correct code question - how to use plugin class file correctly in plugin?

[Jimmi08]

Hi,
I looked at core parts and plugins (f.e. vstore) and there are too many different solutions.
I would like to stick with one and use it in all my plugins.

What I need to know:

• I have a custom plugin
• plugin has file with plugin class (imagine news handler, or forum_class or vstore class) It is class/object with static and other methods.
• plugin stuff can be displayed as single page, menu on other pages or menu on plugin single pages (before or after single page)

In the old way, you would include/ require this file.

vstore is using in single page
/** @var vstore $vstore */

$vstore = e107::getSingleton('vstore', e_PLUGIN.'vstore/vstore.class.php');
$vstore->init();

but menus use:

require_once(e_PLUGIN . 'vstore/vstore.class.php');
$vst = new vstore;

so if the menu is on vstore page, there are 2 vstore classes?

if I use getSingleton() in e_module, should it be available everywhere and with e107::getSingleton('vstore')->anymethod?

The forum plugin is using

require_once(e_PLUGIN . 'forum/forum_class.php');
/** @var e107forum $forum */
$forum = new e107forum;

new forum_front($forum);

and in menu

include_once(e_PLUGIN.'forum/forum_class.php');
$this->forumObj = new e107forum;

Could somebody explain this to me? I vaguely understand the concept (e107 is using Singleton pattern, I know), but what is new code and what is legacy stuff? Why menus are not using e107::getSingleton() too?
And why in some cases is e107::getObject() used and not e107::getSingleton()?

Thanks

[Vodhin]

I'm sure you know that include and require/require_once simply adds the text of the included file to the to the text of the file being loaded, which saves you from writing code more than once.

Use e_module.php to load your required file. It now is available for any page.
require_once(e_PLUGIN . 'vstore/vstore.class.php');

on your plugin page create a new instance for your class.
$vst = new vstore;

on your menu create a new instance for your class.
$vst = new vstore;

This doesn't load the class script twice. If you want to be nice, use unset($vst); at the end of your menu and page to free up server memory.

[Jimmi08]

Thank you. I understand. But this is way how it was used in the past.

Now there getSingleton()... to be sure that class is called only one time.

Just why - if the store is only one advanced example - it can't be coded similarly- the best, recommended - way to be example for other plugins.