// add the subscription index
String fullPath = this.indexStoragePath;
Resource topicIndexResource;
if(userRegistry.resourceExists(fullPath)){
topicIndexResource = userRegistry.get(fullPath);
topicIndexResource.addProperty(subscription.getId(), subscription.getTopicName());
}else{
topicIndexResource = userRegistry.newResource();
topicIndexResource.addProperty(subscription.getId(), subscription.getTopicName());
}
userRegistry.put(fullPath, topicIndexResource);