A couple things jumped out at me when reading this post. First you said "she seems to really dislike this breed. mostly because they try to take her ball." And second you said "the goldendoodle tried to snatch it. now, i made no sudden movements, because i anticipated an attack from mae. which is exactly what she did.

If you have a dog who has a history of dog on dog aggression and you anticipated her attacking the other dog because it wanted to play with her ball, then 1. why didn't you put the ball away before there was a problem and 2. if you anticipated the attack then why didn't you do something to stop it?

I have a very friendly outgoing Golden Retriever male (Dusty) but he is possessive of his frisbee and girl dogs. He doesn't like to share either at all. So when I go to the park and there is another dog who wants to play frisbee too, then I put it away. Nobody gets to play, PERIOD! If there is a girl dog he shows interest in and another male comes, I give him commands to let him know acceptable behavior will be expected. I am always on gaurd to have any situation where Dusty will be attacked or he will attack under quick control. A snap of the leash or a forceful down command always seem to do the trick.

If your dog is not 100% sure of obedience commands and can not do them with distractions, then you need to be even more on the lookout for potential problems at the park. Waiting to find out if your dog will listen in a arroused state is frankly, too late! It doesn't matter how much you spend on obedience classes, it matters that the dog will listen in any situation.

I'm sorry if this seems a little abrupt and not sugar coated but you are responsible for your dog's behavior at the park and if it does attack another dog, you can be sued. If it happens more than twice (at least where I'm from) then you can lose the dog all together.

I believe anyone taking their dog to a dog park needs to be aware that not everyone trains there dog to the level of knowing it will listen no matter what. In fact, very few do. It is natural instinct for them to guard something they love so it has to be our natural instinct to protect them from starting or encountering an attack. It has been a long time since I have had a problem at the park with Dusty, just because I'm quick to see the problem before it happens and to take actions to stop it! You need to anticipate a bit quicker and wiser if you continue to take Mae to the park.

BTW... Welcome to Pet Talk! I hope I didn't scare you away.