public List<PublishedItem> getPublishedItems() {
        return Collections.emptyList();
    }
Returns the list of {@link PublishedItem} that were published to the node. The
returned collection cannot be modified. Collection nodes does not support publishing
of items so an empty list will be returned in that case.

@return the list of PublishedItem that were published to the node.
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/Node.java