The professional blog of Alex Henderson, Software Engineer
I noticed that Ivan
posted a
list of tutorials etc. on his blog... I think it's worth also
adding that there is a site dedicated to these kinds of resources,
as well as snippets, recipes etc. - it's still in it's
infancy, but I think it will end up being quite invaluable as a
resource for castle project users (here's hoping at any
rate!)
http://using.castleproject.org/
So the first 9 posts are up for the container tutorial series... but I haven't made much mention of what can be done to play around with the windsor container yourself while reading this series.
Well first-off ... my thoughts on getting started with the Castle project are generally practical, first off I think it's worth grabbing the second release candidate - check out what castle can do, have a general play, maybe try to generate a monorail project and get it working... and then ... well I would probably uninstall it, and grab the latest cut of the castle project and contributed projects from svn and build it yourself using nant.
This gives you opportunities to use all the "new stuff" that gets added day by day (as well as bug fixes) but also ensures your actually capable of building and contributing patches for any issues you discover.
But that's a bit of an ask for someone experimenting, especially if you don't know anything about svn... so essentially for playing around with the basics of the windsor container, you only need 4 Castle assemblies from the bleeding edge, and I'll give them to you:
And to make life easy I included those assemblies in a folder called "SharedLibs" as part of the following zip file, which contains the code for the first 9 parts... I'll do another code
drop at the end of the container tutorials to round out the series for the sake of posterity... but everything you need for the first 9 tutorials is here:
Files for Parts 1 thru 9
Good Times ;o)
Constructor injection - so far inadvertantly we've been using setter inject to get our configuration information into our components... but you can also use constructors... the useful aspect of constructors is that it makes those parameters compulsory...
So lets take a look at the code for this post, first off there's an interface for a service which takes care of encoding a string for us:
public interface IEncoder
{
string Encode(string source);
}
public class NullEncoder : IEncoder
{
public string Encode(string source)
{
return source;
}
}
public class SillyEncoder : IEncoder
{
private char[] _mixedUp = "YACBDFEGIHJLKMONPRSQTUWVXZ".ToCharArray();public string Encode(string source)
{
string upperSource = source.ToUpper();
char[] encoded = new char[source.Length];
for (int i = 0; i < encoded.length;="">
{
encoded[i] = MapCharacter(upperSource[i]);
}
return new string(encoded);
}private char MapCharacter(char ch)
{
if ((ch >= 'A') && (ch <=>
{
return _mixedUp[ch - 'A'];
}
return ch;
}
}
public class SecretMessageSender
{
private readonly IEncoder _encoder;
private readonly string _from;public SecretMessageSender(string from, IEncoder encoder)
{
_from = from;
_encoder = encoder;
}public void SendMessage(string to, string body)
{
Console.WriteLine("to: {0}rnfrom: {1}rnrn{2}", to, _from, _encoder.Encode(body));
}
}
static void Main(string[] args)
{
WindsorContainer container = new WindsorContainer(new XmlInterpreter());SecretMessageSender sender = container.Resolve
(); sender.SendMessage("hammet", "castle is great!");
Console.Read();
}
type="Castle.Windsor.Configuration.AppDomain.CastleSectionHandler, Castle.Windsor" />
service="IoC.Tutorials.Part9.IEncoder, IoC.Tutorials.Part9"
type="IoC.Tutorials.Part9.SillyEncoder, IoC.Tutorials.Part9" />
service="IoC.Tutorials.Part9.IEncoder, IoC.Tutorials.Part9"
type="IoC.Tutorials.Part9.NullEncoder, IoC.Tutorials.Part9" />
type="IoC.Tutorials.Part9.SecretMessageSender, IoC.Tutorials.Part9">SecretMessageSender
alex@bittercoder.com
So lets have a look at the last one...
type="Castle.Windsor.Configuration.AppDomain.CastleSectionHandler, Castle.Windsor" />
service="IoC.Tutorials.Part9.IEncoder, IoC.Tutorials.Part9"
type="IoC.Tutorials.Part9.SillyEncoder, IoC.Tutorials.Part9" />
service="IoC.Tutorials.Part9.IEncoder, IoC.Tutorials.Part9"
type="IoC.Tutorials.Part9.NullEncoder, IoC.Tutorials.Part9" />
type="IoC.Tutorials.Part9.SecretMessageSender, IoC.Tutorials.Part9">SecretMessageSender
alex@bittercoder.com
${encoder.null}
So I've decided to do a quick little series on the windsor container - all up It'll probably cover 15 to 20 posts... each one should be very short, covering some small concept... just a little nugget.
This series will be a little different then most discussions on IoC and containers... rather then get in your face with concepts like dependency injection, and encouraging testability, it's just going to focus on the container itself, and the ways you can use it... I'm not sure if it'll be of any value, but If nothing else to gets me back into blogging regularly.
The first 7 parts are already up:
So far we've looked at registering one implementation for any one service, you could call them the "default" implementation, because it's the implementation the container returns when you ask for that service... but your not limited to only having one implementation registered, and the way to do this is by giving each implementation that's registered a unique key.
There are many reasons for doing this... but in this example we'll look at one reason - because we want to vary the configuration info used...
So here's our component's code:
public class FileReader
{
private string _fileName;public string FileName
{
get { return _fileName; }
set { _fileName = value; }
}public string ReadToEnd()
{
return File.ReadAllText(_fileName);
}
}
type="Castle.Windsor.Configuration.AppDomain.CastleSectionHandler, Castle.Windsor" />
file1.txt
file2.txt
static void Main(string[] args)
{
WindsorContainer container = new WindsorContainer(new XmlInterpreter());FileReader defaultReader = container.Resolve
();
FileReader file1Reader = container.Resolve("reader.file1");
FileReader file2Reader = container.Resolve("reader.file2"); Console.WriteLine("Default contents: {0}", defaultReader.ReadToEnd());
Console.WriteLine("File1 contents: {0}", file1Reader.ReadToEnd());
Console.WriteLine("File2 contents: {0}", file2Reader.ReadToEnd());Console.Read();
}
Uri uri;
// blah blah blah
string key = "messageSender."+ uri.Scheme;
if (container.Kernel.HasComponent(key))
{
ISender sender = container.Resolve(key);
// send the message at this point...
sender.SendMessage("hi there");
}
else
{
// no implementation registered...
throw new NotImplementedException("no sender registered for scheme: " + uri.Scheme);
}