find out the differences between two java beans for version tracking

Question

say i have a java bean/an entity with 100 fields (inherited or not it is not relevant in this case). After update operations - in a transaction, i want to determine which fi

Answer 1

Hey look at Javers it's exactly what you need - objects auditing and diff framework . With Javers you can persist changes done on your domain objects with a single javers.commit() call after every update. When you persist some changes you can easily read them by javers.getChangeHistory, e.g.

public static void main(String... args) {
    //get Javers instance
    Javers javers = JaversBuilder.javers().build();

    //create java bean
    User user = new User(1, "John");

    //commit current state
    javers.commit("author", user);

    //update operation
    user.setUserName("David");

    //commit change
    javers.commit("author", user);

    //read 100 last changes
    List changes = javers.getChangeHistory(instanceId(1, User.class), 100);

    //print change log
    System.out.printf(javers.processChangeList(changes, new SimpleTextChangeLog()));
}

and the output is:

commit 2.0, author:author, 2015-01-07 23:00:10
  changed object: org.javers.demo.User/1
    value changed on 'userName' property: 'John' -> 'David'
commit 1.0, author:author, 2015-01-07 23:00:10
    new object: 'org.javers.demo.User/1