Ryan Harrison My blog, portfolio and technology related ramblings

Windows 8 Developer Preview Released

Microsoft has now released the developers preview for Windows 8, which includes -

  • A 64-bit Windows Developer Preview
  • Windows SDK for Metro style apps
  • Microsoft Visual Studio 11 Express for Windows Developer Preview
  • 28 Metro style applications including the BUILD Conference app

It’s available here.

Although I haven’t personally installed the release, here are a couple of screenshots from a user running it in a Virtual Machine.

Metro UI

This shows the new ‘Metro’ UI in Windows 8. It consists of a series of tiles and widgets that link to the most common applications. I can’t really see anyone using this on a desktop computer, but I suppose it’s meant to be for mobile devices with touchscreens, which will benefit hugely from the large icons.

Start Menu

Here is the new desktop and start menu in the developer release. Although most of the desktop is similar to that of Windows 7, huge changes can be seen in the new start menu which has been completely revamped to fit in with the new Metro style.

Ribbon in Explorer

One of the main changes in the new release is the new Ribbon in Windows Explorer. For more basic skilled users this could be a real time saver, as it stops people from trawling through the edit menu in order to find ‘Copy’. However on the other hand, on smaller resolutions the Ribbon can take up a lot of real estate, and won’t leave much room for the actual files to be displayed. I can see most advanced users instantly hiding the Ribbon, as most of it’s features can be accomplished with simple keyboard shortcuts.

Task Manager

The task manager has also been given a much needed face lift. It’s now much more graphic, and offers the user more information than in previous versions. This will also apparently be a window that many users will see, as Microsoft have recently said that most people use the task manager on a day to day basis to ‘kill’ programs. This doesn’t really say much for the developers.

Control Panel (Metro)

Metro Apps 

Finally there is the new Metro Control Panel and a possible Metro equivalent to ‘All Programs’. I hope that Microsoft still include the old versions however, as I can see trying to navigate the control panel on a desktop computer taking twice as long as it should do.

Of course this is a very early build of Windows 8, but shows a taster of what’s to come. I find it surprising that Microsoft have made such large changes from Windows 7. Obviously Microsoft are trying to integrate the new release with Windows Phone devices, and Metro will look and feel great on a touchscreen device, but I don’t really think that it offers any use whatsoever to the majority of users sitting at their desks.  Plus considering that Microsoft’s clients are mostly corporate, I can’t see the new changes being that popular with them. It will probably decrease productivity and will confuse many users, especially considering that many businesses have only just made the leap from Windows XP to Windows 7, and from Office 2003 to 2010. The leap has just been made at my college, but not without major problems. Many have had problems using Libraries, and the whole network has been down for hours at a time. Of course the problems will be fixed soon, but it doesn’t bode well for Windows 8 considering that it took the best part 8 years to upgrade to Windows 7.

Expect to see a lot more about the new release in the near future.

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Java 7 Released

A few days ago Oracle announced the availability of their new Java 7 SDK. Some of of the major changes include -;

  • New I/O APIs (Asynchronous I/O)
  • Strings in switch statements
  • Unicode 6.0
  • Elliptic-curve cryptography
  • Translucent and shaped windows
  • Heavyweight/lightweight component mixing
  • Swing Nimbus look-and-feel
  • Swing JLayer component
  • The integral types (byte, short, int and long) can also be expressed using the binary number system. To specify a binary literal, add the prefix 0b or 0B to the number.
  • Any number of underscore characters (_) can appear anywhere between digits in a numerical literal. This feature enables you, for example, to separate groups of digits in numeric literals, which can improve the readability of your code.
  • You can replace the type arguments required to invoke the constructor of a generic class with an empty set of type parameters (<>) as long as the compiler can infer the type arguments from the context. This pair of angle brackets is informally called the diamond.
  • A single catch block can handle more than one type of exception. This enables you to specify more specific exception types in the throws clause of a method declaration and reduces code repetition.
  • The try with-resources statement is a try statement that declares one or more resources. A resource is an object that must be closed after the program is finished with it. The try with-resources statement ensures that each resource is closed at the end of the statement.
  • Java API for XML Processing (JAXP) 1.4.5.

JDK 7 Release Notes

Download Link

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C# The Google Currency API Update

NOTE: The Google Finance API has now been deprecated so this code will no longer work

After testing out the code from the recent post on the Google Currency API, it became apparent that the code had one very significant bug that caused an exception to be thrown when the user enters a value that returns a result over the one million mark. For example -;

http://www.google.com/ig/calculator?hl=en&q=1000000gbp=?usd

which gives back this JSON object -;

{lhs: "1 000 000 British pounds",rhs: "1.6399 million U.S. dollars",error: "",icc: true}

As you can see, instead of returning just a decimal number, it gives a number followed by a String, which caused the previous program to crash.

In this case to fix the bug, the Regex needs to be modified so that it returns not only the number, but also the new String in the same match. With this information, the number can then be multiplied to give the final result as a single decimal.

The Regex now becomes -; rhs: \\\"((\\d|\\s|\\.)*)(\\s[^\\s]+)

(the cluster of backslashes are to escape the possible escape sequences of ‘/d’ and ‘/s’ for example)

The new Regular Expression makes use of ‘Groups’ to store the two pieces of data in the same match -; the first groups contains the number, and the third contains the String due to the way this pattern is designed (it’s probably possible to modify this, yet it doesn’t create too much of a problem and so isn’t worth the effort).

We can now produce a match from the response using the same code as before -;

WebClient client = new WebClient();

string url = string.Format("http://www.google.com/ig/calculator?hl=en&q={0}{1}=?{2}", amount, from.ToUpper(), to.ToUpper());

string response = client.DownloadString(url);

Regex pattern = new Regex("rhs: \\\"((\\d|\\s|\\.)*)(\\s[^\\s]+)");  
Match match = pattern.Match(response);  

Once we have access to the match, we can extract the data into our own variables -;

string number = match.Groups[1].Value;  
number = number.Replace(((char)160).ToString(), "");

decimal num = System.Convert.ToDecimal(number);  
string units = match.Groups[3].Value.Replace(" ","");  

Here, the number is stored as a String from the first group and the ‘spaces’ are removed (for some reason in the returned String, ‘spaces’ have a Unicode value of 160, which is called the ‘Non-breaking space’). Next, the number is converted into a decimal and the units are extracted from the match and stored in the ‘units’ variable.

As the only possible values of the ‘units’ variable are ‘millions’, ‘billions’ and ‘trillions’, we can simply test the variable against each and multiply the number correspondingly to get the overall result. Finally, we just need to round the number to two decimal places to signify a currency, and return the value. Here is the full updated code which hopefully is bug free. The full source code can be found in GitHub.

using System;  
using System.Text.RegularExpressions;

public static class Currency  
{  
	public static decimal Convert(decimal amount, string from, string to)  
	{  
		WebClient client = new WebClient();

		string url = string.Format("http://www.google.com/ig/calculator?hl=en&q={0}{1}=?{2}", amount, from.ToUpper(), to.ToUpper());

		string response = client.DownloadString(url);

		Regex pattern = new Regex("rhs: \\\"((\\d|\\s|\\.)*)(\\s[^\\s]+)");  
		Match match = pattern.Match(response);

		string number = match.Groups[1].Value;  
		number = number.Replace(((char)160).ToString(), "");

		decimal num = System.Convert.ToDecimal(number);  
		string units = match.Groups[3].Value.Replace(" ","");

		if(units.Equals("million"))  
		{  
			num *= 1000000;  
		}  
		else if (units.Equals("billion"))  
		{  
			num *= 1000000000;  
		}  
		else if (units.Equals("trillion"))  
		{  
			num *= 1000000000000;  
		}

		return Math.Round(num, 2);  
	}  
}  
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C# - The Google Currency API

NOTE: The Google Finance API has now been deprecated so this code will no longer work

After I found myself using Google to translate currencies, I wondered whether it would be possible to utilise this functionality in a program. After a little research it turns out that Google offer a huge API that deals with currencies and finance. For the purpose of this post I will show you how to convert currencies, yet you can also use the API to find stock information and even market gains over a period.

Although here I will be using C#, it should be possible to use pretty much any language and get the same results.

This particular feature can be utilised through a simple URL containing the amount to convert from, the currency to convert from, and the currency to convert to. This translates into this URL -;

http://www.google.com/ig/calculator?hl=en&q={AMOUNT}{FROM}=?{TO}

For example -;

http://www.google.com/ig/calculator?hl=en&q=1GBP=?USD

(which converts 1 British Pound to US Dollars) returns the following -;

{lhs: "1 British pound",rhs: "1.6121 U.S. dollars",error: "",icc: true}

The URL responds with a JSON object where the actual result is mixed in with some other information from the request, which presents a minor problem when trying to convert currencies in our program. This will be dealt with a bit later on.

First of all in our program, we to get the output of the request. I used the WebClient class, which will download the response as a String for use in our program. In the following code, the URL is constructed with parameters passed in by the user, and the string is downloaded and stored in the ‘response’ variable.

using System;

public static class CurrencyConverter  
{  
	public static decimal Convert(decimal amount, string from, string to)  
	{  
		WebClient web = new WebClient();

		string url = string.Format("http://www.google.com/ig/calculator?hl=en&q={0}{1}=?{2}", amount, from.ToUpper(), to.ToUpper());

		string response = web.DownloadString(url);  
	}  
}  

This takes care of getting the response with the answer we want, yet we still need to somehow extract the correct data from the string. In this example I will use Regular Expressions however if your prefer not to use them, or your language does not natively support them, it would be perfectly viable to loop through the response one character at a time, and parse out the result.

The Regex pattern will look like this -;

rhs: \\\"(\\d\*.\\d\*)

This pattern essentially searches for the ‘rhs’ which appears just before the result value, and extracts any numbers afterwards until any non-numeric character is reached.

Using the Regex to extract the result, we end up with the following, final code -;

using System;  
using System.Text.RegularExpressions;

public static class CurrencyConverter  
{  
	public static decimal Convert(decimal amount, string from, string to)  
	{  
		WebClient web = new WebClient();

		string url = string.Format("http://www.google.com/ig/calculator?hl=en&q={0}{1}=?{2}", amount, from.ToUpper(), to.ToUpper());

		string response = web.DownloadString(url);

		Regex regex = new Regex("rhs: \\\"(\\d\*.\\d\*)");  
		Match match = regex.Match(response);

		return System.Convert.ToDecimal(match.Groups[1].Value);  
	}  
}  

The full source code can be found in GitHub.

Thats about it for the Google Currency API for now, however I may post snippets on how to use some other features of the extensive API’s Google offer soon.

More Information about the Google Finance API

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Compile from the Command Line

It’s sometimes frustrating when you want to compile and test a short snippet of code, yet find yourself modifying an existing project or even creating a whole new one just to compile the code. Most developers write and compile their code straight from their IDE of choice and never bother compiling from the command prompt. For most situations this is sensible, however in some specific scenarios the command line can save you time when it’s not feasible to modify or create a new project. In this short tutorial I will show you how to compile your Java, C# and C++ code straight from the command line, including all the necessary tweaks of your Environment Variables.

Java

The first language is Java. I will assume that you have the JDK (Java Development Kit) installed, as this is the package that includes the Java compiler.

The first step is to navigate to the installation directory of your JDK installation and copy the path to the bin folder which resides inside. The path should look a bit like this (depending the version of the JDK you have installed) -

JDK Path

Once you have the path in the clipboard, you have to add it to your system’s Environment Variables, which will essentially allow you to run the Java compiler from anywhere on your computer.

In Windows 7, click the Start orb and right click on the Computer shortcut and click on Properties in the context menu. This should take you to a window that looks something like this -

System Properties

Then, click on Advanced System Settings on the right hand side. Under the Advanced tab of the new window, click on Environment Variables….

Next, you want to locate the variable named Path in your System Variables. If you don’t have one, click on the new button to create a new variable (make sure you name it Path). With it selected, click on edit. A new window pops up showing the value of the Path variable. Navigate to the end of the value string and add a semi-colon to signify a new entry.

Finally, simply paste in the path to the JDK’s bin directory and click on OK. The value field should look a little like this -

JDK Environment Variable

We have now configured your system to allow you to compile Java programs from any directory on you hard drive.

To use the compiler from the command line, open up a new command prompt window by typing cmd in the Run box (or search box in the Windows 7/Vista start menu).

Type in javac (stands for Java Compiler) and hit enter. You should see a lot writing being printed to the window. It should look a little like this -

Java Compiler

This signifies that you can actually use the compiler and that you have successfully followed the previous steps.

In this example I will compile and run a simple ‘Hello World!’ program from the desktop.

  
public class javacomp  
{  
  public static void main(String[] args)  
  {  
    System.out.println("Hello World!");
  }  
}  

Save this Java source file to any directory on your computer, (in this case my Desktop) and again open up a command prompt window.

Next, navigate to the directory of your source file using the cd command.

e.g - cd C:\Users\YourUserName\Desktop

When this is done, type javac again, yet this time followed by the name of the source file you just created, (make sure you add the .java extension) and hit enter. If there are no syntax errors you should see a new .class file in the same directory. This is where the compiled bytecode is stored. Finally, to run the program type java and the name of the .class file (this time no need to add the extension). The program will now run the window and you should see something like this -

Compiling and Running the Java Program

More information about the Java compiler, including the many command line arguments.

C#

Next for C#. This is pretty much the same as for Java apart from a different path to the compiler.

In this case you need to copy the path to the .NET Framework folder in the root Windows folder. The path should be a bit like this depending on the version of the .NET framework you have installed -

The Path to the .Net Framework installation

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