XOM API for Processing XML with Java

[Elliotte Harold <elharo AT metalab.unc.edu>]

Wolfgang Hoschek wrote:

> 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

This one came up because someone did it in their code, and I wrote a 
unit test to prove  it. See 
http://www.xom.nu/clover_html/nu/xom/Element.html
Note the 100% test coverage for Element.java including the referenced 
line. I believe it's tested by ParentNodeTest.testCycle:

    public void testCycle() {

        Element a = new Element("test");
        Element b = new Element("test");
        try {
            a.appendChild(b);
            b.appendChild(a);
            fail("Allowed cycle");
        }
        catch (CycleException success) {
            assertNotNull(success.getMessage());
        }

    }

--
Elliotte Rusty Harold  elharo AT metalab.unc.edu
XML in a Nutshell 3rd Edition Just Published!
http://www.cafeconleche.org/books/xian3/
http://www.amazon.com/exec/obidos/ISBN=0596007647/cafeaulaitA/ref=nosim