private boolean isSetter(ExecutableElement executable) {
      if (isJavaLangObject(executable.getEnclosingElement())) {
        return false;
      }

      Naming set = styles.scheme().set;
      boolean notASetter = set.detect(executable.getSimpleName().toString()).isEmpty();
      if (notASetter) {
        return false;
      }

      return !executable.getModifiers().contains(Modifier.STATIC)
             && executable.getModifiers().contains(Modifier.PUBLIC)
             && executable.getParameters().size() == 1
             && executable.getReturnType().getKind() == TypeKind.VOID;
    }
For some reason {@link Elements#getAllMembers(TypeElement)} does not
return fields from parent class. Collecting them manually in this method.
value-processor/src/org/immutables/value/processor/meta/JavaBeanAttributesCollector.java