Java – add values to terms in the map

I'm trying at @ L_ 403_ 0 @ to add a specific value to the map, where the key is very complex, but the value is a simple double

I'm currently using it, where foos is Java util. Treemap < foo, double >, and amount is double. The code is as follows:

for (java.util.Map.Entry<Foo,Double> entry : foos.entrySet()){     
    foos.put(entry.getKey(),entry.getValue() + amount);    
}

But it looks dirty. I have to reinsert the element. I'm worried about invalidating the iterator

Is there a better way? I am using the latest version of Java

Solution

Since you only want to modify the value, you can use map#replaceall:

foos.replaceAll((k,v) -> v + amount);

Merge is useful if you may have new keys to insert, but this is not the case because you iterate over the same set of keys