CommonTreeNodeStream nodes = new CommonTreeNodeStream( t );
nodes.setTokenStream( tokenStream );
SparqlOwlTreeARQ treeWalker = new SparqlOwlTreeARQ( nodes );
Query q = treeWalker.query( null );
if( q.getPrefix( "rdf" ) == null )
q.setPrefix( "rdf", RDF.getURI() );
if( q.getPrefix( "rdfs" ) == null )
q.setPrefix( "rdfs", RDFS.getURI() );