Hence it is quite easy. Animation's would handle Texture "int" bindings in an usual array of int's.
I'm using for myself hashCode() and openGL bindings in a static HashMap that is updated each time it is needed. One thing really I'm sure : storing int's--hashCode's are and bindings so they are--is faster than running over String's. BTW String's have unique hashCode's too.At least you can (watch out you have to re-define hashCode() with correct values--e.g. System.nanoTime()) specify each texture as Object's with specific parameters such as size or color mode.