public void setAffiliation(Affiliation affiliation) {
        this.affiliation = affiliation;
    }
A NodeAffiliate keeps information about the affiliation of an entity with a node. Possible
affiliations are: owner, publisher, none or outcast. All except for outcast affiliations
may have a {@link NodeSubscription} with the node.

@author Matt Tucker
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/NodeAffiliate.java