Add support for lazy loading configuration via JPA 2.1 fetch-/loadgraph. [DATAJPA-466]

[spring-projects-issues]

Thomas Darimont opened DATAJPA-466 and commented

We could leverage the new fetch-group feature from JPA 2.1 to provide support for configuring lazy-loading on repository method level

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Issue Links:

• DATAJPA-208 Support specification of fetch plans in query methods

• DATAJPA-560 Allow programmatic use of entity graphs

Referenced from: pull request #74

1 votes, 4 watchers

[spring-projects-issues]

Thomas Darimont commented

I added prototypic support via PR #74.

FetchGraphs / LoadGraphs can now be defined on the Entity via the @NamedEntityGraphs annotation.

@Entity
@QueryEntity
@NamedEntityGraphs(@NamedEntityGraph(name = "GroupInfo.detail", attributeNodes = @NamedAttributeNode("members")))
public class GroupInfo {
...
@ManyToMany List<GroupMember> members = new ArrayList<GroupMember>(); //default fetch mode is "lazy".
}

The entity graph "GroupInfo.detail" overwrites the fetch-mode of the members collection to be "eager".

The fetch graph to be used can now configured on a repository query method.

@Repository
public interface GroupRepository extends CrudRepository<GroupInfo, String> {

    @EntityGraph(value = "GroupInfo.detail", type = EntityGraphType.LOAD)
    GroupInfo getByGroupName(String name);
}

[spring-projects-issues]

Thomas Darimont commented

Please review

[spring-projects-issues]

Oliver Drotbohm commented

Comments on the pull request

[spring-projects-issues]

Thomas Darimont commented

Applied requested changes from code review.
Please revise

[provocative168]

I encountered that dilemma and discovered a solution https://reedabsentee.github.io/stuart/