stream
.filter
.peak
.map
....

limit, skip, filter, ...

 public long getSurveyResultInProgressCount(long surveyId) {
    return surveyResultIdentitiesPersistDelayedMap.keySet()
      .stream()
      .map(this::getCachedByIdentity)
      .filter(x -> x.getSurveyId() == surveyId)
      .count();
  }

 public long getSurveyResultInProgressCount(long surveyId) {
    return surveyResultIdentitiesPersistDelayedMap.keySet()
      .stream()
      .map(this::getCachedByIdentity)
      .filter(x -> x.getSurveyId() == surveyId)
      .count();
  }

public long getSurveyResultInProgressCount(long surveyId) {
   int count = 0;
   for (int id : surveyResultIdentitiesPersistDelayedMap.keySet){
      SomeClass object = getCachedByIdentity(id);
       if (object.getSurveyId() == surveyId){
          count ++;
       }
    }
return count;
}

T reduce(T identity, BinaryOperator<T> accumulator)

Performs a reduction on the elements of this stream, using the provided identity value
 and an associative accumulation function, and returns the reduced value. 
This is equivalent to:

T result = identity;
for (T element : this stream)
   result = accumulator.apply(result, element)
return result;

T result = identity;
for (T element : this stream)
   result = accumulator.apply(result, element)
return result;