java-tutorials/spark-java/src/main/java/com/baeldung/sparkjava/UserService.java

package com.baeldung.sparkjava;

import java.util.Collection;

public interface UserService {
    public void addUser (User user) ;
    public Collection<User> getUsers () ;
    public User getUser (String id) ;
    public User editUser (User user) throws UserException;
    public void deleteUser (String id) ;
    public boolean userExist (String id);
}