code: public boolean isIncluded() {
          if (isIncluded) {
              return true;
          }
          if (env.shouldDocument(tsym)) {
              // Class is nameable from top-level and
              // the class and all enclosing classes
              // pass the modifier filter.
              if (containingPackage().isIncluded()) {
                  return isIncluded=true;
              }
              ClassDoc outer = containingClass();
              if (outer != null && outer.isIncluded()) {
                  return isIncluded=true;
              }
          }
          return false;
      }
docs: Return true if this class is included in the active set.
  A ClassDoc is included iff either it is specified on the
  commandline, or if it's containing package is specified
  on the command line, or if it is a member class of an
  included class.