arraylist - Check whether list of custom objects have same value for a property in Java 8

Question

I am new to Java 8. I have a list of custom objects of type A, where A is like below:

 class A {
      int id;
      String name;
 }

I would like to determine if all the objects in that list have same name. I can do it by iterating over the list and capturing previous and current value of names. In that context, I found How to count number of custom objects in list which have same value for one of its attribute. But is there any better way to do the same in java 8 using stream?

Answer 1

You can map from A --> String , apply the distinct intermediate operation, utilise limit(2) to enable optimisation where possible and then check if count is less than or equal to 1 in which case all objects have the same name and if not then they do not all have the same name.

boolean result = myList.stream()
                       .map(A::getName)
                       .distinct()
                       .limit(2)
                       .count() <= 1;

With the example shown above, we leverage the limit(2) operation so that we stop as soon as we find two distinct object names.