/** Add a conctat to a shared item */
public void addContact(String share, String contact) throws ShareException, Exception
{
Element s = this.getShareElement(share);
if (s == null)
throw new ShareException("Share not found: "+share);
Element c = this.document.createElement(SharesXML.TAG_CONTACT);
if (c == null)
throw new ShareException("Contact not found: "+contact);
c.setAttribute(SharesXML.ATTR_NAME, contact);
s.appendChild(c);
this.save();
}