TopicExpressionResolutionException,
InvalidTopicExpressionException,
TopicExpressionException
{
String expr = getContent( topicExpr );
NamespaceContext nsContext = getNamespaceContext( topicExpr );
StringTokenizer exprTokenizer = new StringTokenizer( expr, "|" );
Set allMatchedTopics = new HashSet();
while ( exprTokenizer.hasMoreTokens() )
{
QName topicPath = toQName( exprTokenizer.nextToken(), nsContext );