Comments on: Singleton shortcut http://blog.cincura.net/230783-singleton-shortcut/ Taking something that can't be done, and then doing it. Wed, 08 Feb 2012 15:02:30 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: alvar http://blog.cincura.net/230783-singleton-shortcut/#comment-1968 alvar Thu, 27 Aug 2009 14:10:14 +0000 http://blog.cincura.net/?p=230783#comment-1968 The simplest singleton: public sealed class BestSingleton { /// Best implementation of singleton pattern. /// What we really care about is that we get the instance created either on or just before the /// first call to (in this case) the Instance property, and that we have a defined initialization order /// for static variables in a class. With the .NET Framework, this is exactly the behavior we get. /// The Framework, during the JIT process, will initialize the static property when (and only when) any method /// uses this static property. If the property is not used, then the instance is not created. /// More precisely, what happens during JIT is that the class gets constructed and loaded when any static member /// of the class is used by any caller. In this case the result is the same. /// What about thread-safe initialization? The Framework addresses this too. The Framework internally guarantees /// thread safety on static type initialization. In other words, in the example above, there is only one instance /// that would ever be created of the Singleton class. Note also that the property field used to hold the instance /// of the class is called Instance. This choice better illustrates that this value is an instance of the class. /// In the Framework itself there are several classes that use this type of singleton, although the property name used /// is called Value instead. The concept is exactly the same. /// static BestSingleton(){} // Removes beforefieldinit flag from the type public static readonly BestSingleton Instance = new BestSingleton(); private BestSingleton() {/*construct the only instance*/} } The simplest singleton:
public sealed class BestSingleton
{
/// Best implementation of singleton pattern.
/// What we really care about is that we get the instance created either on or just before the
/// first call to (in this case) the Instance property, and that we have a defined initialization order
/// for static variables in a class. With the .NET Framework, this is exactly the behavior we get.
/// The Framework, during the JIT process, will initialize the static property when (and only when) any method
/// uses this static property. If the property is not used, then the instance is not created.
/// More precisely, what happens during JIT is that the class gets constructed and loaded when any static member
/// of the class is used by any caller. In this case the result is the same.
/// What about thread-safe initialization? The Framework addresses this too. The Framework internally guarantees
/// thread safety on static type initialization. In other words, in the example above, there is only one instance
/// that would ever be created of the Singleton class. Note also that the property field used to hold the instance
/// of the class is called Instance. This choice better illustrates that this value is an instance of the class.
/// In the Framework itself there are several classes that use this type of singleton, although the property name used
/// is called Value instead. The concept is exactly the same.
///
static BestSingleton(){} // Removes beforefieldinit flag from the type
public static readonly BestSingleton Instance = new BestSingleton();
private BestSingleton() {/*construct the only instance*/}
}

]]> By: cincura.net http://blog.cincura.net/230783-singleton-shortcut/#comment-1965 cincura.net Wed, 26 Aug 2009 20:32:20 +0000 http://blog.cincura.net/?p=230783#comment-1965 I don't care about thread safety in this example. In fact when I need thread safety I often need more than this (i.e. fine grained locking in methods too etc.). I don’t care about thread safety in this example. In fact when I need thread safety I often need more than this (i.e. fine grained locking in methods too etc.).

]]> By: AndrĂ© http://blog.cincura.net/230783-singleton-shortcut/#comment-1964 AndrĂ© Wed, 26 Aug 2009 20:22:51 +0000 http://blog.cincura.net/?p=230783#comment-1964 Don't use this. They are both the same and not thread safe. When I use singleton, I prefer version 4 from here: http://www.yoda.arachsys.com/csharp/singleton.html Don’t use this. They are both the same and not thread safe.

When I use singleton, I prefer version 4 from here:

http://www.yoda.arachsys.com/csharp/singleton.html

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