question: private void addToMap ( Map < String , Collection < ClusterNode > > cacheMap , String cacheName , ClusterNode rich ) { Collection < ClusterNode > cacheNodes = cacheMap . get ( cacheName ) ; if ( cacheNodes == null ) { cacheNodes = new ArrayList < > ( allNodes . size ( ) ) ; cacheMap . put ( cacheName , cacheNodes ) ; } cacheNodes . add ( rich ) ; }
target:  Adds node to map.