Introduced interface for JdbcPersistentEntity to be consistent with other store implementations.
Introduced JdbcPersistentEntityInformation.getRequiredId(…) to return a value and throw an exception if it can't be obtained.
Added serialVersionUIDs to event implementations. Extracted Unset and SpecifiedIdentifier into top level classes to be able to reduce visibility. Introduced Specified interface and factory methods on Identifier to be able to create Identifier instances in all ways needed (specified / optional).
Extracted JdbcEvent interface from the previously thus named class to be able to let WithId and WithEntity extend that interface to avoid the cast in the default method of WithId. WithId now simply redeclares getId returning Specified so that the guarantees of returned object type simply adapt as soon as event types also implement that interface. Reduced the visibility of SimpleJdbcEvent as listeners could now just refer to JdbcEvent. Switched to a nullable field for the entity in SimpleJdbcEvent as ApplicationEvent already implies potential serializability and Optional is not Serializable.
Reorganized integration test setup to use configuration classes over FactoryBean implementations. Switched to AssertJ for test assertions.
Renamed UnableToSetIdException to UnableToSetId. A bit of Javadoc here and there. Formatting. No abbreviated variable names.
Original pull request: #5.
1af9146f4d