The singleton is a design pattern to ensure that exactly one application-wide instance of a particular class exists.

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Singleton base class

I just wrote a singleton base class for a hobby project I'm currently working on. Python is not my first language, which is why I am not sure if everything is done the pythonic way. I also used ...
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55 views

Manage Sessions within a Singleton

I am looking for advice if the below code is a good idea or not. If not, why? I am building a website which allows a user to purchase items. The user account and cart items will be stored in Session. ...
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31 views

Javascript singleton to notify different objects of changes in viewport size

I'm working on a singleton object to manage size changes in the viewport, I wanted it to be a singleton because there may be different unrelated objects that need to be notified when a change in ...
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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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85 views

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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54 views

Ruby singleton for logging

I currently have a logging setup that looks like this: ...
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104 views

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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1answer
72 views

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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3answers
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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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1answer
114 views

Correct usage for singleton and reusability?

I've made the following DataSetReader, DS Attribute, and DataSetManager. My main concerns ...
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182 views

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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1answer
124 views

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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39 views

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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74 views

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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119 views

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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114 views

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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1answer
137 views

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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73 views

Singleton request validator and sanitizor class

I have tried to code a PHP singleton class for validating multiple/single fields (sanitizing is optional). When validating single field, on success it will return 1 (...
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2answers
274 views

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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1answer
851 views

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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2answers
284 views

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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1answer
91 views

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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470 views

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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2answers
703 views

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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2answers
816 views

Singleton necessary in DAO

I am using a singleton in my DAO. Would I be better with static methods? Also, should I be worried about synchronization of the singleton and my data statures? ...
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Class refactoring including changing instance methods to class methods and adding 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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2answers
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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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2answers
572 views

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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1answer
715 views

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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341 views

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 ...
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1answer
92 views

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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100 views

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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4answers
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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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1answer
206 views

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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2answers
384 views

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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1answer
225 views

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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1answer
715 views

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 ...
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633 views

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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2answers
2k views

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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1answer
90 views

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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1answer
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PHP starting OOP MySQLi singleton

this is my first post on the whole StackExchange network, so I might make some mistakes. And I'm also spanish spearker, so I'll probably have mistakes in my writting too.. Context: I'm starting with ...
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411 views

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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1answer
140 views

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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2answers
602 views

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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1answer
176 views

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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1answer
2k views

PDO class for multiple databases

I have a PDO class below: ...