Method reference is a good way to reduce the noise inside our Java streams.
Say that we have a list of names, and we want to map each of them to full name. We can achieve that by using the code below:
public void example() {
List <String> names = Arrays.asList("Jerome", "Steve", "Cathy", "Lara");
names.stream()
.map((String name) -> {
User user = repository.getUser(name);
String fullname = user.firstname + " " + user.lastname;
return fullname;
})
.forEach((String name) -> System.out.println(name));
}
Streams are not good for readability if your lambda methods contain many lines of codes. I prefer to have a rule of thumb that if it's 3 or more lines then we need to extract the code to its dedicated method.
public String getFullname(String name) {
User user = repository.getUser(name);
String fullName = user.firstname + " " + user.lastname;
return fullname;
}
Then use method reference to make our stream more concise and shorter.
public void example() {
List <String> names = Arrays.asList("Jerome", "Steve", "Cathy", "Lara");
names.stream()
.map(this::getFullname)
.forEach((String name) - > System.out.println(name));
}
Note that a properly name method will make a difference. A code map(this::getFullname) can read as an English sentence. That's a sign of a cleaner and better code.
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