CODEWITHSUNDEEP
javaobjectmethodsreturnjava-stream
Donne
Donne

Reputation: 61

Getting object from stream JAVA

I am trying to find Friend by firstName and lastName using stream. Is it possible to return object from this stream? Like friend with that name and lastname? Because now return is mismatched.

@Override
public Friend findFriend(String firstName, String lastName) throws FriendNotFoundException { 
    if (firstName == null || lastName ==null) {
         throw new IllegalArgumentException("There is no parameters");
    }

           List<Friend> result = friends.stream()
            .filter(x -> (firstName.equals(x.getFirstName())) && 
            (lastName.equals(x.getLastName()))))
            .collect(Collectors.toList());

            return result;

Upvotes: 1

Views: 320

Answers (1)

Ousmane D.
Ousmane D.

Reputation: 56469

utilize findFirst like so:

return friends.stream()
              .filter(x -> firstName.equals(x.getFirstName()) && 
                            lastName.equals(x.getLastName())
                     )
              .findFirst().orElse(null);

or return an Optional<Friend> i.e:

@Override
public Optional<Friend> findFriend(String firstName, String lastName) throws FriendNotFoundException { 
       if (firstName == null || lastName == null) {
          throw new IllegalArgumentException("There is no parameters");
       }

       return friends.stream()
              .filter(x -> firstName.equals(x.getFirstName()) && 
                            lastName.equals(x.getLastName())
                     )
              .findFirst();
}

which then means the method you're overriding must also be declared to return an Optional<Friend> and so forth up the inheritance hierarchy if needed.

Upvotes: 2

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