com.nwawsoft.util.math

Class PrimeNumberFunctions

java.lang.Object

com.nwawsoft.util.math.PrimeNumberFunctions

public class PrimeNumberFunctions
extends java.lang.Object

Supplies functions to generate or check prime numbers.

Constructor Summary

Constructors

Constructor and Description
PrimeNumberFunctions()

Method Summary

Modifier and Type	Method and Description
static int[]	allPrimesFromTo(int lowerBound, int upperBound) Returns all prime numbers between (and including) lowerBound and upperBound.
static int[]	allPrimesTo(int upperBound) Wrapper for allPrimesFromTo(0, upperBound).
static int[]	firstPrimes(int amount) Returns a list containing the first X primes.
static int	generateAnotherPrime(int lowerBound, int upperBound, int lastPrime, int maxTries) Returns a prime number different from lastPrime between lowerBound and upperBound.
static int	generatePrime(int lowerBound, int upperBound) Generates a random prime number between lowerBound and upperBound.
static boolean	isPrime(int number) Returns whether a number is prime or not.
static boolean	isPrime(long number) Returns whether a number is prime or not.
static boolean	isSuperPrime(int number) Returns whether the specified number is a super prime number.
static int	nextPrime(int number) Returns the next prime on the number line after any given number.
static int[]	sieveOfEratosthenes(int upperBound) Returns an array containing all prime numbers from 2 to upperBound.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PrimeNumberFunctions

public PrimeNumberFunctions()

Method Detail

nextPrime

public static int nextPrime(int number)

Returns the next prime on the number line after any given number.

Parameters:

number - any number.

Returns:

the prime after number on the number line.

isPrime

public static boolean isPrime(int number)

Returns whether a number is prime or not.

Parameters:

number - any number.

Returns:

true if number is prime. Else false.

isPrime

public static boolean isPrime(long number)

Returns whether a number is prime or not.

Parameters:

number - any number.

Returns:

true if number is prime. Else false.

isSuperPrime

public static boolean isSuperPrime(int number)

Returns whether the specified number is a super prime number. Super prime numbers are numbers which are prime and whose position in the list of primes got a prime index aswell (starting from 1). Super primes are also known as higher-order primes or prime-indexed primes.

Parameters:

number - any number.

Returns:

true if the number is super prime. Else false.

allPrimesTo

public static int[] allPrimesTo(int upperBound)

Wrapper for allPrimesFromTo(0, upperBound).

Parameters:

upperBound - the upper bound to search for primes up to.

Returns:

all primes between 0 and upperBound.

allPrimesFromTo

public static int[] allPrimesFromTo(int lowerBound,
                                    int upperBound)

Returns all prime numbers between (and including) lowerBound and upperBound.

Parameters:

lowerBound - the lower bound to search for primes from.

upperBound - the upper bound to search for primes up to.

Returns:

all primes between (and including) lowerBound and upperBound.

firstPrimes

public static int[] firstPrimes(int amount)

Returns a list containing the first X primes.

Parameters:

amount - the desired amount of primes

Returns:

an int array containing the first X primes, starting with 2.

generatePrime

public static int generatePrime(int lowerBound,
                                int upperBound)

Generates a random prime number between lowerBound and upperBound.

Parameters:

lowerBound - the lower bound to search for primes from.

upperBound - the upper bound to search for primes up to.

Returns:

a random prime number between lowerBound and upperBound.

generateAnotherPrime

public static int generateAnotherPrime(int lowerBound,
                                       int upperBound,
                                       int lastPrime,
                                       int maxTries)
                                throws NoMorePrimesFoundException

Returns a prime number different from lastPrime between lowerBound and upperBound.

Parameters:

lowerBound - the lower bound to search for primes from.

upperBound - the upper bound to search for primes up to.

lastPrime - any prime within lowerBound and upperBound.

maxTries - the maximum amount of tries to generate a different prime number.

Returns:

a prime between lowerBound and upperBound which is different from lastPrime.

Throws:

NoMorePrimesFoundException - if no different prime than lastPrime is found between lowerBound and upperBound within maxTries tries.

sieveOfEratosthenes

public static int[] sieveOfEratosthenes(int upperBound)

Returns an array containing all prime numbers from 2 to upperBound.

Parameters:

upperBound - any upper Bound. Must be greater than 1.

Returns:

an array containing all prime numbers from 2 to upperBound.