Nested Maps or combined keys in java

Question

I need a Map to make a cache in Java for same values that I have two String keys. My question it\'s better to make nested Maps (one for each key) or make some type of custom

Answer 1

I think that using nested maps is less optimal way. I agree with your second thought - implement a custom class with overriden hashCode

public int hashCode(){
   return str1+str2.hashCode();
}

and equals

public boolean equals(Object o){
   //compare both keys here
}

Also don't forget to override the same methods in the stored object's class.

Then, in case of ["ab", "c"] you will have the same hash code, but different equals result