How to setup global object?

I need to serve some contents to each post. Lots of functions and several classes involved so that I can’t pack them into one single function to be called. I need to setup an object.
In buddypress, I know I can setup a root component, then, can manipulate variables and functions under a component. for example:
$bp->docs->doc->a;
$bp->docs->b;
In WP, which way I can setup a global object like that?

I’m new in php, please help!