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  • PHP class extends not working why and is this how to correctly extend a class?

    - by Matthew
    Hi so I'm trying to understand how inherteince works in PHP using object oriented programming. The main class is Computer, the class that is inheriting is Mouse. I'm extedning the Computer class with the mouse class. I use __construct in each class, when I istinate the class I use the pc type first and if it has mouse after. For some reason computer returns null? why is this? class Computer { protected $type = 'null'; public function __construct($type) { $this->type = $type; } public function computertype() { $this->type = strtoupper($this->type); return $this->type; } } class Mouse extends Computer { protected $hasmouse = 'null'; public function __construct($hasmouse){ $this->hasmouse = $hasmouse; } public function computermouse() { if($this->hasmouse == 'Y') { return 'This Computer has a mouse'; } } } $pc = new Computer('PC', 'Y'); echo $pc->computertype; echo $pc->computermouse;

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  • Hiding elements based on last closed element jquery script

    - by Jared
    Hi my question is, how can I make this jquery script close all previously opened children when entering a new parent? At the moment it traverses thru all the tree structure fine, but switching from one parent to another does not close the previous children, but rather only the each individual parents elements as a user browses. Here is the jquery I'm using: <script type="text/javascript"> $(document).ready($(function(){ $('#nav>li>ul').hide(); $('.children').hide(); $('#nav>li').mousedown(function(){ // check that the menu is not currently animated if ($('#nav ul:animated').size() == 0) { // create a reference to the active element (this) // so we don't have to keep creating a jQuery object $heading = $(this); // create a reference to visible sibling elements // so we don't have to keep creating a jQuery object $expandedSiblings = $heading.siblings().find('ul:visible'); if ($expandedSiblings.size() > 0) { $expandedSiblings.slideUp(0, function(){ $heading.find('ul').slideDown(0); }); } else { $heading.find('ul').slideDown(0); } } }); $('#nav>li>ul>li').mousedown(function(){ // check that the menu is not currently animated if ($('#nav ul:animated').size() == 0) { // create a reference to the active element (this) // so we don't have to keep creating a jQuery object $heading2 = $(this); // create a reference to visible sibling elements // so we don't have to keep creating a jQuery object $expandedSiblings2 = $heading2.siblings().find('.children:visible'); if ($expandedSiblings2.size() > 0) { $expandedSiblings2.slideUp(0, function(){ $heading2.find('.children').slideDown(0); }); } else { $heading2.find('.children').slideDown(0); } } }); })); </script> and here is my html output <ul id="nav"> <li><a href="#">folder 4</a> <ul><li><a href="#">2001</a> <ul><li class="children"><a href="./directory//folder 4/2001/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder 4/2001/doc2.txt">doc2.txt</a></li> <li class="children"><a href="./directory//folder 4/2001/doc3.txt">doc3.txt</a></li> </ul> </li> <li><a href="#">2002</a> <ul><li class="children"><a href="./directory//folder 4/2002/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder 4/2002/doc2.txt">doc2.txt</a></li> <li class="children"><a href="./directory//folder 4/2002/doc3.txt">doc3.txt</a></li> <li class="children"><a href="./directory//folder 4/2002/doc4.txt">doc4.txt</a></li> </ul> </li> <li><a href="#">2003</a> <ul><li class="children"><a href="./directory//folder 4/2003/Copy of doc1.txt">Copy of doc1.txt</a></li> <li class="children"><a href="./directory//folder 4/2003/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder 4/2003/doc2.txt">doc2.txt</a></li> </ul> </li> <li><a href="#">2004</a> <ul><li class="children"><a href="./directory//folder 4/2004/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder 4/2004/doc2.txt">doc2.txt</a></li> <li class="children"><a href="./directory//folder 4/2004/doc3.txt">doc3.txt</a></li> <li class="children"><a href="./directory//folder 4/2004/doc4.txt">doc4.txt</a></li> </ul> </li> </ul> </li> <li><a href="#">folder1</a> <ul><li><a href="#">2001</a> <ul><li class="children"><a href="./directory//folder1/2001/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder1/2001/doc2.txt">doc2.txt</a></li> <li class="children"><a href="./directory//folder1/2001/doc3.txt">doc3.txt</a></li> </ul> </li> <li><a href="#">2002</a> <ul><li class="children"><a href="./directory//folder1/2002/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder1/2002/doc2.txt">doc2.txt</a></li> <li class="children"><a href="./directory//folder1/2002/doc3.txt">doc3.txt</a></li> <li class="children"><a href="./directory//folder1/2002/doc4.txt">doc4.txt</a></li> </ul> </li> <li><a href="#">2003</a> <ul><li class="children"><a href="./directory//folder1/2003/Copy of doc1.txt">Copy of doc1.txt</a></li> <li class="children"><a href="./directory//folder1/2003/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder1/2003/doc2.txt">doc2.txt</a></li> </ul> </li> <li><a href="#">2004</a> <ul><li class="children"><a href="./directory//folder1/2004/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder1/2004/doc2.txt">doc2.txt</a></li> <li class="children"><a href="./directory//folder1/2004/doc3.txt">doc3.txt</a></li> <li class="children"><a href="./directory//folder1/2004/doc4.txt">doc4.txt</a></li> </ul> </li> </ul> </li> <li><a href="#">folder2</a> <ul><li><a href="#">2001</a> <ul><li class="children"><a href="./directory//folder2/2001/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder2/2001/doc2.txt">doc2.txt</a></li> <li class="children"><a href="./directory//folder2/2001/doc3.txt">doc3.txt</a></li> </ul> </li> <li><a href="#">2002</a> <ul><li class="children"><a href="./directory//folder2/2002/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder2/2002/doc2.txt">doc2.txt</a></li> <li class="children"><a href="./directory//folder2/2002/doc3.txt">doc3.txt</a></li> <li class="children"><a href="./directory//folder2/2002/doc4.txt">doc4.txt</a></li> </ul> </li> <li><a href="#">2003</a> <ul><li class="children"><a href="./directory//folder2/2003/Copy of doc1.txt">Copy of doc1.txt</a></li> <li class="children"><a href="./directory//folder2/2003/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder2/2003/doc2.txt">doc2.txt</a></li> </ul> </li> <li><a href="#">2004</a> <ul><li class="children"><a href="./directory//folder2/2004/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder2/2004/doc2.txt">doc2.txt</a></li> <li class="children"><a href="./directory//folder2/2004/doc3.txt">doc3.txt</a></li> <li class="children"><a href="./directory//folder2/2004/doc4.txt">doc4.txt</a></li> </ul> </li> </ul> </li> <li><a href="#">folder3</a> <ul><li><a href="#">2001</a> <ul><li class="children"><a href="./directory//folder3/2001/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder3/2001/doc2.txt">doc2.txt</a></li> <li class="children"><a href="./directory//folder3/2001/doc3.txt">doc3.txt</a></li> </ul> </li> <li><a href="#">2002</a> <ul><li class="children"><a href="./directory//folder3/2002/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder3/2002/doc2.txt">doc2.txt</a></li> <li class="children"><a href="./directory//folder3/2002/doc3.txt">doc3.txt</a></li> <li class="children"><a href="./directory//folder3/2002/doc4.txt">doc4.txt</a></li> </ul> </li> <li><a href="#">2003</a> <ul><li class="children"><a href="./directory//folder3/2003/Copy of doc1.txt">Copy of doc1.txt</a></li> <li class="children"><a href="./directory//folder3/2003/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder3/2003/doc2.txt">doc2.txt</a></li> </ul> </li> <li><a href="#">2004</a> <ul><li class="children"><a href="./directory//folder3/2004/doc1.txt">doc1.txt</a></li> <li class="children"><a href="./directory//folder3/2004/doc2.txt">doc2.txt</a></li> <li class="children"><a href="./directory//folder3/2004/doc3.txt">doc3.txt</a></li> <li class="children"><a href="./directory//folder3/2004/doc4.txt">doc4.txt</a></li> </ul> </li> </ul> </li> </ul> I assume my problem is, jquery isn't closing the children between each new parent so I need to make a call, but I'm a bit lost on how to do that. I know the code is pretty messy, this project was done in a huge rush and a very tight timeframe. Appreciate your answers and any other constructive comments, cheers :)

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  • Extending the IndexController with a BaseController in Zend

    - by BillA
    I'm trying to extend my controllers with a global base controller as such: class BaseController extends Zend_Controller_Action { // common controller actions public function listAction() { // do stuff } } class IndexController extends BaseController { // index controller specific actions } class LoginController extends BaseController { // login controller specific actions } But I get this error: PHP Fatal error: Class 'BaseController' not found in /var/www/Zend/project/application/controllers/IndexController.php on line 3 Any ideas on how to get Zend to "see" this controller?

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  • Combining multiple classes gives me errors

    - by Martti Laine
    Hello I'm creating a website with structure like this: class main { } class mysql extends main { } class user extends main { } class etc extends main { } The idea is for these classes to use functions from each other. This doesn't work. How can I call a function from mysql in user? Martti Laine

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  • IS classOf[] in scala 2.8 different from 2.7?

    - by redtank
    I have an interface from java public class IJava { ... public java.lang.Class getType(); ... } It is inherited in Scala class CScala { def getType() = classOf[Foo] } it worked in scala 2.7.7. But in 2.8.0.RC1, i get type mismatch; found : java.lang.ClassFoo required: java.lang.Class How do i get java.langClass in Scala 2.8

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  • What is the best way to declare sorted association in grails domain classes ?

    - by fabien7474
    It seems that there are two different ways of declaring sorted associations in Grails : Method 1 (see here) using default sort order class Book { String title } class Author { static hasMany = [books : Book] static mapping = { books sort: "title"} } Method 2 (see here) using SortedSet class Book implements Comparable { String title int compareTo(obj) { title <=> obj.title } } class Author { SortedSet books static hasMany = [books : Book] } I am not sure which one to use and what is the difference (if any), pros and cons between using one against the other. I would appreciate any clarification. Thank you

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  • How do I write object classes effectively when dealing with table joins?

    - by Chris
    I should start by saying I'm not now, nor do I have any delusions I'll ever be a professional programmer so most of my skills have been learned from experience very much as a hobby. I learned PHP as it seemed a good simple introduction in certain areas and it allowed me to design simple web applications. When I learned about objects, classes etc the tutor's basic examnples covered the idea that as a rule of thumb each database table should have its own class. While that worked well for the photo gallery project we wrote, as it had very simple mysql queries, it's not working so well now my projects are getting more complex. If I require data from two separate tables which require a table join I've instead been ignoring the class altogether and handling it on a case by case basis, OR, even worse been combining some of the data into the class and the rest as a separate entity and doing two queries, which to me seems inefficient. As an example, when viewing content on a forum I wrote, if you view a thread, I retrieve data from the threads table, the posts table and the user table. The queries from the user and posts table are retrieved via a join and not instantiated as an object, whereas the thread data is called using my Threads class. So how do I get from my current state of affairs to something a little less 'stupid', for want of a better word. Right now I have a DB class that deals with connection and escaping values etc, a parent db query class that deals with the common queries and methods, and all of the other classes (Thread, Upload, Session, Photo and ones thats aren't used Post, User etc ) are children of that. Do I make a big posts class that has the relevant extra attributes that I retrieve from the users (and potentially threads) table? Do I have separate classes that populate each of their relevant attributes with a single query? If so how do I do that? Because of the way my classes are written, based on what I was taught, my db update row method, or insert method both just take the attributes as an array and update all of that, if I have extra attributes from other db tables in each class then how do I rewrite those methods as obbiously updating automatically like that would result in errors? In short I think my understanding is limited right now and I'd like some pointers when it comes to the fundamentals of how to write more complex classes.

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  • Using enums in Java across multiple classes

    - by Richard Mar.
    I have the following class: public class Card { public enum Suit { SPACES, HEARTS, DIAMONDS, CLUBS }; public Card(Suit nsuit, int nrank) { suit = nsuit; rank = nrank; } private Suit suit; private int rank; } I want to instantiate it in another class, but that class doesn't understand the Suit enum. Where should I put the enum to make it publicly visible?

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  • Java: Using Dynamically loaded classes

    - by Snigger
    Hi I'm new to java. I'm trying to use some dynamically loaded classes in my application. The application doesn't know classes , Just it try to load a class by name that its name came from input. It doesn't know class (So I can't use casting) but just needs to call some methods of that class (every class should have that methods). I thought about interfaces but I don't know how. How can I call those methods? Thanks

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  • Access specifier's and classes and objects?

    - by TimothyTech
    Alright, im trying to understand this, so a class is simply creating a template for an object. class Bow { int arrows; }; and an object is simply creating a specific item using the class template. Bow::Bow(arrows) { arrows = 20; } also another question, public specifiers are used to make data members avaible in objects and private specifiers are used to make data memebers only avaialble inside the class?

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  • How to reference or connect a variable to another class without stack overflow?

    - by SystemNetworks
    I really need to re-arrange all my functions. I created a class. All my var, booleans, int, doubles and other things. I created every new variable so they can reference it and so they don't have an error. If your asking why I never just reference my main class vars to my sub-class becuase it will give me stack overflow! When in my main class i link my sub-class. subClass s = new subClass(); Then I reference my fake variable to my real variable for example: This is my sub-class variable(I call it fake) public int x = 0; In my main class, I put it like this: s.x = x; The problem is, it does not work! Maybe this is not the right place but I cant ask any questions on stack overflow because they banned me. If I connect my main class and connect my sub-class it will give me stack overflow. How do I stop it?

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  • How to generate a Program template by generating an abstract class

    - by Byron-Lim Timothy Steffan
    i have the following problem. The 1st step is to implement a program, which follows a specific protocol on startup. Therefore, functions as onInit, onConfigRequest, etc. will be necessary. (These are triggered e.g. by incoming message on a TCP Port) My goal is to generate a class for example abstract one, which has abstract functions as onInit(), etc. A programmer should just inherit from this base class and should merely override these abstract functions of the base class. The rest as of the protocol e.g. should be simply handled in the background (using the code of the base class) and should not need to appear in the programmers code. What is the correct design strategy for such tasks? and how do I deal with, that the static main method is not inheritable? What are the key-tags for this problem? (I have problem searching for a solution since I lack clear statements on this problem) Goal is to create some sort of library/class, which - included in ones code - results in executables following the protocol. EDIT (new explanation): Okay let me try to explain more detailled: In this case programs should be clients within a client server architecture. We have a client server connection via TCP/IP. Each program needs to follow a specific protocol upon program start: As soon as my program starts and gets connected to the server it will receive an Init Message (TcpClient), when this happens it should trigger the function onInit(). (Should this be implemented by an event system?) After onInit() a acknowledgement message should be sent to the server. Afterwards there are some other steps as e.g. a config message from the server which triggers an onConfig and so on. Let's concentrate on the onInit function. The idea is, that onInit (and onConfig and so on) should be the only functions the programmer should edit while the overall protocol messaging is hidden for him. Therefore, I thought using an abstract class with the abstract methods onInit(), onConfig() in it should be the right thing. The static Main class I would like to hide, since within it e.g. there will be some part which connects to the tcp port, which reacts on the Init Message and which will call the onInit function. 2 problems here: 1. the static main class cant be inherited, isn it? 2. I cannot call abstract functions from the main class in the abstract master class. Let me give an Pseudo-example for my ideas: public abstract class MasterClass { static void Main(string[] args){ 1. open TCP connection 2. waiting for Init Message from server 3. onInit(); 4. Send Acknowledgement, that Init Routine has ended successfully 5. waiting for Config message from server 6..... } public abstract void onInit(); public abstract void onConfig(); } I hope you get the idea now! The programmer should afterwards inherit from this masterclass and merely need to edit the functions onInit and so on. Is this way possible? How? What else do you recommend for solving this? EDIT: The strategy ideo provided below is a good one! Check out my comment on that.

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  • Injection of an EJB into a web java class under JBoss 7.1.1

    - by Dobbo
    I am trying to build a website using JBoss 7.1.1 and RESTeasy. I have managed to constructed and deploy and EAR with a both a WAR and an EJB-JAR contained within: voyager-app.ear META-INF/MANIFEST.MF META-INF/application.xml META-INF/jboss-app.xml lib/voyager-lib.jar voyager-adm.war voyager-ejb.jar voyager-web.war So far things are very simple. voyager-adm.war & voyager-lib.jar are empty (just the manifest file) but I know that I'm going to have code for them shortly. There is just one Stateful EJB - HarbourMasterBean (with just a local interface) and a few Database Entity Beans in the EJB jar file: voyager-ejb.jar META-INF/MANIFEST.MF META-INF/persistence.xml com/nutrastat/voyager/db/HarbourMasterBean.class com/nutrastat/voyager/db/HarbourMasterLocal.class com/nutrastat/voyager/db/PortEntity.class com/nutrastat/voyager/db/ShipEntity.class As far as I can tell the EJBs deploy correctly because the database units are created and the log shows that the publication of some HarbourMaster references: java:global/voyager-app/voyager-ejb/harbour-master!com.nutrastat.voyager.db.HarbourMasterLocal java:app/voyager-ejb/harbour-master!com.nutrastat.voyager.db.HarbourMasterLocal java:module/harbour-master!com.nutrastat.voyager.db.HarbourMasterLocal java:global/voyager-app/voyager-ejb/harbour-master java:app/voyager-ejb/harbour-master java:module/harbour-master The problem lies in getting the HarbourMaster EJB injected into my web bean. The reference to it is alway NULL no matter what I try. voyager-web.war META-INF/MANIFEST.MF WEB-INF/web.xml WEB-INF/classes/com/nutrastat/voyager/web/ WEB-INF/classes/com/nutrastat/voyager/web/Ships.class WEB-INF/classes/com/nutrastat/voyager/web/VoyagerApplication.class Ships.java: @Path("fleet") public class Ships { protected transient final Logger log; @EJB private HarbourMasterLocal harbourMaster; public Ships() { log = LoggerFactory.getLogger(getClass()); } @GET @Path("ships") @Produces({"text/plain"}) public String listShips() { if (log.isDebugEnabled()) log.debug("Harbour master value: " + harbourMaster); return "Harbour Master: " + harbourMaster; } } &lt;web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0" &gt; <display-name>Voyager Web Application</display-name> <listener> <listener-class> org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap </listener-class> </listener> <servlet> <servlet-name>Resteasy</servlet-name> <servlet-class> org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher </servlet-class> <init-param> <param-name> javax.ws.rs.Application </param-name> <param-value> com.nutrastat.voyager.web.VoyagerApplication </param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>Resteasy</servlet-name> <url-pattern>/*</url-pattern> </servlet-mapping> &lt;/web-app&gt; I have been searching the web for an answer and read a number of places, both on StackOverflow and elsewhere that suggests is can be done, and that the problems lies with configuration. But they post only snippets and I'm never sure if I'm doing things correctly. Many thanks for any help you can provide. Dobbo

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  • Doxygen for C++ template class member specialization

    - by Ziv
    When I write class templates, and need to fully-specialize members of those classes, Doxygen doesn't recognize the specialization - it documents only the generic definition, or (if there are only specializations) the last definition. Here's a simple example: ===MyClass.hpp=== #ifndef MYCLASS_HPP #define MYCLASS_HPP template<class T> class MyClass{ public: static void foo(); static const int INT_CONST; static const T TTYPE_CONST; }; /* generic definitions */ template<class T> void MyClass<T>::foo(){ printf("Generic foo\n"); } template<class T> const int MyClass<T>::INT_CONST = 5; /* specialization declarations */ template<> void MyClass<double>::foo(); template<> const int MyClass<double>::INT_CONST; template<> const double MyClass<double>::TTYPE_CONST; template<> const char MyClass<char>::TTYPE_CONST; #endif === MyClass.cpp === #include "MyClass.hpp" /* specialization definitions */ template<> void MyClass<double>::foo(){ printf("Specialized double foo\n"); } template<> const int MyClass<double>::INT_CONST = 10; template<> const double MyClass<double>::TTYPE_CONST = 3.141; template<> const char MyClass<char>::TTYPE_CONST = 'a'; So in this case, foo() will be documented as printing "Generic foo," INT_CONST will be documented as set to 5, with no mention of the specializations, and TTYPE_CONST will be documented as set to 'a', with no mention of 3.141 and no indication that 'a' is a specialized case. I need to be able to document the specializations - either within the documentation for MyClass<T>, or on new pages for MyClass<double>, MyClass<char>. How do I do this? Can Doxygen even handle this? Am I possibly doing something wrong in the declarations/code structure that's keeping Doxygen from understanding what I want? I should note two related cases: A) For templated functions, specialization works fine, e.g.: /* functions that are global/in a namespace */ template<class T> void foo(){ printf("Generic foo\n"); } template<> void foo<double>(){ printf("Specialized double foo\n"); } This will document both foo() and foo(). B) If I redeclare the entire template, i.e. template<> class MyClass<double>{...};, then MyClass<double> will get its own documentation page, as a seperate class. But this means actually declaring an entirely new class - there is no relation between MyClass<T> and MyClass<double> if MyClass<double> itself is declared. So I'd have to redeclare the class and all its members, and repeat all the definitions of class members, specialized for MyClass<double>, all to make it appear as though they're using the same template. Very awkward, feels like a kludge solution. Suggestions? Thanks much :) --Ziv

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  • A Communication System for XAML Applications

    - by psheriff
    In any application, you want to keep the coupling between any two or more objects as loose as possible. Coupling happens when one class contains a property that is used in another class, or uses another class in one of its methods. If you have this situation, then this is called strong or tight coupling. One popular design pattern to help with keeping objects loosely coupled is called the Mediator design pattern. The basics of this pattern are very simple; avoid one object directly talking to another object, and instead use another class to mediate between the two. As with most of my blog posts, the purpose is to introduce you to a simple approach to using a message broker, not all of the fine details. IPDSAMessageBroker Interface As with most implementations of a design pattern, you typically start with an interface or an abstract base class. In this particular instance, an Interface will work just fine. The interface for our Message Broker class just contains a single method “SendMessage” and one event “MessageReceived”. public delegate void MessageReceivedEventHandler( object sender, PDSAMessageBrokerEventArgs e); public interface IPDSAMessageBroker{  void SendMessage(PDSAMessageBrokerMessage msg);   event MessageReceivedEventHandler MessageReceived;} PDSAMessageBrokerMessage Class As you can see in the interface, the SendMessage method requires a type of PDSAMessageBrokerMessage to be passed to it. This class simply has a MessageName which is a ‘string’ type and a MessageBody property which is of the type ‘object’ so you can pass whatever you want in the body. You might pass a string in the body, or a complete Customer object. The MessageName property will help the receiver of the message know what is in the MessageBody property. public class PDSAMessageBrokerMessage{  public PDSAMessageBrokerMessage()  {  }   public PDSAMessageBrokerMessage(string name, object body)  {    MessageName = name;    MessageBody = body;  }   public string MessageName { get; set; }   public object MessageBody { get; set; }} PDSAMessageBrokerEventArgs Class As our message broker class will be raising an event that others can respond to, it is a good idea to create your own event argument class. This class will inherit from the System.EventArgs class and add a couple of additional properties. The properties are the MessageName and Message. The MessageName property is simply a string value. The Message property is a type of a PDSAMessageBrokerMessage class. public class PDSAMessageBrokerEventArgs : EventArgs{  public PDSAMessageBrokerEventArgs()  {  }   public PDSAMessageBrokerEventArgs(string name,     PDSAMessageBrokerMessage msg)  {    MessageName = name;    Message = msg;  }   public string MessageName { get; set; }   public PDSAMessageBrokerMessage Message { get; set; }} PDSAMessageBroker Class Now that you have an interface class and a class to pass a message through an event, it is time to create your actual PDSAMessageBroker class. This class implements the SendMessage method and will also create the event handler for the delegate created in your Interface. public class PDSAMessageBroker : IPDSAMessageBroker{  public void SendMessage(PDSAMessageBrokerMessage msg)  {    PDSAMessageBrokerEventArgs args;     args = new PDSAMessageBrokerEventArgs(      msg.MessageName, msg);     RaiseMessageReceived(args);  }   public event MessageReceivedEventHandler MessageReceived;   protected void RaiseMessageReceived(    PDSAMessageBrokerEventArgs e)  {    if (null != MessageReceived)      MessageReceived(this, e);  }} The SendMessage method will take a PDSAMessageBrokerMessage object as an argument. It then creates an instance of a PDSAMessageBrokerEventArgs class, passing to the constructor two items: the MessageName from the PDSAMessageBrokerMessage object and also the object itself. It may seem a little redundant to pass in the message name when that same message name is part of the message, but it does make consuming the event and checking for the message name a little cleaner – as you will see in the next section. Create a Global Message Broker In your WPF application, create an instance of this message broker class in the App class located in the App.xaml file. Create a public property in the App class and create a new instance of that class in the OnStartUp event procedure as shown in the following code: public partial class App : Application{  public PDSAMessageBroker MessageBroker { get; set; }   protected override void OnStartup(StartupEventArgs e)  {    base.OnStartup(e);     MessageBroker = new PDSAMessageBroker();  }} Sending and Receiving Messages Let’s assume you have a user control that you load into a control on your main window and you want to send a message from that user control to the main window. You might have the main window display a message box, or put a string into a status bar as shown in Figure 1. Figure 1: The main window can receive and send messages The first thing you do in the main window is to hook up an event procedure to the MessageReceived event of the global message broker. This is done in the constructor of the main window: public MainWindow(){  InitializeComponent();   (Application.Current as App).MessageBroker.     MessageReceived += new MessageReceivedEventHandler(       MessageBroker_MessageReceived);} One piece of code you might not be familiar with is accessing a property defined in the App class of your XAML application. Within the App.Xaml file is a class named App that inherits from the Application object. You access the global instance of this App class by using Application.Current. You cast Application.Current to ‘App’ prior to accessing any of the public properties or methods you defined in the App class. Thus, the code (Application.Current as App).MessageBroker, allows you to get at the MessageBroker property defined in the App class. In the MessageReceived event procedure in the main window (shown below) you can now check to see if the MessageName property of the PDSAMessageBrokerEventArgs is equal to “StatusBar” and if it is, then display the message body into the status bar text block control. void MessageBroker_MessageReceived(object sender,   PDSAMessageBrokerEventArgs e){  switch (e.MessageName)  {    case "StatusBar":      tbStatus.Text = e.Message.MessageBody.ToString();      break;  }} In the Page 1 user control’s Loaded event procedure you will send the message “StatusBar” through the global message broker to any listener using the following code: private void UserControl_Loaded(object sender,  RoutedEventArgs e){  // Send Status Message  (Application.Current as App).MessageBroker.    SendMessage(new PDSAMessageBrokerMessage("StatusBar",      "This is Page 1"));} Since the main window is listening for the message ‘StatusBar’, it will display the value “This is Page 1” in the status bar at the bottom of the main window. Sending a Message to a User Control The previous example sent a message from the user control to the main window. You can also send messages from the main window to any listener as well. Remember that the global message broker is really just a broadcaster to anyone who has hooked into the MessageReceived event. In the constructor of the user control named ucPage1 you can hook into the global message broker’s MessageReceived event. You can then listen for any messages that are sent to this control by using a similar switch-case structure like that in the main window. public ucPage1(){  InitializeComponent();   // Hook to the Global Message Broker  (Application.Current as App).MessageBroker.    MessageReceived += new MessageReceivedEventHandler(      MessageBroker_MessageReceived);} void MessageBroker_MessageReceived(object sender,  PDSAMessageBrokerEventArgs e){  // Look for messages intended for Page 1  switch (e.MessageName)  {    case "ForPage1":      MessageBox.Show(e.Message.MessageBody.ToString());      break;  }} Once the ucPage1 user control has been loaded into the main window you can then send a message using the following code: private void btnSendToPage1_Click(object sender,  RoutedEventArgs e){  PDSAMessageBrokerMessage arg =     new PDSAMessageBrokerMessage();   arg.MessageName = "ForPage1";  arg.MessageBody = "Message For Page 1";   // Send a message to Page 1  (Application.Current as App).MessageBroker.SendMessage(arg);} Since the MessageName matches what is in the ucPage1 MessageReceived event procedure, ucPage1 can do anything in response to that event. It is important to note that when the message gets sent it is sent to all MessageReceived event procedures, not just the one that is looking for a message called “ForPage1”. If the user control ucPage1 is not loaded and this message is broadcast, but no other code is listening for it, then it is simply ignored. Remove Event Handler In each class where you add an event handler to the MessageReceived event you need to make sure to remove those event handlers when you are done. Failure to do so can cause a strong reference to the class and thus not allow that object to be garbage collected. In each of your user control’s make sure in the Unloaded event to remove the event handler. private void UserControl_Unloaded(object sender, RoutedEventArgs e){  if (_MessageBroker != null)    _MessageBroker.MessageReceived -=         _MessageBroker_MessageReceived;} Problems with Message Brokering As with most “global” classes or classes that hook up events to other classes, garbage collection is something you need to consider. Just the simple act of hooking up an event procedure to a global event handler creates a reference between your user control and the message broker in the App class. This means that even when your user control is removed from your UI, the class will still be in memory because of the reference to the message broker. This can cause messages to still being handled even though the UI is not being displayed. It is up to you to make sure you remove those event handlers as discussed in the previous section. If you don’t, then the garbage collector cannot release those objects. Instead of using events to send messages from one object to another you might consider registering your objects with a central message broker. This message broker now becomes a collection class into which you pass an object and what messages that object wishes to receive. You do end up with the same problem however. You have to un-register your objects; otherwise they still stay in memory. To alleviate this problem you can look into using the WeakReference class as a method to store your objects so they can be garbage collected if need be. Discussing Weak References is beyond the scope of this post, but you can look this up on the web. Summary In this blog post you learned how to create a simple message broker system that will allow you to send messages from one object to another without having to reference objects directly. This does reduce the coupling between objects in your application. You do need to remember to get rid of any event handlers prior to your objects going out of scope or you run the risk of having memory leaks and events being called even though you can no longer access the object that is responding to that event. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “A Communication System for XAML Applications” from the drop down list.

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  • Explicit method tables in C# instead of OO - good? bad?

    - by FunctorSalad
    Hi! I hope the title doesn't sound too subjective; I absolutely do not mean to start a debate on OO in general. I'd merely like to discuss the basic pros and cons for different ways of solving the following sort of problem. Let's take this minimal example: you want to express an abstract datatype T with functions that may take T as input, output, or both: f1 : Takes a T, returns an int f2 : Takes a string, returns a T f3 : Takes a T and a double, returns another T I'd like to avoid downcasting and any other dynamic typing. I'd also like to avoid mutation whenever possible. 1: Abstract-class-based attempt abstract class T { abstract int f1(); // We can't have abstract constructors, so the best we can do, as I see it, is: abstract void f2(string s); // The convention would be that you'd replace calls to the original f2 by invocation of the nullary constructor of the implementing type, followed by invocation of f2. f2 would need to have side-effects to be of any use. // f3 is a problem too: abstract T f3(double d); // This doesn't express that the return value is of the *same* type as the object whose method is invoked; it just expresses that the return value is *some* T. } 2: Parametric polymorphism and an auxilliary class (all implementing classes of TImpl will be singleton classes): abstract class TImpl<T> { abstract int f1(T t); abstract T f2(string s); abstract T f3(T t, double d); } We no longer express that some concrete type actually implements our original spec -- an implementation is simply a type Foo for which we happen to have an instance of TImpl. This doesn't seem to be a problem: If you want a function that works on arbitrary implementations, you just do something like: // Say we want to return a Bar given an arbitrary implementation of our abstract type Bar bar<T>(TImpl<T> ti, T t); At this point, one might as well skip inheritance and singletons altogether and use a 3 First-class function table class /* or struct, even */ TDictT<T> { readonly Func<T,int> f1; readonly Func<string,T> f2; readonly Func<T,double,T> f3; TDict( ... ) { this.f1 = f1; this.f2 = f2; this.f3 = f3; } } Bar bar<T>(TDict<T> td; T t); Though I don't see much practical difference between #2 and #3. Example Implementation class MyT { /* raw data structure goes here; this class needn't have any methods */ } // It doesn't matter where we put the following; could be a static method of MyT, or some static class collecting dictionaries static readonly TDict<MyT> MyTDict = new TDict<MyT>( (t) => /* body of f1 goes here */ , // f2 (s) => /* body of f2 goes here */, // f3 (t,d) => /* body of f3 goes here */ ); Thoughts? #3 is unidiomatic, but it seems rather safe and clean. One question is whether there are any performance concerns with it. I don't usually need dynamic dispatch, and I'd prefer if these function bodies get statically inlined in places where the concrete implementing type is known statically. Is #2 better in that regard?

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  • Validation does not work when I use Validator.TryValidateObject.

    - by ashraf
    DataAnnotations does not work with buddy class. The following code always validate true. Why ? var isValid = Validator.TryValidateObject(new Customer(), Context, results, true); and here is the buddy class. public partial class Customer { public string Name { get; set; } public int Age { get; set; } } [MetadataType(typeof(CustomerMetaData))] public partial class Customer { public class CustomerMetaData { [Required(ErrorMessage = "You must supply a name for a customer.")] public string Name { get; set; } } } Here is another thread with same question., but no answer. link text

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  • World Class Training For Them, an Amazon Gift Certificate For You

    - by Adam Machanic
    We have just two weeks to go before Paul Randal and Kimberly Tripp touch down in the Boston area to deliver their famous SQL Server Immersions course . This is going to be a truly fantastic SQL Server learning experience and we're hoping a few more people will join in the fun. This is where you come in: we have a few vacant seats remaining and we need your help spreading the word. Simply tell your friends and colleagues about the course and e-mail me (adam [at] bostonsqltraining [dot] com) the names...(read more)

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  • Oracle pl\sql question for my homework in oracle 11G class [migrated]

    - by Bjolds
    I am new to oracle 11G programming and i have run into a tough situation with pl\sql funtions and automation. I ame unsure how to create the function for the automation of Registration system for a College registration system. Here is what i want to do. I want to automate the registrations system so that it automaticly registers students. Then I want a procedure to automate the grading system. I have included the code that i am written to make most of this assignment work which it does but unsure how to incorporate Pl\SQL automated fuctions for the registrations system, and the grading system. So Any help or Ideas I would greatly appreciate please. set Linesize 250 set pagesize 150 drop table student; drop table faculty; drop table Course; drop table Section; drop table location; DROP TABLE courseInstructor; DROP TABLE Registration; DROP TABLE grade; create table student( studentid number(10), Lastname varchar2(20), Firstname Varchar2(20), MI Char(1), address Varchar2(20), city Varchar2(20), state Char(2), zip Varchar2(10), HomePhone Varchar2(10), Workphone Varchar2(10), DOB Date, Pin VARCHAR2(10), Status Char(1)); ALTER TABLE Student Add Constraint Student_StudentID_pk Primary Key (studentID); Insert into student values (1,'xxxxxxxx','xxxxxxxxxx','x','xxxxxxxxxxxxxxx','Columbus','oh','44159','xxx-xxx-xxxx','xxx-xxx-xxxx','06-Mar-1957','1211','c'); create table faculty( FacultyID Number(10), FirstName Varchar2(20), Lastname Varchar2(20), MI Char(1), workphone Varchar2(10), CellPhone Varchar2(10), Rank Varchar2(20), Experience Varchar2(10), Status Char(1)); ALTER TABLE Faculty ADD Constraint Faculty_facultyId_PK PRIMARY KEY (FacultyID); insert into faculty values (1,'xxx','xxxxxxxxxxxx',xxx-xxx-xxxx','xxx-xxx-xxxx','professor','20','f'); create table Course( CourseId number(10), CourseNumber Varchar2(20), CourseName Varchar(20), Description Varchar(20), CreditHours Number(4), Status Char(1)); ALTER TABLE Course ADD Constraint Course_CourseID_pk PRIMARY KEY(CourseID); insert into course values (1,'cit 100','computer concepts','introduction to PCs','3.0','o'); insert into course values (2,'cit 101','Database Program','Database Programming','4.0','o'); insert into course values (3,'Math 101','Algebra I','Algebra I Concepts','5.0','o'); insert into course values (4,'cit 102a','Pc applications','Aplications 1','3.0','o'); insert into course values (5,'cit 102b','pc applications','applications 2','3.0','o'); insert into course values (6,'cit 102c','pc applications','applications 3','3.0','o'); insert into course values (7,'cit 103','computer concepts','introduction systems','3.0','c'); insert into course values (8,'cit 110','Unified language','UML design','3.0','o'); insert into course values (9,'cit 165','cobol','cobol programming','3.0','o'); insert into course values (10,'cit 167','C++ Programming 1','c++ programming','4.0','o'); insert into course values (11,'cit 231','Expert Excel','spreadsheet apps','3.0','o'); insert into course values (12,'cit 233','expert Access','database devel.','3.0','o'); insert into course values (13,'cit 169','Java Programming I','Java Programming I','3.0','o'); insert into course values (14,'cit 263','Visual Basic','Visual Basic Prog','3.0','o'); insert into course values (15,'cit 275','system analysis 2','System Analysis 2','3.0','o'); create table Section( SectionID Number(10), CourseId Number(10), SectionNumber VarChar2(10), Days Varchar2(10), StartTime Date, EndTime Date, LocationID Number(10), SeatAvailable Number(3), Status Char(1)); ALTER TABLE Section ADD Constraint Section_SectionID_PK PRIMARY KEY(SectionID); insert into section values (1,1,'18977','r','21-Sep-2011','10-Dec-2011','1','89','o'); create table Location( LocationId Number(10), Building Varchar2(20), Room Varchar2(5), Capacity Number(5), Satus Char(1)); ALTER TABLE Location ADD Constraint Location_LocationID_pk PRIMARY KEY (LocationID); insert into Location values (1,'Clevleand Hall','cl209','35','o'); insert into Location values (2,'Toledo Circle','tc211','45','o'); insert into Location values (3,'Akron Square','as154','65','o'); insert into Location values (4,'Cincy Hall','ch100','45','o'); insert into Location values (5,'Springfield Dome','SD','35','o'); insert into Location values (6,'Dayton Dorm','dd225','25','o'); insert into Location values (7,'Columbus Hall','CB354','15','o'); insert into Location values (8,'Cleveland Hall','cl204','85','o'); insert into Location values (9,'Toledo Circle','tc103','75','o'); insert into Location values (10,'Akron Square','as201','46','o'); insert into Location values (11,'Cincy Hall','ch301','73','o'); insert into Location values (12,'Dayton Dorm','dd245','57','o'); insert into Location values (13,'Springfield Dome','SD','65','o'); insert into Location values (14,'Cleveland Hall','cl241','10','o'); insert into Location values (15,'Toledo Circle','tc211','27','o'); insert into Location values (16,'Akron Square','as311','28','o'); insert into Location values (17,'Cincy Hall','ch415','73','o'); insert into Location values (18,'Toledo Circle','tc111','67','o'); insert into Location values (19,'Springfield Dome','SD','69','o'); insert into Location values (20,'Dayton Dorm','dd211','45','o'); Alter Table Student Add Constraint student_Zip_CK Check(Rtrim (Zip,'1234567890-') is null); Alter Table Student ADD Constraint Student_Status_CK Check(Status In('c','t')); Alter Table Student ADD Constraint Student_MI_CK2 Check(RTRIM(MI,'abcdefghijklmnopqrstuvwxyz')is Null); Alter Table Student Modify pin not Null; Alter table Faculty Add Constraint Faculty_Status_CK Check(Status In('f','a','i')); Alter table Faculty ADD Constraint Faculty_Rank_CK Check(Rank In ('professor','doctor','instructor','assistant','tenure')); Alter table Faculty ADD Constraint Faculty_MI_CK2 Check(RTRIM(MI,'abcdefghijklmnopqrstuvwxyz')is Null); Update Section Set Starttime = To_date('09-21-2011 6:00 PM', 'mm-dd-yyyy hh:mi pm'); Update Section Set Endtime = To_date('12-10-2011 9:50 PM', 'mm-dd-yyyy hh:mi pm'); alter table Section Add Constraint StartTime_Status_CK Check (starttime < Endtime); Alter Table Section Add Constraint Section_StartTime_ck check (StartTime < EndTime); Alter Table Section ADD Constraint Section_CourseId_FK FOREIGN KEY (CourseID) References Course(CourseId); Alter Table Section ADD Constraint Section_LocationID_FK FOREIGN KEY (LocationID) References Location (LocationId); Alter Table Section ADD Constraint Section_Days_CK Check(RTRIM(Days,'mtwrfsu')IS Null); update section set seatavailable = '99'; Alter Table Section ADD Constraint Section_SeatsAvailable_CK Check (SeatAvailable < 100); Alter Table Course Add Constraint Course_CreditHours_ck check(CreditHours < = 6.0); update location set capacity = '99'; Alter Table Location Add Constraint Location_Capacity_CK Check(Capacity < 100); Create Table Registration ( StudentID Number(10), SectionID Number(10), Constraint Registration_pk Primary key (studentId, Sectionid)); Insert into registration values (1, 2); Insert into Registration values (2, 3); Insert into registration values (3, 4); Insert into registration values (4, 5); Insert into registration values (5, 6); Insert into registration values (6, 7); Insert into registration values (7, 8); Insert into registration values (8, 9); insert into registration values (9, 10); insert into registration values (10, 11); insert into registration values (9, 12); insert into registration values (8, 13); insert into registration values (7, 14); insert into registration values (6, 15); insert into registration values (5, 17); insert into registration values (4, 18); insert into registration values (3, 19); insert into registration values (2, 20); insert into registration values (1, 21); insert into registration values (2, 22); insert into registration values (3, 23); insert into registration values (4, 24); insert into registration values (5, 25); Insert into registration values (6, 24); insert into registration values (7, 23); insert into registration values (8, 22); insert into registration values (9, 21); insert into registration values (10, 20); insert into registration values (9, 19); insert into registration values (8, 17); Create Table courseInstructor( FacultyID Number(10), SectionID Number(10), Constraint CourseInstructor_pk Primary key (FacultyId, SectionID)); insert into courseInstructor values (1, 1); insert into courseInstructor values (2, 2); insert into courseInstructor values (3, 3); insert into courseInstructor values (4, 4); insert into courseInstructor values (5, 5); insert into courseInstructor values (5, 6); insert into courseInstructor values (4, 7); insert into courseInstructor values (3, 8); insert into courseInstructor values (2, 9); insert into courseInstructor values (1, 10); insert into courseInstructor values (5, 11); insert into courseInstructor values (4, 12); insert into courseInstructor values (3, 13); insert into courseInstructor values (2, 14); insert into courseInstructor values (1, 15); Create table grade( StudentID Number(10), SectionID Number(10), Grade Varchar2(1), Constraint grade_pk Primary key (StudentID, SectionID)); CREATE OR REPLACE TRIGGER TR_CreateGrade AFTER INSERT ON Registration FOR EACH ROW BEGIN INSERT INTO grade (SectionID,StudentID,Grade) VALUES(:New.SectionID,:New.StudentID,NULL); END TR_createGrade; / CREATE OR REPLACE FORCE VIEW V_reg_student_course AS SELECT Registration.StudentID, student.LastName, student.FirstName, course.CourseName, Registration.SectionID, course.CreditHours, section.Days, TO_CHAR(StartTime, 'MM/DD/YYYY') AS StartDate, TO_CHAR(StartTime, 'HH:MI PM') AS StartTime, TO_CHAR(EndTime, 'MM/DD/YYYY') AS EndDate, TO_CHAR(EndTime, 'HH:MI PM') AS EndTime, location.Building, location.Room FROM registration, student, section, course, location WHERE registration.StudentID = student.StudentID AND registration.SectionID = section.SectionID AND section.LocationID = location.LocationID AND section.CourseID = course.CourseID; CREATE OR REPLACE FORCE VIEW V_teacher_to_course AS SELECT courseInstructor.FacultyID, faculty.FirstName, faculty.LastName, courseInstructor.SectionID, section.Days, TO_CHAR(StartTime, 'MM/DD/YYYY') AS StartDate, TO_CHAR(StartTime, 'HH:MI PM') AS StartTime, TO_CHAR(EndTime, 'MM/DD/YYYY') AS EndDate, TO_CHAR(EndTime, 'HH:MI PM') AS EndTime, location.Building, location.Room FROM courseInstructor, faculty, section, course, location WHERE courseInstructor.FacultyID = faculty.FacultyID AND courseInstructor.SectionID = section.SectionID AND section.LocationID = location.LocationID AND section.CourseID = course.CourseID; SELECT * FROM V_reg_student_course; SELECT * FROM V_teacher_to_course;

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  • SQL Server Master class winner

    - by Testas
     The winner of the SQL Server MasterClass competition courtesy of the UK SQL Server User Group and SQL Server Magazine!    Steve Hindmarsh     There is still time to register for the seminar yourself at:  www.regonline.co.uk/kimtrippsql     More information about the seminar     Where: Radisson Edwardian Heathrow Hotel, London  When: Thursday 17th June 2010  This one-day MasterClass will focus on many of the top issues companies face when implementing and maintaining a SQL Server-based solution. In the case where a company has no dedicated DBA, IT managers sometimes struggle to keep the data tier performing well and the data available. This can be especially troublesome when the development team is unfamiliar with the affect application design choices have on database performance. The Microsoft SQL Server MasterClass 2010 is presented by Paul S. Randal and Kimberly L. Tripp, two of the most experienced and respected people in the SQL Server world. Together they have over 30 years combined experience working with SQL Server in the field, and on the SQL Server product team itself. This is a unique opportunity to hear them present at a UK event which will: Debunk many of the ingrained misconceptions around SQL Server's behaviour    Show you disaster recovery techniques critical to preserving your company's life-blood - the data    Explain how a common application design pattern can wreak havoc in the database Walk through the top-10 points to follow around operations and maintenance for a well-performing and available data tier! Please Note: Agenda may be subject to change  Sessions Abstracts  KEYNOTE: Bridging the Gap Between Development and Production    Applications are commonly developed with little regard for how design choices will affect performance in production. This is often because developers don't realize the implications of their design on how SQL Server will be able to handle a high workload (e.g. blocking, fragmentation) and/or because there's no full-time trained DBA that can recognize production problems and help educate developers. The keynote sets the stage for the rest of the day. Discussing some of the issues that can arise, explaining how some can be avoided and highlighting some of the features in SQL 2008 that can help developers and DBAs make better use of SQL Server, and troubleshoot when things go wrong.   SESSION ONE: SQL Server Mythbusters  It's amazing how many myths and misconceptions have sprung up and persisted over the years about SQL Server - after many years helping people out on forums, newsgroups, and customer engagements, Paul and Kimberly have heard it all. Are there really non-logged operations? Can interrupting shrinks or rebuilds cause corruption? Can you override the server's MAXDOP setting? Will the server always do a table-scan to get a row count? Many myths lead to poor design choices and inappropriate maintenance practices so these are just a few of many, many myths that Paul and Kimberly will debunk in this fast-paced session on how SQL Server operates and should be managed and maintained.   SESSION TWO: Database Recovery Techniques Demo-Fest  Even if a company has a disaster recovery strategy in place, they need to practice to make sure that the plan will work when a disaster does strike. In this fast-paced demo session Paul and Kimberly will repeatedly do nasty things to databases and then show how they are recovered - demonstrating many techniques that can be used in production for disaster recovery. Not for the faint-hearted!   SESSION THREE: GUIDs: Use, Abuse, and How To Move Forward   Since the addition of the GUID (Microsoft’s implementation of the UUID), my life as a consultant and "tuner" has been busy. I’ve seen databases designed with GUID keys run fairly well with small workloads but completely fall over and fail because they just cannot scale. And, I know why GUIDs are chosen - it simplifies the handling of parent/child rows in your batches so you can reduce round-trips or avoid dealing with identity values. And, yes, sometimes it's even for distributed databases and/or security that GUIDs are chosen. I'm not entirely against ever using a GUID but overusing and abusing GUIDs just has to be stopped! Please, please, please let me give you better solutions and explanations on how to deal with your parent/child rows, round-trips and clustering keys!   SESSION 4: Essential Database Maintenance  In this session, Paul and Kimberly will run you through their top-ten database maintenance recommendations, with a lot of tips and tricks along the way. These are distilled from almost 30 years combined experience working with SQL Server customers and are geared towards making your databases more performant, more available, and more easily managed (to save you time!). Everything in this session will be practical and applicable to a wide variety of databases. Topics covered include: backups, shrinks, fragmentation, statistics, and much more! Focus will be on 2005 but we'll explain some of the key differences for 2000 and 2008 as well. Speaker Biographies     Kimberley L. Tripp Paul and Kimberly are a husband-and-wife team who own and run SQLskills.com, a world-renowned SQL Server consulting and training company. They are both SQL Server MVPs and Microsoft Regional Directors, with over 30 years of combined experience on SQL Server. Paul worked on the SQL Server team for nine years in development and management roles, writing many of the DBCC commands, and ultimately with responsibility for core Storage Engine for SQL Server 2008. Paul writes extensively on his blog (SQLskills.com/blogs/Paul) and for TechNet Magazine, for which he is also a Contributing Editor. Kimberly worked on the SQL Server team in the early 1990s as a tester and writer before leaving to found SQLskills and embrace her passion for teaching and consulting. Kimberly has been a staple at worldwide conferences since she first presented at TechEd in 1996, and she blogs at SQLskills.com/blogs/Kimberly. They have written Microsoft whitepapers and books for SQL Server 2000, 2005 and 2008, and are regular, top-rated presenters worldwide on database maintenance, high availability, disaster recovery, performance tuning, and SQL Server internals. Together they teach the SQL MCM certification and throughout Microsoft.In their spare time, they like to find frogfish in remote corners of the world.   Speaker Testimonials  "To call them good trainers is an epic understatement. They know how to deliver technical material in ways that illustrate it well. I had to stop Paul at one point and ask him how long it took to build a particular slide because the animations were so good at conveying a hard-to-describe process." "These are not beginner presenters, and they put an extreme amount of preparation and attention to detail into everything that they do. Completely, utterly professional." "When it comes to the instructors themselves, Kimberly and Paul simply have no equal. Not only are they both ultimate authorities, but they have endless enthusiasm about the material, and spot on delivery. If either ever got tired they never showed it, even after going all day and all week. We witnessed countless demos over the course of the week, some extremely involved, multi-step processes, and I can’t recall one that didn’t go the way it was supposed to." "You might think that with this extreme level of skill comes extreme levels of egotism and lack of patience. Nothing could be further from the truth. ... They simply know how to teach, and are approachable, humble, and patient." "The experience Paul and Kimberly have had with real live customers yields a lot more information and things to watch out for than you'd ever get from documentation alone." “Kimberly, I just wanted to send you an email to let you know how awesome you are! I have applied some of your indexing strategies to our website’s homegrown CMS and we are experiencing a significant performance increase. WOW....amazing tips delivered in an exciting way!  Thanks again” 

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  • A Reusable Builder Class for Javascript Testing

    - by Liam McLennan
    Continuing on my series of builders for C# and Ruby here is the solution in Javascript. This is probably the implementation with which I am least happy. There are several parts that did not seem to fit the language. This time around I didn’t bother with a testing framework, I just append some values to the page with jQuery. Here is the test code: var initialiseBuilder = function() { var builder = builderConstructor(); builder.configure({ 'Person': function() { return {name: 'Liam', age: 26}}, 'Property': function() { return {street: '127 Creek St', manager: builder.a('Person') }} }); return builder; }; var print = function(s) { $('body').append(s + '<br/>'); }; var build = initialiseBuilder(); // get an object liam = build.a('Person'); print(liam.name + ' is ' + liam.age); // get a modified object liam = build.a('Person', function(person) { person.age = 999; }); print(liam.name + ' is ' + liam.age); home = build.a('Property'); print(home.street + ' manager: ' + home.manager.name); and the implementation: var builderConstructor = function() { var that = {}; var defaults = {}; that.configure = function(d) { defaults = d; }; that.a = function(type, modifier) { var o = defaults[type](); if (modifier) { modifier(o); } return o; }; return that; }; I still like javascript’s syntax for anonymous methods, defaults[type]() is much clearer than the Ruby equivalent @defaults[klass].call(). You can see the striking similarity between Ruby hashes and javascript objects. I also prefer modifier(o) to the equivalent Ruby, yield o.

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  • Operator overloading outside class

    - by bobobobo
    There are two ways to overload operators for a C++ class: Inside class class Vector2 { public: float x, y ; Vector2 operator+( const Vector2 & other ) { Vector2 ans ; ans.x = x + other.x ; ans.y = y + other.y ; return ans ; } } ; Outside class class Vector2 { public: float x, y ; } ; Vector2 operator+( const Vector2& v1, const Vector2& v2 ) { Vector2 ans ; ans.x = v1.x + v2.x ; ans.y = v1.y + v2.y ; return ans ; } (Apparently in C# you can only use the "outside class" method.) In C++, which way is more correct? Which is preferable?

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  • Use python decorators on class methods and subclass methods

    - by AlexH
    Goal: Make it possible to decorate class methods. When a class method gets decorated, it gets stored in a dictionary so that other class methods can reference it by a string name. Motivation: I want to implement the equivalent of ASP.Net's WebMethods. I am building this on top of google app engine, but that does not affect the point of difficulty that I am having. How it Would look if it worked: class UsefulClass(WebmethodBaseClass): def someMethod(self, blah): print(blah) @webmethod def webby(self, blah): print(blah) # the implementation of this class could be completely different, it does not matter # the only important thing is having access to the web methods defined in sub classes class WebmethodBaseClass(): def post(self, methodName): webmethods[methodName]("kapow") ... a = UsefulClass() a.post("someMethod") # should error a.post("webby") # prints "kapow" There could be other ways to go about this. I am very open to suggestions

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