#Transactional only on one method - java

I need to make a #Scheduled method that has a list of schemas and for each schema, deletes rows from 2 tables.
#Scheduled(fixedDelay = 10000)
public void scheduleFixedDelayTask() {
List<String> presentSchemas = getPresentSchemas();
for (String schema : presentSchemas) {
deleteFromCustomerTables(schema);
}
}
I've defined deleteFromCustomerTables as #Transactional(propagation = Propagation.REQUIRES_NEW) and inside it i use the EntityManager to delete rows from 2 tables.
In order to make it work i need to add #Transactional to scheduleFixedDelayTask, otherwise i recive a TransactionRequiredException.
My problem is that i do not want the whole scheduler to be #Transactional, if something goes wrong in one schema i do not want to do a rollback of all schemas.
I've also tried without #Transactional and with :
Session session = entityManager.unwrap(Session.class);
Transaction t = session.beginTransaction();
//exec delete
t.commit();
session.close();
But i still recieve TransactionRequiredException.
Do you have a solution?

You have to be sure that you configured the transaction manager something like this:
#Configuration
#EnableTransactionManagement
public class TransactionConfig {
#Bean
#Primary
public PlatformTransactionManager transactionManager() {
return new JpaTransactionManager();
}
}
You have to be sure that method deleteFromCustomerTables is not in the same component, something like this:
#Component
class Component1 {
void scheduleFixedDelayTask(){...}
}
#Component
class Component2 {
void deleteFromCustomerTables(){...}
}
But at a very high level, Spring creates proxies for classes that
declare #Transactional on the class itself or on members. The proxy is
mostly invisible at runtime. It provides a way for Spring to inject
behaviors before, after, or around method calls into the object being
proxied. Transaction management is just one example of the behaviors
that can be hooked in. Security checks are another. And you can
provide your own, too, for things like logging. So when you annotate a
method with #Transactional, Spring dynamically creates a proxy that
implements the same interface(s) as the class you're annotating. And
when clients make calls into your object, the calls are intercepted
and the behaviors injected via the proxy mechanism.

Related

Why transactional does not rollback when RuntimeException occur?

I want to test a non-transactional method in the service layer when inner methods are transactional separately. I want to know what will happen if some method throws an exception. Does it properly roll back or not? I also tried rollbackFor but it did not help. Any suggestions?
Spring v-2.5.1
app.properties
spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.hibernate.ddl-auto=create-drop
server.error.include-message=always
server.error.include-binding-errors=always
Controller
#PostMapping("/test")
public void test(){
service.test();
}
Service
#Service
public class UserService {
#Autowired
private UserRepository userRepository;
#Autowired
private PasswordEncoder passwordEncoder;
public void test() {
User user1 = new User();
String encodedPassword = passwordEncoder.encode("123");
user1.setUsername("username");
user1.setPassword(encodedPassword);
user1.setFirst_name("name1");
user1.setLast_name("family1");
save(user1);
User update = update(user1.getUsername());
throw new RuntimeException();// I expect Spring rollback all data for save and update methods
//but it seems data has been committed before an exception occur.
}
#Transactional
public void save(User user) {
if (userExists(user.getUsername()))
throw new ApiRequestException("Username has already taken!");
else {
User user1 = new User();
String encodedPassword = passwordEncoder.encode(user.getPassword());
user1.setUsername(user.getUsername());
user1.setPassword(encodedPassword);
user1.setFirst_name(user.getFirst_name());
user1.setLast_name(user.getLast_name());
user1.setCreate_date(user.getCreate_date());
user1.setModified_date(user.getModified_date());
user1.setCompany(user.getCompany());
user1.setAddresses(user.getAddresses());
userRepository.save(user1);
// throw new RuntimeException(); Similarly I expect rollback here.
}
}
#Transactional
public User update(String username) {
User userFromDb = userRepository.findByUsername(username);
userFromDb.setFirst_name("new username");
userFromDb.setLast_name("new lastname");
return userRepository.save(userFromDb);
}
}
Due to way spring proxying works by default, you can not call a "proxied" method from within the instance.
Consider that when you put #Transactional annotation on a method, Spring makes a proxy of that class and the proxy is where the transaction begin/commit/rollback gets handled. The proxy calls the actual class instance. Spring hides this from you.
But given that, if you have a method on the class instance (test()), that calls another method on itself (this.save()), that call doesn't goes through the proxy, and so there is no "#Transactional" proxy. There is nothing to do the rollback when the RuntimeException occurs.
There are ways to change the how Spring does the proxying which would allow this to work, but it has changed over the years. There are various alternatives. One way is to create create separate classes. Perhaps UserServiceHelper. The UserServiceHelper contains #Transactional methods that get called by UserService. This same issue occurs when different #Transactional isolations and propagations are needed.
Related answers and info:
Spring #Transaction method call by the method within the same class, does not work?
Does Spring #Transactional attribute work on a private method?
Spring Transaction Doesn't Rollback
Your example code is not very clear as to what you are trying to do. Often, #Transactional would be put on the service class and apply to all public methods (like test()).
To begin with, I'm not sure if you understand what a transaction represents. If there's a unit of work that contains several functionalities to be executed, and you either want them to completely fail or completely pass - that's when you use a transaction.
So in the case of test() method - why should underlying mechanism (in this case Hibernate) care about rolling back something that happened within save() and update() when the test() itself isn't a transaction?
Sorry for asking more than answering, but as far as I can see - you need to annotate test() with the annotation, and not the individual methods. Or you can annotate them all.

Transaction inside transaction support? (multi database) in Spring boot

I have DB1, DB2. I config two DataSource and two PlatformTransactionManager for two database (within the same physical machine).
I have this code:
#Transaction("DB1")
public void A() {
B();
}
#Transaction("DB2")
public void B() {
}
When B() has an SqlException, data in DB1 did not rollback. How to implement rollback DB1?
Thank very much.
#Transaction annotation has an attribute rollbackFor (#Transaction(value = "DB1", rollbackFor = SqlException.class) for example) that may cover your needs.
However, there is only one transaction will be actually used in your code, because B is invoked not via Spring proxy but via inner call (this.B()). To execute method inside a separate transaction method must be invoked via Spring proxy - someService.B(), not this.B().

Spring transaction with restful application

I'm working on spring boot and I need to clarify something regarding to transaction management.
For example, I do have 2 classes that run two separate jobs (the first job is to create profile on database and the second job is to call restful application also profile creation but on different system).
This 2 jobs must be in transactional. Both success needed. It should not create any profile on any data store if one of the job is fails)
Since I'm really new in this Spring. I hope to get suggestion and need to know what is the best practice for this scenario.
There is a facade pattern. I suggest to make a facade service to join the logic of two services. Services must be separate, because working with profiles and communicating with other system are different parts of business logic.
For example, there are ProfileService and OuterService to work with profiles and to outer communication. You can write SomeFacadeService to join two methods and wrap it in one transaction. Default propagation of #Transactional is REQUIRED. So transaction will be created on method SomeFacadeService.doComplexJob and methods profileService.createProfile and outerService.doOuterJob will join the current transaction. If exception occurs in one of them whole SomeFacadeService.doComplexJob will be rolled back.
#Controller
public class SomeController {
#Autowired
SomeFacadeService someFacadeService ;
#RequestMapping("/someMapping")
public void doSomeJob() {
someFacadeService.doComplexJob();
}
}
#Service
public class SomeFacadeService {
#Autowired
ProfileService profileService;
#Autowired
OuterService outerService;
#Transactional
public void doComplexJob() {
profileService.createProfile();
outerService.doOuterJob();
}
}
#Service
public class ProfileService {
#Transactional
public void createProfile() {
// create profile logic
}
}

AbstractRoutingDataSource doesn't change connection

I use AbstractRoutingDataSource to change data source dynamically and ThreadLocal to set up currentLookupKey. It works nice when I use only one data source per http request. I use JpaRepository
#Component
#Primary
public class RoutingDataSource extends AbstractRoutingDataSource {
#Autowired
private DatabaseMap databaseMap;
#Override
public void afterPropertiesSet() {
setTargetDataSources(databaseMap.getSourcesMap());
setDefaultTargetDataSource(databaseMap.getSourcesMap().get("DEFAULT"));
super.afterPropertiesSet();
}
#Override
protected Object determineCurrentLookupKey() {
return DatabaseContextHolder.getDatabaseType();
}
}
public class DatabaseContextHolder {
private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();
public static void setDatabaseType(String string) {
contextHolder.set(string);
}
public static String getDatabaseType() {
return (String) contextHolder.get();
}
public static void clearDatabaseType() {
contextHolder.remove();
}
}
When I try to get data in my REST controller I get data only from one database.
Some code in my REST controller
DatabaseContextHolder.setDatabaseType("db1");
//here I get data from db1 as expected
//I use JpaRepository
DatabaseContextHolder.clearDatabaseType();
DatabaseContextHolder.setDatabaseType("db2");
//here I should get data from db2 but get from db1
I tried to debug and it looks like Spring obtains data source only once in http request.
This method is called only once.
#Override
public Connection getConnection() throws SQLException {
return determineTargetDataSource().getConnection();
}
Is there any way to force Spring to change data source.
Your problem could be related with transaction delimitation.
When you define a #Transactional annotation in your code, Spring will create on your behalf all the stuff necessary to begin and end, and commiting or rollback if required, a transaction.
As you can see in the doBegin method in the source code of the DataSourceTransactionManager class - the same applies to other transaction managers - , Spring obtains a Connection when the transaction is initialized - this is why the method getConnection is invoked only once - , and it will reuse that connection across all the underlying operations against the database within that transaction (it makes sense for ACID preservation).
So, if you need to connect to several data sources within the same request processing, you can define different methods in you service code, every one annotated with a #Transactional annotation, and change the underlying data source as you require before invoke them:
DatabaseContextHolder.setDatabaseType("db1");
// Invoke a service method annotated with #Transactional
// It can use the underlying JpaRepositories that you need
DatabaseContextHolder.clearDatabaseType();
DatabaseContextHolder.setDatabaseType("db2");
// Invoke again another (or the same, what you need) service method
// annotated with #Transactional, You should get data from db2 this time
My suspicion here is you have a method annotated with #Transactional annotation. Before calling that transactional method, you first specify one datasource key and you call the transactional method.Inside the transactional method, you first call repository and it works as expected with datasource look up key you set. However then you set different key, inside the transactional method, and call another repository and it still uses the key you set first time.
DataSource will be chosen by the framework when the transaction starts so if you are using #Transactional annotation, whatever switching you do inside the method is useless. Because the datasource would have been chosen by proxy created for #Transactional annotation. Best option is to have the branching logic in non transactional service or use TransactionTemplate instead of #Transactional
For example, make sure YourRestController does not have class level #Transactional as well as no #Transactional annotation in this yourRestControllerMethod, you will keep them to your service.
#RestController
public class YourRestController {
#Autowired
TransactionalService transactional
public void yourRestControllerMethod(){
//set the datasource look up key to A1 and then
transactional.methodA1();
//change datasource look up key to A2 and then
transactional.methodA2();
}
}
#Service
public class TransactionalService {
#Transactional
public void methodA1(){
}
#Transactional
public void methodA2() {
}
}
I had the same issue, none of the above solution could fix it.. but making my Service method final (in my REST Controller)
public final Response
Set spring.jpa.open-in-view to false.

Spring transaction propagation - Service vs DAO

I have a Service class like below:
#Service("MyService")
public class MyService {
#Autowired
MyDao dao;
public void process() {
getFromDao();
// getMoreFromDao();
// process();
// if all good, then
doStuff();
}
public void getFromDao() {
// do some stuff
dao.getData();
}
#Transactional(transactionManager="simpleDatasourceTxMgr", propagation=Propagation.REQUIRED)
public void doStuff() {
dao.saveData(1);
dao.saveData(2);
dao.saveData(3);
}
}
The DAO called is:
#Repository
public class MyDao {
#Autowired
#Qualifier("myjdbcTemplate")
NamedParameterJdbcTemplate jdbcTemplate;
public void saveData(obj a) {
jdbcTemplate.execute("Query", ...);
}
}
I want my doStuff() method in the service class to run within a transaction and rollback everything if there is an exception in the saveData() method. But this is not running in transaction.
If I add #Transaction to a DAO method looks like it runs in separate transaction. Is this correct?
Update: I have added a process() method to my Service and I call getFromDao() and doStuff() from process(). process() is called from the controller. So looks like if I make the service class #Transactional, then everything executes within a transaction. But I don't want getFromDao() to execute in transaction.
We use just JDBC and no Hibernate.
You can place the #Transactional annotation before an interface
definition, a method on an interface, a class definition, or a public
method on a class. However, the mere presence of the #Transactional
annotation is not enough to activate the transactional behavior. The
#Transactional annotation is simply metadata that can be consumed by
some runtime infrastructure that is #Transactional-aware and that can
use the metadata to configure the appropriate beans with transactional
behavior. In the preceding example, the
element switches on the transactional behavior.
Or if you want annotations you can enable it with
It is not sufficient to tell you simply to annotate your classes with
the #Transactional annotation, add #EnableTransactionManagement to
your configuration, and then expect you to understand how it all
works. This section explains the inner workings of the Spring
Framework’s declarative transaction infrastructure in the event of
transaction-related issues.
http://docs.spring.io/spring/docs/current/spring-framework-reference/html/transaction.html

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