How to avoid the code lose while upgrade the plugin in wordpress

I have been using wordpress plugins and I have customized one of my plugin but I don't want to lose the code what I have created while we upgrade the plugin,is there any way to customize the plugin out side of that plugin folder so we can control it from the theme of the wordpress or some where else.Do any one have solution for this if so please let me kn开发者_StackOverflow中文版ow.

Thanks in advance

Best practice is to use hooks & filters in your wp-theme.

Have a look at:

http://codex.wordpress.org/Plugin_API

http://themeshaper.com/2009/05/03/filters-wordpress-child-themes/