I'm currently working on a Java project and I have a specific scenario where I need to perform operations on a collection of objects. I'm wondering which approach would be more efficient in terms of performance.
Let's say I have an array x of objects of type A, and each object A has a reference to an object of type B as a member (A.c.b). I need to perform some operation on each B object.
Approach 1: Creating a map and then iterating over it
Map<A, B> map = new HashMap<>();
for (A a : x) {
map.put(a, a.c.b);
}
for (Map.Entry<A, B> entry : map.entrySet()) {
entry.getValue().dosomeoperation();
}
Approach 2: Directly performing the operation on the objects
for (A a : x) {
a.c.b.dosomeoperation();
}
I understand that Approach 2 eliminates the overhead of creating and populating a map, but I'm not sure about the actual performance difference between the two approaches. Could someone with expertise shed some light on this?
In my specific case, the size of the x array can vary, and I'm interested in optimizing the performance of my code. It would be helpful to understand the potential performance implications of these approaches and any factors I should consider while making a decision.
Any insights or alternative suggestions would be greatly appreciated. Thank you in advance!
The Map shown in your Question adds no value. It creates an association between the object a and its nested member b. But you already had an association of a to b: the nested field membership is that association.
If you are performing a single operation on a nested member field, just access that field.
No need to involve any collections. Creating a collection with no specific purpose, such as ordering/sorting, is just additional work with no benefit.
for (A a : x) {
a.c.b.dosomeoperation();
}
Or use streams.
Arrays
.stream( x )
.forEach(
( A a ) -> a.c.b.dosomeoperation()
) ;
If you have a concern about some complicating factor or operation, revise your Question to explain.