/**
  * Revokes the permissions of a grantee by removing the grantee from the access control list
  * (ACL).
  *
  * @param grantee The grantee to remove from this ACL.
  */
 public void revokeAllPermissions(Grantee grantee) {
   ArrayList<Grant> grantsToRemove = new ArrayList<Grant>();
   List<Grant> existingGrants = getGrantsAsList();
   for (Grant gap : existingGrants) {
     if (gap.getGrantee().equals(grantee)) {
       grantsToRemove.add(gap);
     }
   }
   grantList.removeAll(grantsToRemove);
 }
 /**
  * Adds a set of grantee/permission pairs to the access control list (ACL), where each item in the
  * set is a {@link Grant} object.
  *
  * @param grantsVarArg A collection of {@link Grant} objects
  */
 public void grantAllPermissions(Grant... grantsVarArg) {
   for (Grant gap : grantsVarArg) {
     grantPermission(gap.getGrantee(), gap.getPermission());
   }
 }