Tips and tricks in C# .NET
February 20, 2015 2 Comments
You can decorate your C# source code with “messages” to the compiler. There are a couple of predefined preprocessors that the compiler understands.
A common scenario is when you’d like to run some part of your code in Debug mode but not in Release mode or any other Build type. The following method shows the ‘if’ and ‘elif’ preprocessors:
February 19, 2015 1 Comment
Introduction
In the previous post we went through a quick introduction of Amazon Elastic MapReduce. In this post we’ll very shortly describe Hadoop first. Then we’ll log into EMR and go through the long section in the GUI which you fill in to specify the details of your cluster.
If you are entirely new to Hadoop and Amazon Web Services then you’ll see a lot of new tools mentioned on this page that hide some complex applications with their own learning curves. So get ready for a lot of reading and research. It can be of great help if you have people in your organisation who already have some prior knowledge of AWS when starting with EMR.
February 18, 2015 Leave a comment
The ‘partial’ keyword helps you divide your classes into multiple files within the same namespace. One obvious usage of partial classes is to split the definition of a large type into smaller chunks. You cannot just use the partial keyword with classes but methods as well.
The partial classes will reside in two – or more – different cs files in the same namespace. Say you have a partial Customer class in the project-name/domains folder:
February 17, 2015 Leave a comment
The Environment class holds a range of properties that help you describe the system your app is running on. Here come some examples with inline comments:
//returns true on my PC as it is a 64-bit OS
bool is64BitOperatingSystem = Environment.Is64BitOperatingSystem;
//returns the machine name, in my case ANDRAS1
string machineName = Environment.MachineName;
//returns information about the operating system version, build, major, minor etc.
OperatingSystem os = Environment.OSVersion;
//returns the platform id as an enumeration, in my case it's Win32NT
PlatformID platform = os.Platform;
//the currently installed service pack, Service Pack 1 in my case
string servicePack = os.ServicePack;
//the toString version of the OS, this is "Microsoft Windows NT 6.1.7601 Service Pack 1" on this PC
string version = os.VersionString;
//I have 4 processors on this PC
int processorCount = Environment.ProcessorCount;
//returns 2 logical drives: C: and D:
string[] logicalDrives = Environment.GetLogicalDrives();
//this is how to find all environmental variables of the system and iterate through them
IDictionary envVars = Environment.GetEnvironmentVariables();
foreach (string key in envVars.Keys)
{
//e.g. the JAVA_HOME env.var is set to "C:\Progra~1\Java\jdk1.7.0_51\"
Debug.WriteLine(string.Concat("key: ", key, ": ", envVars[key]));
}
//retrieve the current CLR version, in my case it's "4.0.30319.18444"
Version clrVersion = Environment.Version;
View all posts related to diagnostics here.
February 16, 2015 Leave a comment
Introduction
Big Data is everywhere nowadays. It’s one of the most (over)used keywords in IT nowadays. Organisations have to process large amounts of information in form of messages in real time in order to make decisions about the future of the company. Companies can also use these messages as data points of something they monitor constantly: sales, response times, stock prices, etc. Their goal is presumably to process the data and extract information from it that they themselves or their customers find useful and are willing to pay for.
Amazon Web Services have a solution for pretty much anything in IT so it’s no surprise that there are at least two solutions for data mining and analysis scenarios:
February 13, 2015 Leave a comment
Say you have a method which accepts a string parameter. The method may need to handle null values in some way. One strategy is to validate the parameter and throw an exception:
private static string Resolve(string input)
{
if (input == null) throw new ArgumentNullException("Input");
.
.
.
}
Another strategy is to provide some default value with an if-else statement:
February 12, 2015 6 Comments
Introduction
In the previous post we looked at how to query our test table in Amazon DynamoDb. That post also completed our main discussion on how to use DynamoDb in .NET.
This post is dedicated to a larger picture: Big Data. This series is part of a large series on cloud-based Big Data infrastructure along with the message handler Amazon Kinesis and the raw data storage S3. Therefore the pre-requisite of following the discussion in this post is familiarity with what we discussed in those posts or at least some knowledge of Big Data. However, I’ll try to write in a way that those of you who’ve only come here for DynamoDb may get a taste of the role it can play in a cloud-based Big Data architecture.
February 11, 2015 1 Comment
Let’s say you have the following three numbers:
…and you’d like to format them as follows:
There’s a special format string that can be used for this purpose. It consists of 3 parts separated by a semi-colon. The first part applies to positive numbers, the second to negative numbers and the third to zeroes:
February 10, 2015 4 Comments
Have you ever tried to hunt down a bug and been blocked by an incomplete stacktrace? The stacktrace might point to a place in your code where you threw the exception with the “throw” keyword but there’s no information on where the exception was originally thrown.
This can happen if you process the exception within the catch clause, e.g. log it somewhere and then throw it back to the call stack.
Consider the following simple code where the first method calls the second which calls the next etc. and the last one throws an exception. The first method catches the exception, prints it to the Debug window and throws it:
February 9, 2015 4 Comments
Introduction
In the previous post we looked at how to delete and update records in Amazon DynamoDb. In this post we’ll investigate how to run queries against the data set in a DynamoDb table. Like in the two posts before this we’ll look at the document and data models separately.
We’ll extend the DynamoDbDemo console application in Visual Studio.
I’ve inserted a couple more records into the demo DynamoDb table in preparation for the queries:
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