public Collection<NodeSubscription> getAllSubscriptions() {
        if (isMultipleSubscriptionsEnabled()) {
            getLogger().trace("Got {} subscription(s)", subscriptionsByID.size());
            return subscriptionsByID.values();
        } else {
            getLogger().trace("Got {} subscription(s)", subscriptionsByJID.size());
            return subscriptionsByJID.values();
        }
    }
Returns all subscriptions to the node. If multiple subscriptions are enabled,
this method returns the subscriptions by {@code subId}, otherwise it returns
the subscriptions by {@link JID}.

@return All subscriptions to the node.
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/Node.java