debugging Transactional annotation in Java Spring

Question

Updating an existing piece of code as shown below:

@Override
@Transactional
public void update(SomeObject someObj) throws BusinessServiceException {
    ...
    someObjectRepository1.update(someObj);
    someObjectRepository2.create(someObj);

    //New code below:
    someObjectRelatedService.doStuff(someObj);  // <--new code
    //Throws error, object does not exist in someObjectRepository2
}

The issue here is that someObjectRelatedService.doStuff needs the latest and most updated version of someObjectRepository2 - but the transactional annotation prevents that from happening, it updates the repository AFTER the method has fully ran. I was able to verify by using a debugger and running a database call in between.

What would be the best way to approach this situation? Is it solely to extract the someObjectRelatedService call outside the transactional method?

Answer 1

In essence, you need to move the boundary of your transaction. While manually flushing the transaction is an option, I would not recommend to do so.

The easiest fix, if the semantics of SomeObjectRepository2#create(...) permit it, would be to annotate this method with @Transactional(isolation = Propagation.REQUIRES_NEW).

If this should not be possible, I propose the following minor redesign. First, we create a new class with one method, which should execute the code related to the data that is needed:

@Component
public class NewClass {
    final SomeObjectRepository2 someObjectRepository2;

    @Autowired
    public NewClass(final SomeObjectRepository2 someObjectRepository2) {
        this.someObjectRepository2 = someObjectRepository2;
    }

    @Transactional(isolation = Propagation.REQUIRES_NEW) // enforces new transaction
    public WhateverNeedsToBereturned newMethod(WhateverType someObject) {
        return someObjectRepository2.create(someObj);
    }
}

And then we rewrite the existing code to use the new class:

@Override
@Transactional
public void update(SomeObject someObj) throws BusinessServiceException {
    ...
    someObjectRepository1.update(someObj);
    newClassInstance.newMethod(someObj);

    //New code below:
    someObjectRelatedService.doStuff(someObj); 
    //Throws error, object does not exist in someObjectRepository2
}

Note that you have to create a new class in order for this to work. Method calls through the this-reference are not proxied and thus the @Transactional annotation does not take effect.

Note further that newClassInstance must be injected through the DI container for the same reason.