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  • How to initialize an Object?

    - by John
    I have a class like this, public class person { name Name {set; get;} string Address {set; get;} } public class name { string First {set; get;} string Last {set; get;} } Now when I create the object an try to set the first or last name I get an error. "Object reference not set to an instance of an object." person Person = new person(); Person.Name.First = "John"; Person.Name.Last ="Smith"; What am I doing wrong?

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  • Hibernate -using Table per subclass - how to link an existing superclass object to a sibclass object

    - by Chandni
    Hi, I have a User hibernate class, Clerk class and Consumer class. All these maps to their own tables in database. The User PK also acts as Clerk's and Consumer's PK. So now my problem is that if a user is initially a Clerk, he has a record in Users table and Clerks table. If that user wants to become a consumer, I want to link that User's record to the new Consumer's record. So even if I pass the userId to the consumer's record, it treats it as a new User to be persisted and gives a duplicate_key exception. How do I tell Hiernate to link the same user object with this new Consumer object. Thanks in advance, -Chandni

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  • NHibernate session management in ASP.NET MVC

    - by Kevin Pang
    I am currently playing around with the HybridSessionBuilder class found on Jeffrey Palermo's blog post: http://jeffreypalermo.com/blog/use-this-nhibernate-wrapper-to-keep-your-repository-classes-simple/ Using this class, my repository looks like this: public class UserRepository : IUserRepository { private readonly ISessionBuilder _sessionBuilder; public UserRepository(ISessionBuilder sessionBuilder) { _sessionBuilder = sessionBuilder; } public User GetByID(string userID) { using (ISession session = _sessionBuilder.GetSession()) { return session.Get<User>(userID); } } } Is this the best way to go about managing the NHibernate session / factory? I've heard things about Unit of Work and creating a session per web request and flushing it at the end. From what I can tell, my current implementation isn't doing any of this. It is basically relying on the Repository to grab the session from the session factory and use it to run the queries. Are there any pitfalls to doing database access this way?

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  • Mongomapper - unit testing with shoulda on rails 2.3.5

    - by egarcia
    I'm trying to implement shoulda unit tests on a rails 2.3.5 app using mongomapper. So far I've: Configured a rails app that uses mongomapper (the app works) Added shoulda to my gems, and installed it with rake gems:install Added config.frameworks -= [ :active_record, :active_resource ] to config/environment.rb so ActiveRecord isn't used. My models look like this: class Account include MongoMapper::Document key :name, String, :required => true key :description, String key :company_id, ObjectId key :_type, String belongs_to :company many :operations end My test for that model is this one: class AccountTest < Test::Unit::TestCase should_belong_to :company should_have_many :operations should_validate_presence_of :name end It fails on the first should_belong_to: ./test/unit/account_test.rb:3: undefined method `should_belong_to' for AccountTest:Class (NoMethodError) Any ideas why this doesn't work? Should I try something different from shoulda? I must point out that this is the first time I try to use shoulda, and I'm pretty new to testing itself.

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  • Consecutive 'if' statements

    - by Ben Packard
    How can I check one thing AND THEN another, if the first is true? For example, say I have a shopping basket object, and I only want to do something if the basket has been created AND it isn't empty. I've tried: if (basket && [basket numberOfItems >0])... But the second condition is evaluated even if the first fails, resulting in a crash (presumably because i'm calling numberOfItems on an object that doesn't exist). I can nest them, but this seems a bit ugly, and more to the point is problematic. Say I want to do one thing if the basket exists AND isn't empty, but another if either isn't true. That doesn't really work well in nested if statements.

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  • declaring a 2D array of pointer objects

    - by Tyler Stennette
    I'm having a tough time figuring out how to instantiate a 2D array of pointer objects. Here is how I'm doing it: Pieces* chessBoard[9][9]; When I want to set it to an actual object pointer, I'm doing the following: chessBoard[1][1] = new Rook(p1Rook); Rook is a class that inherits attributes from the Pieces class and p1Rook is a char variable set to 'R'. This class also implements virtual functions (not pure virtual) from Pieces such as move() or getPiece() that are unique to the particular chess piece. However, when I compile my program, I get the following error: ChessBoard.cpp:69: error: expected type-specifier before ‘Rook’ ChessBoard.cpp:69: error: cannot convert ‘int*’ to ‘Pieces*’ in assignment Can someone please explain what I should change to get rid of this rather annoying persistent error? I would appreciate it.

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  • Why do mainframe greybeards refer to DB2/zOS as "he"? [closed]

    - by Alex Nauda
    If you ask a DB2/zOS engine DBA a question about DB2's behavior, the DBA will refer to the DB2 engine as "he" much the way a sailor uses "she" to refer to his ship. For example: "Once you fill the freespace, DB2 still wants to keep those rows in cluster order in the tablespace. That's why he'll split that page in half, and you end up with lots of half-empty pages. That is, unless the cluster key of the row you've just inserted is the highest in the table, in which case he makes a new empty page, and he puts just your new row into that page. So I wouldn't have to do this REORG if you would just sort your input like I suggested." Does anyone know where this tradition comes from?

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  • ASP.NET MVC - Disable Html Helper control using boolean value from Model

    - by The Matt
    I am outputting a textbox to the page using the Html helpers. I want to add the disabled attribute dynamically based on whether or not a boolean value in my model is true or false. My model has a method that returns a boolean value: <% =Model.IsMyTextboxEnabled() %> I currently render the textbox like follows, but I want to now enabled or disable it: <% =Html.TextBox("MyTextbox", Model.MyValuenew { id = "MyTextbox", @class = "MyClass" })%> If the return value of Model.IsMyTextboxEnabled() == true I want the following to be output: <input class="MyClass" id="MyTextbox" name="MyTextbox" type="text" value="" /> If it == false, I want it to output as: <input class="MyClass" id="MyTextbox" name="MyTextbox" type="text" value="" disabled /> What is the cleanest way to do this?

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  • C# BinarySearch breaks when inheriting from something that implements IComparable<T>?

    - by Ender
    In .NET the BinarySearch algorithm (in Lists, Arrays, etc.) appears to fail if the items you are trying to search inherit from an IComparable instead of implementing it directly: List<B> foo = new List<B>(); // B inherits from A, which implements IComparable<A> foo.Add(new B()); foo.BinarySearch(new B()); // InvalidOperationException, "Failed to compare two elements in the array." Where: public abstract class A : IComparable<A> { public int x; public int CompareTo(A other) { return x.CompareTo(other.x); } } public class B : A {} Is there a way around this? Implementing CompareTo(B other) in class B doesn't seem to work.

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  • Is AutoMapper able to auto resolve types base on existing maps

    - by Chi Chan
    I have the following code: [SetUp] public void SetMeUp() { Mapper.CreateMap<SourceObject, DestinationObject>(); } [Test] public void Testing() { var source = new SourceObject {Id = 123}; var destination1 = Mapper.Map<SourceObject, DestinationObject>(source); var destination2 = Mapper.Map<ObjectBase, ObjectBase>(source); //Works Assert.That(destination1.Id == source.Id); //Fails, gives the same object back Assert.That(destination2 is DestinationObject); } public class ObjectBase { public int Id { get; set; } } public class SourceObject : ObjectBase { } public class DestinationObject : ObjectBase { } So basically, I want AutoMapper to automatically resolve the destination type to "DestinationObject" based on the existing Maps set up in AutoMapper. Is there a way to achieve this?

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  • How does git-diff generate hunk descriptions?

    - by RobM
    (git version 1.6.5.7) When I run git diff the output has a nice scope hint after the line numbers for my Python scripts, e.g.: diff --git a/file.py b/file.py index 024f5bb..c3b5c56 100644 --- a/file.py +++ b/file.py @@ -14,6 +14,8 @@ TITF: Test Infrastructure Tags Format ... @@ -1507,13 +1533,16 @@ class Tags( object ): ... Note that the line numbers are followed by TITF: Test Infrastructure Tags Format and class Tags( object ):. The first patch applies to module scope and the description TITF: Test Infrastructure Tags Format is the module's description. The second patch applies to a method of the Tags class. How does git generate these descriptions? How can I tweak them to show the method name that the patch applies to?

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  • NSArray safeguards

    - by Spider-Paddy
    If there is a chance that an NSArray is empty, is it better to check it and set equal to nil if it's empty when it is assigned or to rather do the check when it is used? e.g. NSArray *myArray; if ([anotherArray count] > 0) <-- Check when assigned myArray = [anotherArray copy]; else myArray = nil; something = [myArray objectAtIndex:x]; or NSArray *myArray; myArray = [anotherArray copy]; if ([myArray count] > 0) <-- Check when used something = [myArray objectAtIndex:x]; Which is better?

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  • Conversion of Linq expressions

    - by Arnis L.
    I'm not sure how exactly argument what I'm trying to achieve, therefore - wrote some code: public class Foo{ public Bar Bar{get;set;} } public class Bar{ public string Fizz{get;set;} } public class Facts{ [Fact] public void fact(){ Assert.Equal(expectedExp(),barToFoo(barExp())); } private Expression<Func<Foo,bool>> expectedExp(){ return f=>f.Bar.Fizz=="fizz"; } private Expression<Func<Bar,bool>> barExp(){ return b=>b.Fizz=="fizz"; } private Expression<Func<Foo,bool>> barToFoo (Expression<Func<Bar,bool>> barExp){ return Voodoo(barExp); //<-------------------------------------------??? } } Is this even possible?

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  • Why should i use EJB?

    - by Nitesh Panchal
    Hello, As we all know that EJB's in 3.1 or 3.0 are simple POJOs. You just need to give annotations here and there and it gets converted to EJB from simple class. So, now my question is why should i use EJBs at all? Can i not do without them? In .Net i created class library and got things done. I never felt the need for anything like EJB. Simple classes were enough. Then, why in Java people stress on EJB? What is difference between a simple POJO and EJB in terms of execution and memory? Further which function should i write in EJB and which should i write in simple class? Should i dump every function in EJB only? or there is some kind of strategy? Does EJB provide anything special?

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  • Grails / GORM, Disable First-level Cache

    - by Stephen Swensen
    Suppose I have the following Domain class mapping to a legacy table, utilizing read-only second-level cache, and having a transient field: class DomainObject { static def transients = ['userId'] Long id Long userId static mapping = { cache usage: 'read-only' table 'SOME_TABLE' } } I have a problem, references to DomainObject are being shared due to first-level caching, and thus transient fields are writing over each other. For example, def r1 = DomainObject.get(1) r1.userId = 22 def r2 = DomainObject.get(1) r2.userId = 34 assert r1.userId == 34 That is, r1 and r2 are references to the same instance. This is undesirable, I would like to cache the table data without sharing references. Any ideas? [Edit] Understanding the situation better now, I believe my question boils down to the following: Is there anyway to disable first level cache for a specific domain class while still using second level cache?

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  • passing request params from jQuery to jersey service using json

    - by ccduga
    hi, im trying to POST (cross domain) some data to a jersey web service and retrieve a response (a GenericEntity object). The post successfully gets mapped to my jersey endpoint however when i pull the parameters from the request they are empty.. $ .ajax({ type: "POST", dataType: "application/json; charset=utf-8", url: jerseyNewUserUrl+'?jsoncallback=?', data:{'id':id, 'firstname':firstname,'lastname':lastname}, success: function(data, textStatus) { $('#jsonResult').html("some data: " + data.responseMsg); }, error: function ( XMLHttpRequest, textStatus, errorThrown){ alert('error'); } }); this is my jersey endpoint.. @POST @Produces( { "application/x-javascript", MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML }) @Path("/new") public JSONWithPadding addNewUser(@QueryParam("jsoncallback") @DefaultValue("empty") final String argJsonCallback, @QueryParam("id") final String argID, @QueryParam("firstname") final String argFirstName, @QueryParam("lastname") final String argLastName) is there something missing from my $.ajax call?

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  • Java: Non-static nested classes and instance.super()

    - by Kiv
    I'm having a hard time wrapping my head around non-static nested classes in Java. Consider the following example, which prints "Inner" and then "Child". class Outer { class Inner { Inner() { System.out.println("Inner"); } } } public class Child extends Outer.Inner { Child(Outer o) { o.super(); System.out.println("Child"); } public static void main(String args[]) { new Child(new Outer()); } } I understand that instances of Inner always have to be associated with an Outer instance, and that that applies to Child too since it extends Inner. My question is what the o.super() syntax means - why does it call the Inner constructor? I've only seen a plain super(args) used to call the superclass constructor and super.method() to call the superclass version of an overridden method, but never something of the form instance.super().

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  • PHP MYSQL Endless Loop

    - by Neb
    Hi, I have a problem with my php/mysql script. It should only output the while loop once but I am getting unlimited loops and an endless page. $query = mysql_query("SELECT * FROM users WHERE username ='".base64_encode($_SESSION['username'])."' LIMIT 1"); $result = mysql_fetch_array($query); if(empty($result)){ echo "No user... Error"; }else{ while($row = $result){ ?> <a href="index.php?user=<?=$row['id']?>"><?=base64_decode($row['username'])?></a> | <a href="javascript:void(0);" id="logout">Logout</a> <?php } } I have tried a similar script with these same lines and it works perfectly $result = mysql_fetch_array($query); if(empty($result)){ echo "No user... Error"; }else{ while($row = $result){ //Something } }

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  • Ruby Metaprogramming

    - by VP
    I'm trying to write a DSL that allows me to do Policy.name do author "Foo" reviewed_by "Bar" end The following code can almost process it: class Policy include Singleton def self.method_missing(name,&block) puts name puts "#{yield}" end def self.author(name) puts name end def self.reviewed_by(name) puts name end end Defining my method as class methods (self.method_name) i can access it using the following syntax: Policy.name do Policy.author "Foo" Policy.reviewed_by "Bar" end If i remove the "self" from the method names, and try to use my desired syntax, then i receive an error "Method not Found" in the Main so it could not find my function until the module Kernel. Its ok, i understand the error. But how can i fix it? How can i fix my class to make it work with my desired syntax that?

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  • c# website login with post method

    - by druffmuff
    Hi, How can I with c sharp log me in into a website by using the post method? Any Ideas how to do this? Here's the html code of the forumlar: <form action="http://www.site.com/login.php" method="post" name="login" id="login"> <table border="0" cellpadding="2" cellspacing="0"> <tbody> <tr><td><b>User:</b></td><td colspan=\"2\"><b>Passwort:</b></td></tr> <tr> <td><input class="inputbg" name="user" type="text"></td> <td><input class="inputbg" name="password" type="password"></td> <td><input type="submit" name="user_control" value="Eingabe" class="buttonbg" ></td> </tr> </tbody></table></form>

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  • How to organize code using an optional assembly reference?

    - by apoorv020
    I am working on a project and want to optionally use an assembly if available. This assembly is only available on WS 2008 R2, and my ideal product whould be a common binary for both computers with and without the assembly. However, I'm primarily developing on a Windows 7 machine, where I cannot install the assembly. How can I organize my code so that I can (with minimum changes) build my code on a machine without the assembly and secondly, how do I ensure that I call the assembly functions only when it is present. (NOTE : The only use of the optional assembly is to instantiate a class in the library and repeatedly call a (single) function of the class, which returns a boolean. The assembly is fsrmlib, which exposes advanced file system management operations on WS08R2.) I'm currently thinking of writing a wrapper class, which will always return true if the assembly is not present. Is this the right way to go about doing this?

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  • Storing year/make/model in a database?

    - by Mark
    Here's what I'm thinking (excuse the Django format): class VehicleMake(Model): name = CharField(max_length=50) class VehicleModel(Model): make = ForeignKey(VehicleMake) name = CharField(max_length=50) class VehicleYear(Model): model = ForeignKey(VehicleModel) year = PositiveIntegerField() This is going to be used in those contingent drop-down select boxes, which would visually be laid out like [- Year -][- Make -][- Model -]. So, to query the data I need I would first have to select all distinct years from the years table, sorted descending. Then I'd find all the vehicle makes that have produced a model in that year. And then all the models by that make in that year. Is this a good way to do it, or should I re-arrange the foreign keys somehow? Or use a many-to-many table for the years/models so that no year is repeated?

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  • Linking Excel and Access

    - by Mel
    I run a sports program where i have a master roll of who is in which class in excel. I want to link this to a database in access that stores the other information about each athlete, e.g. address, parents name, school, medical details. I want to be able to add names to class in the excel speadsheet and have this automatically generate a record for that person in access. There also needs to be some failsafe for athletes that are in multiple classes. I was also doing class roles as pivot tables out of the access database so i need to code for classes and also have this allow for athletes in multiple classes/disciplines.

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  • Django Grouping Query

    - by Matt
    I have the following (simplified) models: class Donation(models.Model): entry_date = models.DateTimeField() class Category(models.Model): name = models.CharField() class Item(models.Model): donation = models.ForeignKey(Donation) category = models.ForeignKey(Category) I'm trying to display the total number of items, per category, grouped by the donation year. I've tried this: Donation.objects.extra(select={'year': "django_date_trunc('year', %s.entry_date)" % Donation._meta.db_table}).values('year', 'item__category__name').annotate(items=Sum('item__quantity')) But I get a Field Error on item__category__name. I've also tried: Item.objects.extra(select={"year": "django_date_trunc('year', entry_date)"}, tables=["donations_donation"]).values("year", "category__name").annotate(items=Sum("quantity")).order_by() Which generally gets me what I want, but the item quantity count is multiplied by the number of donation records. Any ideas? Basically I want to display this: 2010 - Category 1: 10 items - Category 2: 17 items 2009 - Category 1: 5 items - Category 3: 8 items

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  • Generic WithEvents

    - by serhio
    Error: 'WithEvents' variables can only be typed as classes, interfaces or type parameters with class constraints Background: Public Class Tadpole(Of T As IVisibleChanged, P As IVisibleChanged) Private WithEvents _Tad As T ' ERROR ' Private WithEvents _Pole As P ' ERROR ' Public Property Tad() As T ... Public Property Pole() As P ... End Class ''' IVisibleChanged ''' Public Interface IVisibleChanged Property Visible() As Boolean Event VisibleChanged As EventHandler End Interface Workaround: a. Use AddHandler to handle events defined in a structure. EDIT b. use Private WithEvents _Tad AsIVisibleChanged (M.A. Hanin) c. ?

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