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Re: singleton in php?




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On September 2, 2018 at 3:15 PM Jeffry Killen <jekillen@xxxxxxxxxxx> wrote:


Hello;

I have been trying to get a better understanding of "singleton".

It is defined as a class that can only produce one instance of
itself.

In the online explanation, that is accomplished by a
private constructor function that produces an instance
of the class within its instance.

But in php I am of the understanding that a constructor
function has to be made public and can't return anything.

Here is the online reference I am looking at:
https://www.techopedia.com/definition/15830/singleton

So, at some point it seems that the class instance has to
be exported via a return statement at some point, otherwise
how would it be used in other code?

Is there a part of the manual that addresses this?

I have a hard copy text* on PHP that addresses the singleton
and factory pattern, but I have not been able to completely
comprehend either of these.

*I don't have immediate access to the book and don't remember
the title, but the publisher is Friends of Ed / (Apress).

I have been further thrown off by the use of singleton
to refer to an object literal in _javascript_.

I realize that this in not about _javascript_ but the concept
and this use of the term has me confused.

More than one object literal can be created and subsequently
cloned by code, so how is it a singleton, in the general sense?

Thank you for time and attention.

JK