question: private void addSpan ( CacheSpan span ) { TreeSet < CacheSpan > spansForKey = cachedSpans . get ( span . key ) ; if ( spansForKey == null ) { spansForKey = new TreeSet < > ( ) ; cachedSpans . put ( span . key , spansForKey ) ; } spansForKey . add ( span ) ; totalSpace += span . length ; notifySpanAdded ( span ) ; }
target:  Adds a cached span to the in-memory representation.