question: public Parameter createNodeTraitsParameter ( boolean rootNode , boolean internalNodes , boolean leafNodes ) { if ( ! rootNode && ! internalNodes && ! leafNodes ) { throw new IllegalArgumentException ( "At least one of rootNode, internalNodes or leafNodes must be true" ) ; } CompoundParameter parameter = new CompoundParameter ( TreeModelParser . NODE_TRAITS ) ; hasTraits = true ; for ( int i = externalNodeCount ; i < nodeCount ; i ++ ) { Node node = nodes . get ( i ) ; node . createTraitParameter ( ) ; if ( ( rootNode && node == root ) || ( internalNodes && node != root ) ) { parameter . addParameter ( node . traitParameter ) ; } } for ( int i = 0 ; i < externalNodeCount ; i ++ ) { Node node = nodes . get ( i ) ; node . createTraitParameter ( ) ; if ( leafNodes ) { parameter . addParameter ( node . traitParameter ) ; } } return parameter ; }
target:  Create a node traits parameter. Is private because it can only be called by the XMLParser