Performance concern with deferred loading.

Question

I've been reading a great tutorial of making Space Invaders. Each frame, it checks if the sprite is in a HashMap instance. If it finds the key, the value is assigned for drawing. If it's not found, we would load it. This is referred to as differed loading for later complex games. Anyway, my concern is every frame, it checks this hash map. Wouldn't this kill performance? Any better ways of handling this?
Here's a link to the code:
http://www.planetalia.com/cursos/Java-Invaders/JAVA-INVADERS-11.tutorial
Thanks,
Phil

Answer 1

Anyway, my concern is every
frame, it checks this hash map. Wouldn't this kill
performance?Yeah, it might take the frame as much as one microsecond longer to display. But probably not nearly that much.
Computers are fast. Displays are slow. People's perceptions of displays are extremely slow. If you saw the code that runs as you drag a piece of code from one place to another place in your text editor you would (a) be astonished at how much code gets run repeatedly, and (b) notice that that code is much more complicated than just a little hashmap lookup.