public static PublisherModel valueOf(String name) {
        if ("open".equals(name)) {
            return open;
        }
        else if ("publishers".equals(name)) {
            return publishers;
        }
        else if ("subscribers".equals(name)) {
            return subscribers;
        }
        throw new IllegalArgumentException("Unknown publisher model: " + name);
    }
Returns the specific subclass of PublisherModel as specified by the publisher
model name. If an unknown name is specified then an IllegalArgumentException
is going to be thrown.

@param name the name of the subclass.
@return the specific subclass of PublisherModel as specified by the access
        model name.
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/models/PublisherModel.java