用ArrayList重新实现权重随机类：WeightListRandom

CHANGELOG.md

@@ -7,6 +7,7 @@
 ### 🐣新特性
 * 【core   】      SyncFinisher增加setExecutorService方法（issue#IANKQ1@Gitee）
 * 【http   】      HttpConfig增加`setUseDefaultContentTypeIfNull`方法（issue#3719@Github）
+* 【core   】      用ArrayList重新实现权重随机类：WeightListRandom（pr#3720@Github）
 
 ### 🐞Bug修复
 * 【json   】      修复JSONConfig.setDateFormat设置后toBean无效问题（issue#3713@Github）

hutool-core/src/main/java/cn/hutool/core/lang/WeightListPool.java

@@ -1,136 +0,0 @@
-package cn.hutool.core.lang;
-
-import cn.hutool.core.util.RandomUtil;
-
-import java.util.ArrayList;
-import java.util.Iterator;
-import java.util.List;
-import java.util.concurrent.ThreadLocalRandom;
-
-/**
- * 动态按权重随机的随机池，底层是list实现。
- *
- * @param <E> 元素类型
- * @author 王叶峰
- * @date 2024-07-29
- */
-public class WeightListPool<E> {
-
-    /**
-     * 随机元素池
-     */
-    private final ArrayList<EWeight<E>> randomPool;
-
-    public WeightListPool() {
-        randomPool = new ArrayList<>();
-    }
-
-    public WeightListPool(int poolSize) {
-        randomPool = new ArrayList<>(poolSize);
-    }
-
-    public void add(E e, double weight) {
-        Assert.isTrue(weight > 0, "权重必须大于0！");
-        randomPool.add(new EWeight<>(e, sumWeight() + weight));
-    }
-
-    public boolean remove(E e) {
-        boolean removed = false;
-        double weight = 0;
-        int i = 0;
-        Iterator<EWeight<E>> iterator = randomPool.iterator();
-        while (iterator.hasNext()) {
-            EWeight<E> ew = iterator.next();
-            if (!removed && ew.e.equals(e)) {
-                iterator.remove();
-                weight = ew.sumWeight - (i == 0 ? 0 : randomPool.get(i - 1).sumWeight);// 权重=当前权重-上一个权重
-                removed = true;
-            }
-            if (removed) {
-                // 重新计算后续权重
-                ew.sumWeight -= weight;
-            }
-            i++;
-        }
-        return removed;
-    }
-
-    private double sumWeight() {
-        if (randomPool.isEmpty()) {
-            return 0;
-        }
-        return randomPool.get(randomPool.size() - 1).sumWeight;
-    }
-
-    private void checkEmptyPool() {
-        if (isEmpty()) {
-            throw new IllegalArgumentException("随机池为空！");
-        }
-    }
-
-    public E random() {
-        checkEmptyPool();
-
-        if (randomPool.size() == 1) {
-            return randomPool.get(0).e;
-        }
-        ThreadLocalRandom random = RandomUtil.getRandom();
-        double randVal = random.nextDouble() * sumWeight();
-        return binarySearch(randVal);
-    }
-
-    /**
-     * 二分查找小于等于key的最大值的元素
-     *
-     * @param key 目标值
-     * @return 随机池的一个元素或者null 当key大于所有元素的总权重时，返回null
-     */
-    private E binarySearch(double key) {
-        int low = 0;
-        int high = randomPool.size() - 1;
-
-        while (low <= high) {
-            int mid = (low + high) >>> 1;
-            double midVal = randomPool.get(mid).sumWeight;
-
-            if (midVal < key) {
-                low = mid + 1;
-            } else if (midVal > key) {
-                high = mid - 1;
-            } else {
-                return randomPool.get(mid).e;
-            }
-        }
-        return randomPool.get(low).e;
-    }
-
-    /**
-     * 按照给定的总权重随机出一个元素
-     *
-     * @param weight 总权重
-     * @return 随机池的一个元素或者null
-     */
-    public E randomByWeight(double weight) {
-        Assert.isTrue(weight >= sumWeight(), "权重必须大于当前总权重！");
-        ThreadLocalRandom random = RandomUtil.getRandom();
-        double randVal = random.nextDouble() * sumWeight();
-        if (randVal > sumWeight()) {
-            return null;
-        }
-        return binarySearch(randVal);
-    }
-
-    public boolean isEmpty() {
-        return randomPool.isEmpty();
-    }
-
-    private static class EWeight<E> {
-        final E e;
-        double sumWeight;
-
-        public EWeight(E e, double sumWeight) {
-            this.e = e;
-            this.sumWeight = sumWeight;
-        }
-    }
-}

hutool-core/src/main/java/cn/hutool/core/lang/WeightListRandom.java

@@ -0,0 +1,167 @@
+package cn.hutool.core.lang;
+
+import cn.hutool.core.util.RandomUtil;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.concurrent.ThreadLocalRandom;
+
+/**
+ * 动态按权重随机的随机池，底层是list实现。
+ *
+ * @param <E> 元素类型
+ * @author 王叶峰
+ * @since 5.8.33
+ */
+public class WeightListRandom<E> implements Serializable {
+	private static final long serialVersionUID = 6902006276975764032L;
+
+	/**
+	 * 随机元素池
+	 */
+	private final ArrayList<EWeight<E>> randomPool;
+
+	/**
+	 * 构造
+	 */
+	public WeightListRandom() {
+		randomPool = new ArrayList<>();
+	}
+
+	/**
+	 * 构造
+	 *
+	 * @param poolSize 容量
+	 */
+	public WeightListRandom(int poolSize) {
+		randomPool = new ArrayList<>(poolSize);
+	}
+
+	/**
+	 * 添加元素
+	 *
+	 * @param e      元素
+	 * @param weight 权重
+	 */
+	public void add(E e, double weight) {
+		Assert.isTrue(weight > 0, "权重必须大于0！");
+		randomPool.add(new EWeight<>(e, sumWeight() + weight));
+	}
+
+	/**
+	 * 移除元素
+	 *
+	 * @param e 元素
+	 * @return 是否移除成功
+	 */
+	public boolean remove(E e) {
+		boolean removed = false;
+		double weight = 0;
+		int i = 0;
+		Iterator<EWeight<E>> iterator = randomPool.iterator();
+		while (iterator.hasNext()) {
+			EWeight<E> ew = iterator.next();
+			if (!removed && ew.e.equals(e)) {
+				iterator.remove();
+				weight = ew.sumWeight - (i == 0 ? 0 : randomPool.get(i - 1).sumWeight);// 权重=当前权重-上一个权重
+				removed = true;
+			}
+			if (removed) {
+				// 重新计算后续权重
+				ew.sumWeight -= weight;
+			}
+			i++;
+		}
+		return removed;
+	}
+
+	/**
+	 * 随机出一个元素
+	 *
+	 * @return 随机池的一个元素
+	 */
+	public E next() {
+		checkEmptyPool();
+
+		if (randomPool.size() == 1) {
+			return randomPool.get(0).e;
+		}
+		ThreadLocalRandom random = RandomUtil.getRandom();
+		double randVal = random.nextDouble() * sumWeight();
+		return binarySearch(randVal);
+	}
+
+	/**
+	 * 按照给定的总权重随机出一个元素
+	 *
+	 * @param weight 总权重
+	 * @return 随机池的一个元素或者null
+	 */
+	public E randomByWeight(double weight) {
+		Assert.isTrue(weight >= sumWeight(), "权重必须大于当前总权重！");
+		ThreadLocalRandom random = RandomUtil.getRandom();
+		double randVal = random.nextDouble() * sumWeight();
+		if (randVal > sumWeight()) {
+			return null;
+		}
+		return binarySearch(randVal);
+	}
+
+	/**
+	 * 判断随机池是否为空
+	 *
+	 * @return 是否为空
+	 */
+	public boolean isEmpty() {
+		return randomPool.isEmpty();
+	}
+
+	private static class EWeight<E> {
+		final E e;
+		double sumWeight;
+
+		public EWeight(E e, double sumWeight) {
+			this.e = e;
+			this.sumWeight = sumWeight;
+		}
+	}
+
+	/**
+	 * 二分查找小于等于key的最大值的元素
+	 *
+	 * @param key 目标值
+	 * @return 随机池的一个元素或者null 当key大于所有元素的总权重时，返回null
+	 */
+	private E binarySearch(double key) {
+		int low = 0;
+		int high = randomPool.size() - 1;
+
+		while (low <= high) {
+			int mid = (low + high) >>> 1;
+			double midVal = randomPool.get(mid).sumWeight;
+
+			if (midVal < key) {
+				low = mid + 1;
+			} else if (midVal > key) {
+				high = mid - 1;
+			} else {
+				return randomPool.get(mid).e;
+			}
+		}
+		return randomPool.get(low).e;
+	}
+
+	private double sumWeight() {
+		if (randomPool.isEmpty()) {
+			return 0;
+		}
+		return randomPool.get(randomPool.size() - 1).sumWeight;
+	}
+
+	private void checkEmptyPool() {
+		if (isEmpty()) {
+			throw new IllegalArgumentException("随机池为空！");
+		}
+	}
+}

hutool-core/src/test/java/cn/hutool/core/lang/WeightListRandomTest.java

@@ -1,6 +1,7 @@
 package cn.hutool.core.lang;
 
 import cn.hutool.core.util.RandomUtil;
+import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import java.util.HashMap;
@@ -8,14 +9,15 @@ import java.util.Map;
 
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-public class WeightListPoolTest {
+public class WeightListRandomTest {
 
 	@Test
-	public void weightRandomTest() {
+	@Disabled
+	public void nextTest() {
 		Map<Integer, Times> timesMap = new HashMap<>();
 		int size = 100;
 		double sumWeight = 0.0;
-		WeightListPool<Integer> pool = new WeightListPool<>(size);
+		WeightListRandom<Integer> pool = new WeightListRandom<>(size);
 		for (int i = 0; i < size; i++) {
 			double weight = RandomUtil.randomDouble(100);
 			pool.add(i, weight);
@@ -26,7 +28,7 @@ public class WeightListPoolTest {
 		double d = 0.0001;// 随机误差
 		int times = 100000000;// 随机次数
 		for (int i = 0; i < times; i++) {
-			timesMap.get(pool.random()).num++;
+			timesMap.get(pool.next()).num++;
 		}
 		double finalSumWeight = sumWeight;
 		timesMap.forEach((key, times1) -> {
@@ -37,9 +39,7 @@ public class WeightListPoolTest {
 	}
 
 	private static class Times {
-
 		int num;
-
 		double weight;
 
 		public Times(double weight) {