+ default List<Content> children(QName name) {
+ List<Content> res = new ArrayList<>();
+ for (Content child : this) {
+ if (child.getName().equals(name))
+ res.add(child);
+ }
+ return res;
+ }
+
+ default Optional<Content> soleChild(QName name) {
+ List<Content> res = children(name);
+ if (res.isEmpty())
+ return Optional.empty();
+ if (res.size() > 1)
+ throw new IllegalStateException(this + " has multiple children with name " + name);
+ return Optional.of(res.get(0));
+ }
+
+ default Content child(QName name) {
+ return soleChild(name).orElseThrow();
+ }