@Override
    public void updateDefaultConfiguration( PubSubService.UniqueIdentifier serviceIdentifier, DefaultNodeConfiguration config )
    {
        log.debug( "Updating default node configuration for service {} (for leaf type: {}).", serviceIdentifier, config.isLeaf() );
        final String key = getDefaultNodeConfigurationCacheKey( serviceIdentifier, config.isLeaf() );
        defaultNodeConfigurationCache.put( key, config );
    }
Cache that holds all published items (mapped by node ID).
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/InMemoryPubSubPersistenceProvider.java