审计：修改子实体的父实体（Javers / Envers /…+ Hibernate）

Question

I have a kind of parent object in my application which needs to be versioned (audited), by that I mean: Every time an alteration on it is persisted, or on any of its n-deep child objects, a new revision must be created.

@Entity class Document {
    @Id String name;
    // some props ...
    @OneToMany List<Page> pages;
    // getters and setters ...
}

@Entity class Page {
    @Id Long number;
    @ManyToOne Document document;
    // some props ...
    String header;
    // getters and setters ...
}

In the example above, if I were to change the header of a page, a new revision should be persisted for the whole Document entity:

// retrieve document
Document document = documentRepository.findById(myBookId);
// change something on first found page
document.getPages().iterator().next().setHeader("Hello World");
// persist the document
documentRepository.save(document);
// new revision of the document!

I was considering using Javers or Envers but it seems none of them can do it.

Do any of you know how to do something like it on those libs? Or know of any library I can use for this purpose?

Answer 1

You can achieve it in Javers if you map Page class as ValueObject and then if you use Shadow query. Also you should commit Document all the time:

    @Entity
    class Document {
        @Id String name
        @OneToMany List<Page> pages

        @Override
        String toString() {
            "Document $name, pages:$pages"
        }
    }

    @org.javers.core.metamodel.annotation.ValueObject
    @Entity
    @ToString
    class Page {
        @Id Long number
        @ManyToOne Document document
        String header

        @Override
        String toString() {
            "Page $number, $header"
        }
    }

    def "should treat Document as aggregate"(){
      given:
      def javers = JaversBuilder.javers().build()

      def doc = new Document(name:"1", pages: [new Page(header:"a"), new Page(header:"b")])
      javers.commit("author", doc)

      when:
      doc = new Document(name:"1", pages: [new Page(header:"a"), new Page(header:"ccc")])
      javers.commit("author", doc)

      def shadows = javers.findShadows(QueryBuilder.byClass(Document).build())

      then:
      shadows

      shadows.forEach{s -> println(s.commitMetadata.commitDate.toString() + " " + s.get())}
    }

output:

23:25:47.297 [main] INFO  org.javers.core.Javers - Commit(id:1.0, snapshots:3, author:author, changes - NewObject:3), done in 56 millis (diff:45, persist:11)
23:25:47.315 [main] INFO  org.javers.core.Javers - Commit(id:2.0, snapshots:1, author:author, changes - ValueChange:1), done in 17 millis (diff:17, persist:0)
23:25:47.337 [main] DEBUG org.javers.JQL - SHALLOW query: 4 snapshots loaded (entities: 1, valueObjects: 3)
23:25:47.358 [main] DEBUG org.javers.JQL - queryForShadows executed: 
2019-04-08T23:25:47.298618 Document 1, pages:[Page null, a, Page null, ccc]
2019-04-08T23:25:47.275570 Document 1, pages:[Page null, a, Page null, b]