[Reactor Practice] Transform

1. map, flatMap

map : 순서 보장 O, one to one transform

flatMap : 순서 보장 X, one to N transform, one to N으로 변경된 Flux or Mono를 구독하여 downstream으로 보냄

Transform Reactor Practice

package io.pivotal.literx;

//generic imports to help with simpler IDEs (ie tech.io)
import java.util.*;
import java.util.function.*;
import java.time.*;

import io.pivotal.literx.domain.User;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

/**
 * Learn how to transform values.
 *
 * @author Sebastien Deleuze
 */
public class Part04Transform {

//========================================================================================

	// TODO Capitalize the user username, firstname and lastname
	Mono<User> capitalizeOne(Mono<User> mono) {
		return mono.map(user -> 
            new User(user.getUsername().toUpperCase(), user.getFirstname().toUpperCase(), user.getLastname().toUpperCase())
        );
	}

//========================================================================================

	// TODO Capitalize the users username, firstName and lastName
	Flux<User> capitalizeMany(Flux<User> flux) {
		return flux.map(user -> 
            new User(user.getUsername().toUpperCase(), user.getFirstname().toUpperCase(), user.getLastname().toUpperCase())
        );
	}

//========================================================================================

	// TODO Capitalize the users username, firstName and lastName using #asyncCapitalizeUser
	Flux<User> asyncCapitalizeMany(Flux<User> flux) {
		return flux.flatMap(user ->
            asyncCapitalizeUser(user)
        );
	}

	Mono<User> asyncCapitalizeUser(User u) {
		return Mono.just(new User(u.getUsername().toUpperCase(), u.getFirstname().toUpperCase(), u.getLastname().toUpperCase()));
	}

}