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  • Entity Framework Validation & usage

    - by kmsellers
    I'm aware there is an AssociationChanged event, however, this event fires after the association is made. There is no AssociationChanging event. So, if I want to throw an exception for some validation reason, how do I do this and get back to my original value? Also, I would like to default values for my entity based on information from other entities but do this only when I know the entitiy is instanced for insertion into the database. How do I tell the difference between that and the object getting instanced because it is about to be populated based on existing data? Am I supposed to know? Is that considiered business logic that should be outside of my entity business logic? If that's the case, then should I be designing controller classes to wrap all these entities? My concern is that if I deliver back an entity, I want the client to get access to the properties, but I want to retain tight control over validations on how they are set, defaulted, etc. Every example I've seen references context, which is outside of my enity partial class validation, right? BTW, I looked at the EFPocoAdapter and for the life of me cannot determine how to populate lists of from within my POCO class... anyone know how I get to the context from a EFPoco Class?

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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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  • 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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  • 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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  • 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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  • 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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  • 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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  • Is this a variation of the traveling salesman problem?

    - by Ville Koskinen
    I'm interested in a function of two word lists, which would return an order agnostic edit distance between them. That is, the arguments would be two lists of (let's say space delimited) words and return value would be the minimum sum of the edit (or Levenshtein) distances of the words in the lists. Distance between "cat rat bat" and "rat bat cat" would be 0. Distance between "cat rat bat" and "fat had bad" would be the same as distance between "rat bat cat" and "had fat bad", 4. In the case the number of words in the lists are not the same, the shorter list would be padded with 0-length words. My intuition (which hasn't been nurtured with computer science classes) does not find any other solution than to use brute force: |had|fat|bad| a solution ---+---+---+---+ +---+---+---+ cat| 2 | 1 | 2 | | | 1 | | ---+---+---+---+ +---+---+---+ rat| 2 | 1 | 2 | | 3 | | | ---+---+---+---+ +---+---+---+ bat| 2 | 1 | 1 | | | | 4 | ---+---+---+---+ +---+---+---+ Starting from the first row, pick a column and go to the next rows without ever revisiting a column you have already visited. Do this over and over again until you've tried all combinations. To me this sounds a bit like the traveling salesman problem. Is it, and how would you solve my particular problem?

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  • autotools: no rule to make target all

    - by Raffo
    I'm trying to port an application I'm developing to autotools. I'm not an expert in writing makefiles and it's a requisite for me to be able to use autotools. In particular, the structure of the project is the following: .. ../src/Main.cpp ../src/foo/ ../src/foo/x.cpp ../src/foo/y.cpp ../src/foo/A/k.cpp ../src/foo/A/Makefile.am ../src/foo/Makefile.am ../src/bar/ ../src/bar/z.cpp ../src/bar/w.cpp ../src/bar/Makefile.am ../inc/foo/ ../inc/bar/ ../inc/foo/A ../configure.in ../Makefile.am The root folder of the project contains a "src" folder containing the main of the program AND a number of subfolders containing the other sources of the program. The root of the project also contains an "inc" folder containing the .h files that are nothing more than the definitions of the classes in "src", thus "inc" reflects the structure of "src". I have written the following configure.in in the root: AC_INIT([PNAME], [1.0]) AC_CONFIG_SRCDIR([src/Main.cpp]) AC_CONFIG_HEADER([config.h]) AC_PROG_CXX AC_PROG_CC AC_PROG_LIBTOOL AM_INIT_AUTOMAKE([foreign]) AC_CONFIG_FILES([Makefile src/Makefile src/foo/Makefile src/foo/A/Makefile src/bar/Makefile]) AC_OUTPUT And the following is ../Makefile.am SUBDIRS = src and then in ../src where the main of the project is contained: bin_PROGRAMS = pname gsi_SOURCES = Main.cpp AM_CPPFLAGS = -I../../inc/foo\ -I../../inc/foo/A \ -I../../inc/bar/ pname_LDADD= foo/libfoo.a bar/libbar.a SUBDIRS = foo bar and in ../src/foo noinst_LIBRARIES = libfoo.a libfoo_a_SOURCES = \ x.cpp \ y.cpp AM_CPPFLAGS = \ -I../../inc/foo \ -I../../inc/foo/A \ -I../../inc/bar And the analogous in src/bar. The problem is that after calling automake and autoconf, when calling "make" the compilation fails. In particular, the program enters the directory src, then foo and creates libfoo.a, but the same fail for libbar.a, with the following error: Making all in bar make[3]: Entering directory `/user/Raffo/project/src/bar' make[3]: *** No rule to make target `all'. Stop. I have read the autotools documentation, but I'm not able to find a similar example to the one I am working on. Unfortunately I can't change the directory structure as this is a fixed requisite of the project I'm working on. I don't know if you can help me or give me any hint, but maybe you can guess the error or give me a link to a similar structured example. Thank you.

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  • Is there an ORM that supports composition w/o Joins

    - by Ken Downs
    EDIT: Changed title from "inheritance" to "composition". Left body of question unchanged. I'm curious if there is an ORM tool that supports inheritance w/o creating separate tables that have to be joined. Simple example. Assume a table of customers, with a Bill-to address, and a table of vendors, with a remit-to address. Keep it simple and assume one address each, not a child table of addresses for each. These addresses will have a handful of values in common: address 1, address 2, city, state/province, postal code. So let's say I'd have a class "addressBlock" and I want the customers and vendors to inherit from this class, and possibly from other classes. But I do not want separate tables that have to be joined, I want the columns in the customer and vendor tables respectively. Is there an ORM that supports this? The closest question I have found on StackOverflow that might be the same question is linked below, but I can't quite figure if the OP is asking what I am asking. He seems to be asking about foregoing inheritance precisely because there will be multiple tables. I'm looking for the case where you can use inheritance w/o generating the multiple tables. Model inheritance approach with Django's ORM

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  • Objective-C and NSURL: where am I supposed to declare receivedData?

    - by jthomas
    I have a two classes, a controller called "AppController" and a class called "URLDelegate" that encapsulates the sample NSURL code from Apple's URL Loading System Programming Guide. The guide repeatedly mentions declaring the receivedData instance variable "elsewhere." I assume this means outside of the URLDelagate class, because if I declare it in the URLDelegate class, my controller class can't "see" the data that has been downloaded. I know that data is received, because in my connectionDidFinishLoading function, I have NSLog display the results: NSLog(@"Succeeded! Received %d bytes of data",[receivedData length]); receivedText=[[NSString alloc] initWithData:receivedData encoding: NSASCIIStringEncoding]; NSLog(@"receivedText=%@",receivedText); So I'm a bit stumped with the following questions: Where should I declare receivedData? My controller class? A third class? Can I just declare it like any normal NSMutableData variable? How do I give my URLDelegate class "access" to this variable? E.g., if I declare receivedData in my AppController class, wouldn't I have to instantiate AppController within URLDelegate? But how would this possible if it's the AppController class which is instantiating the URLDelegate class in the first place? Especially with regard to the last question, I feel like I must be overlooking something blindingly obvious and fundamental. If anyone could point me in the right direction, I would really appreciate it. Thank you!

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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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  • why MVC instead of good old asp.net? Still not grasping why I should go this route??

    - by RJ
    I know this question has been asked before and I read all the answers but they still don't give me the answers I am looking for. I need something concrete. I volunteered to give a presentation on MVC to other developers in our group which forces me to learn it. The big question everyone has is: "What can MVC bring to the table that we can't do in asp.net or MVC can do faster. I have just gone through Nerd Dinner and actually created a complete website that sort of mimics Nerd Dinner. But as great a job that Scott Guthrie did on it, there are big gaps that aren't answered such as, how do I throw a textbox on the listing page with a button and do a simple search. In asp.net, I would throw a textbox, button and grid on the page and bind it to a sproc and away I go. What is the equivalent in MVC. I guess I need a really good tutorial on how to use MVC without using Linq-to-Sql. I know I am sort of babbling on about this but it is a very serious question that still seems to go unanswered. On a side note, the View page of MVC brings back nightmares of classic asp with all the in-line code that we got away from way back when with code behind pages. Yes, MVC has Controller and Model classes which are great but I still don't like the classic asp tags in the html. Help me out here, I really like the concept of MVC and want it to be successful but I need more!

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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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  • 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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  • Storing records in a dropdownlist from DB without using LINQ Data source

    - by user1318369
    I have a website for dance academy where Users can register and add/drop dance classes. In the web page to drop a particular dance, for a particular user, the dropdown displays her registered dances. Now I want to delete one of the dances from the list. So i'll remove the row from the table and also from the dropdownlist. The problem is that everytime the item with the lowest ID (index) is getting deleted, no matter which one the user selects. I think I am storing the DataTextField and DataValueField for the dropdown incorrectly. Can someone please help me out? The code is: private void PopulateDanceDropDown() { var registereddanceList = from dd in context.DANCER_AND_DANCE where dd.UserId == dancerId select new { Text = dd.DanceName, Value = dd.DanceId }; dances.DataSource = registereddanceList; dances.DataTextField = "Text"; dances.DataValueField = "Value"; dances.DataBind(); } protected void dropthedance(object o, EventArgs e) { String strDataValueField = dances.SelectedItem.Value; int danceIDFromDropDown = Convert.ToInt32(strDataValueField); var dancer_dance = from dd in context.DANCER_AND_DANCE where dd.DanceId == danceIDFromDropDown select dd; foreach (var dndd in dancer_dance) { context.DANCER_AND_DANCE.DeleteOnSubmit(dndd); } try { context.SubmitChanges(); } catch (Exception ex) { Console.WriteLine(ex); } PopulateDanceDropDown(); }

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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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  • Wordpress/CSS: List Style Problem.

    - by Ben
    Hi all! I am reasonably new to Wordpress custom themes but I do have some knowlege of CSS, although I am terrible at customising other peoples code which is why I have the problem I am about to explain. I have started a website that my girlfriend and I are doing together. It uses the Simplo Wordpress theme which is pretty cool but when you add a post that has a list in it. It doesn't show the bullets on each of the items. I have tried adding 'list-style:circle;' to a the.postItem class and a couple of other divs and classes that I thought were relevant but it doesn't work. You can take a look for yourself, it may be easier to understand my problem that way. If you go to: http://brokeandstarving.com/234/bennos-shepherds-pie/ there is a list of ingredients and also the steps under the method is a list as well. My question is, where do I edit the CSS to make the bullets appear next to the list items? I hope that makes sense. Thanks in advance, - Ben

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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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  • 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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  • 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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  • jQuery sliding animation not working

    - by Jake Zeitz
    I have three divs stacked on each other but offset so that a part of each div is visible. When one of the bottom divs is clicked I want the top div to animate out and back into the stack at the bottom, then the div that is clicked will appear at the top. So far I only have the code for when the middle div is clicked, but I cannot get it to work properly. What am I doing wrong? (I also realize that the code I wrote is probably terrible, this is the first jQuery code I have written.) The css is very very simple: .first { z-index: 3; } .second { z-index: 2; } .third { z-index: 1; } The basic html is this: <div class="first"></div> <div class="second"></div> <div class="third"></div> Here is my code: $("div.second").click(function () { $("div.first").animate({ left: "-=200px"}, {duration: "fast", complete: function () { $("div.first").removeClass("first").addClass("third").animate({left: "+=350px", top: "+=60px"}, "fast"); } }); $("div.second").animate({ left: "-=24px", top: "-=30px"}, {duration: "fast", complete: function () { $("div.second").removeClass("second").addClass("first"); } }); $("div.third").animate({ left: "-=24px", top: "-=30px"}, {duration: "fast", complete: function () { $("div.third").removeClass("third").addClass("second"); } }); }); I can get the div.first to move to the side and back. But now I can't get the classes to stay changed. What keeps happening is the div.second will remove it's class and add .first in the animation, but when the animation is complete, it acts like it still has a class of .second.

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  • toggleClass messing something up.

    - by Mathias Nielsen
    Hi I am using playing around with the Pretty-checkboxes-plugin and have a problem. The plugin can be seen here http://aaronweyenberg.com/90/pretty-checkboxes-with-jquery As you can see, this uses two links to select and deselect. I want it to only use one link and then change the class to make it work the other way the next time it is clicked. It should be simple enough. I have been trying to get it working with toggleClass. I simply put in the toggleClass statement so the code looks like so: $(document).ready(function() { /* see if anything is previously checked and reflect that in the view*/ $(".checklist input:checked").parent().addClass("selected"); /* handle the user selections */ $(".checklist .checkbox-select").click( function(event) { event.preventDefault(); $(this).parent().addClass("selected"); $(this).parent().find(":checkbox").attr("checked","checked"); $(this).toggleClass("checkbox-select checkbox-deselect"); } ); $(".checklist .checkbox-deselect").click( function(event) { event.preventDefault(); $(this).parent().removeClass("selected"); $(this).parent().find(":checkbox").removeAttr("checked"); $(this).toggleClass("checkbox-select checkbox-deselect"); } ); }); This works to some extend. The classes toggle just fine, but the rest of the code only works the first time it is run. All subsequent clicks just toggle the class og the link and nothing else. Does anyone have any idea why this is?

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  • Interface vs Abstract Class (general OO)

    - by Kave
    Hi, I have had recently two telephone interviews where I've been asked about the differences between an Interface and an Abstract class. I have explained every aspect of them I could think of, but it seems they are waiting for me to mention something specific, and I dont know what it is. From my experience I think the following is true, if i am missing a major point please let me know: Interface: Every single Method declared in an Interface will have to be implemented in the subclass. Only Events, Delegates, Properties (C#) and Methods can exist in a Interface. A class can implement multiple Interfaces. Abstract Class Only Abstract methods have to be implemented by the subclass. An Abstract class can have normal methods with implementations. Abstract class can also have class variables beside Events, Delegates, Properties and Methods. A class can only implement one abstract class only due non-existence of Multi-inheritance in C#. 1) After all that the interviewer came up with the question What if you had an Abstract class with only abstract methods, how would that be different from an interface? I didnt know the answer but I think its the inheritance as mentioned above right? 2) An another interviewer asked me what if you had a Public variable inside the interface, how would that be different than in Abstract Class? I insisted you can't have a public variable inside an interface. I didn't know what he wanted to hear but he wasn't satisfied either. Many Thanks for clarification, Kave See Also: When to use an interface instead of an abstract class and vice versa Interfaces vs. Abstract Classes How do you decide between using an Abstract Class and an Interface?

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  • Is there any reason to use C instead of C++ for embedded development?

    - by Piotr Czapla
    Question I have two compilers on my hardware C++ and C89 I'm thinking about using C++ with classes but without polymorphism (to avoid vtables). The main reasons I’d like to use C++ are: I prefer to use “inline” functions instead of macro definitions. I’d like to use namespaces as I prefixes clutter the code. I see C++ a bit type safer mainly because of templates, and verbose casting. I really like overloaded functions and constructors (used for automatic casting). Do you see any reason to stick with C89 when developing for very limited hardware (4kb of RAM)? Conclusion Thank you for your answers, they were really helpful! I though the subject through and I will stick with C mainly because: It is easier to predict actual code in C and this is really important if you have only 4kb of ram. My team consists of C developers mainly so advance features of C++ won't be frequently used. I've found a way to inline functions in my C compiler (C89). It is hard to accept one answer as you provided so many good answers. Unfortunately I can't create a wiki and accept it so I will choose one answer that made me think most.

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