add WeightListRandomSelector

hutool-core/src/test/java/org/dromara/hutool/core/lang/selector/WeightListRandomSelectorTest.java

@@ -0,0 +1,77 @@
+package org.dromara.hutool.core.lang.selector;
+
+import org.dromara.hutool.core.date.DateUtil;
+import org.dromara.hutool.core.date.StopWatch;
+import org.dromara.hutool.core.lang.Console;
+import org.dromara.hutool.core.util.RandomUtil;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class WeightListRandomSelectorTest {
+
+	@Test
+	@Disabled
+	public void weightListRandomTest() {
+		final Map<Integer, Times> timesMap = new HashMap<>();
+		final int size = 100;
+		int sumWeight = 0;
+		final WeightListRandomSelector<Integer> pool = new WeightListRandomSelector<>(size);
+		for (int i = 0; i < size; i++) {
+			final int weight = RandomUtil.randomInt(1, 100);
+			pool.add(i, weight);
+			sumWeight += weight;
+			timesMap.put(i, new Times(weight));
+		}
+
+		final int times = 100000000;// 随机次数
+		for (int i = 0; i < times; i++) {
+			timesMap.get(pool.select()).num++;
+		}
+
+		final int finalSumWeight = sumWeight;
+		timesMap.forEach((key, times1) -> {
+			final double expected = times1.weight / finalSumWeight;// 期望概率
+			final double actual = (double) timesMap.get(key).num / times;// 真实随机概率
+			Console.log(expected, actual);
+		});
+	}
+
+	private static class Times {
+		int num;
+		double weight;
+
+		public Times(final double weight) {
+			this.weight = weight;
+		}
+	}
+
+	@Test
+	public void weightRandomBenchTest() {
+		final int size = 100;
+		final WeightListRandomSelector<Integer> pool = new WeightListRandomSelector<>(size);
+		final WeightRandomSelector<Integer> pool2 = new WeightRandomSelector<>();
+		for (int i = 0; i < size; i++) {
+			final int weight = RandomUtil.randomInt(1, 100);
+			pool.add(i, weight);
+			pool2.add(i, weight);
+		}
+
+		final int count = 1000;
+		final StopWatch stopWatch = DateUtil.createStopWatch();
+		stopWatch.start("WeightListRandomSelector");
+		for (int i = 0; i < count; i++) {
+			pool.select();
+		}
+		stopWatch.stop();
+		stopWatch.start("WeightRandomSelector");
+		for (int i = 0; i < count; i++) {
+			pool2.select();
+		}
+		stopWatch.stop();
+
+		//Console.log(stopWatch.prettyPrint());
+	}
+}