* uuid: added uuid v7, can be used as db friendly primary key

Signed-off-by: neo <1100909+neowu@users.noreply.github.com>

CHANGELOG.md

@@ -16,6 +16,8 @@ try (EventSource source = client.sse(request)) {
 }
 ```
 
+* uuid: added uuid v7, can be used as db friendly primary key
+
 ### 9.1.0 (6/12/2024 - 7/9/2024)
 
 * jre: published neowu/jre:21.0.3

core-ng/src/main/java/core/framework/util/UUIDv7.java

@@ -0,0 +1,41 @@
+package core.framework.util;
+
+import java.nio.ByteBuffer;
+import java.security.SecureRandom;
+import java.util.UUID;
+
+/**
+ * @author neo
+ */
+public class UUIDv7 {
+    // refer to https://www.ietf.org/archive/id/draft-peabody-dispatch-new-uuid-format-04.html#name-uuid-version-7
+    private static final SecureRandom RANDOM = new SecureRandom();
+
+    public static UUID randomUUID() {
+        byte[] value = randomBytes();
+        ByteBuffer buf = ByteBuffer.wrap(value);
+        long high = buf.getLong();
+        long low = buf.getLong();
+        return new UUID(high, low);
+    }
+
+    private static byte[] randomBytes() {
+        byte[] value = new byte[16];
+        RANDOM.nextBytes(value);
+
+        long timestamp = System.currentTimeMillis();
+        // timestamp
+        value[0] = (byte) ((timestamp >> 40) & 0xFF);
+        value[1] = (byte) ((timestamp >> 32) & 0xFF);
+        value[2] = (byte) ((timestamp >> 24) & 0xFF);
+        value[3] = (byte) ((timestamp >> 16) & 0xFF);
+        value[4] = (byte) ((timestamp >> 8) & 0xFF);
+        value[5] = (byte) (timestamp & 0xFF);
+
+        // version and variant
+        value[6] = (byte) ((value[6] & 0x0F) | 0x70);
+        value[8] = (byte) ((value[8] & 0x3F) | 0x80);
+
+        return value;
+    }
+}

core-ng/src/test/java/core/framework/util/UUIDv7Test.java

@@ -0,0 +1,15 @@
+package core.framework.util;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.UUID;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class UUIDv7Test {
+    @Test
+    void randomUUID() {
+        UUID uuid = UUIDv7.randomUUID();
+        assertThat(uuid.version()).isEqualTo(7);
+    }
+}