Questions tagged [singleton]
The singleton is a design pattern to ensure that exactly one application-wide instance of a particular class exists.
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Building in the built-in declarations
In order for Rubberduck to be able to "recognize" the built-in VBA functions, procedures and objects, I added yet another constructor parameter to my Declaration ...
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Dependency injection thread safety
Is it OK to mix different lifetime of ISerializer and ICacheProvider in this case? I am using Unity DI. In this case, whenever <...
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A Singleton Base and derived class
I have a base and derived class since I need to have different kinds of concrete classes.
I cannot use the getInstance() function in the base class since I cannot ...
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Reducing lock contention for a caching utility, or make it totally lockless but threadsafe
My Java program is a module called configProxy which fetches configuration entries from a remote node (say from a Redis instance). When the caller calls the ...
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Swift 1.2 Singleton Implementation
I am pretty new to Swift, as a solo developer I was wondering if somebody could pass comments on the singleton implementation below. The code does work, but being new to Swift and knowing that there ...
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Correct usage for singleton and reusability?
I've made the following DataSetReader, DS Attribute, and DataSetManager.
My main concerns ...
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Design of a remoteControl class for connecting to electronic devices
In a course that I'm taking on learning object oriented programming in java, I have completed an assignment for modeling a home entertainment system and the ability for a user to be able to use a ...
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PHP framework building: initializer and object loader classes
I am building a PHP framework and would like to get some feedback on a few different sections of the project. I consider myself still a neophyte in PHP so I would like to ask if I'm going about ...
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Managing a collection of object instances and getting them back out with instance manager / service locator
I'm creating an event loop for an asynchronous event execution library for PHP in PHP. Note that this is for a library and not an application. My event loop is just that -- a simple event loop that ...
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Execute startup method asynchronously
The goal is to call startManager on application start so that the manager is initialized in background without blocking application main thread.
Is it a safe ...
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Storing messages for the application's runtime
I am currently writing a well.. manual testing site for a chat-based bot. The full code can be found on github.
For that purpose I had to keep track of the messages currently in the "system". The ...
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Blocking builder with singleton
I am trying to implement a singleton builder that would be shared across
multiple builder threads for Coordinate objects.
Here is the simplified target class ...
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Ensure only a single instance of static template class member
I am interacting with a C library, whose documentation states that certain functions are not thread safe. Since its functions deal heterogeneously with multiple types, I have written a template ...
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Thread-safe Phoenix Singleton class template with Boost
I've implemented the phoenix-singleton as a class template with boost inspired by Modern C++ Design. The code compiles fine with MSVC 2013 - and it seems to work, but I'm new
to multi-threaded ...
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Can we now `implement Singleton` using Java 8?
After my success with extending enum - I thought I would try to make Singleton creation as simple as possible since Java-8 makes ...
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Proper way to wait end of a service and singleton design
My code works fine and I would like to know if I chose the best strategy to implement my code, or if It can written better (more fast, more clear, best use of design pattern, etc).
In my android ...
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Lazy singleton with BackboneJS
I am trying to have a Backbone.Model which is a singleton and I wish to instantiate it lazily. I only need to support modern browsers so please do not worry about the use of ES5 getter.
Is this the ...
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Singleton Database class
Currently my team is building an application involving a database. We have to write a lot of data (approx 2,000,000 records) to the database and therefore we decided to open a connection once and ...
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Singleton Database wrapper
Before everybody yells at me about why I wrote a PDO wrapper class, it's to avoid writing try/catch, ...
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Correct way to implement a Singleton field
I have a helper class that does HTTP operations on Android. Every method uses a client field. I think it's a good idea to make this client a singleton since every method in the class uses it.
The ...
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Necessary singleton in DAO
I am using a singleton in my DAO. Would I be better off with static methods? Also, should I be worried about synchronization of the singleton and my data structures?...
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Address book with singletons
My main goal with this refactor was to change instance methods that should have been class methods in the first place into class methods. My secondary goal was to add singletons to these classes ...
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Static variable representing program state accessed with multiple functions
I have this method that performs certain functions based on the state that the algorithm is currently at:
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PHP Trait Singleton
An implementation of the singleton pattern in PHP using a trait (added in 5.4). Is there anything missing, any ways to create a second copy of the class?
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Searching for songs on an Android application
In my application I need to search for some songs on my external storage card every now and then. On startup I read everything, however when it comes to new activities I thought I could just pass the ...
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Android global data
I have a huge list of song objects in my program and I need those objects in almost all activities. Well, at least a part of it up to everything.
So I created a class which looks pretty much like ...
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Is this good design for custom email template?
I read effective Java by Joshua Bloch. And it said use enums over int constant. So I was thinking instead of using hard coded strings I could also use enums. The forgotpassword.txt and confirmation....
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Manage a collection of settings in memory with global scope
I have a WPF app and a bunch of read/write settings that need to be accessible from various view models. a setting can be any type (string, ...
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Singleton-like pattern for a project [closed]
I'm changing the inner implementation of a project. In order to do so, I've created an interface that will be implemented in 2 different ways.
One of this ways is by class ...
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Sound manager for Android
I created a singleton class for managing sound effects on Android. This class will only be instanced and loaded once at the beginning, and each activity will use the loaded songs.
I don't know either ...
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Singleton With Sub-Singletons
I've found myself wanting an easy way to implement chat into various apps, so I developed a set of classes for the firebase.com backend that make it easy for me to quickly set up the nuts and bolts of ...
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Singleton design pattern
I am a beginner in PHP-OOP and design patterns. I have got this basic piece of code in Singleton Pattern and I changed it in order to understand its behavior. I can see that it works as expected.
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A parametrized Config singleton
Here is an attempt to code a specific kind of Singleton - the one geared for our configuration needs. It needs to be initialized with a configuration location, do not allow copies or other instances, ...
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ResourceManager Singleton
As I understand creating lots of resource managers in C# may be a bad idea so I thought that the best thing to do would be to create a singleton for this.
However, I'm not 100% if this is a good idea,...
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Simple Java Singleton
Below is a Singleton that I designed as a piece of sample code for a website I'm working on for fun. The goal is to use the Singleton to hold an Earth object since ...
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Using a singleton class to get and set program wide settings
The following code works and does what I want, but I'd like to confirm I'm using this OOP concept correctly. I'm using the following class to get and set some configuration parameters for my program. ...
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How do I avoid explicit type switching when operation based on state?
I've encountered a problem that I have to solve using dynamic_cast to invoke different functions, depending on the type of class State family.
I was re-factoring a ...
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OOP MySQLi singleton
I'm starting with object oriented programming, but I know PHP procedural style "pretty well" I'd say. I'm working on a ticket support site for this website.
This ...
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Singleton SpinLock: Making Random Thread-Safe
Is this a valid and safe use of .NET's System.Threading.SpinLock?
Why am I doing this?
Random's public methods are not ...
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Creating a singleton container class for intrer-class messaging
My question is for validation of my code (any loop holes / bugs) and guidance the best methodology to implement for my requirement.
I am developing a Python application that will have many classes. ...
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I need code review on using singleton to access local database
As I get to some performance issues in my app and find that I use database access in a bad way.
So I decided to move to singleton pattern.
I need someone to review this code and confirm me that I made ...
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Singleton has logic and state, and logic has state
------edit---------
note: this is for a MUD client, so the commands are issued to the MUD game server
-----end edit--------
For an overview, here's the structure of the project:
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Global data singleton
I need a global data in my application. My application uses several threads to access and add items to my global variable. The global variable is a ...
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Prime Numbers Store
Let's say we need to create a store for selling prime numbers.
Users enter the store and ask to buy a number.
If the number asked is a prime number,
1.1. then it's either available for sale
1.2. ...
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Singleton interface in Java
I've created a singleton by means of an interface. I don't want to make a thing with getInstance() etc because I don't care about inheritance, and it's redundant ...
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