org.javers.core

Class Javers

java.lang.Object

org.javers.core.Javers

public class Javers
extends java.lang.Object

Facade to JaVers instance.
Should be constructed by JaversBuilder provided with your domain model configuration.

For example, to deeply compare two objects or two arbitrary complex graphs of objects, call:

 Javers javers = JaversBuilder.javers().build();
 Diff diff = javers.compare(oldVersion, currentVersion);
 

See Also:

http://javers.org/documentation

Constructor Summary

Constructors

Constructor and Description
Javers(DiffFactory diffFactory, TypeMapper typeMapper, JsonConverter jsonConverter, CommitFactory commitFactory, JaversExtendedRepository repository, SnapshotDiffer snapshotDiffer) JaVers instance should be constructed by JaversBuilder

Method Summary

Modifier and Type	Method and Description
Commit	commit(java.lang.String author, java.lang.Object currentVersion) Persists current version of given domain object in JaVers repository.
Diff	compare(java.lang.Object oldVersion, java.lang.Object currentVersion) JaVers core function, deeply compares two arbitrary complex objects graphs.
java.util.List<Change>	getChangeHistory(GlobalIdDTO globalId, int limit) Changes history (diff sequence) of given object, in reverse chronological order.
JsonConverter	getJsonConverter()
Optional<CdoSnapshot>	getLatestSnapshot(GlobalIdDTO globalId) Latest snapshot of given object or Optional#EMPTY if object is not versioned.
java.util.List<CdoSnapshot>	getStateHistory(GlobalIdDTO globalId, int limit) Snapshots (historical versions) of given object, in reverse chronological order.
IdBuilder	idBuilder()
Diff	initial(java.lang.Object newDomainObject) Initial diff is a kind of snapshot of given domain objects graph.
<T> T	processChangeList(java.util.List<Change> changes, ChangeProcessor<T> changeProcessor) Generic purpose method for processing a changes list.
java.lang.String	toJson(Diff diff) Diff serialized to pretty JSON, useful if you are not using JaversRepository

Methods inherited from class java.lang.Object

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

Constructor Detail

Javers

public Javers(DiffFactory diffFactory,
              TypeMapper typeMapper,
              JsonConverter jsonConverter,
              CommitFactory commitFactory,
              JaversExtendedRepository repository,
              SnapshotDiffer snapshotDiffer)

JaVers instance should be constructed by JaversBuilder

Method Detail

commit

public Commit commit(java.lang.String author,
                     java.lang.Object currentVersion)

Persists current version of given domain object in JaVers repository. JaVers applies commit() to given object and all objects navigable from it. You can capture state of arbitrary complex objects graph with single commit() call.

Parameters:

currentVersion - Standalone object or handle to objects graph

compare

public Diff compare(java.lang.Object oldVersion,
                    java.lang.Object currentVersion)

JaVers core function, deeply compares two arbitrary complex objects graphs.

To calculate diff, just provide two versions of the same object or handles to two versions of the same objects graph.
The handle could be a root of an aggregate, tree root or any node in an objects graph from where all other nodes are navigable.

This function is used for ad-hoc objects comparing. In order to use data auditing feature, call commit(String, Object).

Diffs can be converted to JSON with toJson(Diff).

See Also:

http://javers.org/documentation/diff-examples

initial

public Diff initial(java.lang.Object newDomainObject)

Initial diff is a kind of snapshot of given domain objects graph. Use it alongside with compare(Object, Object)

toJson

public java.lang.String toJson(Diff diff)

Diff serialized to pretty JSON, useful if you are not using JaversRepository

idBuilder

public IdBuilder idBuilder()

getStateHistory

public java.util.List<CdoSnapshot> getStateHistory(GlobalIdDTO globalId,
                                                   int limit)

Snapshots (historical versions) of given object, in reverse chronological order.

For example, to list 5 last snapshots of "bob" Person, call:

 javers.getStateHistory(InstanceIdDTO.instanceId("bob", Person.class), 5);
 

Parameters:

globalId - given object ID

limit - choose reasonable limit

Returns:

empty List if object is not versioned

getLatestSnapshot

public Optional<CdoSnapshot> getLatestSnapshot(GlobalIdDTO globalId)

Latest snapshot of given object or Optional#EMPTY if object is not versioned.

For example, to get last snapshot of "bob" Person, call:

 javers.getStateHistory(InstanceIdDTO.instanceId("bob", Person.class), 5);
 

getChangeHistory

public java.util.List<Change> getChangeHistory(GlobalIdDTO globalId,
                                               int limit)

Changes history (diff sequence) of given object, in reverse chronological order. For example, to get change history of "bob" Person, call:

 javers.getChangeHistory(InstanceIdDTO.instanceId("bob", Person.class), 5);
 

Parameters:

globalId - given object ID

limit - choose reasonable limit

Returns:

empty List, if object is not versioned or was committed only once

getJsonConverter

public JsonConverter getJsonConverter()

processChangeList

public <T> T processChangeList(java.util.List<Change> changes,
                               ChangeProcessor<T> changeProcessor)

Generic purpose method for processing a changes list. After iterating over given list, returns data computed by ChangeProcessor.result().
It's more convenient than iterating over changes on your own. ChangeProcessor frees you from if + inctanceof boilerplate.

Additional features:
- when several changes in a row refers to the same Commit, ChangeProcessor.onCommit(CommitMetadata) is called only for first occurrence
- similarly, when several changes in a row affects the same object, ChangeProcessor.onAffectedObject(GlobalId) is called only for first occurrence

For example, to get pretty change log, call:

 List<Change> changes = javers.getChangeHistory(...);
 String changeLog = javers.processChangeList(changes, new SimpleTextChangeLog());
 System.out.println( changeLog );
 

See Also:

SimpleTextChangeLog