The singleton pattern is a design pattern that is used to restrict instantiation of a class to one object instance. Although I know how to code the singleton pattern in C++ and Java, I was wondering if anyone know how to implement it in Ruby?...
Is there a way to implement a singleton object in C++ that is: Lazily constructed in a thread safe manner (two threads might simultaneously be the first user of the singleton - it should still only be constructed once). Doesn't rely on static variables being constructed beforehand (so the singleton object is itself safe to use during t...
In other words, is this Singleton implementation thread safe: public class Singleton { private static Singleton instance; private Singleton() { } static Singleton() { instance = new Singleton(); } public static Singleton Instance { get { return instance; } } } ...
Singletons are a hotly debated design pattern, so I am interested in what the Stack Overflow community thought about them. Please provide reasons for your opinions, not just "Singletons are for lazy programmers!" Here is a fairly good article on the issue, although it is against the use of Singletons: scientificninja.com: performant-si...
I'm a moderately skilled programmer using JavaScript but I am no guru. I know you can do some pretty powerful things with it, I just haven't seen much other than fairly basic DOM manipulation. I'm wondering if people could provide some examples of traditional design pattern concepts such as Factory Method, Singleton, etc using JavaScript...
I am merging a CVS branch and one of the larger changes is the replacement wherever it occurs of a Singleton pattern with abstract classes that have a static initialisation block and all static methods. Is this something that's worth keeping since it will require merging a lot of conflicts, what sort of situation would I be looking at f...
There seem to be many ways to define Singletons in python. I was wondering if there is a consensus opinion on StackOverflow. ...
I have a Singleton/Factory object that I'd like to write a JUnit test for. The Factory method decides which implementing class to instantiate based upon a classname in a properties file on the classpath. If no properties file is found, or the properties file does not contain the classname key, then the class will instantiate a default im...
I have a C# singleton class that multiple classes use. Is access through Instance to the Toggle() method thread-safe? If yes, by what assumptions, rules, etc. If no, why and how can I fix it? public class MyClass { private static readonly MyClass instance = new MyClass(); public static MyClass Instance { get { retur...
What is the best way to implement the singleton pattern in Python? It seems impossible to declare the constructor private or protected as is normally done with the Singleton pattern... ...
I read that the unit of granularity for static fields in .Net are per AppDomain, not per process. Is it possible to create a process-wide singleton object? ...
Efficient way to implement singleton pattern in Java? ...
Edit: From another question I provided an answer that has links to a lot of questions/answers about singeltons: More info about singletons here: So I have read the thread Singletons: good design or a crutch? And the argument still rages. I see Singletons as a Design Pattern (good and bad). The problem with Singleton is not the Patte...
Do not waste your time with this question. Follow up to: http://stackoverflow.com/questions/137975/what-is-so-bad-about-singletons Please feel free to bitch on Singleton. Inappropriate usage of Singleton may cause lot of paint. What kind of problem do you experienced with singleton? What is common misuse of this pattern? After som...
I got this síngleton cache object and it exposes an IEnumerable property which just returns a private IEnumerable variable. I have a static method on my singleton object that updates this member variable (that exists on the single 'Instance' instance of this cache object). Let's say some thread is currently iterating over this IEnumer...
What is the benefit of using singleton instead of global for database connections in PHP? I feel using singleton instead of global makes the code unnecessarily complex. Code with Global $conn = new PDO(...); function getSomething() { global $conn; . . . } Code with Singleton class DB_Instance { private static $d...
Since AS3 does not allow private constructors, it seems the only way to construct a singleton and guarantee the constructor isn't explicitly created via "new" is to pass a single parameter and check it. I've heard two recommendations, one is to check the caller and ensure it's the static getInstance(), and the other is to have a private...
When should you NOT use a singleton class although it might be very tempting to do so? It would be very nice if we had a list of most common instances of 'singletonitis' that we should take care to avoid. ...
The Singleton pattern is a fully paid up member of the GoF Patterns Book but lately seems rather orphaned by the developer world. I still use quite a lot of singletons, especially for Factory classes, and while you have to be a bit careful about multithreading issues (like any class actually) fail to see why they are so awful. This site...
Following on from Ewan Makepeace 's excellent earlier question about the Singleton pattern, I thought I would ask "when does the Community believe that it is appropriate to use a Singleton?" Let me offer up an example to critique: I have an "IconManager" singleton. It begins by reading a properties file which indicates where my icons ...