The singleton is a design pattern to ensure that exactly one application-wide instance of a particular class exists.
3
votes
2answers
92 views
Caching all the prepared statements in thread safe way
I have a below Singleton class where in my getStatement method, I populate a CHM by doing if check.
...
3
votes
2answers
68 views
Singleton Pattern + unavoidable Public Constructor
We have an object that needs to be converted to a different type before storing it in database. For that purpose, the library provides an annotation over the field that specifies the appropriate class[...
8
votes
1answer
78 views
Unit-testing friendly singleton
In my project we have a few singletons, which tends to be problematic in unit tests. So I wanted to find solution for the problem. Here is what I came with so far:
smart_singleton.h
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0
votes
2answers
93 views
Header only c++ singleton pattern implementation
I want to implement the singleton pattern in a header only c++ library. (Please refrain from sharing your opinion on the pattern itself!) This would be trivial if I could rely on the compiler ...
4
votes
1answer
90 views
JSON loader with event bus, cache, and session
I have an Android application which needs to retrieve JSON files from a server and then display the information in my app. To accomplish this I have the following architecture:
The main activity adds ...
2
votes
3answers
127 views
Base class for singletons
Even though singletons are bad practice and often unnecessary, I still see many developers using this pattern over and over. Since implementation of this pattern usually requires some common code, I ...
1
vote
1answer
77 views
Singleton Provider
I've taken over a code base that is still very much in it's infancy, and stumbled across this class. I'm just wondering if it's actually worth it to have a ...
0
votes
1answer
41 views
How can I extract these similar codes into only one method? [closed]
I have implemented three ways of Singleton idiom in Java, and now I want to write some test code to see there performance. Here is my code:
...
2
votes
1answer
55 views
Storing global constants in app delegate or singleton
I am converting a non ARC projecs to ARC. I just found that after login in my old app, the data is stored in app delegate objects, like Home_DataArray, various ...
1
vote
1answer
118 views
2
votes
0answers
35 views
Java interface to C library - Refactoring to singleton usage
I am currently writing a Java interface to a C library. It mostly just delegates calls and adds a object oriented layer on top of it to make integration into a regular Java program more natural.
The ...
4
votes
4answers
218 views
Client to connect to server and show a text menu
First of all: Sorry for my English, that said...
I am developing an obligatory for my University, so far it has a class that provides the user with options to connect to a server (once connected it ...
3
votes
2answers
120 views
2
votes
3answers
137 views
Settings class in C# application
I made a settings class for my own C# application. My main goal was to reach this class from every other class (this is why I choose the Singleton pattern). I also wanted to distinguish the different ...
3
votes
0answers
76 views
JavaScript Singleton Pattern/Class “Methods”
I have a library that will be called in multiple places. Here is my implementation:
var vessel1 = new Vessel();
var vessel2 = new Vessel();
...
0
votes
1answer
42 views
Generalizing the Initialization of Singleton Derived Classes
I have the following construct for storing and restoring my applications settings to and from XML.
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2
votes
0answers
64 views
Data structure of in-memory database [closed]
I am learning OOP, SOLID principles and design patterns. I have designed data structure of in-memory database in C#. Please provide suggestions to improve it better considering solid principles, OOP ...
-4
votes
1answer
61 views
Does this work for Singleton Class concept? Trying to fill older HashTable once on login [closed]
I am trying to fill a hashtable with LicenseID and FullName when user first logs in. I don't have access to the Licenses database right now. So "Context" is a place holder. I am at loss if what I am ...
3
votes
1answer
58 views
Composite implementation of a prototype singleton registry
I am studying design patterns and I've implemented a composite prototype pattern which is also a singleton (one instance per JVM). The main and most important part of the code is the ...
3
votes
2answers
86 views
ResourceManager class consisting of multiple singletons
I've implemented a class, which provides access to different static resources, which are used by different frontends. I'm hesitating, because in Java getters and setters are quite wide spread. So my ...
0
votes
1answer
172 views
Singleton manager/service classes with mockable dependencies in swift
In our swift project, there are multiple service classes that encapsulate functions, mostly network-api calls. They implement a protocol, and depend on other service classes, e.g. an authorization ...
2
votes
1answer
141 views
Singleton method for Redis connection in Python
Here's my class for providing a singleton instance of a Redis connection. What do you think?
...
1
vote
0answers
162 views
Using a singleton for a collection of discounts to calculate?
I'm wondering if using a Singleton for a storage of discounts is the right way to go. This is because I will be looping over all added discounts in another class.
client code
...
2
votes
2answers
1k views
Simple singleton database connection pool
I'm studying design patterns, and to demonstrate a singleton, I've implemented a primitive database connection pool.
ConnectionPool.java
...
1
vote
0answers
157 views
JavaScript to connect to Redis using Singleton
I'm trying to create a class to connect to Redis in Express. I don't think my code is good enough as I got variable db hanging out.
...
0
votes
2answers
37 views
Initialization lock for singleton
I'd like someone to double-check my use of Atomic primitives, because multi-threading is hard.
What I don't want to do is locking the whole get method, or having too many pre-checks per get() call.
<...
1
vote
1answer
140 views
Throwing exception in the singleton pattern in C#
I'm implementing an HTTP client shell that's going to be used for the lifetime of my application in C#. It needs to be initialized before the instance can be accessed. It looks something like this:
...
2
votes
1answer
110 views
Singleton implementation of Cache Dependency Manager
I am trying to implement a singleton CacheDependencyManager, by combining this CacheDependencyManager from Steve Greatrex with a singleton pattern from Jon Skeet (example 6).
I'd really appreciate ...
1
vote
0answers
80 views
JavaScript sound manager (singleton / static object using observer pattern)
I have some JavaScript code i would like your feedback on please.
My goals:
SoundManager should be a singleton/static class that has one instance.
...
-1
votes
1answer
92 views
Singleton Service Initialization [closed]
Is it ok to have a Singleton Service with Initialization like this?
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1
vote
0answers
92 views
Claims authorization service usage
I'm doing an AuthorizationService. I'm not sure how to do the usage interface of this service, so that it's practical and handy. It doesn't necessarily has to be an ...
-2
votes
1answer
108 views
Enum Singleton implementation in Java
I just wanted to implement the enum singleton in java. Here is my implementation where I have tried to create a singleton DataSource instance:
...
0
votes
0answers
100 views
Ingest data from an RDBMS to Hadoop Hive database using Sqoop
Context: The below code will run a series of steps in an ETL workflow. I would like the code to be reviewed to avoid memory bottlenecks and null pointer exceptions etc.
UseCase:
Ingest the data from ...
6
votes
1answer
188 views
Generic singleton array with archiving and insertion functions
I find that I often have to maintain a singleton primarily to hold an array that is sometimes persisted between user sessions, that should have only one class of items, and that sometimes needs to be ...
3
votes
1answer
115 views
Singleton Class for WordPress Plugin
I'm developing a WordPress plugin using the singleton pattern with the following requirements:
There should ever exist one instance of the plugin
Another instance of the object should never be ...
6
votes
3answers
238 views
Loading Configurations from plist into singleton
In my iOS application, I've created a singleton class that reads a configuration plist file and provides accessor methods to easily retrieve the values:
...
3
votes
0answers
64 views
Threadsafe singleton factory to use in Apache thrift server RPC system
My goal was to write a factory that the code did not have to be edited. Thus I am registering my factory functions into a singleton factory. I am going to be using this code in Apache thrift server ...
1
vote
1answer
57 views
Application Configuration in PHP
I'm learning PHP and I know too many ways to configure the application.
I use this method:
Folder:
app
config
app.php
db.php
src
class.php
index.php
...
2
votes
1answer
123 views
(Y.E.S.E.J.) Yet Another Singleton with Enum in Java
I have a Java class which has to be generated only once for all the objects that I have - it is a small program. This singleton class holds a mapping of characters. I Googled stack overflow and found ...
6
votes
1answer
118 views
Android app with config and customization classes
I have an Android app with three different Activity classes. Each of the Activities uses and changes config and user-customization data stored in a wrapped ...
6
votes
2answers
252 views
Singleton-ish RMI Server
In this program there is a single remote server which performs miscellaneous work. Because there is only one server, it seems like a singleton pattern could fit well.
The problem that a distributed ...
6
votes
1answer
79 views
Creating an in-memory ViewCounter that commits to database every 10 minutes
This singleton is responsible for counting every pageview (called Routes in our case) we get by id, until the timer runs out and commits the results to the database in one query. Then the counter gets ...
2
votes
1answer
245 views
Global.asax singleton
Please help me decide whether this should be good or bad idea to declare a Singleton variable in Global.asax file. (It is not actually singleton pattern, I just want to make sure that only one ...
3
votes
1answer
313 views
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 ...
3
votes
2answers
597 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. ...
2
votes
1answer
47 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 ...
2
votes
1answer
53 views
6
votes
2answers
211 views
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 ...
1
vote
1answer
357 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 <...
0
votes
1answer
280 views
