CustomSqlChange: how access database metadata ?

Hi,

For version 2 of liquibase, I wrote a CustomSqlChange accessing java.sql.DatabaseMetaData in order to get the list of constraints :

Set<UniqueConstraint> constraints = SnapshotGeneratorFactory.getInstance()
.createSnapshot(null, database).getDatabaseMetaData().getUniqueConstraints();


But with version 3, this is not possible anymore and so I'm unable to upgrade.

How could I get access to the constraint list with the new API?

Thanks