Linked Questions
15 questions linked to/from So Singletons are bad, then what?
72
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When is Singleton appropriate? [duplicate]
There is a widely accepted opinion that Singleton is an anti-pattern. As usual, there are always exceptions to the rule. Can you explain why Singleton is a bad choice in general and give an example of ...
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38
votes
3
answers
75k
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When to use a Singleton and when to use a static class [duplicate]
I've searched about this here and on StackOverflow and found some differences between the two.
But I'm still not sure in what cases one would prefer a Singleton, and in what cases one would choose to ...
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26
votes
7
answers
4k
views
The Singleton Pattern [duplicate]
Possible Duplicate:
When is Singleton appropriate?
I am a new programmer (4 months into my first job) and have recently taken an interest in design patterns. One that I have used recently is the ...
- 2,175
31
votes
5
answers
36k
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What is the difference between all-static-methods and applying a singleton pattern? [duplicate]
I am making a database to store information about the users of my website (I am using stuts2 and hence Java EE technology). For the database I'll be making a DBManager. Should I apply singleton ...
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5
votes
5
answers
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How do I deal with global variables in existing legacy code (or, what's better, global hell or pattern hell)?
So... We have this fairly complex project (~10k LOC, but there's duplicated code so it's hard to tell) with hundreds of global variables. The project has more dependencies on other projects, and many ...
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5
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2
answers
4k
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What alternatives to a singleton are there for a class which only can have one instance?
I need to represent an abstraction over various parts of the hardware for a game. I'm trying to decouple the code that does things like manage the logic of the game from the code that is API/platform ...
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4
votes
2
answers
4k
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What's wrong with using a Singleton?
I'm working on a Python application in which there are two Singleton classes: App and Configuration.
The former seems straight forward, only ever instantiate one App instance; the latter seems ...
- 1,047
5
votes
2
answers
5k
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What is a relation between Dependency Injection, single instance, and singletons?
I read So Singletons are bad, then what? which was a great explanation of dependency injection as the solution for inversion of control. The asker assumed singleton and single instance were synonyms, ...
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1
vote
3
answers
3k
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Why does dependency injection encourage collaboration to be exposed via constructors?
The general approach to DI that I see in answers like
So Singletons are bad, then what? encourages
business objects that collaborate with other objects to (a) not
directly create those instances and (...
4
votes
2
answers
821
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A module which is used by most other modules
I am pursuing object oriented design. So we don't want to use globals but yet sometime we have a module that most other modules use. This means we have to just pass it to all other modules and this ...
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2
votes
4
answers
334
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Do more object declarations affect the program?
I am programming in Windows Forms and MySQL.
If I declare this in the program, I can use the connection and command objects in the whole .cs page:
MySqlConnection connection = null;
MySqlCommand ...
- 205
1
vote
2
answers
364
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Is singleton the right way to go in the case of a game?
I've been reading the top posts of stackoverflow and SE and all over the place it says how bad singletons are but I am unsure how to rewrite my code.
As of now I have two projects that bind into a ...
- 119
0
votes
2
answers
195
views
Why session should be a param when you write a query function?
I read a lot of examples where I read code like this:
def get_user_by_id(session, id)
...
and the function that calls that function needs to create or get the DB session a pass to the function.
the ...
- 387
0
votes
1
answer
1k
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Why use the Singleton pattern over class functions and fields? [duplicate]
I'm going to start by saying that I understand that programming in mostly class functions and variables can be harmful to object-orientation, and that most of the time an instance is preferred. I'll ...
- 545
2
votes
0
answers
119
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Convert singleton to single instance with concrete Go example
I have been using singletons in the past.
However, reading articles like Singletons are Pathological Liars have led me to explore alternatives to singletons.
There are a few posts discussion ...
- 121