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HHH-18377 Simplified UUID v7 generation

This commit is contained in:
Čedomir Igaly 2024-09-26 16:38:44 +02:00 committed by Christian Beikov
parent d8dd5e7c0d
commit 2e42db82dd
1 changed files with 10 additions and 16 deletions
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26
hibernate-core/src/main/java/org/hibernate/id/uuid/UuidVersion7Strategy.java
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@ -5,7 +5,6 @@
package org.hibernate.id.uuid;
import java.security.SecureRandom;
import java.time.Duration;
import java.time.Instant;
import java.util.UUID;
import java.util.concurrent.atomic.AtomicLong;
@ -16,7 +15,6 @@ import org.hibernate.Internal;
import org.hibernate.engine.spi.SharedSessionContractImplementor;
import org.hibernate.id.UUIDGenerationStrategy;
import static java.time.Instant.EPOCH;
import static java.time.temporal.ChronoUnit.MILLIS;
/**
@ -50,15 +48,15 @@ public class UuidVersion7Strategy implements UUIDGenerationStrategy, UuidValueGe
private final Lock lock = new ReentrantLock( true );
private final AtomicLong clockSequence;
private Duration currentTimestamp;
private Instant currentTimestamp;
@Internal
public UuidVersion7Strategy() {
this( getCurrentTimestamp(), 0 );
this( Instant.now(), 0 );
}
@Internal
public UuidVersion7Strategy(final Duration currentTimestamp, final long clockSequence) {
public UuidVersion7Strategy(final Instant currentTimestamp, final long clockSequence) {
this.currentTimestamp = currentTimestamp;
this.clockSequence = new AtomicLong( clockSequence );
}
@ -78,12 +76,12 @@ public class UuidVersion7Strategy implements UUIDGenerationStrategy, UuidValueGe
@Override
public UUID generateUuid(SharedSessionContractImplementor session) {
final Duration currentTimestamp = getCurrentTimestamp();
final Instant currentTimestamp = Instant.now();
final long seq = getSequence( currentTimestamp );
final long millis = currentTimestamp.getSeconds() * 1000 + currentTimestamp.getNano() / 1_000_000;
final long nanosPart = Math.round( ( currentTimestamp.getNano() % 1_000_000L ) * 0.004096 );
final long millis = currentTimestamp.toEpochMilli();
final long nanosPart = (long) ( ( currentTimestamp.getNano() % 1_000_000L ) * 0.004096 );
return new UUID(
// MSB bits 0-47 - 48-bit big-endian unsigned number of the Unix Epoch timestamp in milliseconds
@ -101,12 +99,12 @@ public class UuidVersion7Strategy implements UUIDGenerationStrategy, UuidValueGe
);
}
private long getSequence(final Duration currentTimestamp) {
private long getSequence(final Instant currentTimestamp) {
lock.lock();
try {
if ( !this.currentTimestamp.equals( currentTimestamp ) ) {
this.currentTimestamp = currentTimestamp;
clockSequence.set( 0 );
if ( this.currentTimestamp.toEpochMilli() < currentTimestamp.toEpochMilli() ) {
this.currentTimestamp = currentTimestamp.truncatedTo( MILLIS );
clockSequence.updateAndGet( l -> l & 0x1FFFL );
}
}
finally {
@ -114,8 +112,4 @@ public class UuidVersion7Strategy implements UUIDGenerationStrategy, UuidValueGe
}
return clockSequence.getAndIncrement();
}
private static Duration getCurrentTimestamp() {
return Duration.between( EPOCH, Instant.now() ).truncatedTo( MILLIS );
}
}