The pattern allows strings matching the following EBNF:
TopicPathExpression ::= TopicPath ( '|' TopicPath )*
TopicPath ::= RootTopic ChildTopicExpression*
RootTopic ::= (QName | '*')
ChildTopicExpression ::= '/' (NCName | '*' | ‘/*’)
The pattern allows strings matching the following EBNF:
ConcreteTopicPath ::= RootTopic ChildTopic*
RootTopic ::= QName
ChildTopic ::= '/' NCName