I am new to reactive and not able to get around this.
I have following Dtos:
public class User {
int id;
Map<String, Car> carsMap;
}
public class Car {
String carName;
}
// Response object
public class VehiclesInfo {
List<String> vehicleName;
}
From database I am getting Mono<User> when querying by userId.
And I have to return Mono<VehiclesInfo>.
So, I have to map the carsMap received from Mono<User> into List i.e. List of carName and set that into VehiclesInfo and return that as Mono i.e. Mono<VehiclesInfo>.
I am doing it like below. Please let me know how this can be done without blocking.
// userMono is returned by database query
Mono<User> userMono = getUserInfoById(userId);
Optional<User> userOptional = userMono.blockOptional();
if (userOptional.isPresent()) {
User user1 = userOptional.get();
Flux<Car> carFlux = Flux.fromIterable(user1.getCarsMap().keySet())
.flatMap(i -> {
final Car c = new Car();
c.setCarName(i);
return Mono.just(c);
});
carFlux.subscribe(c -> System.out.println(c.getCarName()));
}
Related
I am new to Reactive programming and I got stuck writing a custom Insert query.
So far I have a FriendshipRepository.java class.
public interface FriendshipRepository extends R2dbcRepository<Friendship, String> {
#Query(value = "INSERT INTO public.friendship(requester_id, addressee_id) values (:requesterid::uuid, :addresseeid::uuid)")
public Mono<Void> insertFriendRequest(
#Param("requesterid") String requesterId,
#Param("addresseeid") String addresseeId
);
}
And a FriendshipController.java class.
#RestController
public class FriendsController {
private final FriendshipRepository friendshipRepository;
public FriendsController(FriendshipRepository friendshipRepository) {
this.friendshipRepository = friendshipRepository;
}
#PostMapping(value = "/request", produces = "application/json")
public Mono<ResponseEntity<RequestResponse>> sendFriendRequest(#RequestBody FriendRequest friendRequest, #AuthenticationPrincipal Mono<User> principal) throws Exception {
String id = principal.map(User::getId).toFuture().get();
return friendshipRepository.insertFriendRequest(id, friendRequest.getUserId()).log()
.then(Mono.just("NEXT"))
.map(e -> {
return ResponseEntity.status(HttpStatus.CREATED).body(new RequestResponse("Success", ResponseCode.SUCCESS));
}).onErrorResume(e -> {
return Mono.just(ResponseEntity.status(HttpStatus.FORBIDDEN).body(new RequestResponse("Friend request was unsuccessful ", ResponseCode.REFUSED)));
});
}
}
This is a working example.
But I dont understand why I have to call .then(Mono.just("NEXT")) and create a new Mono to be able to return a custom ResponseEntity<RequestResponse>>. I also tried merge the the whole process. I meen by this at the begining when I get the Id from the ReactiveSpringSecutiryContext that is a blocking line of code and If I know it correctly that is a bad approach in Reactive programming.
I tried this approach but in this case, I can only retrun the Id of the user.
Mono<String> userId = principal.map(User::getId);
return userId.doOnNext(id -> {
friendshipRepository.insertFriendRequest(id, friendRequest.getUserId()).log()
.map(e -> {
return ResponseEntity.status(HttpStatus.CREATED).body(new RequestResponse("SIKER", ResponseCode.SUCCESS));
})
.onErrorResume(e -> {
return Mono.just(ResponseEntity.status(HttpStatus.FORBIDDEN).body(new RequestResponse("Friend request was unsuccessful ", ResponseCode.REFUSED)));
}).subscribe();
// .doOnSuccess(e -> ServerResponse.noContent().build((new RequestResponse("SIKER", ResponseCode.SUCCESS)), Void.class));
});
How could I rewrite this endpoint? Or does my whole approach inaproptirate?
Thank you in advance for your help.
Probably not the nicest solution, but better then it was.
My query:
public interface FriendshipRepository extends R2dbcRepository<Friendship, String> {
#Query(value = "INSERT INTO public.friendship(requester_id, addressee_id) values (:requesterid::uuid, :addresseeid::uuid) RETURNING id")
public Mono<String> insertFriendRequest(
#Param("requesterid") String requesterId,
#Param("addresseeid") String addresseeId
);
}
My api:
#PostMapping(value = "/request", produces = "application/json")
public Mono<ResponseEntity<RequestResponse>> sendFriendRequest(#RequestBody FriendRequest friendRequest, #AuthenticationPrincipal Mono<User> principal) throws Exception {
String id = principal.map(User::getId).toFuture().get();
return friendshipRepository.insertFriendRequest(id, friendRequest.getUserId()).log()
.map(e -> {
return ResponseEntity.status(HttpStatus.CREATED).body(new RequestResponse("Success", ResponseCode.SUCCESS));
}).onErrorResume(e -> {
return Mono.just(ResponseEntity.status(HttpStatus.FORBIDDEN).body(new RequestResponse("Friend request was unsuccessful ", ResponseCode.REFUSED)));
});
}
I started working with spring boot's rest API and ended up having some specific problems returning the last two topics
1- GET animals/number/{number}
You should list the animals with the number/code {number}
2- GET animals/name/{name}
You should list the animals with the name {name}
3- GET animals/species/{species}
You should list the animalsof the species {species}. Note, more than one animal can be returned for each species.
4- GET animals /type/{type}
You should list the animals of the type {type}. Note, more than one animal can be returned for each type. Due to the nature of this field, you should perform a substring search. For example, the value “poison” for the {type} should return the animals with the type "reptile/Poison".
what I got
#RequestMapping(value="/animals/number/{number}", method=RequestMethod.GET)
public ResponseEntity<?> getNumber(#PathVariable(name = "number") String number) {
Optional<Animal> o = repository.findByNumber(number);
if (!o.isPresent())
return new ResponseEntity<>(o, HttpStatus.NOT_FOUND);
return new ResponseEntity<>(o, HttpStatus.FOUND);
}
#RequestMapping(value="/animals/name/{name}", method=RequestMethod.GET)
public ResponseEntity<?> getName(#PathVariable(name = "name") String name) {
Optional<Animal> o = repository.findByName(name);
if (!o.isPresent())
return new ResponseEntity<>(o, HttpStatus.NOT_FOUND);
return new ResponseEntity<>(o, HttpStatus.FOUND);
}
I tried to do topic 3 but I'm not able to:
#RequestMapping(value="/animals/species/{species}", method=RequestMethod.GET)
public ResponseEntity<?> getSpecies(#PathVariable(name = "species") String species) {
List<Animal> p = repository.findAll();
if (species == null)
repository.findAll().forEach(p::contains);
else
repository.findByTitleContaining(species).forEach(p::contains);
if (p.isEmpty()) {
return new ResponseEntity<>(HttpStatus.NO_CONTENT);
}
return new ResponseEntity<>(p, HttpStatus.OK);
}
#Repository
public interface AnimalRepository extends JpaRepository<Animal, Integer> {
Optional<Animal> findByNumber(String number);
Optional<Animal> findByName(String name);
Optional<Animal> findByspecie(String species);
}
i put for test //localhost:8081/animals/name/Animalname
You can query all animals matching the searched specie using a Spring Data generated query (as the one you seem to have defined):
List<Animal> findByTitleContaining(String specie);
Then you can group the returned elements using the java.util.stream.Collectors#groupingBy using the Animal types:
#RequestMapping(value="/animals/species/{species}", method=RequestMethod.GET)
public ResponseEntity<?> getSpecies(#PathVariable(name = "species") String species) {
List<Animal> matchingAnimals = repository.findByTitleContaining(species);
if (!matchingAnimals.isEmpty()) {
final Map<String, List<Animal>> groupedAnimals = matchingAnimals.stream()
.collect(Collectors.groupingBy(Animal::getType));
return new ResponseEntity<>(groupedAnimals, HttpStatus.OK);
} else {
return new ResponseEntity<>(HttpStatus.NO_CONTENT);
}
}
I am trying to learn map function in Stream
public class EmployeeInformationTest {
public static void main(String args[]) {
List<Employee> employees = Arrays.asList(
new Employee("Jai"),
new Employee("Adithya"),
new Employee("Raja"));
List<String> names = employees.stream()
.map(s -> s.getEmployeeName()) // Lambda Expression
.collect(Collectors.toList());
System.out.println(names);
}
}
we have above code and somehow it is giving us List of String from List of Employee. Say, we have other class Person in which we have field as name
public class Person {
private String name;
}
so is it feasible via map or some other function in stream so that I can get the List of Person rather than List of String in above code
sure thing, just change the map function to:
.map(s -> new Person(s.getEmployeeName()))
or if there is no such constructor:
.map(s -> {
Person p = new Person();
p.setName(s.getEmployeeName());
return p;
})
I have two classes - Student and StudentDetails.
My goal is to get data in the form of Map <studentName,Map<subjectName, subjectNo>>.
When using streams, not able to fetch data of parent class(Student).
public class Student {
private String studentName;
private Map<String, Long> studentDetails;
public Map<String, Long> getStudentDetails() {
return studentDetails;
}
public String getStudentName() {
return studentName;
}
}
class StudentDetails {
private String subjectName;
private String subjectNo;
public String getFSubjectName() {
return subjectName;
}
public String getSubjectNo() {
return subjectNo;
}
}
public class Main {
public static void main(String[] args) {
Collection<Student> student = null;
Map<String, Map<String, Long>> sts = student.stream()
.map(st -> st.getStudentDetails().values())
.flatMap(st -> st.stream())
.collect(Collectors.groupingBy(Student::getStudentName,
Collectors.toMap(StudentDetails :: getFatherName, StudentDetails:: getRollNo )));
}
}
Error : The type Student does not define getStudentName(T) that is applicable here.
You "lost" your Student while doing:
.map(st -> st.getStudentDetails().values())
.flatMap(st -> st.stream()) // this is a Stream<StudentDetails> now
Thus if you need it just map it:
.flatMap(st -> st.getStudentDetails()
.values()
.stream()
.map(sd -> new SimpleEntry<>(st, sd)))
.collect(Collectors.groupingBy(
en -> en.getKey().getStudentName(),
Collectors.toMap(
en -> en.getValue().getFartherName(),
en -> en.getValue().getRollNo()
)
))
This can be done without Streams too; you could try to look at Map::compute
I'm trying to create a #select input for a enum field. Everything works fine until the form is submitted. It fails with a weird validation error -> "error.invalid"
here's my code
Enum class
package model;
...
public enum UserType {
UserType_Admin("Administrator"), UserType_Monitor("Monitor"), UserType_Audit("Audit");
private String desc;
private UserType(String desc) {
this.desc = desc;
}
#Override
public String toString() {
return Messages.get(desc);
}
public String getLabel() {
return toString();
}
public String getKey() {
return super.toString();
}
public static Map<String, String> options() {
LinkedHashMap<String, String> options = new LinkedHashMap<String, String>();
for (UserType ut : UserType.values()) {
Integer o = ut.ordinal();
options.put(o.toString(), ut.desc);
}
return options;
}
}
My Entity
#Entity
public class User extends Model {
...
#Id
public Long userID;
public UserType user_type;
}
Scala template
#form(routes.Users.save(userID)) {
#select(
userForm("user_type"),
options(model.UserType.options),
'_label -> Messages("UserType"), '_default -> Messages("choose_user_type"),
'_showConstraints -> true
)
}
on the controller the Save method:
public static Result save(Long userID) {
Form<User> userForm = form(User.class).bindFromRequest();
if (userForm.hasErrors()) { <- here it says that has errors
return badRequest(useredit.render(new Session(session()), userID,
userForm, new User()));
}
...
}
if I inspect the userForm variable, I get:
Form(of=class model.User, data={user_type=0}, value=None,
errors={user_type=[ValidationError(user_type,error.invalid,[])]})
The field user_type has the correct value, 0 if I choose the first item, 1 for the second, etc.
Screenshot
Anyone has a clue or a workaround for this? Maybe disable validation for this field? Tks guys