Sponsored Content
Full Discussion: What is singleton class ?
Top Forums Programming What is singleton class ? Post 302470401 by parusasi on Wednesday 10th of November 2010 03:39:06 AM
Old 11-10-2010
Hi ,
A singleton class means you instantiate only one object of that class at a time. For example if you want to make an application in such a way that only one instance of that exe should execute at a time, you can make that class a singleton class. To make a class a singleton class, you have to make its contrustors private and write a static method for creating an object.
 

10 More Discussions You Might Find Interesting

1. UNIX Desktop Questions & Answers

It's first class!

Hi..!!!You have a very nice web-site! Good work!I am also webmaster and I like this one!Thank you! (1 Reply)
Discussion started by: Hardan
1 Replies

2. UNIX for Dummies Questions & Answers

car class (not school class)

im just trying to have some fun and kill some time writing a c++ program that has a person type in a car make and model then gives them a year and a price. or something like that. i always have problems getting it goin but once the ball is rolling im usually pretty good. anyone wanna help me out? ... (1 Reply)
Discussion started by: rickym2626
1 Replies

3. Programming

C++ class definition with a member of the same class

Hi, i have a question about C++. Is it possible to declare a class with a member ot the same class? For example, a linked list or i want to convert this C code to C++ class (Elemento) typedef struct elemento { char name; char value; List<struct elemento> ltElementos; ... (7 Replies)
Discussion started by: pogdorica
7 Replies

4. Programming

static use for class inside the same class c++

Hi, I believe the next code is wrong: class Egg { Egg e; int i; Egg(int ii=0) : i(ii) {} }; because you would end up with an endless definition (memory allocation) of Egg objects, thus int i. Ok, so God Eckel proposes for a singleton: class Egg { static Egg e; int... (5 Replies)
Discussion started by: xavipoes
5 Replies

5. Programming

C++ abstract (singleton) factory implementation...

I want to create an abstract factory template which will allow me to pass in an "ID" for a subclass and return the singleton instance of that class stored in the factory. It'd be easy to adapt for "multi-ton", but for its present use this isn't necessary. The requirements are: - I don't want... (2 Replies)
Discussion started by: DreamWarrior
2 Replies

6. Programming

C++ singleton

How to write a class that can only be instancialized once? what about my implementation below? #include<iostream> #include<stdexcept> using namespace std; class Singleton { public: int b; Singleton(); private: static int num; }; int Singleton::num = 1; (10 Replies)
Discussion started by: vistastar
10 Replies

7. UNIX for Advanced & Expert Users

Get pointer for existing device class (struct class) in Linux kernel module

Hi all! I am trying to register a device in an existing device class, but I am having trouble getting the pointer to an existing class. I can create a class in a module, get the pointer to it and then use it to register the device with: *cl = class_create(THIS_MODULE, className);... (0 Replies)
Discussion started by: hdaniel@ualg.pt
0 Replies

8. Programming

Size of Derived class, upon virtual base class inheritance

I have the two class definition as follows. class A { public: int a; }; class B : virtual public A{ }; The size of class A is shown as 4, and size of class B is shown as 16. Why is this effect ?. (2 Replies)
Discussion started by: techmonk
2 Replies

9. Programming

C++ : Base class member function not accessible from derived class

Hello All, I am a learner in C++. I was testing my inheritance knowledge with following piece of code. #include <iostream> using namespace std; class base { public : void display() { cout << "In base display()" << endl; } void display(int k) {... (2 Replies)
Discussion started by: anand.shah
2 Replies

10. UNIX for Beginners Questions & Answers

AIX errpt : ( E7A89C7D Local adapter disabled after unstable singleton for long time )

Medel : 9117-MMC OS: AIX 6.1 Patch level : 6100-07-04-1216 Hacmp version : HACMP v 6.1.0.8 Oracle : 11.2.0.3 RAC Node : 2 node Dear, my one node server has been restarted early this morning, So, i tried to start HA and Oracle database. after that, the follow error appears at the node... (1 Reply)
Discussion started by: tomato00
1 Replies
MooseX::Singleton(3)					User Contributed Perl Documentation				      MooseX::Singleton(3)

NAME
MooseX::Singleton - turn your Moose class into a singleton VERSION
version 0.29 SYNOPSIS
package MyApp; use MooseX::Singleton; has env => ( is => 'rw', isa => 'HashRef[Str]', default => sub { \%ENV }, ); package main; delete MyApp->env->{PATH}; my $instance = MyApp->instance; my $same = MyApp->instance; DESCRIPTION
A singleton is a class that has only one instance in an application. "MooseX::Singleton" lets you easily upgrade (or downgrade, as it were) your Moose class to a singleton. All you should need to do to transform your class is to change "use Moose" to "use MooseX::Singleton". This module uses metaclass roles to do its magic, so it should cooperate with most other "MooseX" modules. METHODS
A singleton class will have the following additional methods: Singleton->instance This returns the singleton instance for the given package. This method does not accept any arguments. If the instance does not yet exist, it is created with its defaults values. This means that if your singleton requires arguments, calling "instance" will die if the object has not already been initialized. Singleton->initialize(%args) This method can be called only once per class. It explicitly initializes the singleton object with the given arguments. Singleton->_clear_instance This clears the existing singleton instance for the class. Obviously, this is meant for use only inside the class itself. Singleton->new This method currently works like a hybrid of "initialize" and "instance". However, calling "new" directly will probably be deprecated in a future release. Instead, call "initialize" or "instance" as appropriate. BUGS
Please report any bugs or feature requests to "bug-moosex-singleton@rt.cpan.org", or through the web interface at <http://rt.cpan.org>. We will be notified, and then you'll automatically be notified of progress on your bug as we make changes. SOME CODE STOLEN FROM
Anders Nor Berle <debolaz@gmail.com> AND PATCHES FROM
Ricardo SIGNES <rjbs@cpan.org> AUTHOR
Shawn M Moore <sartak@gmail.com> COPYRIGHT AND LICENSE
This software is copyright (c) 2011 by Shawn M Moore. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. perl v5.18.2 2011-12-08 MooseX::Singleton(3)
All times are GMT -4. The time now is 07:35 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy