Add dedicated RevisionSort to easily capture the desire to sort by revision number [DATACMNS-888]

[spring-projects-issues]

Oliver Drotbohm opened DATACMNS-888 and commented

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Reference URL: spring-projects/spring-data-envers#55

[spring-projects-issues]

Matthias Müller commented

Just as a hint/suggestion, it would also be possible to sort by any number of attributes.
A implementation would look like this:

public Page<Revision<N, T>> findRevisions(ID id, Pageable pageable) {
	Class<T> type = entityInformation.getJavaType();
	AuditReader reader = AuditReaderFactory.get(entityManager);
	List<Number> allRevisionNumbers = reader.getRevisions(type, id);
	if (pageable.getOffset() > allRevisionNumbers.size()) {
		return new PageImpl<Revision<N, T>>(Collections.<Revision<N, T>> emptyList(), pageable, 0);
	}
	AuditQuery query = reader.createQuery().forRevisionsOfEntity(type, type.getName(), false, true);
	query.addProjection(AuditEntity.revisionNumber());
	query.add(AuditEntity.id().eq(id));
	query.setFirstResult(pageable.getOffset());
	query.setMaxResults(pageable.getPageSize());
	if (null == pageable.getSort()) {
		query.addOrder(AuditEntity.revisionNumber().asc());
	} else {
		for (Sort.Order order : pageable.getSort()) {
			AuditProperty<?> property = "revisionNumber".equals(order.getProperty())
				? AuditEntity.id() : AuditEntity.property(order.getProperty());
			boolean asc = Direction.ASC.equals(order.getDirection());
			query.addOrder(asc ? property.asc() : property.desc());
		}
	}
	List<N> revisionNumbers = query.getResultList();
	List<Revision<N, T>> content = new ArrayList<Revision<N, T>>();
	for (N revisionNumber : revisionNumbers) {
		content.add(findRevision(id, revisionNumber));
	}
	return new PageImpl<Revision<N, T>>(content, pageable, allRevisionNumbers.size());
}