apache-flink: sliding window in output -

i'm coding small application understand sliding windowing in flink (with data input apache-kafka topic):

//split kafka stream comma , create tuple  datastream<tuple3<string, integer, date>> parsedstream = stream     .map((line) -> {        string[] cells = line.split(",");        return new tuple3(cells[1], integer.parseint(cells[4]), f.parse(cells[2]));     });  datastream<tuple3<string, integer, date>> parsedstreamwithtswm = parsedstream         .assigntimestampsandwatermarks(new boundedoutofordernesstimestampextractor<tuple3<string, integer, date>>(time.minutes(1)) {              @override             public long extracttimestamp(tuple3<string, integer, date> element) {                 return element.f2.gettime();             }         });  //sum values per windows , per id datastream<tuple3<string, integer, date>>  aggstream = parsedstreamwithtswm     .keyby(0)     .window(slidingeventtimewindows.of(time.minutes(30), time.minutes(1)))     .sum(1);  aggstream.print(); 

is possible improve output (aggstream.print();) adding window details produce aggregation output ?

$ tail -f flink-chapichapo-jobmanager-0.out (228035740000002,300,fri apr 07 14:42:00 cest 2017) (228035740000000,28,fri apr 07 14:42:00 cest 2017) (228035740000002,300,fri apr 07 14:43:00 cest 2017) (228035740000000,27,fri apr 07 14:43:00 cest 2017) (228035740000002,300,fri apr 07 14:44:00 cest 2017) (228035740000000,26,fri apr 07 14:44:00 cest 2017) (228035740000001,27,fri apr 07 14:44:00 cest 2017) (228035740000002,300,fri apr 07 14:45:00 cest 2017) (228035740000000,25,fri apr 07 14:45:00 cest 2017) 

thank in advance

you can use generic function apply have access window info.

public interface windowfunction<in, out, key, w extends window> extends function, serializable {      /**      * evaluates window , outputs none or several elements.      *      * @param key key window evaluated.      * @param window window being evaluated.      * @param input elements in window being evaluated.      * @param out collector emitting elements.      *      * @throws exception function may throw exceptions fail program , trigger recovery.      */     void apply(key key, w window, iterable<in> input, collector<out> out) throws exception; } 

see docs