Process spel values of @QueryHint

[ujhazib]

Some query hints are very specific values, rather than a boolean, like a timeout on an SQL query. Usually it is not too hard wired in a production grade system but configurable. It is impossible to achieve this behavior with @QueryHints({@QueryHint...}) since the value of QueryHint is not going through on expression language lookup (which would help to get the value at least from a properties/yaml file). Another possibility I see, and it is somewhat covered in this ticket, is that the JpaRepository interface methods should support some kind of List<QueryHint> structure as an input so we can pass them in programatically when we call those methods.

[gregturn]

@ujhazib Can you show an example of a type of query hint you'd like to be able to apply in some repository definition?

[gregturn]

It should be noted that injecting a SpelExpressionParser into the objects that need it to do the evaluation is a bit tricky.

[ujhazib]

Sorry for the slow feedback, was on vacation. One example would be

@QueryHints(
   { @QueryHint(name = org.hibernate.jpa.QueryHints.SPEC_HINT_TIMEOUT, "#{someConfigBean.someTimeoutSetting}") }
)

To detach the timeout setting from a binary compilation and to depend rather on a config file in this case.