code: public RunList<R> node(final Node node) {
          return filter(new Predicate<R>() {
              public boolean apply(R r) {
                  return (r instanceof AbstractBuild) && ((AbstractBuild)r).getBuiltOn()==node;
              }
          });
      }
docs: Filter the list to builds on a single node only
  <em>Warning:</em> this method mutates the original list and then returns it.