returns the result of interpreting the object as an instance of ` document ' . this implementation returns null ; returning a non-null result will terminate the switch . concode_field_sep MappedsuperclassPackage modelPackage concode_field_sep T caseParentDocument concode_elem_sep T caseTestReference concode_elem_sep T doSwitch concode_elem_sep T doSwitch concode_elem_sep T doSwitch concode_elem_sep T caseAddIDDocument concode_elem_sep T caseSpecificDocument concode_elem_sep T defaultCase
T function ( Document arg0 ) { return null ; }