* Verifies that Axis names are valid and unique.
*/
private void checkAxisNames(Iterable<Axis> newAxes) throws FormException {
HashSet<String> axisNames = new HashSet<String>();
for (Axis a : newAxes) {
FormValidation fv = a.getDescriptor().doCheckName(a.getName());
if (fv.kind!=Kind.OK)
throw new FormException(Messages.MatrixProject_DuplicateAxisName(),fv,"axis.name");
if (axisNames.contains(a.getName()))
throw new FormException(Messages.MatrixProject_DuplicateAxisName(),"axis.name");