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Achieving transactional integrity using two service operations in a rest controller

I have a question regarding the transactional boundaries in REST-Controllers using Java/Jakarta EE and JAX-RS.
Given the following controller, when a user is created in the #POST method, first the user is created using a dedicated service. Afterwards, the user´s permissions are stored using a different service.
Both services wrap incoming calls in a container managed transaction.
#Path("/users")
public class UserController {
#Inject
private UserService userService;
#Inject
private PermissionService permissionService;
#POST
public UserDto createUser(UserDto userDto) {
User user = mapToUser(userDto);
User createdUser = userService.create(user);
Permissions perms = mapToPermissions(userDto);
permissionService.createPermissions(createdUser.getId());
return mapToUserDto(createdUser);
}
}
From my point of view, there exists a transactional boundary around userService.create() and a second one around permissionService.createPermissions(). Can you confirm that this is true?
Secondly, if the previous statement is true, and the applications shuts down mid processing, the users permissions might not be persisted. Is this appraoch considered bad practise and should both operations be performed in a single transaction (or in the REST-paradigm under different ressources / endpoints)?

You are correct, there are two transactions, so the first could succeed while the second fails.
A common practice is using a Service Façade pattern. A coarse grained service that sets the transactions boundaries, and call the services to achieve the result.

Graphql rest controller

I am new to graphql. I want to implement backend in spring boot using graphql. I am still confused about endpints. So if i have 2 entities user and product. so do i have to implement 2 endpoints
#RequestMapping(value="/graphql/user", method=RequestMethod.POST, produces = "application/json")
public GraphQLResponse<Object> getService(#RequestHeader HttpHeaders headers, #RequestBody GraphQLRequest graphql) {
GraphQLResponse<Object> execute = graphQLService.execute(headers, graphql);
return execute;
}
like this one for user and another one for product. or just one.

No you need only one Endpoint. I suggest you to use this library. With this library it is very easy to start into the world of GraphQL:
https://github.com/leangen/GraphQL-SPQR
And a good example with this library and Springboot you find here, just clone the repo and run it local:
https://github.com/leangen/graphql-spqr-samples
Install this Plugin in Chrome to get read and query your schema easely:
https://chrome.google.com/webstore/detail/chromeiql/fkkiamalmpiidkljmicmjfbieiclmeij
I hoped this answer helped you.

With spring-boot-grpahql, there's no need to write controller at all. You just need to write ORM layer rest will be taken care by it. Here's an example implementation of GraphQL in java using spring-boot, gradle, spring-jpa and mongo.

Graphql exposes only one endpoint and depending on your setup it may be accessible like this: http://localhost:8080/graphql. Usually you never access graphql directly but rather via libraries that perform actions that allow you to communicate with graphql (like type-checking, converting between graphql types and your types and more).
Java GraphQL Kickstart is one of them and all you do is define schema and write resolvers for your queries, mutations and subscriptions:
schema {
query: Query
}
type Query {
allUsers: User
}
type User {
id: ID!
firstName: String
lastName: String!
}
And your resolver:
package your.project.resolvers;
import graphql.kickstart.tools.GraphQLQueryResolver;
import org.springframework.stereotype.Service;
import your.project.domain.persistence.User;
import your.project.repository.UserRepository;
import java.util.List;
#Service
public class UserResolver implements GraphQLQueryResolver {
private final UserRepository userRepository;
// be carefull about the name of this method
public List<User> allUsers() {
// perform actions based on your needs
return userRepository.findAll();
}
}
Notice that I'm using service annotation because this is basically performing some business logic on data retrieved from persistence layer. Also the name of the method allUsers() in the UserResolver is important. GraphQL will look for it based on your schema like this:
trying exact match with allUsers
prepending get: getAllUsers

Need a way to annotate service methods following repository pattern

I'm trying to refactor the existing code base of one of my project following Repository pattern, so that i can make the project more re-usable and testable.
I've written services, repositories, when I try to set Authentication, Authorization and Transactional annotation on service layer, I am facing issues.
These annotations works only on controller level, but not on service layer, so I want a way for annotate service methods.
Is it possible to do so?
It would be helpful, if someone points me samples using repository pattern on Play framework or better way to proceed further.

Authentication and authorization only make sense on a request, so sticking them on anything but a controller method is not going to work either way.
Transactional is just a helper annotation to wrap the entire request in a JPA transaction. It is usually advisable to do the wrapping yourself anyway, so you don't really need that. Example taken from the documentation:
#Inject
private JPAApi jpaApi;
public void updateSomething() {
// do something with the entity manager, per instance
// save, update or query model objects.
jpaApi.withTransaction(() -> {
EntityManager em = jpaApi.em();
Query query = em.createNativeQuery("update people set active = 1 where age > 18");
query.executeUpdate();
});
}

Java Spring REST + MongoDB (custom URI? using MongoDB Template instead of respository class? what about the xml config files?)

I currently have been reading and trying out MongoDB with Spring REST framework.
I have the following code for the controller:
#RestController
#RequestMapping("/users")
public class UserController {
#Autowired
private UserRepository userRepo;
#RequestMapping(value = "/info2", method = RequestMethod.GET)
public List<User> getAllUser(){
List<User> users = userRepo.findByEmail("test#test.com");
return users;
}
#RequestMapping(value = "/save", method=RequestMethod.POST)
public User createUser(#RequestBody User user){
return userRepo.save(user);
}
}
However, when I call
localhost:8080/users, it returns back
{
_links: {
self: {
href: "http://localhost:8080/users{?page,size,sort}"
templated: true
}-
search: {
href: "http://localhost:8080/users/search"
}-
}-
page: {
size: 20
totalElements: 0
totalPages: 0
number: 0
}-
}
I want the URI /users/info2 to return back the list of users by that particular email. How do I do that?
Also, here are the outstanding questions I have:
Can I just use MongoDBTemplate instead of the MongoRepository? I want more customized queries, and I couldn't find any in depth examples on the web.
How does Spring framework map the xml config file, for example, in cases like when I setup multiple MongoDB connections?

So without your configs, but looking at your existing code and service response, one can make some general assumptions. Your Repository is annotated with #RepositoryRestController which not only provides Spring Data access but also exposes a common ReST endpoint for your repository.
This can be determined from two aspects of your post. First you don't appear to be using HATEOAS in your Controller class, yet your service exposes JSON + HAL. Furthermore your response exposes the paging and sorting feature of Mongo Repository as well as the search behavior of Spring Data Repositories when annotated with #RepositoryRestController.
If you don't want this behavior, change the annotation on your Repository to #Repository instead.
Also to answer your other questions:
1. you can annotate methods if you want with queries on Spring Data Repositories, you can also use any class in the stack managed by spring you want, but why?
I suggest reading about the bean lifecycle to understand the dependency management within spring, there are plenty of presentations (including one in my github repo). If you have multiple connections, you can define your repository beans to utilize anything you wire it. There is a lot more manual operations at that point, and it will take some understanding and through to make it work. There is no way to give you a simple "do xyz" type answer without a lot more information.

how to properly use Models on Spring 4?

I am new using Spring's MVC (but Ive been using it for some years at other php frameworks).
I have many doubts, I read the spring info and seems to be right and all.. then Ichecked this tutorial http://javahash.com/spring-4-mvc-hello-world-tutorial-full-example/ and it works and all, but on the controller part, there is a code I dont understand, and Id like to know how to properly use the Models on Spring.
As far as I know, the models should call make the calls to the db, so, what about the services (interfaces and implementations) and the DTOs?
At the example they make something like this:
#Controller
public class HelloWorldController {
#RequestMapping("/hello")
public String hello(#RequestParam(value="name", required=false, defaultValue="World") String name, Model model) {
model.addAttribute("name", name);
return "helloworld";
}
}
It receives a model as parameter... I bet if there is any, Spring would use a default one, what if I want to add more interaction and lets say, specifiy a model to call the db? Any idea how I could do that?
And if I want to add a service... I am a little bit clueless about it, if someone could help me to understand...
Thanks in advance

Model is a map representing the data that the view needs. It can contain one or more entities, or simple objects, or strings, or whatever you want.
MVC doesn't require the use of a database. The model does not "call the db". You can inject a repository into your controller to load data from a db into your model.
#Controller
#RequestMapping("/foo")
public class FooController {
#Autowired
private FooRepository fooRepository;
#RequestMapping
String getFoos(Model model) {
List<Foo> foos = fooRepository.findAll();
model.addAttribute("foos", foos);
model.addAttribute("someOtherDataYourViewNeeds", "bar");
return "foo/list";
}
}

This Model Object is injected by spring, and his content will be sent to the view.
You can see the documentation for Model interface here http://docs.spring.io/spring-framework/docs/current/javadoc-api/.
If you wanna access some object on your view, you can you use
model.addAttribute(object).
I think you could read The IoC Container documentation to understand how spring works.