package org.hibernate.envers.strategy;
import java.io.Serializable;
import java.util.Date;
import java.util.List;
import java.util.Map;
import org.hibernate.Session;
import org.hibernate.envers.RevisionType;
import org.hibernate.envers.configuration.AuditConfiguration;
import org.hibernate.envers.configuration.AuditEntitiesConfiguration;
import org.hibernate.envers.configuration.GlobalConfiguration;
import org.hibernate.envers.entities.mapper.PersistentCollectionChangeData;
import org.hibernate.envers.entities.mapper.id.IdMapper;
import org.hibernate.envers.entities.mapper.relation.MiddleComponentData;
import org.hibernate.envers.entities.mapper.relation.MiddleIdData;
import org.hibernate.envers.tools.query.Parameters;
import org.hibernate.envers.tools.query.QueryBuilder;
import org.hibernate.property.Getter;
/**
* Audit strategy which persists and retrieves audit information using a validity algorithm, based on the
* start-revision and end-revision of a row in the audit tables.
* <p>This algorithm works as follows:
* <ul>
* <li>For a <strong>new row</strong> that is persisted in an audit table, only the <strong>start-revision</strong> column of that row is set</li>
* <li>At the same time the <strong>end-revision</strong> field of the <strong>previous</strong> audit row is set to this revision</li>
* <li>Queries are retrieved using 'between start and end revision', instead of a subquery.</li>
* </ul>
* </p>
*
* <p>
* This has a few important consequences that need to be judged against against each other:
* <ul>
* <li>Persisting audit information is a bit slower, because an extra row is updated</li>
* <li>Retrieving audit information is a lot faster</li>
* </ul>
* </p>
*
* @author Stephanie Pau
* @author Adam Warski (adam at warski dot org)
*/
public class ValidityAuditStrategy implements AuditStrategy {
/** getter for the revision entity field annotated with @RevisionTimestamp */
private Getter revisionTimestampGetter = null;
public void perform(Session session, String entityName, AuditConfiguration auditCfg, Serializable id, Object data,
Object revision) {
AuditEntitiesConfiguration audEntCfg = auditCfg.getAuditEntCfg();
String auditedEntityName = audEntCfg.getAuditEntityName(entityName);
// Update the end date of the previous row if this operation is expected to have a previous row
if (getRevisionType(auditCfg, data) != RevisionType.ADD) {
/*
Constructing a query:
select e from audited_ent e where e.end_rev is null and e.id = :id
*/
QueryBuilder qb = new QueryBuilder(auditedEntityName, "e");
// e.id = :id
IdMapper idMapper = auditCfg.getEntCfg().get(entityName).getIdMapper();
idMapper.addIdEqualsToQuery(qb.getRootParameters(), id, auditCfg.getAuditEntCfg().getOriginalIdPropName(), true);
addEndRevisionNulLRestriction(auditCfg, qb);
@SuppressWarnings({"unchecked"})
List<Object> l = qb.toQuery(session).list();
updateLastRevision(session, auditCfg, l, id, auditedEntityName, revision);
}
// Save the audit data
session.save(auditedEntityName, data);
}
@SuppressWarnings({"unchecked"})
public void performCollectionChange(Session session, AuditConfiguration auditCfg,
PersistentCollectionChangeData persistentCollectionChangeData, Object revision) {
final QueryBuilder qb = new QueryBuilder(persistentCollectionChangeData.getEntityName(), "e");
// Adding a parameter for each id component, except the rev number
final String originalIdPropName = auditCfg.getAuditEntCfg().getOriginalIdPropName();
final Map<String, Object> originalId = (Map<String, Object>) persistentCollectionChangeData.getData().get(
originalIdPropName);
for (Map.Entry<String, Object> originalIdEntry : originalId.entrySet()) {
if (!auditCfg.getAuditEntCfg().getRevisionFieldName().equals(originalIdEntry.getKey())) {
qb.getRootParameters().addWhereWithParam(originalIdPropName + "." + originalIdEntry.getKey(),
true, "=", originalIdEntry.getValue());
}
}
addEndRevisionNulLRestriction(auditCfg, qb);
final List<Object> l = qb.toQuery(session).list();
// Update the last revision if one exists.
// HHH-5967: with collections, the same element can be added and removed multiple times. So even if it's an
// ADD, we may need to update the last revision.
if (l.size() > 0) {
updateLastRevision(session, auditCfg, l, originalId, persistentCollectionChangeData.getEntityName(), revision);
}
// Save the audit data
session.save(persistentCollectionChangeData.getEntityName(), persistentCollectionChangeData.getData());
}
private void addEndRevisionNulLRestriction(AuditConfiguration auditCfg, QueryBuilder qb) {
// e.end_rev is null
qb.getRootParameters().addWhere(auditCfg.getAuditEntCfg().getRevisionEndFieldName(), true, "is", "null", false);
}
public void addEntityAtRevisionRestriction(GlobalConfiguration globalCfg, QueryBuilder rootQueryBuilder,
String revisionProperty,String revisionEndProperty, boolean addAlias,
MiddleIdData idData, String revisionPropertyPath, String originalIdPropertyName,
String alias1, String alias2) {
Parameters rootParameters = rootQueryBuilder.getRootParameters();
addRevisionRestriction(rootParameters, revisionProperty, revisionEndProperty, addAlias);
}
public void addAssociationAtRevisionRestriction(QueryBuilder rootQueryBuilder, String revisionProperty,
String revisionEndProperty, boolean addAlias, MiddleIdData referencingIdData,
String versionsMiddleEntityName, String eeOriginalIdPropertyPath, String revisionPropertyPath,
String originalIdPropertyName, MiddleComponentData... componentDatas) {
Parameters rootParameters = rootQueryBuilder.getRootParameters();
addRevisionRestriction(rootParameters, revisionProperty, revisionEndProperty, addAlias);
}
public void setRevisionTimestampGetter(Getter revisionTimestampGetter) {
this.revisionTimestampGetter = revisionTimestampGetter;
}
private void addRevisionRestriction(Parameters rootParameters,
String revisionProperty, String revisionEndProperty, boolean addAlias) {
// e.revision <= _revision and (e.endRevision > _revision or e.endRevision is null)
Parameters subParm = rootParameters.addSubParameters("or");
rootParameters.addWhereWithNamedParam(revisionProperty, addAlias, "<=", "revision");
subParm.addWhereWithNamedParam(revisionEndProperty + ".id", addAlias, ">", "revision");
subParm.addWhere(revisionEndProperty, addAlias, "is", "null", false);
}
@SuppressWarnings({"unchecked"})
private RevisionType getRevisionType(AuditConfiguration auditCfg, Object data) {
return (RevisionType) ((Map<String, Object>) data).get(auditCfg.getAuditEntCfg().getRevisionTypePropName());
}
@SuppressWarnings({"unchecked"})
private void updateLastRevision(Session session, AuditConfiguration auditCfg, List<Object> l,
Object id, String auditedEntityName, Object revision) {
// There should be one entry
if (l.size() == 1) {
// Setting the end revision to be the current rev
Object previousData = l.get(0);
String revisionEndFieldName = auditCfg.getAuditEntCfg().getRevisionEndFieldName();
((Map<String, Object>) previousData).put(revisionEndFieldName, revision);
if (auditCfg.getAuditEntCfg().isRevisionEndTimestampEnabled()) {
// Determine the value of the revision property annotated with @RevisionTimestamp
Date revisionEndTimestamp;
String revEndTimestampFieldName = auditCfg.getAuditEntCfg().getRevisionEndTimestampFieldName();
Object revEndTimestampObj = this.revisionTimestampGetter.get(revision);
// convert to a java.util.Date
if (revEndTimestampObj instanceof Date) {
revisionEndTimestamp = (Date) revEndTimestampObj;
} else {
revisionEndTimestamp = new Date((Long) revEndTimestampObj);
}
// Setting the end revision timestamp
((Map<String, Object>) previousData).put(revEndTimestampFieldName, revisionEndTimestamp);
}
// Saving the previous version
session.save(auditedEntityName, previousData);
} else {
throw new RuntimeException("Cannot find previous revision for entity " + auditedEntityName + " and id " + id);
}
}
}