diff --git a/plusone-commons/src/main/java/xyz/zhouxy/plusone/commons/util/RandomTools.java b/plusone-commons/src/main/java/xyz/zhouxy/plusone/commons/util/RandomTools.java index 376cbca..d9d2841 100644 --- a/plusone-commons/src/main/java/xyz/zhouxy/plusone/commons/util/RandomTools.java +++ b/plusone-commons/src/main/java/xyz/zhouxy/plusone/commons/util/RandomTools.java @@ -24,6 +24,9 @@ import java.security.SecureRandom; import java.util.Random; import java.util.concurrent.ThreadLocalRandom; +import com.google.common.collect.BoundType; +import com.google.common.collect.Range; + /** * 随机工具类 *

@@ -116,6 +119,52 @@ public final class RandomTools { return randomStrInternal(DEFAULT_SECURE_RANDOM, sourceCharacters, length); } + /** + * 生成随机整数 + * + * @param min 最小值(包含) + * @param max 最大值(不包含) + * @return 在区间 {@code [min, max)} 内的随机整数 + */ + public static int randomInt(int min, int max) { + return randomIntInternal(ThreadLocalRandom.current(), min, max); + } + + /** + * 生成随机整数 + * + * @param min 最小值(包含) + * @param max 最大值(不包含) + * @return 在区间 {@code [min, max)} 内的随机整数 + */ + public static int randomInt(Random random, int min, int max) { + checkArgumentNotNull(random, "Random cannot be null."); + return randomIntInternal(random, min, max); + } + + /** + * 生成随机整数 + * + * @param range 整数区间 + * @return 在指定区间内的随机整数 + */ + public static int randomInt(Range range) { + checkArgumentNotNull(range, "Range cannot be null."); + return randomIntInternal(ThreadLocalRandom.current(), range); + } + + /** + * 生成随机整数 + * + * @param range 整数区间 + * @return 在指定区间内的随机整数 + */ + public static int randomInt(Random random, Range range) { + checkArgumentNotNull(random, "Random cannot be null."); + checkArgumentNotNull(range, "Range cannot be null."); + return randomIntInternal(random, range); + } + /** * 使用传入的随机数生成器,生成指定长度的字符串 * @@ -158,6 +207,31 @@ public final class RandomTools { return String.valueOf(result); } + /** + * 生成随机整数 + * + * @param min 最小值(包含) + * @param max 最大值(不包含) + * @return 在区间 {@code [min, max)} 内的随机整数 + */ + private static int randomIntInternal(Random random, int min, int max) { + return random.nextInt(max - min) + min; + } + + /** + * 生成随机整数 + * + * @param range 整数区间 + * @return 在指定区间内的随机整数 + */ + private static int randomIntInternal(Random random, Range range) { + Integer lowerEndpoint = range.lowerEndpoint(); + Integer upperEndpoint = range.upperEndpoint(); + int min = range.lowerBoundType() == BoundType.CLOSED ? lowerEndpoint : lowerEndpoint + 1; + int max = range.upperBoundType() == BoundType.OPEN ? upperEndpoint : upperEndpoint + 1; + return random.nextInt(max - min) + min; + } + private RandomTools() { throw new IllegalStateException("Utility class"); } diff --git a/plusone-commons/src/test/java/xyz/zhouxy/plusone/commons/util/RandomToolsTests.java b/plusone-commons/src/test/java/xyz/zhouxy/plusone/commons/util/RandomToolsTests.java index 7a05601..aa30262 100644 --- a/plusone-commons/src/test/java/xyz/zhouxy/plusone/commons/util/RandomToolsTests.java +++ b/plusone-commons/src/test/java/xyz/zhouxy/plusone/commons/util/RandomToolsTests.java @@ -21,6 +21,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals; import static org.junit.jupiter.api.Assertions.assertFalse; import static org.junit.jupiter.api.Assertions.assertInstanceOf; import static org.junit.jupiter.api.Assertions.assertThrows; +import static org.junit.jupiter.api.Assertions.assertTrue; import java.lang.reflect.Constructor; import java.security.SecureRandom; @@ -30,6 +31,8 @@ import java.util.Random; import org.junit.jupiter.api.BeforeAll; import org.junit.jupiter.api.Test; +import com.google.common.collect.Range; + @SuppressWarnings("null") public class RandomToolsTests { @@ -107,6 +110,50 @@ public class RandomToolsTests { assertEquals(5, result.length()); } + @Test + public void randomInt_WithMinAndMax() { + for (int i = 0; i < 1000_0000; i++) { + int r = RandomTools.randomInt(random, -2, 3); + assertTrue(r >= -2 && r < 3); + } + } + + @Test + public void randomInt_WithClosedOpenRange() { + Range co = Range.closedOpen(-2, 3); + for (int i = 0; i < 1000_0000; i++) { + int rco = RandomTools.randomInt(random, co); + assertTrue(rco >= -2 && rco < 3); + } + } + + @Test + public void randomInt_WithClosedRange() { + Range cc = Range.closed(-2, 3); + for (int i = 0; i < 1000_0000; i++) { + int rcc = RandomTools.randomInt(random, cc); + assertTrue(rcc >= -2 && rcc <= 3); + } + } + + @Test + public void randomInt_WithOpenClosedRange() { + Range oc = Range.openClosed(-2, 3); + for (int i = 0; i < 1000_0000; i++) { + int roc = RandomTools.randomInt(random, oc); + assertTrue(roc > -2 && roc <= 3); + } + } + + @Test + public void randomInt_WithOpenRange() { + Range oo = Range.open(-2, 3); + for (int i = 0; i < 1000_0000; i++) { + int roo = RandomTools.randomInt(random, oo); + assertTrue(roo > -2 && roo < 3); + } + } + @Test void test_constructor_isNotAccessible_ThrowsIllegalStateException() { Constructor[] constructors = RandomTools.class.getDeclaredConstructors();