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  • MySQL COUNT help

    - by space
    I'm trying to count all the ids form table3 that are related to the first two tables but I think my SQL code is wrong can some one help me fix it? Here is the code: $dbc = mysqli_query($mysqli,"SELECT table1.*, table2.*, COUNT(id) as num, table3.id FROM table1 INNER JOIN table2 ON table1.id = table2.id INNER JOIN table3 ON table2.id = table3.id WHERE table2.id = '$id'"); Here is the error message. Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 4

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  • Scope of Groovy's ExpandoMetaClass?

    - by TicketMonster
    Groovy exposes an ExpandoMetaClass that allows you to dynamically add instance and class methods/properties to a POJO. I would like to use it to add an instance method to one of my Java classes: public class Fizz { // ...etc. } Fizz fizz = new Fizz(); fizz.metaClass.doStuff = { String blah -> fizz.buzz(blah) } This would be the equivalent to refactoring the Fizz class to have: public class Fizz { // ctors, getters/setters, etc... public void doStuff(String blah) { buzz(blah); } } My question: Does this add doStuff(String blah) to only this particular instance of Fizz? Or do all instances of Fizz now have a doStuff(String blah) instance method? If the former, how do I get all instances of Fizz to have the doStuff instance method? I know that if I made the Groovy: fizz.metaClass.doStuff << { String blah -> fizz.buzz(blah) } Then that would add a static class method to Fizz, such as Fizz.doStuff(String blah), but that's not what I want. I just want all instances of Fizz to now have an instance method called doStuff. Ideas?

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  • Error : The Type Initializer of Daemon.Global threw an exception in c#

    - by srk
    I am using the below class file, where some variables are declared to use in the entire application. Now I used that variable BlockLogOut in another class file to make the value true. I just put this below line and getting error in it.. TypeInitializationException Global.BlockLogOut = True; The weird thing is, it was working fine for many months and i am getting this error now on the above line. Of course i was modifying some other stuffs in the application, but surely not this class file. What would have been the problem? namespace Daemon { class Global { public static bool BlockLogOut = false; } }

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  • Is inheritance bad nowadays?

    - by mafutrct
    Personally, I think inheritance is a great tool, that, when applied reasonably, can greatly simplify code. However, I seems to me that many modern tools dislike inheritance. Let's take a simple example: Serialize a class to XML. As soon as inheritance is involved, this can easily turn into a mess. Especially if you're trying to serialize a derived class using the base class serializer. Sure, we can work around that. Something like a KnownType attribute and stuff. Besides being an itch in your code that you have to remember to update every time you add a derived class, that fails, too, if you receive a class from outside your scope that was not known at compile time. (Okay, in some cases you can still work around that, for instance using the NetDataContract serializer in .NET. Surely a certain advancement.) In any case, the basic principle still exists: Serialization and inheritance don't mix well. Considering the huge list of programming strategies that became possible and even common in the past decade, I feel tempted to say that inheritance should be avoided in areas that relate to serialization (in particular remoting and databases). Does that make sense? Or am messing things up? How do you handle inheritance and serialization?

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  • Null reference but it's not?

    - by Clint Davis
    This is related to my previous question but it is a different problem. I have two classes: Server and Database. Public Class Server Private _name As String Public Property Name() As String Get Return _name End Get Set(ByVal value As String) _name = value End Set End Property Private _databases As List(Of Database) Public Property Databases() As List(Of Database) Get Return _databases End Get Set(ByVal value As List(Of Database)) _databases = value End Set End Property Public Sub LoadTables() Dim db As New Database(Me) db.Name = "test" Databases.Add(db) End Sub End Class Public Class Database Private _server As Server Private _name As String Public Property Name() As String Get Return _name End Get Set(ByVal value As String) _name = value End Set End Property Public Property Server() As Server Get Return _server End Get Set(ByVal value As Server) _server = value End Set End Property Public Sub New(ByVal ser As Server) Server = ser End Sub End Class Fairly simple. I use like this: Dim s As New Server s.Name = "Test" s.LoadTables() The problem is in the LoadTables in the Server class. When it hits Databases.Add(db) it gives me a NullReference error (Object reference not set). I don't understand how it is getting that, all the objects are set. Any ideas? Thanks.

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  • (Java) Get value of string loaded into dynamic-type object?

    - by Michael
    I'm very new to Java (~10 days), so my code is probably pretty bad, but here's what I've got: ArgsDataHolder argsData = new ArgsDataHolder(); // a class that holds two // ArrayList's where each element // representing key/value args Class thisArgClass; String thisArgString; Object thisArg; for(int i=2; i< argsString.length; i++) { thisToken = argsString[i]; thisArgClassString = getClassStringFromToken(thisToken).toLowerCase(); System.out.println("thisArgClassString: " + thisArgClassString); thisArgClass = getClassFromClassString(thisArgClassString); // find closing tag; concatenate middle Integer j = new Integer(i+1); thisArgString = getArgValue(argsString, j, "</" + thisArgClassString + ">"); thisArg = thisArgClass.newInstance(); thisArg = thisArgClass.valueOf(thisArgString); argsData.append(thisArg, thisArgClass); } The user basically has to input a set of key/value arguments into the command prompt in this format: <class>value</class>, e.g. <int>62</int>. Using this example, thisArgClass would be equal to Integer.class, thisArgString would be a string that read "62", and thisArg would be an instance of Integer that is equal to 62. I tried thisArg.valueOf(thisArgString), but I guess valueOf(<String>) is only a method of certain subclasses of Object. For whatever reason, I can't seem to be able to cast thisArg to thisArgClass (like so: thisArg = (thisArgClass)thisArgClass.newInstance();, at which point valueOf(<String>) should become accessible. There's got to be a nice, clean way of doing this, but it is beyond my abilities at this point. How can I get the value of the string loaded into a dynamically-typed object (Integer, Long, Float, Double, String, Character, Boolean, etc.)? Or am I just overthinking this, and Java will do the conversion for me? :confused:

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  • Trying to change img src if another element is visible with jQuery

    - by R.J.
    I have a div ("panel" class) on my page that toggles open/closed on the click of a paragraph element ("flip" class), which has an image inside of it. Here's the HTML: <div class="panel">Contact info</div> <p class="flip"><img src="images/contactExpand.png" />Expand</p> And the jQuery: $(".flip").click(function(){ $(".panel").slideToggle("slow"); }); Everything works fine so far, but I want the image src to change to "contactCollapse.png" when the panel div is visible. This doesn't seem to do anything (image just stays the same): if ($(".panel").is(":visible") == true) { $(".flip img").attr("src","../images/contactCollapse.png") } else { $(".flip img").attr("src","../images/contactExpand.png") } Am I missing something? Thanks for any help!

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  • Quick question regarding MVC framework for a java game

    - by Jason
    I have a question regarding the use of the MVC framework for a blackjack game im writing in java. As I understand, my model would be a class that stores the state of the game, and more specifically, each players hand. Within the model class, I would have an array of listeners, which would be notified each time the game state changes (ie a player has drawn a new card). These listeners would be my viewer, which is the class that handles the display of the game. This class would implement the ActionListener interface, and each time the model changes, it would call/"notify" my viewer's actionPerformed method. My question is as follows: I intend to have two JPanels, each devoted to displaying the respective player's hand. As a player draws a new card, a new ImageIcon would be added to the panel. My question is how would the viewer class know what card has been added to the player's hand? I suppose I could store the player's hand before a notify event, and then upon the notification event, compare the new state with the old, to find out what has changed. I'm a complete novice here, so I could be completely wrong, but it seems a bit tedious to do this. Is there a more efficient/common way of detecting what has changed in the model between the before and after state? Another solution would be to redraw the entire panel each time the notification occurs? Would this be a better idea?

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  • Singelton restricted to instance of dll

    - by codeySmurf
    If I create a singleton class in the context of a dll, the singleton class is instantiated once and used by all instances of the dll. I am using a dll as a plug-in for an application. Now the following thing came to my mind: If I use a singleton Class, it will be shared across multiple instances of the plug-in. However, this makes it difficult to manage the lifetime of the singleton class efficiently. The only way I could think of would be to use a reference count and to make the singleton delete its self when the reference count is 0. Does anyone have any better ideas on that? Is there any good way to restrict the singleton object to one instance of the dll? Language is c++

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  • How can I use the HTML5 <button> tag in Drupal 6

    - by Frankie Yale
    I have the following HTML which I'd like to use in my Drupal 6 theme. It needs to replace the search-box code. <fieldset class="search"> <input type="text" class="box font-myriad" /> <button class="btn" title="Submit Search">Search</button> </fieldset> I'm trying stuff like $vars['form']['button']['#attributes'] = array('class' => 'btn'); in template.php, but no luck so far. Couldn't find much help on drupal.org.

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  • Inferring type from method generics

    - by ng
    I am from a Java background and I am looking from the equivalent in c# for the following. public interface Reader { <T> T read(Class<? extends T> type); } Such that I can do the following, constraining the parameter and inferring the return type. Cat cat = reader.read(Cat.class); Dog dog = reader.read(Dog.class); I was hoping something like this would work in c# but I am not sure it will. public interface Reader { T Read<T>(); } And and do this. public class TypeReader : Reader { public T Read<T>() { Type type = T.GetType(); ... } } Is something like this even possible in c#?

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  • "Add another item" form functionality

    - by GSTAR
    I have a form that lets a user enter their career history - it's a very simple form with only 3 fields - type (dropdown), details (textfield) and year (dropdown). Basically I want to include some dynamic functionality whereby the user can enter multiple items on the same page and then submit them all in one go. I had a search on Google and found some examples but they were all based on tables - my markup is based on DIV tags: <div class="form-fields"> <div class="row"> <label for="type">Type</label> <select id="type" name="type"> <option value="Work">Work</option> </select> </div> <div class="row"> <label for="details">Details</label> <input id="details" type="text" name="details" /> </div> <div class="row"> <label for="year">Year</label> <select id="year" name="year"> <option value="2010">2010</option> </select> </div> </div> So basically the 3 DIV tags with class "row" need to be duplicated, or to simplify things - the div "form-fields" could just be duplicated. I am also aware that the input names would have to converted to array format. Additionally each item will require a "remove" button. There will be a main submit button at the bottom which submits all the data. Anyone got an elegant solution for this?

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  • Problems with capturing an event in child object in Actionscript

    - by Raigomaru
    I have two classes. The first one (the starting class): package { import flash.display.Sprite; import flash.events.KeyboardEvent; import tetris.*; public class TetrisGame extends Sprite { private var _gameWell:Well; public function TetrisGame() { _gameWell = new Well(); addChild(_gameWell); } } } The second: package tetris { import flash.display.Sprite; import flash.events.KeyboardEvent; public class Well extends Sprite { public function Well() { super(); addEventListener(KeyboardEvent.KEY_DOWN, onKeyboard); } private function onKeyboard():void { //some code is here } } } But when I press any buttons on my keyboard, the child class Well doesn't have any reaction. What's the problem?

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  • c++ compilation error

    - by clamp
    hello, i got a compile error which i do not understand. i have a h/cpp file combination that does not contain a class but just defines some utility functions. when i try to use a struct that is defined in another class i get the error: error C2027: use of undefined type so, stripped down to the problem, the h file looks like this namespace A { void foo(B::C::SStruct const & Var); } the definition of SStruct is in a class which is in another h-file, that is of course included. namespace B { Class C { struct SStruct { }; } } what am i missing here? thanks!

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  • Container of Generic Types in java

    - by Cyker
    I have a generic class Foo<T> and parameterized types Foo<String> and Foo<Integer>. Now I want to put different parameterized types into a single ArrayList. What is the correct way of doing this? Candidate 1: public class MMM { public static void main(String[] args) { Foo<String> fooString = new Foo<String>(); Foo<Integer> fooInteger = new Foo<Integer>(); ArrayList<Foo<?> > list = new ArrayList<Foo<?> >(); list.add(fooString); list.add(fooInteger); for (Foo<?> foo : list) { // Do something on foo. } } } class Foo<T> {} Candidate 2: public class MMM { public static void main(String[] args) { Foo<String> fooString = new Foo<String>(); Foo<Integer> fooInteger = new Foo<Integer>(); ArrayList<Foo> list = new ArrayList<Foo>(); list.add(fooString); list.add(fooInteger); for (Foo foo : list) { // Do something on foo. } } } class Foo<T> {} In a word, it is related to the difference between Foo<?> and the raw type Foo. Update: Grep What is the difference between the unbounded wildcard parameterized type and the raw type? on this link may be helpful.

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  • Conditional on WebClient

    - by CarryFlag
    Given: thin client (JS) model services client use services. services use model. Model consists of (for sample): Rect Circle ... Ellipse services: class CanvasProviger { public Canvas getCanvas() { return new Canvas(); } } model: class Canvas ... { private List < Figure > figures = new List < Figure >; ... } class Circle extends Figure { private int x, y, r; } class Rect extends Figure { private x, y, w, h; } client: ... var figure = MyJSRPCImpl.getCanvas().nextFigure(); if(figure == JSLocalModel.Rect) { drawRect(figure); } else if(figure == JSLocalModel.Circle) { drawCircle(figure); } ... How else can do way conditional? In rich client I used pattern Visitor. // my bad english, I know =(

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  • Finding object count where a field is unique in Django

    - by Johnd
    I have a model that is something like this: class Input(models.Model): details = models.CharField(max_length=1000) user = models.ForeignKey(User) class Case(Input): title = models.CharField(max_length=200) views = models.IntegerField() class Argument(Input): case = models.ForeignKey(Case) side = models.BooleanField() A user can submit many arguments, per case. I want to be able to say how many users have submitted side=true arguments. I mean if 1 user had 10 arguments and another user had 2 arguments (both side=true) I'd want the count to be 2, not 12.

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  • What is a truly empty std::vector in C++?

    - by RyanG
    I've got a two vectors in class A that contain other class objects B and C. I know exactly how many elements these vectors are supposed to hold at maximum. In the initializer list of class A's constructor, I initialize these vectors to their max sizes (constants). If I understand this correctly, I now have a vector of objects of class B that have been initialized using their default constructor. Right? When I wrote this code, I thought this was the only way to deal with things. However, I've since learned about std::vector.reserve() and I'd like to achieve something different. I'd like to allocate memory for these vectors to grow as large as possible because adding to them is controlled by user-input, so I don't want frequent resizings. However, I iterate through this vector many, many times per second and I only currently work on objects I've flagged as "active". To have to check a boolean member of class B/C on ever iteration is silly. I don't want these objects to even BE there for my iterators to see when I run through this list. Is reserving the max space ahead of time and using push_back to add a new object to the vector a solution to this?

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  • How to check if TypeIdenitifier(T) is an Object?

    - by John
    I'm creating a generic list class that has a member of type Array(Array of ). The problem is the class descruction,because the class is supposed to be used for types from byte to types inheriting TObject. Specifically: destructor Destroy; var elem:T; begin /*if(T is Tobject) then //Check if T inherits TObject {Compiler error!} for elem in FData do TObject(elem).Free;*/ // do not know how to do it SetLength(FItems,0); //FItems : Array of T inherited Destroy; end; How do I check if T is TObject so I can free every member if the typeidenitifier is a class,for example?

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  • Integration testing - can it be done right?

    - by Max
    I used TDD as a development style on some projects in the past two years, but I always get stuck on the same point: how can I test the integration of the various parts of my program? What I am currently doing is writing a testcase per class (this is my rule of thumb: a "unit" is a class, and each class has one or more testcases). I try to resolve dependencies by using mocks and stubs and this works really well as each class can be tested independently. After some coding, all important classes are tested. I then "wire" them together using an IoC container. And here I am stuck: How to test if the wiring was successfull and the objects interact the way I want? An example: Think of a web application. There is a controller class which takes an array of ids, uses a repository to fetch the records based on these ids and then iterates over the records and writes them as a string to an outfile. To make it simple, there would be three classes: Controller, Repository, OutfileWriter. Each of them is tested in isolation. What I would do in order to test the "real" application: making the http request (either manually or automated) with some ids from the database and then look in the filesystem if the file was written. Of course this process could be automated, but still: doesn´t that duplicate the test-logic? Is this what is called an "integration test"? In a book i recently read about Unit Testing it seemed to me that integration testing was more of an anti-pattern?

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  • How do I write a Guice Provider that doesn't explicitly create objects?

    - by ripper234
    Say I have a ClassWithManyDependencies. I want to write a Guice Provider for this class, in order to create a fresh instance of the class several times in my program (another class will depend on this Provider and use it at several points to create new instances). One way to achieve this is by having the Provider depend on all the dependencies of ClassWithManyDependencies. This is quite ugly. Is there a better way to achieve this? Note - I certainly don't want the Provider to depend on the injector. Another option I considered is having ClassWithManyDependencies and ClassWithManyDependenciesProvider extend the same base class, but it's butt ugly.

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  • Should i keep css of home page and landing pages in seperate css?

    - by metal-gear-solid
    Should i keep CSS of home page and landing pages in separate CSS file of big sites. ? If i make site with a 7-8 different templates where 1 templates of home pages 1 is for inner content pages and other template for different type of landing pages. and different style needed for same HTML elements in website , For example : for inner pages H2 has different style but for landing pages H2 is different in color, font -size, line height, top bottom margin How i should manage all this ? any tips to make good,easily manageable, scan-able CSS. Thanks in advance.

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  • Strange C++ thread function invocation

    - by Tony
    I have the following: class DThread { virtual void run()=0; _beginthreadex(NULL,0,tfunc,this,0,&m_UIThreadID); // class itself being passed as param to thread function... static unsigned int __stdcall tfunc(void* thisptr) { static_cast<DThread*>(thisptr)->run(); return 0; } //other stuff } The run function is implemented in a derived class. Why is the function that's being called in the thread being called through a cast this pointer? Is this good practise? Can't it just be called directly? The actual function needing to run is in the derived class. My question is

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