feat:实现正则表达式编译缓存功能

Author: ban-xiu

core/src/main/java/com/taobao/arthas/core/util/RegexCacheManager.java

@@ -0,0 +1,65 @@
+package com.taobao.arthas.core.util;
+
+import com.taobao.arthas.core.shell.term.impl.http.session.LRUCache;
+import java.util.regex.Pattern;
+
+/**
+ * 正则表达式缓存管理器
+ * 用于缓存编译后的正则表达式对象，避免重复编译的开销
+ */
+public class RegexCacheManager {
+    private static final RegexCacheManager INSTANCE = new RegexCacheManager();
+    
+    // 使用 LRUCache 替代 ConcurrentHashMap
+    private final LRUCache<String, Pattern> regexCache;
+    
+    // 缓存大小限制
+    private static final int MAX_CACHE_SIZE = 100;
+    
+    private RegexCacheManager() {
+        // 初始化 LRUCache，设置最大缓存大小
+        this.regexCache = new LRUCache<>(MAX_CACHE_SIZE);
+    }
+
+    public static RegexCacheManager getInstance() {
+        return INSTANCE;
+    }
+
+    /**
+     * 获取正则表达式Pattern对象，优先从缓存获取，缓存未命中则编译并缓存
+     */
+    public Pattern getPattern(String regex) {
+        if (regex == null || regex.isEmpty()) {
+            return null;
+        }
+
+        // 从 LRUCache 获取
+        Pattern pattern = regexCache.get(regex);
+        if (pattern != null) {
+            return pattern;
+        }
+
+        // 缓存未命中，编译正则表达式
+        pattern = Pattern.compile(regex);
+        
+        // 缓存编译结果
+        regexCache.put(regex, pattern);
+        
+        return pattern;
+    }
+    
+    /**
+     * 清理缓存
+     */
+    public void clearCache() {
+        regexCache.clear();
+    }
+    
+    /**
+     * 获取缓存大小
+     */
+    public int getCacheSize() {
+        return regexCache.usedEntries();
+    }
+
+}

core/src/main/java/com/taobao/arthas/core/util/matcher/RegexMatcher.java

@@ -1,21 +1,25 @@
 package com.taobao.arthas.core.util.matcher;
 
+import com.taobao.arthas.core.util.RegexCacheManager;
+import java.util.regex.Pattern;
+
 /**
  * regex matcher
  * @author ralf0131 2017-01-06 13:16.
  */
 public class RegexMatcher implements Matcher<String> {
 
-    private final String pattern;
+    private final Pattern pattern;
 
     public RegexMatcher(String pattern) {
-        this.pattern = pattern;
+        // 使用正则表达式缓存
+        this.pattern = RegexCacheManager.getInstance().getPattern(pattern);
     }
 
     @Override
     public boolean matching(String target) {
         return null != target
                 && null != pattern
-                && target.matches(pattern);
+                && pattern.matcher(target).matches();
     }
 }

core/src/test/java/com/taobao/arthas/core/util/RegexCacheManagerTest.java

@@ -0,0 +1,107 @@
+package com.taobao.arthas.core.util;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.regex.Pattern;
+
+/**
+ * RegexCacheManager测试类
+ */
+public class RegexCacheManagerTest {
+    private RegexCacheManager cacheManager;
+
+    @Before
+    public void setUp() {
+        // 获取单例实例
+        cacheManager = RegexCacheManager.getInstance();
+        // 清理缓存，确保测试环境干净
+        cacheManager.clearCache();
+    }
+
+    /**
+     * 测试基本缓存功能
+     */
+    @Test
+    public void testBasicCacheFunctionality() {
+        // 测试缓存未命中的情况
+        String regex1 = ".*Test.*";
+        Pattern pattern1 = cacheManager.getPattern(regex1);
+        Assert.assertNotNull(pattern1);
+        Assert.assertEquals(1, cacheManager.getCacheSize());
+
+        // 测试缓存命中的情况
+        Pattern pattern1Cached = cacheManager.getPattern(regex1);
+        Assert.assertNotNull(pattern1Cached);
+        Assert.assertSame(pattern1, pattern1Cached); // 应该是同一个对象
+        Assert.assertEquals(1, cacheManager.getCacheSize()); // 缓存大小应该保持不变
+
+        // 测试多个正则表达式
+        String regex2 = "^Test.*";
+        Pattern pattern2 = cacheManager.getPattern(regex2);
+        Assert.assertNotNull(pattern2);
+        Assert.assertEquals(2, cacheManager.getCacheSize());
+
+        // 测试空正则表达式
+        Pattern nullPattern = cacheManager.getPattern(null);
+        Assert.assertNull(nullPattern);
+
+        Pattern emptyPattern = cacheManager.getPattern("");
+        Assert.assertNull(emptyPattern);
+    }
+
+    /**
+     * 测试LRU淘汰策略
+     */
+    @Test
+    public void testLRUEvictionPolicy() {
+        // 生成多个正则表达式，超过最大缓存大小
+        int maxCacheSize = 100;
+        for (int i = 0; i < maxCacheSize + 5; i++) {
+            String regex = "TestRegex" + i;
+            Pattern pattern = cacheManager.getPattern(regex);
+            Assert.assertNotNull(pattern);
+        }
+
+        // 缓存大小应该等于最大缓存大小
+        Assert.assertTrue(cacheManager.getCacheSize() <= 100); // 100 是实际的最大缓存大小
+
+        // 测试访问顺序，确保 LRU 策略生效
+        String firstRegex = "TestRegex0";
+
+        // 再次访问第一个正则表达式，使其成为最近使用的
+        Pattern firstPattern = cacheManager.getPattern(firstRegex);
+        Assert.assertNotNull(firstPattern);
+
+        // 再添加一个新的正则表达式，应该淘汰最久未使用的
+        String newRegex = "NewTestRegex";
+        Pattern newPattern = cacheManager.getPattern(newRegex);
+        Assert.assertNotNull(newPattern);
+
+        // 第一个正则表达式应该仍然在缓存中（因为刚被访问过）
+        Pattern firstPatternAgain = cacheManager.getPattern(firstRegex);
+        Assert.assertNotNull(firstPatternAgain);
+    }
+
+    /**
+     * 测试缓存清理功能
+     */
+    @Test
+    public void testCacheClear() {
+        // 添加一些缓存项
+        cacheManager.getPattern(".*Test1");
+        cacheManager.getPattern(".*Test2");
+        Assert.assertTrue(cacheManager.getCacheSize() > 0);
+
+        // 清理缓存
+        cacheManager.clearCache();
+        Assert.assertEquals(0, cacheManager.getCacheSize());
+
+        // 清理后应该可以重新添加缓存项
+        Pattern pattern = cacheManager.getPattern(".*Test3");
+        Assert.assertNotNull(pattern);
+        Assert.assertEquals(1, cacheManager.getCacheSize());
+    }
+
+}