XOM API for Processing XML with Java

[Johannes Döbler <jd AT aztecrider.com>]

> 4. By default most nodes created in memory will have null base URIs unless 
> specifcally set otherwise. What happens when such a URI is appended to or 
> inserted in a parent that has a base URI? Doe sit inherit the base URI of 
> its parent or not?
>
> 5. If nodes with null URIs do inherit their parent's base URI, what 
> happens when the node is detached? Does it keep the parent's base URI?
> What if it's later added to a different node with a different base URI?
>
> 6. How do I handle xml:base attributes? Should they be included in an 
> element's list of attributes? Should the setBaseURI method check for 
> conflicts with an xml:base attribute? What should it do if it notices one? 
> Should extra xml:base attributes be automatically generated as necessary 
> when the document is serialized?

The baseUri value should be inherited imho.
I would not use an own property to store the base uri value (with the 
exception of the Document class), but rather map getBaseUri, setBaseUri to 
the existence of xml:base attributes.
setBaseURI() makes only sense for Element and Document nodes.

Therefore:

Node
{
    public String getBaseURI()
    {
        return getParent().getBaseURI();
    }
}

Element
{
    public String getBaseURI()
    {
        String uri = readAttribute("xml:base");
        return uri != null ? uri : getParent().getBaseURI();
    }

    public void setBaseURI(String uri)
    {
        if (uri == null)
            removeAttribute("xml:base");
        else
            addAttribute(new Attribute("xml:base", uri));
    }
}

Document
{
    public String getBaseURI()
    {
        return baseUri_;
    }

    public void setBaseURI(String uri)
    {
        baseUri_ = uri;
    }

    private String baseUri_;
}

regards,
Johannes