Status message

Maintenant, vous regardez: Singleton

Singleton

Submitted by elyzium on Thu, 2019-03-21 17:12

Real world example: There can only be one president of a country at a time. The same president has to be brought to action, whenever duty calls. President here is singleton.
Purpose: To have only one instance of this object in the application that will handle all calls.

Key: To create a singleton, make the constructor private, disable cloning, disable extension and create a static variable to house the instance

  1. namespace DesignPatterns\Creational\Singleton;
  2.  
  3. final class Singleton
  4. {
  5.     /**
  6.      * @var Singleton
  7.      */
  8.     private static $instance;
  9.  
  10.     /**
  11.      * gets the instance via lazy initialization (created on first usage)
  12.      */
  13.     public static function getInstance(): Singleton
  14.     {
  15.         if (null === static::$instance) {
  16.             static::$instance = new static();
  17.         }
  18.  
  19.         return static::$instance;
  20.     }
  21.  
  22.     /**
  23.      * is not allowed to call from outside to prevent from creating multiple instances,
  24.      * to use the singleton, you have to obtain the instance from Singleton::getInstance() instead
  25.      */
  26.     private function __construct()
  27.     {
  28.     }
  29.  
  30.     /**
  31.      * prevent the instance from being cloned (which would create a second instance of it)
  32.      */
  33.     private function __clone()
  34.     {
  35.     }
  36.  
  37.     /**
  38.      * prevent from being unserialized (which would create a second instance of it)
  39.      */
  40.     private function __wakeup()
  41.     {
  42.     }
  43. }

Test:

  1. $firstCall = Singleton::getInstance();
  2. $secondCall = Singleton::getInstance();
  3.  
  4. var_dump($firstCall === $secondCall); // true

Tags:

Comments

AlfredoLow (not verified)

Sat, 2020-02-01 22:38

http://tribtaiti.webcindario.com/ reputable canadian prescriptions online
online pharmacies mexico http://tribtaiti.webcindario.com/
canadian medications list http://tribtaiti.webcindario.com/

AlfredoLow (not verified)

Sun, 2020-02-02 21:13

https://viagracwithoutdoctor.com/ canadian drugstore
are canadian online pharmacies safe https://viagracwithoutdoctor.com/
trust pharmacy canada https://viagracwithoutdoctor.com/

AlfredoLow (not verified)

Sun, 2020-02-02 23:21

https://viagracwithoutdoctor.com/ canada medication prices
drugstore online canada https://viagracwithoutdoctor.com/
drugs for sale on internet https://viagracwithoutdoctor.com/

AlfredoLow (not verified)

Mon, 2020-02-03 01:37

https://canadianlpharmacy.com/ canadian pharmacies shipping to usa
canadian discount pharmacies in canada https://canadianlpharmacy.com/
Northwest Pharmacy https://canadianlpharmacy.com/

Dirk (not verified)

Tue, 2020-08-25 01:32

Great delivery. Great arguments. Keep up the great spirit.

My blog post - v bucks free

AlfredoLow (not verified)

Mon, 2020-02-03 02:40

https://canadianlpharmacy.com/ canadian pharmacy
canada online pharmacy https://canadianlpharmacy.com/
pharmacy canada online prescriptions https://canadianlpharmacy.com/

Susana (not verified)

Tue, 2020-08-25 03:48

hello there and thank you for your information – I've definitely picked up anything new from right

here. I did however expertise some technical points using this site, as I experienced to reload the

site lots of times previous to I could get it to load

correctly. I had been wondering if your web host is OK? Not that I'm complaining,

but slow loading instances times will often affect

your placement in google and can damage your quality score if ads and marketing

with Adwords. Anyway I am adding this RSS to my email and could look out for

a lot more of your respective intriguing content.

Make sure you update this again very soon.

My web-site :: free vbucks generator

Finley (not verified)

Tue, 2020-08-25 06:37

Howdy just wanted to give you a quick heads

up. The text in your article seem to be running off

the screen in Firefox. I'm not sure if this is a formatting issue or something to do

with internet browser compatibility but I thought I'd post to let you know.

The style and design look great though! Hope you

get the issue fixed soon. Many thanks

My web site; free vbucks generator

Randall (not verified)

Tue, 2020-08-25 06:54

Heya i am for the first time here. I came across this board

and I find It truly useful & it helped me out much.

I hope to give something back and aid others like you aided me.

Feel free to visit my page - free vbucks generator

AlfredoLow (not verified)

Mon, 2020-02-03 03:44

https://viagracwithoutdoctor.com/ aarp recommended canadian online pharmacies
pharmacy canada https://viagracwithoutdoctor.com/
canadian medications pharmacy https://viagracwithoutdoctor.com/

Mari (not verified)

Tue, 2020-08-25 00:13

Good day! Do you know if they make any plugins to help with Search Engine Optimization? I'm trying to get my

blog to rank for some targeted keywords but

I'm not seeing very good success. If you know of any please share.

Many thanks!

Look at my blog post; v bucks free generator

AlfredoLow (not verified)

Mon, 2020-02-03 04:51

https://canadianlpharmacy.com/ canada vagra
canadian discount pharmacies in ocala fl https://canadianlpharmacy.com/
online drug store https://canadianlpharmacy.com/

Maricela (not verified)

Tue, 2020-08-25 00:44

Thank you for the auspicious writeup. It in fact was

once a enjoyment account it. Look complicated to far brought agreeable from

you! By the way, how could we keep in touch?

Look into my web site free vbucks generator

Lien (not verified)

Tue, 2020-08-25 05:11

Appreciation to my father who stated to me about this weblog, this website is in fact awesome.

Also visit my blog post; v bucks free generator

AlfredoLow (not verified)

Mon, 2020-02-03 06:00

https://canadianlpharmacy.com/ Canadian Pharmacy USA
safe canadian online pharmacies https://canadianlpharmacy.com/
pharmacy canada https://canadianlpharmacy.com/

AlfredoLow (not verified)

Mon, 2020-02-03 07:06

https://viagracwithoutdoctor.com/ canadian pharmaceuticals reviews
canadian drug https://viagracwithoutdoctor.com/
canadian pharmaceuticals stocks https://viagracwithoutdoctor.com/

AlfredoLow (not verified)

Mon, 2020-02-03 08:09

https://canadianhpharmacy.com/ pharmacy canada 24
canadian medications https://canadianhpharmacy.com/
best canadian pharmacies online https://canadianhpharmacy.com/

AlfredoLow (not verified)

Mon, 2020-02-03 09:13

https://viagrawwithoutdoctor.com/ trusted pharmacy canada
drugs for sale in mexico https://viagrawwithoutdoctor.com/
canada medication cost https://viagrawwithoutdoctor.com/

AlfredoLow (not verified)

Mon, 2020-02-03 10:23

https://canadianlpharmacy.com/ canada online pharmacy
drugs for sale https://canadianlpharmacy.com/
online canadian pharmacy https://canadianlpharmacy.com/

Selina (not verified)

Tue, 2020-08-25 06:38

You're so cool! I don't think I've truly

read through something like this before. So great to find another person with a few unique thoughts on this subject.

Seriously.. thanks for starting this up. This site is one thing that's needed

on the internet, someone with some originality!

Here is my website - v bucks free generator

AlfredoLow (not verified)

Mon, 2020-02-03 11:31

https://viagrawwithoutdoctor.com/ drugs for sale in mexico
drugs for sale in mexico https://viagrawwithoutdoctor.com/
canadian pharmaceuticals online https://viagrawwithoutdoctor.com/

AlfredoLow (not verified)

Mon, 2020-02-03 12:36

https://viagrawwithoutdoctor.com/ canada pharmacies
canada online pharmacies for men https://viagrawwithoutdoctor.com/
canadian pharmacy https://viagrawwithoutdoctor.com/

AlfredoLow (not verified)

Mon, 2020-02-03 14:29

https://viagracwithoutdoctor.com/ top rated canadian pharmacies online
how safe are canadian online pharmacies https://viagracwithoutdoctor.com/
trust pharmacy of canada https://viagracwithoutdoctor.com/

Tayla (not verified)

Tue, 2020-08-25 00:17

Yes! Finally something about free the vbucks.

Review my blog post; free vbucks

AlfredoLow (not verified)

Mon, 2020-02-03 15:15

https://canadianhpharmacy.com/ drugs for sale in mexico
drugs for sale deep web https://canadianhpharmacy.com/
canadian medications, liraglutide https://canadianhpharmacy.com/

Nidia (not verified)

Tue, 2020-08-25 00:10

Very nice write-up. I certainly love this website.

Stick with it!

My webpage - free vbucks

AlfredoLow (not verified)

Mon, 2020-02-03 16:18

https://canadianhpharmacy.com/ order canadian prescriptions online
trusted pharmacy canada scam https://canadianhpharmacy.com/
canada pharmaceuticals online https://canadianhpharmacy.com/

AlfredoLow (not verified)

Mon, 2020-02-03 16:56

https://canadianlpharmacy.com/ canadian pharmacy cialis
canada medication prices https://canadianlpharmacy.com/
drugstore online canada https://canadianlpharmacy.com/

AlfredoLow (not verified)

Mon, 2020-02-03 17:37

https://viagrawwithoutdoctor.com/ pharmacy
canada medications cheap https://viagrawwithoutdoctor.com/
buy viagra usa https://viagrawwithoutdoctor.com/

AlfredoLow (not verified)

Mon, 2020-02-03 18:20

https://canadianhpharmacy.com/ is trust pharmacy in canada legitimate
canadian online pharmacies rated https://canadianhpharmacy.com/
online canadian pharmacy https://canadianhpharmacy.com/

AlfredoLow (not verified)

Mon, 2020-02-03 19:05

https://canadianlpharmacy.com/ aarp recommended canadian online pharmacies
pharmacy canada best https://canadianlpharmacy.com/
canadian online pharmacies reviews https://canadianlpharmacy.com/

AlfredoLow (not verified)

Mon, 2020-02-03 20:43

https://canadianhpharmacy.com/ prescriptions from canada without
best canadian pharmacies online https://canadianhpharmacy.com/
canadian discount pharmacies in ocala fl https://canadianhpharmacy.com/

AlfredoLow (not verified)

Mon, 2020-02-03 21:38

https://canadianhpharmacy.com/ buy vistagra online safe
canadian pharmacy no prescription https://canadianhpharmacy.com/
canadian medications pharmacy https://canadianhpharmacy.com/

Angelica (not verified)

Wed, 2020-03-11 13:35

When some one searches for his necessary thing, so he/she

wants to be available that in detail, so that thing is

maintained over here.

accordionists (Orlando)

Gina (not verified)

Tue, 2020-08-25 05:11

Very soon this web site will be famous among all blog viewers, due to it's fastidious

content

My website - v bucks free

AlfredoLow (not verified)

Mon, 2020-02-03 22:31

https://canadianlpharmacy.com/ trusted pharmacy canada
canadian pharmaceuticals online https://canadianlpharmacy.com/
canadian pharcharmy online24 https://canadianlpharmacy.com/

AlfredoLow (not verified)

Mon, 2020-02-03 23:16

https://viagrawwithoutdoctor.com/ canada medications cheap
canadian medications, liraglutide https://viagrawwithoutdoctor.com/
drugs for sale deep web https://viagrawwithoutdoctor.com/

AlfredoLow (not verified)

Tue, 2020-02-04 00:09

https://canadianlpharmacy.com/ northwest pharmacy canada
drugs for sale deep web https://canadianlpharmacy.com/
canadian discount pharmacies in ocala fl https://canadianlpharmacy.com/

AlfredoLow (not verified)

Tue, 2020-02-04 00:54

https://viagracwithoutdoctor.com/ online pharmacies of canada
pharmacy onesource https://viagracwithoutdoctor.com/
how safe are canadian online pharmacies https://viagracwithoutdoctor.com/

AlfredoLow (not verified)

Tue, 2020-02-04 01:38

https://canadianlpharmacy.com/ canadian pharmacies that ship to us
drugstore online shopping reviews https://canadianlpharmacy.com/
buy viagra now https://canadianlpharmacy.com/

AlfredoLow (not verified)

Tue, 2020-02-04 02:27

https://canadianlpharmacy.com/ cialis canadian pharmacy
northwest pharmacies mail order https://canadianlpharmacy.com/
is trust pharmacy in canada legitimate https://canadianlpharmacy.com/

AlfredoLow (not verified)

Tue, 2020-02-04 03:11

https://viagracwithoutdoctor.com/ canadian pharmacy king
canadian medications pharmacy https://viagracwithoutdoctor.com/
canadian pharmacy no prescription https://viagracwithoutdoctor.com/

Michelle (not verified)

Tue, 2020-08-25 06:42

After checking out a handful of the articles on your blog, I honestly like your

technique of blogging. I book-marked it to my bookmark webpage list and will be checking back soon. Take a look at my web site too and

let me know how you feel.

Also visit my web page free the vbucks

AlfredoLow (not verified)

Tue, 2020-02-04 03:56

https://canadianlpharmacy.com/ canada medication prices
online canadian discount pharmacies https://canadianlpharmacy.com/
pharmacy canada plus https://canadianlpharmacy.com/

Karl (not verified)

Tue, 2020-08-25 02:53

You made some really good points there. I checked on the web for more information about

the issue and found most individuals will go along with your views on this website.

Feel free to visit my webpage v bucks free

Sima (not verified)

Tue, 2020-08-25 03:15

Nice blog here! Additionally your web site loads up fast!

What host are you the use of? Can I get your

associate hyperlink for your host? I desire my website

loaded up as quickly as yours lol

Visit my blog :: v bucks free

Erma (not verified)

Tue, 2020-08-25 04:45

I know this if off topic but I'm looking into starting my

own blog and was curious what all is required to get set up?

I'm assuming having a blog like yours would cost a pretty penny?

I'm not very internet smart so I'm not 100% certain. Any recommendations or advice would be greatly appreciated.

Thank you

my webpage - v bucks free

AlfredoLow (not verified)

Tue, 2020-02-04 04:38

https://canadianhpharmacy.com/ buy viagra 25mg
canadian pharmacy king https://canadianhpharmacy.com/
buy viagra online usa https://canadianhpharmacy.com/

AlfredoLow (not verified)

Tue, 2020-02-04 05:22

https://canadianlpharmacy.com/ online canadian discount pharmacies
canadian pharmacy viagra https://canadianlpharmacy.com/
prescriptions from canada without https://canadianlpharmacy.com/

AlfredoLow (not verified)

Tue, 2020-02-04 06:54

https://viagrawwithoutdoctor.com/ canadianpharmacy
canadian discount pharmacies in canada https://viagrawwithoutdoctor.com/
rx from canada https://viagrawwithoutdoctor.com/

Pages

Add new comment

More information about text formats

Filtered HTML

  • Web page addresses and e-mail addresses turn into links automatically.
  • Allowed HTML tags: <a> <em> <strong> <cite> <blockquote> <code> <ul> <ol> <li> <dl> <dt> <dd>
  • Lines and paragraphs break automatically.

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
4 + 6 =
Solve this simple math problem and enter the result. E.g. for 1+3, enter 4.