修复LRUCache移除事件监听失效

CHANGELOG.md

@@ -3,7 +3,7 @@
 
 -------------------------------------------------------------------------------------------------------------
 
-# 5.8.9.M1 (2022-10-09)
+# 5.8.9.M1 (2022-10-12)
 
 ### 🐣新特性
 * 【core   】     DateUtil增加isLastDayOfMonth、getLastDayOfMonth方法（pr#824@Gitee）
@@ -17,6 +17,7 @@
 * 【http   】     修复Http重定全局设置无效问题（pr#2639@Github）
 * 【core   】     修复ReUtil.replaceAll替换变量错误问题（pr#2639@Github）
 * 【core   】     修复FileNameUtil.mainName二级扩展名获取错误问题（issue#2642@Github）
+* 【cache  】     修复LRUCache移除事件监听失效问题（issue#2647@Github）
 
 -------------------------------------------------------------------------------------------------------------
 

hutool-cache/src/main/java/cn/hutool/cache/impl/LRUCache.java

@@ -1,5 +1,6 @@
 package cn.hutool.cache.impl;
 
+import cn.hutool.core.lang.mutable.Mutable;
 import cn.hutool.core.map.FixedLinkedHashMap;
 
 import java.util.Iterator;
@@ -42,7 +43,13 @@ public class LRUCache<K, V> extends ReentrantCache<K, V> {
 		this.timeout = timeout;
 
 		//链表key按照访问顺序排序，调用get方法后，会将这次访问的元素移至头部
-		cacheMap = new FixedLinkedHashMap<>(capacity);
+		final FixedLinkedHashMap<Mutable<K>, CacheObj<K, V>> fixedLinkedHashMap = new FixedLinkedHashMap<>(capacity);
+		fixedLinkedHashMap.setRemoveListener(entry -> {
+			if(null != listener){
+				listener.onRemove(entry.getKey().get(), entry.getValue().getValue());
+			}
+		});
+		cacheMap = fixedLinkedHashMap;
 	}
 
 	// ---------------------------------------------------------------- prune

hutool-cache/src/test/java/cn/hutool/cache/LRUCacheTest.java

@@ -3,11 +3,13 @@ package cn.hutool.cache;
 import cn.hutool.cache.impl.LRUCache;
 import cn.hutool.core.thread.ThreadUtil;
 import cn.hutool.core.util.RandomUtil;
+import cn.hutool.core.util.StrUtil;
 import org.junit.Assert;
 import org.junit.Ignore;
 import org.junit.Test;
 
 import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * 见：https://github.com/dromara/hutool/issues/1895<br>
@@ -20,7 +22,7 @@ public class LRUCacheTest {
 	@Ignore
 	public void putTest(){
 		//https://github.com/dromara/hutool/issues/2227
-		LRUCache<String, String> cache = CacheUtil.newLRUCache(100, 10);
+		final LRUCache<String, String> cache = CacheUtil.newLRUCache(100, 10);
 		for (int i = 0; i < 10000; i++) {
 			//ThreadUtil.execute(()-> cache.put(RandomUtil.randomString(5), "1243", 10));
 			ThreadUtil.execute(()-> cache.get(RandomUtil.randomString(5), ()->RandomUtil.randomString(10)));
@@ -30,15 +32,15 @@ public class LRUCacheTest {
 
 	@Test
 	public void readWriteTest() throws InterruptedException {
-		LRUCache<Integer, Integer> cache = CacheUtil.newLRUCache(10);
+		final LRUCache<Integer, Integer> cache = CacheUtil.newLRUCache(10);
 		for (int i = 0; i < 10; i++) {
 			cache.put(i, i);
 		}
 
-		CountDownLatch countDownLatch = new CountDownLatch(10);
+		final CountDownLatch countDownLatch = new CountDownLatch(10);
 		// 10个线程分别读0-9 10000次
 		for (int i = 0; i < 10; i++) {
-			int finalI = i;
+			final int finalI = i;
 			new Thread(() -> {
 				for (int j = 0; j < 10000; j++) {
 					cache.get(finalI);
@@ -49,7 +51,7 @@ public class LRUCacheTest {
 		// 等待读线程结束
 		countDownLatch.await();
 		// 按顺序读0-9
-		StringBuilder sb1 = new StringBuilder();
+		final StringBuilder sb1 = new StringBuilder();
 		for (int i = 0; i < 10; i++) {
 			sb1.append(cache.get(i));
 		}
@@ -58,10 +60,29 @@ public class LRUCacheTest {
 		// 新加11，此时0最久未使用，应该淘汰0
 		cache.put(11, 11);
 
-		StringBuilder sb2 = new StringBuilder();
+		final StringBuilder sb2 = new StringBuilder();
 		for (int i = 0; i < 10; i++) {
 			sb2.append(cache.get(i));
 		}
 		Assert.assertEquals("null123456789", sb2.toString());
 	}
+
+	@Test
+	public void issue2647Test(){
+		final AtomicInteger removeCount = new AtomicInteger();
+
+		final LRUCache<String, Integer> cache = CacheUtil.newLRUCache(3,1);
+		cache.setListener((key, value) -> {
+			// 共移除7次
+			removeCount.incrementAndGet();
+			//Console.log("Start remove k-v, key:{}, value:{}", key, value);
+		});
+
+		for (int i = 0; i < 10; i++) {
+			cache.put(StrUtil.format("key-{}", i), i);
+		}
+
+		Assert.assertEquals(7, removeCount.get());
+		Assert.assertEquals(3, cache.size());
+	}
 }

hutool-core/src/main/java/cn/hutool/core/map/FixedLinkedHashMap.java

@@ -1,21 +1,28 @@
 package cn.hutool.core.map;
 
 import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.function.Consumer;
 
 /**
  * 固定大小的{@link LinkedHashMap} 实现<br>
  * 注意此类非线程安全，由于{@link #get(Object)}操作会修改链表的顺序结构，因此也不可以使用读写锁。
  *
- * @author looly
- *
  * @param <K> 键类型
  * @param <V> 值类型
+ * @author looly
  */
 public class FixedLinkedHashMap<K, V> extends LinkedHashMap<K, V> {
 	private static final long serialVersionUID = -629171177321416095L;
 
-	/** 容量，超过此容量自动删除末尾元素 */
+	/**
+	 * 容量，超过此容量自动删除末尾元素
+	 */
 	private int capacity;
+	/**
+	 * 移除监听
+	 */
+	private Consumer<Map.Entry<K, V>> removeListener;
 
 	/**
 	 * 构造
@@ -45,10 +52,26 @@ public class FixedLinkedHashMap<K, V> extends LinkedHashMap<K, V> {
 		this.capacity = capacity;
 	}
 
+	/**
+	 * 设置自定义移除监听
+	 *
+	 * @param removeListener 移除监听
+	 */
+	public void setRemoveListener(final Consumer<Map.Entry<K, V>> removeListener) {
+		this.removeListener = removeListener;
+	}
+
 	@Override
 	protected boolean removeEldestEntry(java.util.Map.Entry<K, V> eldest) {
 		//当链表元素大于容量时，移除最老（最久未被使用）的元素
-		return size() > this.capacity;
+		if (size() > this.capacity) {
+			if (null != removeListener) {
+				// 自定义监听
+				removeListener.accept(eldest);
+			}
+			return true;
+		}
+		return false;
 	}
 
 }