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  • Naming convention: Final fields (not static)

    - by Zeeker
    Today I had a discussion with a co-worker about the naming of final fields in Java classes. In his opionion final fields should also be considered constants since their values won't change after the creation of the instance. This would lead to the following naming convention for final fields: public class Foo { private static final String BLA_BLA = "bla"; private final String BAR_BATZ; ... } In my opinion only static final fields should be considered constants while fields which are only final should follow the usual camelCase naming convention. public class Foo { private static final String BLA = "bla"; private final String barBatz; ... } Now I'm a bit uncertain since he is a far more experienced programmer than I am and I usually agree with his opinions and consider him a very good developer. Any input on this?

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  • What is the proper way to pass the parameters into a MVC system?

    - by gunbuster363
    I am trying to learn java servlet/jsp with the MVC concept and built the simplest MVC application. Now I want give more detail to it to enhance my understanding. If I would need to register a new row in a table in the database, how should we pass the various value of column into the system? For example, the user might want to register a new event in his planner and the detail of the event involves the 'where', 'when', 'who', 'detail', etc. Should pass all this long value from the servlet's parameter, i.e: the http link? String accNo = request.getParameter("account_number"); String a = request.getParameter("..."); String b = request.getParameter("..."); String c = request.getParameter("..."); String d = request.getParameter("..."); To illustrate my view that it is really unprofessional to show all the parameter on the link: http://localhost:8080/domain1/servlet1?param1=55555555555555&param2=666666666666666666666666666666666666666666666666666666666666&param3='Some random detail written by user.........................' Is there other way to pass them?

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  • Part 3 of 4 : Tips/Tricks for Silverlight Developers.

    - by mbcrump
    Part 1 | Part 2 | Part 3 | Part 4 I wanted to create a series of blog post that gets right to the point and is aimed specifically at Silverlight Developers. The most important things I want this series to answer is : What is it?  Why do I care? How do I do it? I hope that you enjoy this series. Let’s get started: Tip/Trick #11) What is it? Underline Text in a TextBlock. Why do I care? I’ve seen people do some crazy things to get underlined text in a Silverlight Application. In case you didn’t know there is a property for that. How do I do it: On a TextBlock you have a property called TextDecorations. You can easily set this property in XAML or CodeBehind with the following snippet: <UserControl x:Class="SilverlightApplication19.MainPage" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400"> <Grid x:Name="LayoutRoot" Background="White"> <TextBlock Name="txtTB" Text="MichaelCrump.NET" TextDecorations="Underline" /> </Grid> </UserControl> or you can do it in CodeBehind… txtTB.TextDecorations = TextDecorations.Underline;   Tip/Trick #12) What is it? Get the browser information from a Silverlight Application. Why do I care? This will allow you to program around certain browser conditions that otherwise may not be aware of. How do I do it: It is very easy to extract Browser Information out a Silverlight Application by using the BrowserInformation class. You can copy/paste this code snippet to have access to all of them. string strBrowserName = HtmlPage.BrowserInformation.Name; string strBrowserMinorVersion = HtmlPage.BrowserInformation.BrowserVersion.Minor.ToString(); string strIsCookiesEnabled = HtmlPage.BrowserInformation.CookiesEnabled.ToString(); string strPlatform = HtmlPage.BrowserInformation.Platform; string strProductName = HtmlPage.BrowserInformation.ProductName; string strProductVersion = HtmlPage.BrowserInformation.ProductVersion; string strUserAgent = HtmlPage.BrowserInformation.UserAgent; string strBrowserVersion = HtmlPage.BrowserInformation.BrowserVersion.ToString(); string strBrowserMajorVersion = HtmlPage.BrowserInformation.BrowserVersion.Major.ToString(); Tip/Trick #13) What is it? Always check the minRuntimeVersion after creating a new Silverlight Application. Why do I care? Whenever you create a new Silverlight Application and host it inside of an ASP.net website you will notice Visual Studio generates some code for you as shown below. The minRuntimeVersion value is set by the SDK installed on your system. Be careful, if you are playing with beta’s like “Lightswitch” because you will have a higher version of the SDK installed. So when you create a new Silverlight 4 project and deploy it your customers they will get a prompt telling them they need to upgrade Silverlight. They also will not be able to upgrade to your version because its not released to the public yet. How do I do it: Open up the .aspx or .html file Visual Studio generated and look for the line below. Make sure it matches whatever version you are actually targeting. Tip/Trick #14) What is it? The VisualTreeHelper class provides useful methods for involving nodes in a visual tree. Why do I care? It’s nice to have the ability to “walk” a visual tree or to get the rendered elements of a ListBox. I have it very useful for debugging my Silverlight application. How do I do it: Many examples exist on the web, but say that you have a huge Silverlight application and want to find the parent object of a control.  In the code snippet below, we would get 3 MessageBoxes with (StackPanel first, Grid second and UserControl Third). This is a tiny application, but imagine how helpful this would be on a large project. <UserControl x:Class="SilverlightApplication18.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400"> <Grid x:Name="LayoutRoot" Background="White"> <StackPanel> <Button Content="Button" Height="23" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" /> </StackPanel> </Grid> </UserControl> private void button1_Click(object sender, RoutedEventArgs e) { DependencyObject obj = button1; while ((obj = VisualTreeHelper.GetParent(obj)) != null) { MessageBox.Show(obj.GetType().ToString()); } } Tip/Trick #15) What is it? Add ChildWindows to your Silverlight Application. Why do I care? ChildWindows are a great way to direct a user attention to a particular part of your application. This could be used when saving or entering data. How do I do it: Right click your Silverlight Application and click Add then New Item. Select Silverlight Child Window as shown below. Add an event and call the ChildWindow with the following snippet below: private void button1_Click(object sender, RoutedEventArgs e) { ChildWindow1 cw = new ChildWindow1(); cw.Show(); } Your main application can still process information but this screen forces the user to select an action before proceeding. The code behind of the ChildWindow will look like the following: namespace SilverlightApplication18 { public partial class ChildWindow1 : ChildWindow { public ChildWindow1() { InitializeComponent(); } private void OKButton_Click(object sender, RoutedEventArgs e) { this.DialogResult = true; //TODO: Add logic to save what the user entered. } private void CancelButton_Click(object sender, RoutedEventArgs e) { this.DialogResult = false; } } } Thanks for reading and please come back for Part 4.  Subscribe to my feed CodeProject

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  • How to remove the last character from Stringbuilder

    - by hmloo
    We usually use StringBuilder to append string in loops and make a string of each data separated by a delimiter. but you always end up with an extra delimiter at the end. This code sample shows how to remove the last delimiter from a StringBuilder. using System; using System.Collections.Generic; using System.Text; using System.Linq; class Program { static void Main() { var list =Enumerable.Range(0, 10).ToArray(); StringBuilder sb = new StringBuilder(); foreach(var item in list) { sb.Append(item).Append(","); } sb.Length--;//Just reduce the length of StringBuilder, it's so easy Console.WriteLine(sb); } } //Output : 0,1,2,3,4,5,6,7,8,9 Alternatively,  we can use string.Join for the same results, please refer to blow code sample. using System; using System.Collections.Generic; using System.Text; using System.Linq; class Program { static void Main() { var list = Enumerable.Range(0, 10).Select(n => n.ToString()).ToArray(); string str = string.Join(",", list); Console.WriteLine(str); } }

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  • how to call web method in java application?.

    - by user12344
    Hi, I have created java web application(Web Service). I want to call the setName() method in java application(GUI). how is call web method in application?. package sv; import javax.jws.WebMethod; import javax.jws.WebParam; import javax.jws.WebService; @WebService() public class MyService { @WebMethod(operationName = "setName") public String setName(@WebParam(name = "name") String name) { return "my string is "+ name; } }

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  • Can data classes contain methods for validation?

    - by Arturas M
    OK, say I have a data class for a user: public class User { private String firstName; private String lastName; private long personCode; private Date birthDate; private Gender gender; private String email; private String password; Now let's say I want to validate email, whether names are not empty, whether birth date is in normal range, etc. Can I put that validation method in this class together with data? Or should it be in UserManager which in my case handles the lists of these users?

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  • How will closures in Java impact the Java Community?

    - by Ryan Delucchi
    It is one of the most talked about features planned for Java: Closures. Many of us have been longing for them. Some of us (including I) have grown a bit impatient and have turned to scripting languages to fill the void. But, once closures have finally arrived to Java: how will they effect the Java Community? Will the advancement of VM-targetted scripting languages slow to a crawl, stay the same, or acclerate? Will people flock to the new closure syntax, thus turning Java code-bases all-around into more functionally structured implementations? Will we only see closures sprinkled in Java throughout? What will be the effect on tool/IDE support? How about performance? And finally, what will it mean for Java's continued adoption, as a language, compared with other languages that are rising in popularity? To provide an example of one of the latest proposed Java Closure syntax specs: public interface StringOperation { String invoke(String s); } // ... (new StringOperation() { public invoke(String s) { new StringBuilder(s).reverse().toString(); } }).invoke("abcd"); would become ... String reversed = { String s => new StringBuilder(s).reverse().toString() }.invoke("abcd"); [source: http://tronicek.blogspot.com/2007/12/closures-closure-is-form-of-anonymous_28.html]

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  • LINQ/LAMBDA filter query by date [on hold]

    - by inquisitive_one
    I'm trying to use LINQ to SQL to retrieve earnings data for a particular date range. Currently the table is set up as follows: Comp Eps Year Quarter IBM .5 2012 2 IBM .65 2012 3 IBM .60 2012 4 IBM .5 2011 2 IBM .7 2013 1 IBM .8 2013 2 Except for Eps, all fields have a data type of string or char. Eps has a data type of double. Here's my code: var myData = myTable .Where(t => t.Comp.Equals("IBM") && Convert.Int32(string.Format("{0}{1}", t.Year, t.Quarter)) <= 20131); I get the following error when I tried that code: Method 'System.String Format(System.String, System.Object, System.Object)' has no supported translation to SQL How can I select all Eps that has a year & quarter less than "20132" using a lambda expression?

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  • Simple HTML5 Friendly Markup Sample

    - by Geertjan
    From a demo done by David Heffelfinger (who has a great Java EE 7 screencast series here), on HTML5 friendly markup. index.xhtml:  <?xml version='1.0' encoding='UTF-8' ?> <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:jsf="http://xmlns.jcp.org/jsf"> <title>Data Entry Page</title> <body> <form method="POST" jsf:id='form'> <table> <tr> <td>Name:</td> <td><input jsf:id='name' type="text" jsf:value="${person.name}" /></td> </tr> <tr> <td>City</td> <th><input jsf:id='city' type="text" jsf:value="${person.city}"/></th> </tr> <tr> <td><input type="submit" value="Submit" jsf:action="confirmation" /></td> </tr> </table> </form> </body> </html> confirmation.xhtml: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Data Confirmation Page</title> </head> <body> <h1>#{person.name}</h1> from <h2>#{person.city}</h2> </body> </html> Person.java: package org.demo; import javax.enterprise.inject.Model; @Model public class Person { String name; String city; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getCity() { return city; } public void setCity(String city) { this.city = city; } }

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  • gnome shell with very high CPU usage

    - by 501 - not implemented
    i'm running ubuntu gnome 13.10 on my dell latiude e6510 with a i5 m560. The I5 comes with a embedded Intel HD 3400 Graphics. The average cpu usage of the gnome-shell is by 160% it's to high, I think. Is there a problem with a driver? If i call the command glxinfo | grep OpenGL it returns: OpenGL vendor string: VMware, Inc. OpenGL renderer string: Gallium 0.4 on llvmpipe (LLVM 3.3, 128 bits) OpenGL version string: 2.1 Mesa 9.2.1 OpenGL shading language version string: 1.30 OpenGL extensions: Greetings

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  • List has no value after adding values in

    - by Sigh-AniDe
    I am creating a a ghost sprite that will mimic the main sprite after 10 seconds of the game. I am storing the users movements in a List<string> and i am using a foreach loop to run the movements. The problem is when i run through the game by adding breakpoints the movements are being added to the List<string> but when the foreach runs it shows that the list has nothing in it. Why does it do that? How can i fix it? this is what i have: public List<string> ghostMovements = new List<string>(); public void UpdateGhost(float scalingFactor, int[,] map) { // At this foreach, ghostMovements has nothing in it foreach (string s in ghostMovements) { // current position of the ghost on the tiles int mapX = (int)(ghostPostition.X / scalingFactor); int mapY = (int)(ghostPostition.Y / scalingFactor); if (s == "left") { switch (ghostDirection) { case ghostFacingUp: angle = 1.6f; ghostDirection = ghostFacingRight; Program.form.direction = ""; break; case ghostFacingRight: angle = 3.15f; ghostDirection = ghostFacingDown; Program.form.direction = ""; break; case ghostFacingDown: angle = -1.6f; ghostDirection = ghostFacingLeft; Program.form.direction = ""; break; case ghostFacingLeft: angle = 0.0f; ghostDirection = ghostFacingUp; Program.form.direction = ""; break; } } } } // The movement is captured here and added to the list public void captureMovement() { ghostMovements.Add(Program.form.direction); }

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  • F# Objects &ndash; Integration with the other .Net Languages &ndash; Part 2

    - by MarkPearl
    So in part one of my posting I covered the real basics of object creation. Today I will hopefully dig a little deeper… My expert F# book brings up an interesting point – properties in F# are just syntactic sugar for method calls. This makes sense… for instance assume I had the following object with the property exposed called Firstname. type Person(Firstname : string, Lastname : string) = member v.Firstname = Firstname I could extend the Firstname property with the following code and everything would be hunky dory… type Person(Firstname : string, Lastname : string) = member v.Firstname = Console.WriteLine("Side Effect") Firstname   All that this would do is each time I use the property Firstname, I would see the side effect printed to the screen saying “Side Effect”. Member methods have a very similar look & feel to properties, in fact the only difference really is that you declare that parameters are being passed in. type Person(Firstname : string, Lastname : string) = member v.FullName(middleName) = Firstname + " " + middleName + " " + Lastname   In the code above, FullName requires the parameter middleName, and if viewed from another project in C# would show as a method and not a property. Precomputation Optimizations Okay, so something that is obvious once you think of it but that poses an interesting side effect of mutable value holders is pre-computation of results. All it is, is a slight difference in code but can result in quite a huge saving in performance. Basically pre-computation means you would not need to compute a value every time a method is called – but could perform the computation at the creation of the object (I hope I have got it right). In a way I battle to differentiate this from lazy evaluation but I will show an example to explain the principle. Let me try and show an example to illustrate the principle… assume the following F# module namespace myNamespace open System module myMod = let Add val1 val2 = Console.WriteLine("Compute") val1 + val2 type MathPrecompute(val1 : int, val2 : int) = let precomputedsum = Add val1 val2 member v.Sum = precomputedsum type MathNormalCompute(val1 : int, val2 : int) = member v.Sum = Add val1 val2 Now assume you have a C# console app that makes use of the objects with code similar to the following… using System; using myNamespace; namespace CSharpTest { class Program { static void Main(string[] args) { Console.WriteLine("Constructing Objects"); var myObj1 = new myMod.MathNormalCompute(10, 11); var myObj2 = new myMod.MathPrecompute(10, 11); Console.WriteLine(""); Console.WriteLine("Normal Compute Sum..."); Console.WriteLine(myObj1.Sum); Console.WriteLine(myObj1.Sum); Console.WriteLine(myObj1.Sum); Console.WriteLine(""); Console.WriteLine("Pre Compute Sum..."); Console.WriteLine(myObj2.Sum); Console.WriteLine(myObj2.Sum); Console.WriteLine(myObj2.Sum); Console.ReadKey(); } } } The output when running the console application would be as follows…. You will notice with the normal compute object that the system would call the Add function every time the method was called. With the Precompute object it only called the compute method when the object was created. Subtle, but something that could lead to major performance benefits. So… this post has gone off in a slight tangent but still related to F# objects.

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  • Class or Dictionary

    - by user2038134
    I want to create a immutable Scale class in C#. public sealed class Scale { string _Name; string _Description; SomeOrderedCollection _ScaleValueDefinitions; Unit _Unit // properties .... // methods ContainsValue(double value) .... // constructors // all parameters except scalevaluedefinitions are optional // for a Scale to be useful atleast 1 ScaleValueDefinition should exist public Scale(string name, string description, SomeOrderedCollection scaleValueDefinitions, unit) { /* initialize */} } so first a ScaleValueDefinition should be represented by to values: Value (double) Definition (string) these values are known before the Scale class is created and should be unique. so what is the best approach. create a immutable class ScaleValueDefinition with value and definition as properties and use it in a list. use a dictionary. use another way i didn't think of... and how to implement it. for option 1. i can use params ScaleValueDefinition[] ValueDefinitions in the constructor, but how to do it for the other options? and as last at what amount of value's (properties) should i choose one option over the other?

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  • Parsing Concerns

    - by Jesse
    If you’ve ever written an application that accepts date and/or time inputs from an external source (a person, an uploaded file, posted XML, etc.) then you’ve no doubt had to deal with parsing some text representing a date into a data structure that a computer can understand. Similarly, you’ve probably also had to take values from those same data structure and turn them back into their original formats. Most (all?) suitably modern development platforms expose some kind of parsing and formatting functionality for turning text into dates and vice versa. In .NET, the DateTime data structure exposes ‘Parse’ and ‘ToString’ methods for this purpose. This post will focus mostly on parsing, though most of the examples and suggestions below can also be applied to the ToString method. The DateTime.Parse method is pretty permissive in the values that it will accept (though apparently not as permissive as some other languages) which makes it pretty easy to take some text provided by a user and turn it into a proper DateTime instance. Here are some examples (note that the resulting DateTime values are shown using the RFC1123 format): DateTime.Parse("3/12/2010"); //Fri, 12 Mar 2010 00:00:00 GMT DateTime.Parse("2:00 AM"); //Sat, 01 Jan 2011 02:00:00 GMT (took today's date as date portion) DateTime.Parse("5-15/2010"); //Sat, 15 May 2010 00:00:00 GMT DateTime.Parse("7/8"); //Fri, 08 Jul 2011 00:00:00 GMT DateTime.Parse("Thursday, July 1, 2010"); //Thu, 01 Jul 2010 00:00:00 GMT Dealing With Inaccuracy While the DateTime struct has the ability to store a date and time value accurate down to the millisecond, most date strings provided by a user are not going to specify values with that much precision. In each of the above examples, the Parse method was provided a partial value from which to construct a proper DateTime. This means it had to go ahead and assume what you meant and fill in the missing parts of the date and time for you. This is a good thing, especially when we’re talking about taking input from a user. We can’t expect that every person using our software to provide a year, day, month, hour, minute, second, and millisecond every time they need to express a date. That said, it’s important for developers to understand what assumptions the software might be making and plan accordingly. I think the assumptions that were made in each of the above examples were pretty reasonable, though if we dig into this method a little bit deeper we’ll find that there are a lot more assumptions being made under the covers than you might have previously known. One of the biggest assumptions that the DateTime.Parse method has to make relates to the format of the date represented by the provided string. Let’s consider this example input string: ‘10-02-15’. To some people. that might look like ‘15-Feb-2010’. To others, it might be ‘02-Oct-2015’. Like many things, it depends on where you’re from. This Is America! Most cultures around the world have adopted a “little-endian” or “big-endian” formats. (Source: Date And Time Notation By Country) In this context,  a “little-endian” date format would list the date parts with the least significant first while the “big-endian” date format would list them with the most significant first. For example, a “little-endian” date would be “day-month-year” and “big-endian” would be “year-month-day”. It’s worth nothing here that ISO 8601 defines a “big-endian” format as the international standard. While I personally prefer “big-endian” style date formats, I think both styles make sense in that they follow some logical standard with respect to ordering the date parts by their significance. Here in the United States, however, we buck that trend by using what is, in comparison, a completely nonsensical format of “month/day/year”. Almost no other country in the world uses this format. I’ve been fortunate in my life to have done some international travel, so I’ve been aware of this difference for many years, but never really thought much about it. Until recently, I had been developing software for exclusively US-based audiences and remained blissfully ignorant of the different date formats employed by other countries around the world. The web application I work on is being rolled out to users in different countries, so I was recently tasked with updating it to support different date formats. As it turns out, .NET has a great mechanism for dealing with different date formats right out of the box. Supporting date formats for different cultures is actually pretty easy once you understand this mechanism. Pulling the Curtain Back On the Parse Method Have you ever taken a look at the different flavors (read: overloads) that the DateTime.Parse method comes in? In it’s simplest form, it takes a single string parameter and returns the corresponding DateTime value (if it can divine what the date value should be). You can optionally provide two additional parameters to this method: an ‘System.IFormatProvider’ and a ‘System.Globalization.DateTimeStyles’. Both of these optional parameters have some bearing on the assumptions that get made while parsing a date, but for the purposes of this article I’m going to focus on the ‘System.IFormatProvider’ parameter. The IFormatProvider exposes a single method called ‘GetFormat’ that returns an object to be used for determining the proper format for displaying and parsing things like numbers and dates. This interface plays a big role in the globalization capabilities that are built into the .NET Framework. The cornerstone of these globalization capabilities can be found in the ‘System.Globalization.CultureInfo’ class. To put it simply, the CultureInfo class is used to encapsulate information related to things like language, writing system, and date formats for a certain culture. Support for many cultures are “baked in” to the .NET Framework and there is capacity for defining custom cultures if needed (thought I’ve never delved into that). While the details of the CultureInfo class are beyond the scope of this post, so for now let me just point out that the CultureInfo class implements the IFormatInfo interface. This means that a CultureInfo instance created for a given culture can be provided to the DateTime.Parse method in order to tell it what date formats it should expect. So what happens when you don’t provide this value? Let’s crack this method open in Reflector: When no IFormatInfo parameter is provided (i.e. we use the simple DateTime.Parse(string) overload), the ‘DateTimeFormatInfo.CurrentInfo’ is used instead. Drilling down a bit further we can see the implementation of the DateTimeFormatInfo.CurrentInfo property: From this property we can determine that, in the absence of an IFormatProvider being specified, the DateTime.Parse method will assume that the provided date should be treated as if it were in the format defined by the CultureInfo object that is attached to the current thread. The culture specified by the CultureInfo instance on the current thread can vary depending on several factors, but if you’re writing an application where a single instance might be used by people from different cultures (i.e. a web application with an international user base), it’s important to know what this value is. Having a solid strategy for setting the current thread’s culture for each incoming request in an internationally used ASP .NET application is obviously important, and might make a good topic for a future post. For now, let’s think about what the implications of not having the correct culture set on the current thread. Let’s say you’re running an ASP .NET application on a server in the United States. The server was setup by English speakers in the United States, so it’s configured for US English. It exposes a web page where users can enter order data, one piece of which is an anticipated order delivery date. Most users are in the US, and therefore enter dates in a ‘month/day/year’ format. The application is using the DateTime.Parse(string) method to turn the values provided by the user into actual DateTime instances that can be stored in the database. This all works fine, because your users and your server both think of dates in the same way. Now you need to support some users in South America, where a ‘day/month/year’ format is used. The best case scenario at this point is a user will enter March 13, 2011 as ‘25/03/2011’. This would cause the call to DateTime.Parse to blow up since that value doesn’t look like a valid date in the US English culture (Note: In all likelihood you might be using the DateTime.TryParse(string) method here instead, but that method behaves the same way with regard to date formats). “But wait a minute”, you might be saying to yourself, “I thought you said that this was the best case scenario?” This scenario would prevent users from entering orders in the system, which is bad, but it could be worse! What if the order needs to be delivered a day earlier than that, on March 12, 2011? Now the user enters ‘12/03/2011’. Now the call to DateTime.Parse sees what it thinks is a valid date, but there’s just one problem: it’s not the right date. Now this order won’t get delivered until December 3, 2011. In my opinion, that kind of data corruption is a much bigger problem than having the Parse call fail. What To Do? My order entry example is a bit contrived, but I think it serves to illustrate the potential issues with accepting date input from users. There are some approaches you can take to make this easier on you and your users: Eliminate ambiguity by using a graphical date input control. I’m personally a fan of a jQuery UI Datepicker widget. It’s pretty easy to setup, can be themed to match the look and feel of your site, and has support for multiple languages and cultures. Be sure you have a way to track the culture preference of each user in your system. For a web application this could be done using something like a cookie or session state variable. Ensure that the current user’s culture is being applied correctly to DateTime formatting and parsing code. This can be accomplished by ensuring that each request has the handling thread’s CultureInfo set properly, or by using the Format and Parse method overloads that accept an IFormatProvider instance where the provided value is a CultureInfo object constructed using the current user’s culture preference. When in doubt, favor formats that are internationally recognizable. Using the string ‘2010-03-05’ is likely to be recognized as March, 5 2011 by users from most (if not all) cultures. Favor standard date format strings over custom ones. So far we’ve only talked about turning a string into a DateTime, but most of the same “gotchas” apply when doing the opposite. Consider this code: someDateValue.ToString("MM/dd/yyyy"); This will output the same string regardless of what the current thread’s culture is set to (with the exception of some cultures that don’t use the Gregorian calendar system, but that’s another issue all together). For displaying dates to users, it would be better to do this: someDateValue.ToString("d"); This standard format string of “d” will use the “short date format” as defined by the culture attached to the current thread (or provided in the IFormatProvider instance in the proper method overload). This means that it will honor the proper month/day/year, year/month/day, or day/month/year format for the culture. Knowing Your Audience The examples and suggestions shown above can go a long way toward getting an application in shape for dealing with date inputs from users in multiple cultures. There are some instances, however, where taking approaches like these would not be appropriate. In some cases, the provider or consumer of date values that pass through your application are not people, but other applications (or other portions of your own application). For example, if your site has a page that accepts a date as a query string parameter, you’ll probably want to format that date using invariant date format. Otherwise, the same URL could end up evaluating to a different page depending on the user that is viewing it. In addition, if your application exports data for consumption by other systems, it’s best to have an agreed upon format that all systems can use and that will not vary depending upon whether or not the users of the systems on either side prefer a month/day/year or day/month/year format. I’ll look more at some approaches for dealing with these situations in a future post. If you take away one thing from this post, make it an understanding of the importance of knowing where the dates that pass through your system come from and are going to. You will likely want to vary your parsing and formatting approach depending on your audience.

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  • How do I combine the two methods of cryptography, CBC cipher block and Vingenere Chiper [on hold]

    - by Bangpe
    Code Vingenere static String encrypt(String text, final String key) { String res = ""; text = text.toUpperCase(); for (int i = 0, j = 0; i < text.length(); i++) { char c = text.charAt(i); if (c < 'A' || c > 'Z') continue; res += (char)((c + key.charAt(j) - 2 * 'A') % 26 + 'A'); j = ++j % key.length(); } return res; } Code CBC Chiper public CbcBlockCipher( BlockCipher blockCipher ) { super( blockCipher.keySize(), blockCipher.blockSize() ); this.blockCipher = blockCipher; iv = new byte[blockSize()]; zeroBlock( iv ); temp = new byte[blockSize()]; }

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  • Unit testing a text index

    - by jplot
    Consider a text index such as a suffix tree or a suffix array supporting Count queries (number of occurrences of a pattern) and Locate queries (the positions of all the occurrences of a pattern) over a given text. How would you go about unit testing such a class ? What I have in mind is to generate a big random string then extract a random substring from this big string and compare the results of both queries with naive implementations (such as string::find). Another idea I have is to find the most frequent substring of length l appearing in the original string (using perhaps a naive method) and use these substrings for testing the index. This isn't the best way, so what would be a good design of the unit tests for a text index ? In case it matters, this is in C++ using google test.

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  • DataTable to Generic List Conversion

    using System;using System.Collections.Generic;using System.Linq;using System.Data;namespace ConsoleApplication1{ class Program { static void Main(string[] args) { DataTable table = new DataTable { Columns = { {"Number", typeof(int)}, {"Name", typeof(string)} } }; //Just adding few test rows to datatable. for (int i = 1; i <= 5; i++) { table.Rows.Add(i, "Name" + i); } var returnList = from row in table.AsEnumerable() select new MyObject { Number = row.Field<int>("Number"), Name = row.Field<String>("Name") }; //Displaying converted collection foreach (MyObject item in returnList) { Console.WriteLine("{0}\t{1}", item.Number, item.Name); } } } class MyObject { public int Number { get; set; } public String Name { get; set; } }} span.fullpost {display:none;}

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  • strlen returns incorrect value when called in gdb

    - by alesplin
    So I'm noticing some severely incorrect behavior from calls to standard library functions inside GDB. I have the following program to illustrate: #include <stdio.h> #include <stdlib.h> #include <string.h> int main(int argc, char *argv[]) { char *s1 = "test"; char *s2 = calloc(strlen("test")+1,sizeof(char)); snprintf(s2,strlen("test")+1,"test"); printf("string constant: %lu\n", strlen(s1)); printf("allocated string: %lu\n", strlen(s2)); free(s2); return 0; } When run from the command-line, this program outputs just what you'd expect: string constant: 4 allocated string: 4 However, in GDB, I get the following, incorrect output from calls to strlen(): (gdb) p strlen(s1) $1 = -938856896 (gdb) p strlen(s2) $2 = -938856896 I'm pretty sure this is a problem with glibc shipped with Ubuntu (I'm using 10.10), but this is a serious problem for those of us who spend lots of time in GDB. Is anyone else experiencing this kind of error? What's the best way to fix it? Build glibc from source? (I'm already running a version of GDB built from source)

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  • Is spreading code with refactoring comments a good idea?

    - by Uooo
    I am working on a "spaghetti-code" project, and while I am fixing bugs and implementing new features, I also do some refactoring in order to make the code unit-testable. The code is often so tightly coupled or complicated that fixing a small bug would result in a lot of classes being rewritten. So I decided to draw a line somewhere in the code where I stop refactoring. To make this clear, I drop some comments in the code explaining the situation, like: class RefactoredClass { private SingletonClass xyz; // I know SingletonClass is a Singleton, so I would not need to pass it here. // However, I would like to get rid of it in the future, so it is passed as a // parameter here to make this change easier later. public RefactoredClass(SingletonClass xyz) { this.xyz = xyz; } } Or, another piece of cake: // This might be a good candidate to be refactored. The structure is like: // Version String // | // +--> ... // | // +--> ... // | // ... and so on ... // Map map = new HashMap<String, Map<String, Map<String, List<String>>>>(); Is this a good idea? What should I keep in mind when doing so?

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  • Regular expression in mySQL [migrated]

    - by Rayne
    I have a mysql table that has 2 columns - Column 1 contains a string value, and Column 2 contains the number of times that string value occurred. I'm trying to find the string abc.X.def, where the beginning of the string is "abc.", followed by one or more characters, then the string ".def". There could be more characters following ".def". How can I find such strings, then add the occurrence of such strings and display the results? For example, if I have abc.111.def23 1 abc.111.def 2 abc.22.def444 1 abc.111.def 1 Then I will get abc.111.def23 1 abc.111.def 3 abc.22.def444 1 Thank you.

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  • [LINQ] Master &ndash; Detail Same Record(II)

    - by JTorrecilla
    In my previous post, I introduced my problem, but I didn’t explain the problem with Entity Framework When you try the solution indicated you will take the following error: LINQ to Entities don’t recognize the method 'System.String Join(System.String, System.Collections.Generic.IEnumerable`1[System.String])’ of the method, and this method can’t be translated into a stored expression. The query that produces that error was: 1: var consulta = (from TCabecera cab in 2: contexto_local.TCabecera 3: let Detalle = (from TDetalle detalle 4: in cab.TDetalle 5: select detalle.Nombre) 6: let Nombres = string.Join(",",Detalle ) 7: select new 8: { 9: cab.Campo1, 10: cab.Campo2, 11: Nombres 12: }).ToList(); 13: grid.DataSource=consulta;   Why is this error happening? This error happens when the query couldn’t be translated into T-SQL. Solutions? To quit that error, we need to execute the query on 2 steps: 1: var consulta = (from TCabecera cab in 2: contexto_local.TCabecera 3: let Detalle = (from TDetalle detalle 4: in cab.TDetalle 5: select detalle.Nombre) 6: select new 7: { 8: cab.Campo1, 9: cab.Campo2, 10: Detalle 11: }).ToList(); 12: var consulta2 = (from dato in consulta 13: let Nombes = string.Join(",",dato.Detalle) 14: select new 15: { 16: dato.Campo1, 17: dato.Campo2, 18: Nombres 19: }; 20: grid.DataSource=consulta2.ToList(); Curiously This problem happens with Entity Framework but, the same problem can’t be reproduced on LINQ – To – SQL, that it works fine in one unique step. Hope It’s helpful Best Regards

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  • Missing error handling in Streaming-AJAX-Proxy Log

    - by Michael Freidgeim
    We are using AjaxProxy(FROM http://www.codeproject.com/KB/ajax/ajaxproxy.aspx) on our web site, but started to notice errors accessing log.txt file. I found that the file is created by Log class and doesn't have ability to switch it off and error handling. I've added reading file name from configuration and try/catch block   public static class Log     {         private static StreamWriter logStream;         private static object lockObject = new object ();     public static void WriteLine(string msg)         {                       string logFileName = ConfigurationExtensions.GetAppSetting("AjaxStreamingProxy.LogFile" ,"");                       if (logFileName.IsNullOrEmpty())                             return;                       try                      {                             if (logStream == null )                            {                                    lock (lockObject)                                   {                                           if (logStream == null )                                          {                            logStream = File.AppendText(Path .Combine(AppDomain.CurrentDomain.BaseDirectory, logFileName));                                          }                                   }                            }                            logStream.WriteLine(msg);                      }                       catch (Exception exc)                      {                             string ignoredMsg = String .Format("The error occured while logging {0}, but processing will continue.\n {1} ", exc);                             LoggerHelper.LogEvent(ignoredMsg, MyCategorySource, TraceEventType .Warning, true);                      }         }

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  • Retrieving recent tweets using LINQ

    - by brian_ritchie
    There are a few different APIs for accessing Twitter from .NET.  In this example, I'll use linq2twitter.  Other APIs can be found on Twitter's development site. First off, we'll use the LINQ provider to pull in the recent tweets. .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: Consolas, "Courier New", Courier, Monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 1: public static Status[] GetLatestTweets(string screenName, int numTweets) 2: { 3: try 4: { 5: var twitterCtx = new LinqToTwitter.TwitterContext(); 6: var list = from tweet in twitterCtx.Status 7: where tweet.Type == StatusType.User && 8: tweet.ScreenName == screenName 9: orderby tweet.CreatedAt descending 10: select tweet; 11: // using Take() on array because it was failing against the provider 12: var recentTweets = list.ToArray().Take(numTweets).ToArray(); 13: return recentTweets; 14: } 15: catch 16: { 17: return new Status[0]; 18: } 19: } Once they have been retrieved, they would be placed inside an MVC model. Next, the tweets need to be formatted for display. I've defined an extension method to aid with date formatting: .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: Consolas, "Courier New", Courier, Monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 1: public static class DateTimeExtension 2: { 3: public static string ToAgo(this DateTime date2) 4: { 5: DateTime date1 = DateTime.Now; 6: if (DateTime.Compare(date1, date2) >= 0) 7: { 8: TimeSpan ts = date1.Subtract(date2); 9: if (ts.TotalDays >= 1) 10: return string.Format("{0} days", (int)ts.TotalDays); 11: else if (ts.Hours > 2) 12: return string.Format("{0} hours", ts.Hours); 13: else if (ts.Hours > 0) 14: return string.Format("{0} hours, {1} minutes", 15: ts.Hours, ts.Minutes); 16: else if (ts.Minutes > 5) 17: return string.Format("{0} minutes", ts.Minutes); 18: else if (ts.Minutes > 0) 19: return string.Format("{0} mintutes, {1} seconds", 20: ts.Minutes, ts.Seconds); 21: else 22: return string.Format("{0} seconds", ts.Seconds); 23: } 24: else 25: return "Not valid"; 26: } 27: } Finally, here is the piece of the view used to render the tweets. .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: Consolas, "Courier New", Courier, Monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 1: <ul class="tweets"> 2: <% 3: foreach (var tweet in Model.Tweets) 4: { 5: %> 6: <li class="tweets"> 7: <span class="tweetTime"><%=tweet.CreatedAt.ToAgo() %> ago</span>: 8: <%=tweet.Text%> 9: </li> 10: <%} %> 11: </ul>  

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