using an ORM mapper ok I see the basic definitions of each in books, etc. but I can't visualize this all together. Meaning an example structure (DL, BL, PL). So what, you have your DL objects that contain your CRUD methods, then your BL objects which are "mapped" using an ORM back to your DL objects? What about DTOs...they're your DL objects right? I'm confused. Can anyone really explain all this together or send me example code? I'm just trying to put this together. I am determining whether to go LINQ to SQL or EF 4 (not sure about NHibrernate yet). Just not getting the concepts as in physical layers and code layers here and what each type of object contains (just properties for DTOs, and CRUDs for your core DL classes that match the table fields???). I just need some guidance here. I'm reading Fowler's books and starting to read Evans but just not all there yet.

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  • confused about how to use JSON in C#

    - by Josh
    The answer to just about every single question about using C# with json seems to be "use JSON.NET" but that's not the answer I'm looking for. the reason I say that is, from everything I've been able to read in the documentation, JSON.NET is basically just a better performing version of the DataContractSerializer built into the .net framework... Which means if I want to deserialize a JSON string, I have to define the full, strongly-typed class for EVERY request I might have. so if I have a need to get categories, posts, authors, tags, etc, I have to define a new class for every one of these things. This is fine if I built the client and know exactly what the fields are, but I'm using someone else's api, so I have no idea what the contract is unless I download a sample response string and create the class manually from the JSON string. Is that the only way it's done? Is there not a way to have it create a kind of hashtable that can be read with json["propertyname"]? Finally, if I do have to build the classes myself, what happens when the API changes and they don't tell me (as twitter seems to be notorious for doing)? I'm guessing my entire project will break until I go in and update the object properties... So what exactly is the general workflow when working with JSON? And by general I mean library-agnostic. I want to know how it's done in general, not specifically to a target library... I hope that made sense, this has been a very confusing area to get into... thanks!

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  • Is there a way to restrict access to a public method to only a specific class in C#?

    - by Anon
    I have a class A with a public method in C#. I want to allow access to this method to only class B. Is this possible? UPDATE: This is what i'd like to do: public class Category { public int NumberOfInactiveProducts {get;} public IList<Product> Products {get;set;} public void ProcessInactiveProduct() { // do things... NumberOfInactiveProducts++; } } public class Product { public bool Inactive {get;} public Category Category {get;set;} public void SetInactive() { this.Inactive= true; Category.ProcessInactiveProduct(); } } I'd like other programmers to do: var prod = Repository.Get<Product>(id); prod.SetInactive(); I'd like to make sure they don't call ProcessInactiveProduct manually: var prod = Repository.Get<Product>(id); prod.SetInactive(); prod.Category.ProcessInactiveProduct(); I want to allow access of Category.ProcessInactiveProduct to only class Product. Other classes shouldn't be able to call Category.ProcessInactiveProduct.

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  • Problem using Lazy<T> from within a generic abstract class

    - by James Black
    I have a generic class that all my DAO classes derive from, which is defined below. I also have a base class for all my entities, but that is not generic. The method GetIdOrSave is going to be a different type than how I defined SabaAbstractDAO, as I am trying to get the primary key to fulfill the foreign key relationships, so this function goes out to either get the primary key or save the entity and then get the primary key. The last code snippet has a solution on how it will work if I get rid of the generic part, so I think this can be solved by using variance, but I can't figure out how to write an interface that will compile. public abstract class SabaAbstractDAO<T> { ... public K GetIdOrSave<K>(K item, Lazy<SabaAbstractDAO<BaseModel>> lazyitemdao) where K : BaseModel { if (item != null && item.Id.IsNull()) { var itemdao = lazyitemdao.Value; item.Id = itemdao.retrieveID(item); if (item.Id.IsNull()) { return itemdao.SaveData(item); } } return item; } } I am getting this error, when I try to compile: Argument 2: cannot convert from 'System.Lazy<ORNL.HRD.LMS.Dao.SabaCourseDAO>' to 'System.Lazy<ORNL.HRD.LMS.Dao.SabaAbstractDAO<ORNL.HRD.LMS.Models.BaseModel>>' I am trying to call it this way: GetIdOrSave(input.OfferingTemplate, new Lazy<SabaCourseDAO>( () => { return new SabaCourseDAO() { Dao = Dao }; }) ); If I change the definition to this, it works. public K GetIdOrSave<K>(K item, Lazy<SabaCourseDAO> lazyitemdao) where K : BaseModel { So, how can I get this to compile using variance (if needed) and generics, so I can have a very general method that will only work with BaseModel and AbstractDAO<BaseModel>? I expect I should only need to make the change in the method and perhaps abstract class definition, the usage should be fine.

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  • Change classloader

    - by Chris
    I'm trying to switch the class loader at runtime: public class Test { public static void main(String[] args) throws Exception { final InjectingClassLoader classLoader = new InjectingClassLoader(); Thread.currentThread().setContextClassLoader(classLoader); Thread thread = new Thread("test") { public void run() { System.out.println("running..."); // approach 1 ClassLoader cl = TestProxy.class.getClassLoader(); try { Class c = classLoader.loadClass("classloader.TestProxy"); Object o = c.newInstance(); c.getMethod("test", new Class[] {}).invoke(o); } catch (Exception e) { e.printStackTrace(); } // approach 2 new TestProxy().test(); }; }; thread.setContextClassLoader(classLoader); thread.start(); } } and: public class TestProxy { public void test() { ClassLoader tcl = Thread.currentThread().getContextClassLoader(); ClassLoader ccl = ClassToLoad.class.getClassLoader(); ClassToLoad classToLoad = new ClassToLoad(); } } (it is not relevant what the InjectingClassLoader is) I'd like to make the result of "approach 1" and "approach 2" exactly same, but it looks like thread.setContextClassLoader(classLoader) does nothing and the "approach 2" always uses the system classloader (can be determined by comparing tcl and ccl variables while debugging). Is it possible to make all classes loaded by new thread use given classloader?

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  • UIViewController memory management

    - by jAmi
    Hi I have a very basic issue of memory management with my UIViewController (or any other object that I create); The problem is that in Instruments my Object allocation graph is always rising even though I am calling release on then assigning them nil. I have 2 UIViewController sub-classes each initializing with a NIB; I add the first ViewController to the main window like [window addSubView:first.view]; Then in my first ViewController nib file I have a Button which loads the second ViewController like : -(IBAction)loadSecondView{ if(second!=nil){ //second is set as an iVar and @property (nonatomic, retain)ViewController2* sceond; [second release]; second=nil; } second=[[ViewController2* second]initWithNibName:@"ViewController2" bundle:nil]; [self.view addSubView:second.view]; } In my (second) ViewController2 i have a button with an action method -(IBAction) removeSecond{ [self.view removeFromSuperView]; } Please let me know if the above scheme works in a managed way for memory...? In Instruments It does not show release of any allocation and keeps the bar status graph keeps on rising.

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  • Having Issue with Bounded Wildcards in Generic

    - by Sanjiv
    I am new to Java Generics, and I'm currently experimenting with Generic Coding....final goal is to convert old Non-Generic legacy code to generic one... I have defined two Classes with IS-A i.e. one is sub-class of other. public class Parent { private String name; public Parent(String name) { super(); this.name = name; } } public class Child extends Parent{ private String address; public Child(String name, String address) { super(name); this.address = address; } } Now, I am trying to create a list with bounded Wildcard. and getting Compiler Error. List<? extends Parent> myList = new ArrayList<Child>(); myList.add(new Parent("name")); // compiler-error myList.add(new Child("name", "address")); // compiler-error myList.add(new Child("name", "address")); // compiler-error Bit confused. please help me on whats wrong with this ?

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  • What can cause my code to run slower when the server JIT is activated?

    - by durandai
    I am doing some optimizations on an MPEG decoder. To ensure my optimizations aren't breaking anything I have a test suite that benchmarks the entire codebase (both optimized and original) as well as verifying that they both produce identical results (basically just feeding a couple of different streams through the decoder and crc32 the outputs). When using the "-server" option with the Sun 1.6.0_18, the test suite runs about 12% slower on the optimized version after warmup (in comparison to the default "-client" setting), while the original codebase gains a good boost running about twice as fast as in client mode. While at first this seemed to be simply a warmup issue to me, I added a loop to repeat the entire test suite multiple times. Then execution times become constant for each pass starting at the 3rd iteration of the test, still the optimized version stays 12% slower than in the client mode. I am also pretty sure its not a garbage collection issue, since the code involves absolutely no object allocations after startup. The code consists mainly of some bit manipulation operations (stream decoding) and lots of basic floating math (generating PCM audio). The only JDK classes involved are ByteArrayInputStream (feeds the stream to the test and excluding disk IO from the tests) and CRC32 (to verify the result). I also observed the same behaviour with Sun JDK 1.7.0_b98 (only that ist 15% instead of 12% there). Oh, and the tests were all done on the same machine (single core) with no other applications running (WinXP). While there is some inevitable variation on the measured execution times (using System.nanoTime btw), the variation between different test runs with the same settings never exceeded 2%, usually less than 1% (after warmup), so I conclude the effect is real and not purely induced by the measuring mechanism/machine. Are there any known coding patterns that perform worse on the server JIT? Failing that, what options are available to "peek" under the hood and observe what the JIT is doing there?

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