spring-projects
Issue with @DomainEvents with a spring data repository having @cacheable decorated methods [DATACMNS-1247]
Gaurav Rawat opened DATACMNS-1247 and commented
Have any one had issues with using @DomainEvents with a Spring Data repository having @Cacheable decorated methods. It seems the domainEvents object don't get initialized when data comes from cache and hence give a NPE . This happens cause the transient variable not getting initialized when the data is coming from cache.
public class AbstractAggregateRoot<A extends AbstractAggregateRoot<A>> {
private transient final @Transient List<Object> domainEvents = new ArrayList<>();
My caching repository is pretty simple looks like this, just the cache implementation I am using is based on Apache ignite. As a workaround currently I am not using domain events for cacheable methods, but I hope we can resolve this to get over the boilerplate and NPE issues
Affects: 1.13.8 (Ingalls SR8), 2.0.2 (Kay SR2)
Oliver Drotbohm commented
The caching interceptor is ordered before all other one, including the one publishing domain events. The entire scenario looks pretty weird as caching mutable objects is a bad idea in the first place as now all of a sudden, multiple threads will have access to instances that are usually only accessible in a single thread
Gaurav Rawat commented
Agree with your point about caching mutable entities .
But there could be a case where we do need to cache a search method or api in the repository , and this does break when the same data is say retrieved from cache ,modified and persisted.And subsequently domain events are fired .
This could be handled if I seperate the command and query as I have done now but we have a case where we do some intensive processing in memory and don't want to go every time to our persistence store .Also we have reverted to simple spring events right now .
Another approach we have done is using write behind in our apache ignite repositories and not using the @cacheable abstraction for our use case.
If you would like us to look at this issue, please provide the requested information. If the information is not provided within the next 7 days this issue will be closed.
We do not intend to provide a general utility to make domain events work with cached object instances as we consider that approach invalid usage. With Spring's extension points, you can provide your application-specific interceptor to materialize domain events and decouple object instances to avoid shared mutable state.
