Ok, this might be a little hard to explain. I'm looking for a way to build a Hashmap of some sort, which will be populated with keys that I already know (because they are properties of the object I am creating). Each of these known keys will have values that are either a String, an int or float (which will be autoboxed), or - later - some kind of object/ function (I still don't know how I'll do that part, but it'll be further along the way anyway). I also want to set which type accepts each of the key (say key "x" will only accept an Integer type of value, key "equation" will only accept a string, etc.).
Just to give more context, my goal is to build a Tweener utility, as I found no such library in Java, except for SumoTween, that doesn't fit my needs at all. I'm kind of trying to build my classes the way Caurina is. If you have a better alternative that would save me time and trouble, please feel free to share (be it about Tweeners or about my Hashmap question). By the way, I'm doing this Tweener to use it in an Android game I'm building, in order to do animations on bitmap/drawable objects (can't use the animation classes for those afaik).
PS : This is my first question on this website, I hope I don't sound too confused; Please bear with me.
Why are you using a hashmap for this? If you have known "keys", just make a class with those members and then you can type them however you want.
If you really must use a hashmap for some reason, you can just extend it and override the put() method to check for your magic values. But I strongly recommend against that, it's poor design.