does anyone know a map class where the

Entry

objects stay valid when the backing map is modified? I want to hold on to the

Entry

object so I don't have to access the map every time when all I need is that one entry

Why can't you access the map every time you need an item from it?

Because that's an unnecessary access and entries are accessed potentially many many times. So why not just keep ahold of the entry

Pretty much the one thing maps are good at is element access.

if you only care about complexity, yes. But the constant cost is high. Every time the hash function has to be computed again. If the

Entry

can be cached, each subsequent access only costs an additional pointer dereference over a regular variable

Fair enough.