question: public PunctuationTrie < T > lookup ( CharSequence s ) { PunctuationTrie < T > t = this ; for ( int i = 0 , n = s . length ( ) ; i < n ; ++ i ) { t = t . lookup ( s . charAt ( i ) ) ; if ( null == t ) { break ; } } return t ; }
target:  The descendant of this trie corresponding to the string for this trie appended with s.