XOM API for Processing XML with Java

[Wolfgang Hoschek <whoschek AT lbl.gov>]

Can anyone give an example situation where
                throw new CycleException(
                  "Cannot add an ancestor as a child");

is reachable in the method below? I can't see how it could 
theoretically be reached, given that child.getParent() != null has 
already been tested, and it's only for cases where child.isElement? An 
ancestor always has getParent != null, otherwise it can't be an 
ancestor in the first place. If it is indeed unreachable, the whole 
block

        else if (child.getChildCount() > 0 && isCycle(child, this)) {

can be removed without changing any semantics.
Wolfgang.


Element.java:
    void insertionAllowed(Node child, int position) {

        if (child == null) {
            throw new NullPointerException(
             "Tried to insert a null child in the tree");
        }
        else if (child.getParent() != null) {
            throw new MultipleParentException(child.toString()
              + " child already has a parent.");
        }
        else if (child.isElement()) {
            if (child == this) {
                throw new CycleException(
                  "Cannot add a node to itself");
            }
            else if (child.getChildCount() > 0 && isCycle(child, this)) 
{
                throw new CycleException(
                  "Cannot add an ancestor as a child");
            }
            return;
        }
        else if (child.isText()
          || child.isProcessingInstruction()
          || child.isComment()) {
            return;
        }
        else {
            throw new IllegalAddException("Cannot add a "
             + child.getClass().getName() + " to an Element.");
        }

    }