OCP Solution Part 1

O_OpenClosedSolution.java

public class O_OpenClosedSolution {

    private interface Authentication {
        boolean login(User user);
    }

    private static class AuthenticationLinkedin implements Authentication {
        @Override
        public boolean login(User user) {
            //autêntica o login com o Oauth Linkedin.
        }
    }

    private static class AuthenticationFacebook implements Authentication {
        @Override
        public boolean login(User user) {
            //autêntica o login com o Oauth Facebook.
        }
    }

    private static class AuthenticationDatabase implements Authentication {
        @Override
        public boolean login(User user) {
            ConnectionDAO connectionDAO = new ConnectionDAO("root", "");
            Connection connection = connectionDAO.createConnection();
            //autêntica o login com informações do banco de dados
        }
    }
}