Filtering avoiding unexpected null using lambda's inline

Question

I have list for each element I would like to do this (using Java 8):

disabledUsersOnLDAP.stream().forEach(user -> usersRepository
                .findEnabledB         


        

Answer 1

Some alternatives to the @assylias answser.

Use a method reference to Objects==nonNull for the null check:

disabledUsersOnLDAP.stream()
    .map(User::getUsername)
    .map(usersRepository::findEnabledByUsername)
    .filter(Objects::nonNull)
    .forEach(userEntity -> userEntity.setEnabled(false));

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if you can update UserEntity with a disable method

class UserEntity {
    public void disable() {
        setEnabled(false);
    }
}

you can again use a method reference (UserEntity::disable) :

disabledUsersOnLDAP.stream()
    .map(User::getUsername)
    .map(usersRepository::findEnabledByUsername)
    .filter(Objects::nonNull)
    .forEach(UserEntity::disable);

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Some resources:

• Method References on the java tutorial
• JSR 335: Lambda Expressions for the JavaTM Programming Language