private Set<String> getArtifactCkecksumList(RevisionDescriptor rd, ChecksumProvider provider) {
Set categories = rd.getCategories();
Set<String> result = new HashSet<String>();
for (Iterator iter = categories.iterator(); iter.hasNext();) {
Category cat = (Category)iter.next();
if (Category.ARTIFACT.equals(cat.getName())) {
Collection items = rd.getItems(cat);
for (Iterator iterator = items.iterator(); iterator.hasNext();) {
CategoryItem item = (CategoryItem)iterator.next();
try {
InputStream is = FSHelper.openInputStream(_explorer.getRevisionDir(item.getRevision()).toURL().toString(), item.getPath());