Paweł Szymczyk

Bartosz Walacik

javers project

• Open source library
• Technology agnostic
• Based on Reflection & JSON
• https://github.com/javers/javers
• javers.org
• compile 'org.javers:javers-core:0.7.0'

What Javers can do for you?

• Find diff between two graphs of objects
• Data audit

Allegro category tree - Use Case

Show time!

                git clone https://github.com/javers/javers-demo.git
                gradlew bootRun
            

Javers Domain

Commit

    package org.javers.core.commit
    ...
    public final class Commit {
        private final CommitId id;
        private final List<CdoSnapshot> snapshots;
        private final String author;
        private final LocalDateTime commitDate;
        private final Diff diff;
        ...
     }
             

Snapshot

     package org.javers.core.metamodel.object;
     ...
     public final class CdoSnapshot extends Cdo {
        private CommitId commitId;
        private final Map<Property, Object> state;
        ...
     }
            

Diff

    package org.javers.core.diff;
    ...
    public class Diff implements Visitable<ChangeVisitor>{
        private final List<Change> changes;
    ...
    }
            

Change

    package org.javers.core.diff;
    ...
    public abstract class Change implements Visitable<ChangeVisitor> {
        private final GlobalCdoId affectedCdoId;
        private transient Optional<Object> affectedCdo;
        ...
    }
            

OJM

Client model mapping

User classes are mapped to:

• Entity
• ValueObject
• Value

Java types are mapped to:

• Primitive
• Value (ex BigDecimal)
• Array, Set, List, Map

Looking for early adopters

Looking for contributors

Profits for contributors

• Knowledge sharing
• Build your Karma
• No UI, no servers, no deployments
• We choose technology stack: Spock, Groovy, Pico, Gson, Gradle, MongoDB

Javers Team

How do we work?

BDD

def "should append newObjects to diff"() {

    given:
    def left =  buildLiveGraph(dummyUser().withName("1")
                                            .build())
    def right = buildLiveGraph(dummyUser().withName("1").withDetails(5)
                                            .build())

    when:
    def changes = new NewObjectAppender()
                        .getChangeSet(new GraphPair(left, right))

    then:
    changes.size() == 1
    assertThat(changes[0]).isNewObject()
}

Pair programming via hangouts

Code review

About project

• Src in Java 7
• Tests in Spock, Groovy
• 11 kloc src
• 8 klock test
• 420 BDD tests
• 87% coverage

Dziękujemy za uwagę!

Q & A ...

Contact us