JavaScript
x
/**
* Get all cities near current city in radius.
*
* @param cityName - city
* @param radius - radius in kilometers for search
* @throws IllegalArgumentException if city with cityName city doesn't exist.
*/
public List<String> getCitiesNear(String cityName, int radius) {
List<String> nearCities = new ArrayList<>();
List<Integer> distances = new ArrayList<>();
for (int i = 0; i < this.citiesNames().size(); i++) {
distances.add(this.getDistance(cityName, this.citiesNames().get(i)));
}
for (int i = 0; i < distances.size(); i++) {
if (distances.get(i) <= radius) {
if (!this.citiesNames().get(i).equals(cityName)) {
nearCities.add(this.citiesNames().get(i));
}
}
}
return nearCities;
}
Method citiesNames() returns List<“String”>. The names of cities.
Method “int getDistance(String srcCityName, String destCityName)” returns distance between srcCityName and srcCityName.
PS: It is forbidden to use loops, iterators inside this class. Only streams and methods that accept predicates can be used. You cannot declare other fields in the class.
This is my homework)
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Answer
JavaScript
if (citiesNames().contains(cityName) {
return citiesNames().stream()
.filter(city -> getDistance(cityName, city) <= radius)
.collect(Collectors.toList());
}
else {
throw new IllegalArgumentException(cityName + " not found.");
}
filter
method returns a stream that contains only the near cities.
collect
method creates a List
containing all the elements in the filtered stream.