org.javers.model.domain

Class Diff

java.lang.Object

org.javers.model.domain.Diff

public class Diff
extends Object

Main entity in Javers model

Diff is a set of (atomic) changes between two graphs of objects.

Typically it is used to capture and trace changes made by user on his domain data. In this case diff is done between previous and current state of a bunch of domain objects.

Diff holds following data:

• who did change the data - getUserId()
• when the change was made - getDiffDate()
• list of atomic changes between two graphs

Diff is similar notion to commit in GIT or revision in SVN.

Hints for DiffRepository implementation

• In Domain-driven design language, Diff is an aggregate, while Change is a Value Object.
• After persisting in database, Diff is considered immutable so it can not be updated.
• Since Diff is an aggregate it can be neatly persisted in document database like MongoDB.
• Persisting Diff in any kind of database is easy. Javers provides flexible JSON serialization/deserialization engine, designed as abstraction layer between Java types and specific database types.
• Essentially, object-oriented data are persisted as JSON.

Author:

bartosz walacik

See Also:

JsonConverter

Constructor Summary

Constructors

Constructor and Description
Diff(String userId)

Method Summary

Methods

Modifier and Type	Method and Description
void	addChange(Change change)
void	addChanges(Collection<Change> changeSet)
List<Change>	getChanges()
org.joda.time.LocalDateTime	getDiffDate() date when change was made by user
long	getId() Unique revision identifier, assigned by DiffRepository
String	getUserId() user identifier in clients data base, typically login or numeric id
boolean	hasChanges()
boolean	isNew() Returns true if revision hasn't been persisted yet and has no id assigned.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Diff

public Diff(String userId)

Method Detail

getId

public long getId()

Unique revision identifier, assigned by DiffRepository

See Also:

assignId(long)

getUserId

public String getUserId()

user identifier in clients data base, typically login or numeric id

getDiffDate

public org.joda.time.LocalDateTime getDiffDate()

date when change was made by user

getChanges

public List<Change> getChanges()

Returns:

unmodifiable list

isNew

public boolean isNew()

Returns true if revision hasn't been persisted yet and has no id assigned. State new is similar to transient in Hibernate
Returns false if revision was persisted

Returns:

id == 0

See Also:

getId()

addChange

public void addChange(Change change)

hasChanges

public boolean hasChanges()

addChanges

public void addChanges(Collection<Change> changeSet)