Java examples for java.lang:Math Prime Number
is Prime Factor
/*// w ww . jav a 2s . co m * UniCrypt * * UniCrypt(tm) : Cryptographical framework allowing the implementation of cryptographic protocols e.g. e-voting * Copyright (C) 2014 Bern University of Applied Sciences (BFH), Research Institute for * Security in the Information Society (RISIS), E-Voting Group (EVG) * Quellgasse 21, CH-2501 Biel, Switzerland * * Licensed under Dual License consisting of: * 1. GNU Affero General Public License (AGPL) v3 * and * 2. Commercial license * * * 1. This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * * * 2. Licensees holding valid commercial licenses for UniCrypt may use this file in * accordance with the commercial license agreement provided with the * Software or, alternatively, in accordance with the terms contained in * a written agreement between you and Bern University of Applied Sciences (BFH), Research Institute for * Security in the Information Society (RISIS), E-Voting Group (EVG) * Quellgasse 21, CH-2501 Biel, Switzerland. * * * For further information contact <e-mail: unicrypt@bfh.ch> * * * Redistributions of files must retain the above copyright notice. */ import java.math.BigInteger; import java.util.Arrays; import java.util.HashSet; public class Main{ public static final int NUMBER_OF_PRIME_TESTS = 40; private static boolean isPrimeFactor(final BigInteger value, final BigInteger factor) { return isPositive(value) && isPrime(factor) && value.gcd(factor).equals(factor); } /** * Tests if a given BigInteger value is positive. * <p> * @param value A potential positive number * @return {@literal true} if {@literal value} is positive, {@literal false} otherwise */ public static boolean isPositive(final BigInteger value) { if (value == null) { return false; } return value.signum() == 1; } /** * Tests if a given BigInteger value is a positive prime number. * <p> * @param value A potential prime number * @return {@literal true} if {@literal value} is prime, {@literal false} otherwise */ public static boolean isPrime(final BigInteger value) { return isPositive(value) && value.isProbablePrime(MathUtil.NUMBER_OF_PRIME_TESTS); } }