Java examples for java.lang:int prime
Returns the list of primes less or equal to the provided boundary.
//package com.java2s;
import java.util.List;
import java.util.stream.IntStream;
import static java.util.stream.Collectors.toList;
public class Main {
/**//w w w . jav a 2 s. c o m
* Returns the list of primes less or equal to the provided <code>boundary</code>.
*
* @param boundary - test boundary
* @return list of primes
*/
public static List<Integer> getPrimes(int boundary) {
return IntStream.rangeClosed(2, boundary).filter(n -> isPrime(n)).boxed().collect(toList());
}
/**
* Tests if provided <code>number</code> is prime.
*
* @param number - a number to test
* @return <code>true</code> if <code>number</code> is prime, <code>false</code> otherwise.
*/
public static boolean isPrime(int number) {
if (number <= 1) {
return false;
}
double testBoundary = Math.sqrt(number);
return IntStream.rangeClosed(2, (int) testBoundary).noneMatch(i -> number % i == 0);
}
}