if (JCR_MIXINNODETYPES.equals(propertyName)) {
// remove all mixin nodetypes
try {
Node n = (Node)item;
for (NodeType mixin : n.getMixinNodeTypes()) {
n.removeMixin(mixin.getName());
}
} catch (RepositoryException e) {
// NoSuchNodeTypeException, ConstraintViolationException should never occur...
throw new JcrDavException(e);
}