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删除 SafeConcurrentHashMap。注意使用 ConcurrentHashMap#computeIfAbsent 方法时，mappingFunction 里不要调用该 map 的 computeIfAbsent 即可。

unit-tests
ZhouXY108 2024-12-27 15:47:31 +08:00
parent 8871f35749
commit 4ec59e7fd7
4 changed files with 1 additions and 266 deletions
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63
src/main/java/xyz/zhouxy/plusone/commons/base/JRE.java
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@ -1,63 +0,0 @@
/*
* Copyright 2023-2024 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.base;
import xyz.zhouxy.plusone.commons.util.StringTools;
/**
* JRE version
*/
public class JRE {
private static final int JAVA_8 = 8;
public static final int CURRENT_VERSION = getJre();
public static boolean isJava8() {
return CURRENT_VERSION == JAVA_8;
}
private static int getJre() {
String version = System.getProperty("java.version");
boolean isNotBlank = StringTools.isNotBlank(version);
if (isNotBlank && version.startsWith("1.8")) {
return JAVA_8;
}
// if JRE version is 9 or above, we can get version from
// java.lang.Runtime.version()
try {
return getMajorVersion(version);
} catch (Exception e) {
// assuming that JRE version is 8.
}
// default java 8
return JAVA_8;
}
private static int getMajorVersion(String version) {
if (version.startsWith("1.")) {
return Integer.parseInt(version.substring(2, 3));
} else {
int dotIndex = version.indexOf(".");
return (dotIndex != -1) ? Integer.parseInt(version.substring(0, dotIndex)) : Integer.parseInt(version);
}
}
private JRE() {
throw new IllegalStateException("Utility class");
}
}

7
src/main/java/xyz/zhouxy/plusone/commons/collection/AbstractMapWrapper.java
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@ -23,7 +23,6 @@ import java.util.Map.Entry;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Consumer;
import java.util.function.Function;
@ -33,7 +32,6 @@ import javax.annotation.Nullable;
import com.google.common.annotations.Beta;
import xyz.zhouxy.plusone.commons.util.AssertTools;
import xyz.zhouxy.plusone.commons.util.ConcurrentHashMapTools;
/**
* AbstractMapWrapper
@ -159,13 +157,8 @@ public abstract class AbstractMapWrapper<K, V, T extends AbstractMapWrapper<K, V
}
return value;
};
if (this.map instanceof ConcurrentHashMap) {
return ConcurrentHashMapTools.computeIfAbsent(
(ConcurrentHashMap<K, V>) this.map, key, func);
} else {
return this.map.computeIfAbsent(key, func);
}
}
public final Map<K, V> exportMap() {
return this.map;

121
src/main/java/xyz/zhouxy/plusone/commons/collection/SafeConcurrentHashMap.java
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@ -1,121 +0,0 @@
/*
* Copyright 2023-2024 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.collection;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Function;
import javax.annotation.concurrent.ThreadSafe;
import xyz.zhouxy.plusone.commons.base.JRE;
import xyz.zhouxy.plusone.commons.util.ConcurrentHashMapTools;
/**
* SafeConcurrentHashMap
*
* <p>
* Java 8 的 {@link ConcurrentHashMap#computeIfAbsent(Object, Function)} 方法有 bug，
* 使用 Java 8 时，可使用这个类进行替换。
*
* @author <a href="http://zhouxy.xyz:3000/ZhouXY108">ZhouXY</a>
* @since 1.0
* @see ConcurrentHashMap
* @see ConcurrentHashMapTools#computeIfAbsentForJava8(ConcurrentHashMap, Object, Function)
*/
@ThreadSafe
public class SafeConcurrentHashMap<K, V> extends ConcurrentHashMap<K, V> {
private static final long serialVersionUID = 4352954948768449595L;
/**
* Creates a new, empty map with the default initial table size (16).
*/
public SafeConcurrentHashMap() {
}
/**
* Creates a new, empty map with an initial table size
* accommodating the specified number of elements without the need
* to dynamically resize.
*
* @param initialCapacity The implementation performs internal
* sizing to accommodate this many elements.
* @throws IllegalArgumentException if the initial capacity of
* elements is negative
*/
public SafeConcurrentHashMap(int initialCapacity) {
super(initialCapacity);
}
/**
* Creates a new map with the same mappings as the given map.
*
* @param m the map
*/
public SafeConcurrentHashMap(Map<? extends K, ? extends V> m) {
super(m);
}
/**
* Creates a new, empty map with an initial table size based on
* the given number of elements ({@code initialCapacity}) and
* initial table density ({@code loadFactor}).
*
* @param initialCapacity the initial capacity. The implementation
* performs internal sizing to accommodate this many elements,
* given the specified load factor.
* @param loadFactor the load factor (table density) for
* establishing the initial table size
* @throws IllegalArgumentException if the initial capacity of
* elements is negative or the load factor is nonpositive
* @since 1.6
*/
public SafeConcurrentHashMap(int initialCapacity, float loadFactor) {
super(initialCapacity, loadFactor);
}
/**
* Creates a new, empty map with an initial table size based on
* the given number of elements ({@code initialCapacity}), table
* density ({@code loadFactor}), and number of concurrently
* updating threads ({@code concurrencyLevel}).
*
* @param initialCapacity the initial capacity. The implementation
* performs internal sizing to accommodate this many elements,
* given the specified load factor.
* @param loadFactor the load factor (table density) for
* establishing the initial table size
* @param concurrencyLevel the estimated number of concurrently
* updating threads. The implementation may use this value as
* a sizing hint.
* @throws IllegalArgumentException if the initial capacity is
* negative or the load factor or concurrencyLevel are
* nonpositive
*/
public SafeConcurrentHashMap(int initialCapacity, float loadFactor, int concurrencyLevel) {
super(initialCapacity, loadFactor, concurrencyLevel);
}
/** {@inheritDoc} */
@Override
public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
return JRE.isJava8()
? ConcurrentHashMapTools.computeIfAbsentForJava8(this, key, mappingFunction)
: super.computeIfAbsent(key, mappingFunction);
}
}

74
src/main/java/xyz/zhouxy/plusone/commons/util/ConcurrentHashMapTools.java
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@ -1,74 +0,0 @@
/*
* Copyright 2023-2024 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");
}
}