Multiple and Fluent Comparisons

Let’s look at the new convenience methods added to the Comparator interface and use them to compare with ease based on multiple properties.

We’ll continue with the example from the previous section. To sort people by their name we used this:

 
people.stream()
 
.sorted((person1, person2) ->
 
person1.getName().compareTo(person2.getName()));

The syntax is quite concise compared to the inner-classes syntax from yesteryear. But we can do better thanks to convenience functions in the Comparator interface. We can more fluently express our objectives using them. For example, to sort people by comparing their names, we can write this:

compare/fpij/Compare.java
 
final​ Function<Person, ​String​> byName = person -> person.getName(); ...

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