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Articles indexed in May 2010

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  • Is my method for avoiding dynamic_cast<> faster than dynamic_cast<> itself ?

    - by ereOn
    Hi, I was answering a question a few minutes ago and it raised to me another one: In one of my projects, I do some network message parsing. The messages are in the form of: [1 byte message type][2 bytes payload length][x bytes payload] The format and content of the payload are determined by the message type. I have a class hierarchy, based on a common class Message. To instanciate my messages, i have a static parsing method which gives back a Message* depending on the message type byte. Something like: Message* parse(const char* frame) { // This is sample code, in real life I obviously check that the buffer // is not NULL, and the size, and so on. switch(frame[0]) { case 0x01: return new FooMessage(); case 0x02: return new BarMessage(); } // Throw an exception here because the mesage type is unknown. } I sometimes need to access the methods of the subclasses. Since my network message handling must be fast, I decived to avoid dynamic_cast<> and I added a method to the base Message class that gives back the message type. Depending on this return value, I use a static_cast<> to the right child type instead. I did this mainly because I was told once that dynamic_cast<> was slow. However, I don't know exactly what it really does and how slow it is, thus, my method might be as just as slow (or slower) but far more complicated. What do you guys think of this design ? Is it common ? Is it really faster than using dynamic_cast<> ? Any detailed explanation of what happen under the hood when one use dynamic_cast<> is welcome !

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  • Paypal NVP API - Keep getting error 81002

    - by Andree
    Hi there, I am new to PayPal API, and I'm having trouble calling SetExpressCheckout using CURL in PHP. I have set everything correctly, as far as I'm concerned, but I kept getting an 81002 error "Method Specified is not Supported". The code snippet is below. I got the CA Root certificates file from here. <?php $paypal_data = array( 'USER' => urlencode('andree_1272823561_biz_api1.gmail.com'), 'PWD' => urlencode('1272823576'), 'SIGNATURE' => urlencode('Am1t0wiu2tv7VwZ5ebdeY9zv1GF6Ad0PFz-qTGFFf7vbWU6ee4bxy8KL'), 'VERSION' => urlencode('52.0'), 'PAYMENTACTION' => urlencode('Sale'), 'METHOD' => urlencode('SetExpressCheckout'), 'AMT' => urlencode('52.00'), 'RETURNURL' => urlencode('get_express_checkout_details.php'), 'CANCELURL' => urlencode('index.php') ); $url = 'https://api-3t.sandbox.paypal.com/nvp?' . http_build_query($paypal_data); $curl = curl_init(); curl_setopt($curl, CURLOPT_URL, $url); curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1); curl_setopt($curl, CURLOPT_CAINFO, dirname(__FILE__) . '/cacert.pem'); $result = curl_exec($curl); curl_close($curl); parse_str($result, $result); ?> <pre>Data sent: <?php print_r($paypal_data); ?></pre> <pre>Result: <?php print_r($result); ?></pre> When I run the code, the output is the following: Data sent: Array ( [USER] => andree_1272823561_biz_api1.gmail.com [PWD] => 1272823576 [SIGNATURE] => Am1t0wiu2tv7VwZ5ebdeY9zv1GF6Ad0PFz-qTGFFf7vbWU6ee4bxy8KL [VERSION] => 52.0 [PAYMENTACTION] => Sale [METHOD] => SetExpressCheckout [AMT] => 52.00 [RETURNURL] => get_express_checkout_details.php [CANCELURL] => index.php ) Result: Array ( [ACK] => Failure [L_ERRORCODE0] => 81002 [L_SHORTMESSAGE0] => Unspecified Method [L_LONGMESSAGE0] => Method Specified is not Supported [L_SEVERITYCODE0] => Error ) Anyone knows what could be the problem? Regards, Andree.

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  • Windows 64-bit registry v.s. 32-bit registry

    - by George2
    Hello everyone, I heard on Windows x64 architecture, in order to support to run both x86 and x64 application, there is two separate/different sets of Windows registry -- one for x86 application to access and the other for x64 application to access? For example, if a COM registers CLSID in the x86 set of registry, then x64 application will never be able to access the COM component by CLSID, because x86/x64 have different sets of registry? So, my question is whether my understanding of the above sample is correct? I also want to get some more documents to learn this topic, about the two different sets of registry on x64 architecture. (I did some search, but not found any valuable information.) thanks in advance, George

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  • Changing Dropdown based on Other Dropdown Menu

    - by Shaded
    I've seen a few questions like this, but mine is a bit more specific so I hope this isn't considered a repost. I am working on a website that is built with struts 2 and hibernate. I need to dynamically populate a drop down menu using data from a sql query based on an option selected in another drop down menu. So basically when the first option is selected I need to rehit the server and get the results from a query like SELECT column FROM table WHERE option = dropDownOption On top of that, I would really like to use ajax to only refresh the affected elements, however I'm really unfamiliar with ajax. I have jquery on this project and I found they have some ajax built in, but is this a good method for using it? any advice on this topic would be appreciated.

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  • SSIS For Each File Loop and File System Task to copy Files

    - by Marlon
    I'm using a files system task inside a for each loop container, just as described here: link text However, when I execute the package I get this error: [File System Task] Error: An error occurred with the following error message: "The process cannot access the file 'C:\Book1.xlsx' because it is being used by another process.". I do not have the file open, and I assume no one else does, as I am able to copy, and open, and overwrite the file. Any suggestions would be appreciated. If you want an example package plz let me know.

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  • Le Windows SDK for Windows 7 et pour.NET 4 est annoncé pour la mi Juin

    Couplé à la sortie de la nouvelle monture de développement Visual Studio 2010 devait sortir une nouvelle version de Windows SDK. D'après le blog officiel, cette version 7.1, Windows SDK for Windows 7 and .NET 4 Frameworks, ne devrait finalement pas être disponible avant mi Juin. Pour tous les concernés en attente afin de compléter la migration vers VS2010, plus qu'un mois et demi à tenir Source : http://blogs.msdn.com/windowssdk/arc....aspx#10005513...

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  • "Invite your friends" feature in RoR

    - by Nisanio
    Hi, many social networks let to invite your gmail-hotmail-yahoo friends (even Outlook, but I thinks that is more difficult) to the social network. Basically the app read your email friends list and sent a email invitation. How can I achieve this in RoR? Thanks

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  • why the class of subclass is superclass

    - by Raj
    def singleton_class class << self self end end end class Human proc = lambda { puts 'proc says my class is ' + self.name.to_s } singleton_class.instance_eval do define_method(:lab) do proc.call end end end class Developer < Human end Human.lab # class is Human Developer.lab # class is Human ; oops Why Developer.lab is reporting that it is Human ?

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  • Callback for camera shutter open event

    - by Raj
    Hi all, I have been working around in UIImagePickerController and am struck with a problem where I need to get the precise moment when the camera shutter opens in UIImagePickerController when the source type is set to camera (UIImagePickerControllerSourceTypeCamera). I have done some googling around and have realized that no one had such strange requirement! I looked around the docs of UIImagePickerController and UIImagePickerControllerDelegate hoping to get some delegate method / callback indicating the camera shutter open event, but did not find any. Any suggestions? Thanks for any help, Raj Pawan

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  • SEM/SEO tasks doubts

    - by Josemalive
    Hello, Actually i think that i have an strong knowledge of SEO, but im having some doubts about the following: I will have to increase the position in Google of certain product pages of a company in the next months. I supposed that not only will be sufficient the following tasks: Improve usability of those pages. Change the pages title. Add meta description and keywords. Url's in a REST way. 301's http header to dont lose page rank for the new URLS Optimizing content for Google. Configure links of the website (follow and no follow attributes) Get more inbounds links (Link building tasks). Create RSS. Put main website in Twitter (using twitter feed) using the RSS. Put main website in Facebook. Create a Youtube channel. Invest in Adwords. Invest in other online advertising companies. Use sitemap.xml and Google Webmaster tools. Use Google Trends to analyze the volume of searches of certain keywords. Use Google Analytics to analyze weak points and good points of your site, and find new oportunities in keywords. Use tools to find new keywords related with your content. Do you have some internet links, or knowledge about all the tasks that a SEO Expert should do? Could you share some knowledge about what kind of business could be do with another companies (B2B) to increase the search engine position of those product pages. Do you know more tecniques about how to get more inbound links? (i only know the link interchange) Thanks in advance. Best Regards. Jose.

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  • jquery ui cannot reload current tab

    - by 0plus1
    I need to reload the current tab in jquery ui (loaded with ajax). I'm doing this: function reloadtab(){ $('#tabs').tabs('load', $('#tabs').tabs('option', 'selected')); } Before you begin wondering: $('#tabs').tabs('option', 'selected'); returns 3. When I call reloadtab() I get no error, it simply doesn't work. Why does this happens? Thank you very much EDIT: I'm an idiot, it was working, was a problem with cache. Sorry.

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  • How to dynamically change the content of a facet in a custom component?

    - by romaintaz
    Hello, Let's consider that I want to extend an existing JSF component, such as the <rich:datatable/>. My main requirement is to dynamically modify the content of a <f:facet>, to change its content. What is the best way to achieve that? Or where is the best place in the code to achieve that? In my faces-config.xml, I have the following declaration: <faces-config> ... <component> <component-type>my.component.dataTable</component-type> <component-class>my.project.component.table.MyHtmlDataTable</component-class> </component> ... <render-kit> <render-kit-id>HTML_BASIC</render-kit-id> <renderer> <component-family>org.richfaces.DataTable</component-family> <renderer-type>my.renderkit.dataTable</renderer-type> <renderer-class>my.project.component.table.MyDataTableRenderer</renderer-class> </renderer> ... Also, my my-project.taglib.xml file (as I use Facelets) looks like: <facelet-taglib> <namespace>http://my.project/jsf</namespace> <tag> <tag-name>dataTable</tag-name> <component> <component-type>my.component.dataTable</component-type> <renderer-type>my.renderkit.dataTable</renderer-type> </component> </tag> So as you can see, I have two classes in my project for my custom datatable: MyHtmlDataTable and MyDataTableRenderer. One of my idea is to modify the content of the <f:facet> directly in the doEncodeBegin() method of my renderer. This is working (in fact almost working), but I don't really think that's the better place to achieve my modification. What do you think? Technical information: JSF 1.2, Facelets, Richfaces 3.3.2, Java 1.6

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  • Microsoft Quotation

    - by Asad Jibran Ahmed
    I don't know if this is the right place to ask this question, but I honestly have exhausted my self searching for the last hour. I am looking for a quotation made about Microsofts software. It goes something along the lines of: "They may make 2nd grade crappy software, but by God they know how to design interfaces" It was by a somewhat popular open source personality about the lack of good interface design in open source software. Does any one know the exact quotation? It will be a great help if someone can point me in the right direction.

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  • Rotating in OpenGL relative to the viewport

    - by Nick
    I'm trying to display an object in the view which can be rotated naturally by dragging the cursor/touchscreen. At the moment I've got X and Y rotation of an object like this glRotatef(rotateX, 0f, 1f, 0f); // Dragging along X, so spin around Y axis glRotatef(rotateY, 1f, 0f, 0f); I understand why this doesn't do what I want it to do (e.g. if you spin it right 180 degrees, up and down spinning gets reversed). I just can't figure out a way for both directions to stay left-right and up-down relative to the viewer. I can assume that the camera is fixed and looking along the Z axis. Any ideas?

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  • jQuery and jQuery UI (Dual Licensing)

    - by John Hartsock
    OK I have read many posts regarding Dual Licensing using MIT and GPL licenses. But Im curious still, as the wording seems to be inclusive. Many of the Dual Licenses state that the software is licensed using "MIT AND GPL". The "AND" is what confuses me. It seems to me that the word "AND" in the terms, means you will be licensing the product using both licenses. Most of the posts, here on stackoverflow, say you can license the software using one "OR" the other. JQuery specifically states "OR", whereas JQuery UI specifically States "AND". Another Instance of the "AND" would be JQGrid. Im not a lawyer but, it seems to me that a legal interpretation of this would state that use of the software would mean that your using the software under both licenses. Has anyone who has contacted a lawyer gotten clarification or a definitive answer as to what is true? Can you use Dual licensed software products that state "AND" in the terms of agreement under either license?

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  • How can I make a family of singletons?

    - by Jay
    I want to create a set of classes that share a lot of common behavior. Of course in OOP when you think that you automatically think "abstract class with subclasses". But among the things I want these classes to do is to each have a static list of instances of the class. The list should function as sort of a singleton within the class. I mean each of the sub-classes has a singleton, not that they share one. "Singleton" to that subclass, not a true singleton. But if it's a static, how can I inherit it? Of course code like this won't work: public abstract A { static List<A> myList; public static List getList() { if (myList==null) myList=new ArrayList<A>(10); return myList; } public static A getSomethingFromList() { List listInstance=getList(); ... do stuff with list ... } public int getSomethingFromA() { ... regular code acting against current instance ... } } public class A1 extends A { ... } public class A2 extends A { ... } A1 somethingfromA1List=(A1) A1.getSomethingFromList(); A2 somethingfromA2List=(A2) A2.getSomethingFromList(); The contents of the list for each subclass would be different, but all the code to work on the lists would be the same. The problem with the above code is that I'd only have one list for all the subclasses, and I want one for each. Yes, I could replicate the code to declare the static list in each of the subclasses, but then I'd also have to replicate all the code that adds to the lists and searches the list, etc, which rather defeats the purpose of subclassing. Any ideas on how to do this without replicating code?

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  • Did Java invent interfaces?

    - by Jordão
    I know about C++ pure virtual classes, but Java went one step further and created a first-class (no pun intended) concept for multiple-interface (not implementation) inheritance, the interface. It's now a staple of major statically-typed languages. Did Java invent the interface concept? Or did it appear in older languages also as a first-class concept?

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  • WPF Databinding- Part 2 of 3

    - by Shervin Shakibi
    This is a follow up to my previous post WPF Databinding- Not your fathers databinding Part 1-3 you can download the source code here  http://ssccinc.com/wpfdatabinding.zip Example 04   In this example we demonstrate  the use of default properties and also binding to an instant of an object which is part of a collection bound to its container. this is actually not as complicated as it sounds. First of all, lets take a look at our Employee class notice we have overridden the ToString method, which will return employees First name , last name and employee number in parentheses, public override string ToString()        {            return String.Format("{0} {1} ({2})", FirstName, LastName, EmployeeNumber);        }   in our XAML we have set the itemsource of the list box to just  “Binding” and the Grid that contains it, has its DataContext set to a collection of our Employee objects. DataContext="{StaticResource myEmployeeList}"> ….. <ListBox Name="employeeListBox"  ItemsSource="{Binding }" Grid.Row="0" /> the ToString in the method for each instance will get executed and the following is a result of it. if we did not have a ToString the list box would look  like this: now lets take a look at the grid that will display the details when someone clicks on an Item, the Grid has the following DataContext DataContext="{Binding ElementName=employeeListBox,            Path=SelectedItem}"> Which means its bound to a specific instance of the Employee object. and within the gird we have textboxes that are bound to different Properties of our class. <TextBox Grid.Row="0" Grid.Column="1" Text="{Binding Path=FirstName}" /> <TextBox Grid.Row="1" Grid.Column="1" Text="{Binding Path=LastName}" /> <TextBox Grid.Row="2" Grid.Column="1" Text="{Binding Path=Title}" /> <TextBox Grid.Row="3" Grid.Column="1" Text="{Binding Path=Department}" />   Example 05   This project demonstrates use of the ObservableCollection and INotifyPropertyChanged interface. Lets take a look at Employee.cs first, notice it implements the INotifyPropertyChanged interface now scroll down and notice for each setter there is a call to the OnPropertyChanged method, which basically will will fire up the event notifying to the value of that specific property has been changed. Next EmployeeList.cs notice it is an ObservableCollection . Go ahead and set the start up project to example 05 and then run. Click on Add a new employee and the new employee should appear in the list box.   Example 06   This is a great example of IValueConverter its actuall a two for one deal, like most of my presentation demos I found this by “Binging” ( formerly known as g---ing) unfortunately now I can’t find the original author to give him  the credit he/she deserves. Before we look at the code lets run the app and look at the finished product, put in 0 in Celsius  and you should see Fahrenheit textbox displaying to 32 degrees, I know this is calculating correctly from my elementary school science class , also note the color changed to blue, now put in 100 in Celsius which should give us 212 Fahrenheit but now the color is red indicating it is hot, and finally put in 75 Fahrenheit and you should see 23.88 for Celsius and the color now should be black. Basically IValueConverter allows us different types to be bound, I’m sure you have had problems in the past trying to bind to Date values . First look at FahrenheitToCelciusConverter.cs first notice it implements IValueConverter. IValueConverter has two methods Convert and ConvertBack. In each method we have the code for converting Fahrenheit to Celsius and vice Versa. In our XAML, after we set a reference in our Windows.Resources section. and for txtCelsius we set the path to TxtFahrenheit and the converter to an instance our FahrenheitToCelciusConverter converter. no need to repeat this for TxtFahrenheit since we have a convert and ConvertBack. Text="{Binding  UpdateSourceTrigger=PropertyChanged,            Path=Text,ElementName=txtFahrenheit,            Converter={StaticResource myTemperatureConverter}}" As mentioned earlier this is a twofer Demo, in the second demo, we basically are converting a double datatype to a brush. Lets take a look at TemperatureToColorConverter, notice we in our Covert Method, if the value is less than our cold temperature threshold we return a blue brush and if it is higher than our hot temperature threshold we return a redbrush. since we don’t have to convert a brush to double value in our example the convert back is not being implemented. Take time and go through these three examples and I hope you have a better understanding   of databinding, ObservableCollection  and IValueConverter . Next blog posting we will talk about ValidationRule, DataTemplates and DataTemplate triggers.

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