public void deleteById(@NotNull String uid) throws StorageException {
        Preconditions.requireNonBlank(uid, "uid must be non-blank");
        EntityManager em = super.getActiveEntityManager();
        em.flush();
        em.createQuery("DELETE "
                            + "FROM BlobEntity b "
                            + "WHERE b.refCount <= 1 "
                            + "AND b.id = :uid")
          .setParameter("uid", uid)
          .executeUpdate();

        em.createQuery("UPDATE BlobEntity b "
                            + "SET b.refCount = b.refCount-1"
                            + "WHERE b.id = :uid")
          .setParameter("uid", uid)
          .executeUpdate();
    }
Delete by provided ID (nb: not name, its ID set when stored).

<p>Does not truly delete the file if there are other (i.e. deduplicated) references to this blob. In this case
the reference counter is decremented.
manager/api/jpa/src/main/java/io/apiman/manager/api/jpa/blobstore/BlobStoreRepository.java