February 2014
Intermediate to advanced
160 pages
4h 59m
English
Content preview from Functional Programming in Java
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
Start your free trial
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(); ... |