private void startSubscriptionAttributes(Attributes atts) {
    String ip = atts.getValue(INTEREST_POLICY);
    SubscriptionAttributes sa;
    if (ip == null) {
      sa = new SubscriptionAttributes();
    } else if (ip.equals(ALL)) {
      sa = new SubscriptionAttributes(InterestPolicy.ALL);
    } else if (ip.equals(CACHE_CONTENT)) {
      sa = new SubscriptionAttributes(InterestPolicy.CACHE_CONTENT);
    } else {
      throw new InternalGemFireException(
          String.format("Unknown interest-policy: %s", ip));
    }
    RegionAttributesCreation rattrs = (RegionAttributesCreation) stack.peek();
    rattrs.setSubscriptionAttributes(sa);
  }
When a <code>subscription-attributes</code> element is first encountered, we create an
SubscriptionAttibutes?? object from the element's attributes and stick it in the current region
attributes.
geode-core/src/main/java/org/apache/geode/internal/cache/xmlcache/CacheXmlParser.java