Java 8 streams: find items from one list that match conditions calculated based on values from another list

Question

Have two classes and two corresponding lists:

class Click {
   long campaignId;
   Date date;
}

class Campaign {
   long campaignId;
   Date start;
   Date end;         


        

Answer 1

public List findMatchingClicks(List cmps, List clicks) {
    List cmpsProspective = cmps.stream().filter(cmp -> "prospective".equals(cmp.type)).collect(Collectors.toList());
    return clicks.stream().filter(c -> matchesAnyCmp(c, cmpsProspective).collect(Collectors.toList());
}

public boolean matchesAnyCmp(Click click, List cmps) {
     return cmps.stream().anyMatch(click -> cmp.start.before(click.date) && cmp.end.after(click.date));
}

Replace fields for getters, just wrote it quick.