完成 ID 生成器的单元测试

ProgressOfTesting.txt

@@ -1,7 +1,7 @@
-[ ] 未开始测试 - 15 (21.43%)
-[-] 测试未完成 - 10 (14.29%)
-[Y] 测试完成 - 24 (34.29%)
-[x] 无需测试 - 21 (30.00%)
+[ ] 未开始测试 - 10 (14.93%)
+[-] 测试未完成 - 9 (13.43%)
+[Y] 测试完成 - 27 (40.30%)
+[x] 无需测试 - 21 (31.34%)
 
 xyz.zhouxy.plusone.commons
     ├───annotation
@@ -20,7 +20,6 @@ xyz.zhouxy.plusone.commons
     │       IWithCode.java                        [Y]
     │       IWithIntCode.java                     [Y]
     │       IWithLongCode.java                    [Y]
-    │       JRE.java                              [ ]
     │       LongRef.java                          [Y]
     │       Ref.java                              [Y]
     │
@@ -28,7 +27,6 @@ xyz.zhouxy.plusone.commons
     │       AbstractMapWrapper.java               [ ]
     │       CollectionTools.java                  [Y]
     │       MapWrapper.java                       [ ]
-    │       SafeConcurrentHashMap.java            [ ]
     │
     ├───constant
     │       PatternConsts.java                    [ ]
@@ -86,16 +84,15 @@ xyz.zhouxy.plusone.commons
             ArrayTools.java                       [-]
             AssertTools.java                      [Y]
             BigDecimals.java                      [Y]
-            ConcurrentHashMapTools.java           [-]
             DateTimeTools.java                    [-]
             Enumeration.java                      [Y]
             EnumTools.java                        [Y]
-            IdGenerator.java                      [ ]
-            IdWorker.java                         [ ]
+            IdGenerator.java                      [Y]
+            IdWorker.java                         [Y]
             Numbers.java                          [Y]
             OptionalTools.java                    [Y]
             RandomTools.java                      [ ]
             RegexTools.java                       [ ]
-            SnowflakeIdGenerator.java             [ ]
+            SnowflakeIdGenerator.java             [Y]
             StringTools.java                      [Y]
             TreeBuilder.java                      [Y]

src/main/java/xyz/zhouxy/plusone/commons/base/JRE.java

@@ -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");
-    }
-}

src/main/java/xyz/zhouxy/plusone/commons/collection/AbstractMapWrapper.java

@@ -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
@@ -159,12 +157,7 @@ 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);
-        }
+        return this.map.computeIfAbsent(key, func);
     }
 
     public final Map<K, V> exportMap() {

src/main/java/xyz/zhouxy/plusone/commons/collection/SafeConcurrentHashMap.java

@@ -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);
-    }
-}

src/main/java/xyz/zhouxy/plusone/commons/util/ConcurrentHashMapTools.java

@@ -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");
-    }
-}

src/main/java/xyz/zhouxy/plusone/commons/util/IdGenerator.java

@@ -21,9 +21,17 @@ import java.util.Objects;
 import java.util.UUID;
 import java.util.concurrent.ConcurrentHashMap;
 
-import com.google.common.annotations.Beta;
-
-@Beta
+/**
+ * ID 生成器
+ *
+ * <p>
+ * 生成 UUID 和 修改版雪花ID（Seata 版本）
+ * </p>
+ *
+ * @see UUID
+ * @see IdWorker
+ * @author <a href="http://zhouxy.xyz:3000/ZhouXY108}">ZhouXY</a>
+ */
 public class IdGenerator {
 
     // ===== UUID =====

src/main/java/xyz/zhouxy/plusone/commons/util/IdWorker.java

@@ -24,7 +24,26 @@ import java.util.concurrent.atomic.AtomicLong;
 
 import xyz.zhouxy.plusone.commons.exception.system.NoAvailableMacFoundException;
 
-
+/**
+ * Seata 提供的修改版雪花ID。
+ * <p>
+ * 大体思路为：
+ * <ol>
+ * <li>每个机器线程安全地生成序列，前面加上机器的id，这样就不会与其它机器的id相冲突。</li>
+ * <li>时间戳作为序列的“预留位”，它更像是应用启动时最开始的序列的一部分，在一个时间戳里生成 4096 个 id 之后，直接生成下一个时间戳的 id。</li>
+ * </ol>
+ * </p>
+ * <p>
+ * 详情见以下介绍：
+ * <ul>
+ * <li><a href="https://seata.apache.org/zh-cn/blog/seata-analysis-UUID-generator/">Seata基于改良版雪花算法的分布式UUID生成器分析</a></li>
+ * <li><a href="https://seata.apache.org/zh-cn/blog/seata-snowflake-explain">关于新版雪花算法的答疑</a></li>
+ * <li><a href="https://juejin.cn/post/7264387737276203065">在开源项目中看到一个改良版的雪花算法，现在它是你的了。</a></li>
+ * <li><a href="https://juejin.cn/post/7265516484029743138">关于若干读者，阅读“改良版雪花算法”后提出的几个共性问题的回复。</a></li>
+ * </ul>
+ * </p>
+ * @author <a href="http://zhouxy.xyz:3000/ZhouXY108}">ZhouXY</a>
+ */
 public class IdWorker {
 
     /**

src/main/java/xyz/zhouxy/plusone/commons/util/SnowflakeIdGenerator.java

@@ -18,12 +18,9 @@ package xyz.zhouxy.plusone.commons.util;
 
 import java.util.concurrent.TimeUnit;
 
-import com.google.common.annotations.Beta;
-
 /**
- * Twitter_Snowflake
+ * Twitter 版雪花算法
  */
-@Beta
 public class SnowflakeIdGenerator {
 
     // ==============================Fields===========================================
@@ -67,9 +64,6 @@ public class SnowflakeIdGenerator {
     /** 上次生成 ID 的时间截 */
     private long lastTimestamp = -1L;
 
-    /** 锁对象 */
-    private final Object lock = new Object();
-
     // ==============================Constructors=====================================
 
     /**
@@ -93,51 +87,47 @@ public class SnowflakeIdGenerator {
      *
      * @return SnowflakeId
      */
-    public long nextId() {
-        long timestamp;
-        synchronized (lock) {
-            timestamp = timeGen();
+    public synchronized long nextId() {
+        long timestamp = timeGen();
 
-            // 发生了回拨，此刻时间小于上次发号时间
-            if (timestamp < lastTimestamp) {
-                long offset = lastTimestamp - timestamp;
-                if (offset <= 5) {
-                    // 时间偏差大小小于5ms，则等待两倍时间
-                    try {
-                        TimeUnit.MILLISECONDS.sleep(offset << 1);
-                    } catch (InterruptedException e) {
-                        Thread.currentThread().interrupt();
-                        throw new IllegalStateException(e);
-                    }
-                    timestamp = timeGen();
-                    if (timestamp < lastTimestamp) {
-                        // 还是小于，抛异常上报
-                        throwClockBackwardsEx(lastTimestamp, timestamp);
-                    }
-                } else {
+        // 发生了回拨，此刻时间小于上次发号时间
+        if (timestamp < lastTimestamp) {
+            long offset = lastTimestamp - timestamp;
+            if (offset <= 5) {
+                // 时间偏差大小小于5ms，则等待两倍时间
+                try {
+                    TimeUnit.MILLISECONDS.sleep(offset << 1);
+                } catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                    throw new IllegalStateException(e);
+                }
+                timestamp = timeGen();
+                if (timestamp < lastTimestamp) {
+                    // 还是小于，抛异常上报
                     throwClockBackwardsEx(lastTimestamp, timestamp);
                 }
+            } else {
+                throwClockBackwardsEx(lastTimestamp, timestamp);
             }
-
-            // 如果是同一时间生成的，则进行毫秒内序列
-            if (lastTimestamp == timestamp) {
-                sequence = (sequence + 1) & SEQUENCE_MASK;
-                // 毫秒内序列溢出
-                if (sequence == 0) {
-                    // 阻塞到下一个毫秒,获得新的时间戳
-                    timestamp = tilNextMillis(lastTimestamp);
-                }
-            }
-            // 时间戳改变，毫秒内序列重置
-            else {
-                sequence = 0L;
-            }
-
-            // 上次生成 ID 的时间截
-            lastTimestamp = timestamp;
-
         }
 
+        // 如果是同一时间生成的，则进行毫秒内序列
+        if (lastTimestamp == timestamp) {
+            sequence = (sequence + 1) & SEQUENCE_MASK;
+            // 毫秒内序列溢出
+            if (sequence == 0) {
+                // 阻塞到下一个毫秒,获得新的时间戳
+                timestamp = tilNextMillis(lastTimestamp);
+            }
+        }
+        // 时间戳改变，毫秒内序列重置
+        else {
+            sequence = 0L;
+        }
+
+        // 上次生成 ID 的时间截
+        lastTimestamp = timestamp;
+
         // 移位并通过或运算拼到一起组成64位的ID
         return ((timestamp - TWEPOCH) << TIMESTAMP_LEFT_SHIFT) | datacenterIdAndWorkerId | sequence;
     }

src/test/java/xyz/zhouxy/plusone/commons/util/AssertToolsTests.java

@@ -925,9 +925,10 @@ public class AssertToolsTests {
 
     // #region - Condition
 
+    static final class MyException extends RuntimeException {}
+
     @Test
     void testCheckCondition() {
-        class MyException extends RuntimeException {}
 
         AssertTools.checkCondition(true, MyException::new);
 

src/test/java/xyz/zhouxy/plusone/commons/util/IdGeneratorTests.java

@@ -0,0 +1,68 @@
+package xyz.zhouxy.plusone.commons.util;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.jupiter.api.Test;
+
+import cn.hutool.core.collection.ConcurrentHashSet;
+import cn.hutool.core.exceptions.UtilException;
+import cn.hutool.core.lang.Snowflake;
+import cn.hutool.core.thread.ThreadUtil;
+
+public class IdGeneratorTests {
+
+    final ThreadPoolExecutor executor = new ThreadPoolExecutor(10, 10,
+            0L, TimeUnit.MILLISECONDS,
+            new LinkedBlockingQueue<Runnable>());
+
+    @Test
+    void testSnowflakeIdGenerator() {
+        final SnowflakeIdGenerator snowflake = new SnowflakeIdGenerator(0, 0);
+        final Set<Long> ids = new ConcurrentHashSet<>();
+        for (int i = 0; i < 10000; i++) {
+            executor.execute(() -> {
+                for (int j = 0; j < 50000; j++) {
+                    if (false == ids.add(snowflake.nextId())) {
+                        throw new RuntimeException("重复ID！");
+                    }
+                }
+            });
+        }
+    }
+
+    @Test
+    void testIdWorker() {
+        final IdWorker idWorker = new IdWorker(0L);
+        final Set<Long> ids = new ConcurrentHashSet<>();
+        for (int i = 0; i < 10000; i++) {
+            executor.execute(() -> {
+                for (int j = 0; j < 50000; j++) {
+                    if (false == ids.add(idWorker.nextId())) {
+                        throw new RuntimeException("重复ID！");
+                    }
+                }
+            });
+            executor.execute(() -> {
+                for (int j = 0; j < 50000; j++) {
+                    if (false == ids.add(IdGenerator.nextSnowflakeId(0))) {
+                        throw new RuntimeException("重复ID！");
+                    }
+                }
+            });
+        }
+    }
+
+    @Test
+    void testToSimpleString() {
+        UUID id = UUID.randomUUID();
+        assertEquals(id.toString().replaceAll("-", ""),
+                IdGenerator.toSimpleString(id));
+    }
+
+}