统一工具类命名规则。

2024-04-03 16:20:41 +08:00
parent 09b5b1e0f3
commit cc34af04c2
12 changed files with 37 additions and 74 deletions
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/ConcurrentHashMapTools.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/ConcurrentHashMapTools.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2022-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xyz.zhouxy.plusone.commons.util;
+
+import java.util.Objects;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Function;
+
+import xyz.zhouxy.plusone.commons.base.JRE;
+import xyz.zhouxy.plusone.commons.collection.SafeConcurrentHashMap;
+
+/**
+ * ConcurrentHashMapTools
+ *
+ * <p>
+ * Java 8 的 {@link ConcurrentHashMap#computeIfAbsent(Object, Function)} 方法有 bug，
+ * 可使用这个工具类的 {@link computeIfAbsentForJava8} 进行替换。
+ *
+ * <p>
+ * <b>NOTE: 方法来自Dubbo，见：issues#2349</b>
+ * 
+ * @author <a href="http://zhouxy.xyz:3000/ZhouXY108">ZhouXY</a>
+ * @since 1.0
+ * @see ConcurrentHashMap
+ * @see SafeConcurrentHashMap
+ */
+public class ConcurrentHashMapTools {
+
+    public static <K, V> V computeIfAbsent(
+            ConcurrentHashMap<K, V> map, final K key, // NOSONAR
+            final Function<? super K, ? extends V> mappingFunction) {
+        Objects.requireNonNull(map, "map");
+        return JRE.isJava8()
+                ? computeIfAbsentForJava8(map, key, mappingFunction)
+                : map.computeIfAbsent(key, mappingFunction);
+    }
+
+    public static <K, V> V computeIfAbsentForJava8(
+            ConcurrentHashMap<K, V> map, final K key, // NOSONAR
+            final Function<? super K, ? extends V> mappingFunction) {
+        Objects.requireNonNull(key);
+        Objects.requireNonNull(mappingFunction);
+        V v = map.get(key);
+        if (null == v) {
+            v = mappingFunction.apply(key);
+            if (null == v) {
+                return null;
+            }
+            final V res = map.putIfAbsent(key, v);
+            if (null != res) {
+                return res;
+            }
+        }
+        return v;
+    }
+
+    private ConcurrentHashMapTools() {
+        throw new IllegalStateException("Utility class");
+    }
+}