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Merged
gavinking merged 1 commit into from
Sep 27, 2025
Merged

light code improvements to id.uuid package #11022

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47 changes: 25 additions & 22 deletions hibernate-core/src/main/java/org/hibernate/id/uuid/CustomVersionOneStrategy.java
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,12 @@
import org.hibernate.internal.build.AllowSysOut;
import org.hibernate.internal.util.BytesHelper;

import static java.lang.System.arraycopy;
import static java.lang.System.currentTimeMillis;
import static org.hibernate.id.uuid.Helper.getAddressBytes;
import static org.hibernate.id.uuid.Helper.getCountBytes;
import static org.hibernate.id.uuid.Helper.getJvmIdentifierBytes;

/**
* Applies a version 1 (time-based) generation strategy (using ip address rather than mac address) but applies them in a
* different layout. The strategy is very similar to the legacy {@link org.hibernate.id.UUIDHexGenerator} id generator
Expand All @@ -31,22 +37,21 @@ public int getGeneratedVersion() {

public CustomVersionOneStrategy() {
// generate the "most significant bits" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
byte[] hiBits = new byte[8];
// use address as first 32 bits (8 * 4 bytes)
System.arraycopy( Helper.getAddressBytes(), 0, hiBits, 0, 4 );
final byte[] hiBits = new byte[8];
// use address as the first 32 bits (8 * 4 bytes)
arraycopy( getAddressBytes(), 0, hiBits, 0, 4 );
// use the "jvm identifier" as the next 32 bits
System.arraycopy( Helper.getJvmIdentifierBytes(), 0, hiBits, 4, 4 );
arraycopy( getJvmIdentifierBytes(), 0, hiBits, 4, 4 );
// set the version (rfc term) appropriately
hiBits[6] &= 0x0f;
hiBits[6] |= 0x10;

mostSignificantBits = BytesHelper.asLong( hiBits );
}

@Override
public UUID generateUuid(SharedSessionContractImplementor session) {
long leastSignificantBits = generateLeastSignificantBits( System.currentTimeMillis() );
return new UUID( mostSignificantBits, leastSignificantBits );
return new UUID( mostSignificantBits,
generateLeastSignificantBits( currentTimeMillis() ) );
}

@Override
Expand All @@ -59,33 +64,31 @@ public long getMostSignificantBits() {
}

public static long generateLeastSignificantBits(long seed) {
byte[] loBits = new byte[8];

short hiTime = (short) ( seed >>> 32 );
int loTime = (int) seed;
System.arraycopy( BytesHelper.fromShort( hiTime ), 0, loBits, 0, 2 );
System.arraycopy( BytesHelper.fromInt( loTime ), 0, loBits, 2, 4 );
System.arraycopy( Helper.getCountBytes(), 0, loBits, 6, 2 );
final byte[] loBits = new byte[8];
final short hiTime = (short) ( seed >>> 32 );
final int loTime = (int) seed;
arraycopy( BytesHelper.fromShort( hiTime ), 0, loBits, 0, 2 );
arraycopy( BytesHelper.fromInt( loTime ), 0, loBits, 2, 4 );
arraycopy( getCountBytes(), 0, loBits, 6, 2 );
loBits[0] &= 0x3f;
loBits[0] |= ((byte)2 << (byte)6 );

loBits[0] |= ((byte)2 << (byte)6);
return BytesHelper.asLong( loBits );
}

@AllowSysOut
public static void main(String[] args) {
CustomVersionOneStrategy strategy = new CustomVersionOneStrategy();
final var strategy = new CustomVersionOneStrategy();

for ( int i = 0; i < 1000; i++ ) {
System.out.println( "Generation # " + i + " ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~" );
byte[] loBits = new byte[8];

long sysTime = System.currentTimeMillis();
short hiTime = (short) ( System.currentTimeMillis() >>> 32 );
long sysTime = currentTimeMillis();
short hiTime = (short) ( currentTimeMillis() >>> 32 );
int loTime = (int) sysTime;
System.arraycopy( BytesHelper.fromShort( hiTime ), 0, loBits, 0, 2 );
System.arraycopy( BytesHelper.fromInt( loTime ), 0, loBits, 2, 4 );
System.arraycopy( Helper.getCountBytes(), 0, loBits, 6, 2 );
arraycopy( BytesHelper.fromShort( hiTime ), 0, loBits, 0, 2 );
arraycopy( BytesHelper.fromInt( loTime ), 0, loBits, 2, 4 );
arraycopy( getCountBytes(), 0, loBits, 6, 2 );

System.out.println( " before bit setting ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~" );
System.out.println( " loBits[0] : " + BytesHelper.toBinaryString( loBits[0] ) );
Expand Down
8 changes: 4 additions & 4 deletions hibernate-core/src/main/java/org/hibernate/id/uuid/Helper.java
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Expand Up @@ -98,15 +98,15 @@ public static byte[] getCountBytes() {
// Helper methods ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

public static String format(int value) {
final String formatted = Integer.toHexString( value );
StringBuilder buf = new StringBuilder( "00000000" );
final var formatted = Integer.toHexString( value );
final var buf = new StringBuilder( "00000000" );
buf.replace( 8 - formatted.length(), 8, formatted );
return buf.toString();
}

public static String format(short value) {
String formatted = Integer.toHexString( value );
StringBuilder buf = new StringBuilder( "0000" );
final var formatted = Integer.toHexString( value );
final var buf = new StringBuilder( "0000" );
buf.replace( 4 - formatted.length(), 4, formatted );
return buf.toString();
}
Expand Down
52 changes: 21 additions & 31 deletions hibernate-core/src/main/java/org/hibernate/id/uuid/UuidGenerator.java
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Original file line number Diff line number Diff line change
Expand Up @@ -57,19 +57,15 @@ public UuidGenerator(
org.hibernate.annotations.UuidGenerator config,
MemberDetails memberDetails) {
generator = determineValueGenerator( config, memberDetails.getDeclaringType().getName(), memberDetails.getName() );

final Class<?> memberType = memberDetails.getType().determineRawClass().toJavaClass();
valueTransformer = determineProperTransformer( memberType );
valueTransformer = determineProperTransformer( memberDetails.getType().determineRawClass().toJavaClass() );
}

@Internal
public UuidGenerator(
org.hibernate.annotations.UuidGenerator config,
Member idMember) {
generator = determineValueGenerator( config, idMember.getDeclaringClass().getName(), idMember.getName() );

final Class<?> propertyType = getPropertyType( idMember );
this.valueTransformer = determineProperTransformer( propertyType );
valueTransformer = determineProperTransformer( getPropertyType( idMember ) );
}

public UuidGenerator(
Expand Down Expand Up @@ -106,39 +102,34 @@ private static UuidValueGenerator determineValueGenerator(
org.hibernate.annotations.UuidGenerator config,
String memberDeclaringClassName,
String memberName) {
if ( config != null ) {
if ( config == null ) {
return StandardRandomStrategy.INSTANCE;
}
else {
// there is an annotation
final var style = config.style();
if ( config.algorithm() != UuidValueGenerator.class ) {
// the annotation specified a custom algorithm
if ( config.style() != AUTO ) {
if ( style != AUTO ) {
throw new MappingException(
String.format(
Locale.ROOT,
"Style [%s] should not be specified with custom UUID value generator : %s.%s",
config.style().name(),
"Style [%s] should not be specified with custom UUID value generator: %s.%s",
style.name(),
memberDeclaringClassName,
memberName
)
);
}
return instantiateCustomGenerator( config.algorithm() );
}
if ( config.style() == TIME ) {
return new CustomVersionOneStrategy();
}
if ( config.style() == VERSION_6 ) {
return UuidVersion6Strategy.INSTANCE;
}
if ( config.style() == VERSION_7 ) {
return UuidVersion7Strategy.INSTANCE;
}
// NOTE : AUTO falls through
return switch ( style ) {
case TIME -> new CustomVersionOneStrategy();
case VERSION_6 -> UuidVersion6Strategy.INSTANCE;
case VERSION_7 -> UuidVersion7Strategy.INSTANCE;
default -> StandardRandomStrategy.INSTANCE;
};
}

// Either -
// 1. there is no annotation
// 2. the annotation specified AUTO (with no custom algorithm)
return StandardRandomStrategy.INSTANCE;
}

private static UuidValueGenerator instantiateCustomGenerator(Class<? extends UuidValueGenerator> algorithmClass) {
Expand All @@ -154,15 +145,14 @@ private ValueTransformer determineProperTransformer(Class<?> propertyType) {
if ( UUID.class.isAssignableFrom( propertyType ) ) {
return UUIDJavaType.PassThroughTransformer.INSTANCE;
}

if ( String.class.isAssignableFrom( propertyType ) ) {
else if ( String.class.isAssignableFrom( propertyType ) ) {
return UUIDJavaType.ToStringTransformer.INSTANCE;
}

if ( byte[].class.isAssignableFrom( propertyType ) ) {
else if ( byte[].class.isAssignableFrom( propertyType ) ) {
return UUIDJavaType.ToBytesTransformer.INSTANCE;
}

throw new HibernateException( "Unanticipated return type [" + propertyType.getName() + "] for UUID conversion" );
else {
throw new HibernateException( "Unanticipated return type [" + propertyType.getName() + "] for UUID conversion" );
}
}
}
24 changes: 8 additions & 16 deletions hibernate-core/src/main/java/org/hibernate/id/uuid/UuidVersion6Strategy.java
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Expand Up @@ -40,23 +40,16 @@ public static class Holder {
static final long EPOCH_1582_SECONDS = LocalDate.of( 1582, 10, 15 )
.atStartOfDay( ZoneId.of( "UTC" ) )
.toInstant().getEpochSecond();

}

private record State(long lastTimestamp, int lastSequence) {
public State getNextState() {
final long now = instantToTimestamp();
if ( this.lastTimestamp < now ) {
return new State(
now,
randomSequence()
);
if ( lastTimestamp < now ) {
return new State( now, randomSequence() );
}
else if ( lastSequence == 0x3FFF ) {
return new State(
this.lastTimestamp + 1,
randomSequence()
);
return new State( lastTimestamp + 1, randomSequence() );
}
else {
return new State( lastTimestamp, lastSequence + 1 );
Expand All @@ -68,7 +61,7 @@ private static int randomSequence() {
}

private static long instantToTimestamp() {
final Instant instant = Instant.now();
final var instant = Instant.now();
final long seconds = instant.getEpochSecond() - Holder.EPOCH_1582_SECONDS;
return seconds * 10_000_000 + instant.getNano() / 100;
}
Expand Down Expand Up @@ -101,20 +94,19 @@ public UUID generateUUID(final SharedSessionContractImplementor session) {

@Override
public UUID generateUuid(final SharedSessionContractImplementor session) {
final State state = lastState.updateAndGet( State::getNextState );

final var state = lastState.updateAndGet( State::getNextState );
return new UUID(
// MSB bits 0-47 - most significant 32 bits of the 60-bit starting timestamp
// MSB bits 0-47 - the most significant 32 bits of the 60-bit starting timestamp
state.lastTimestamp << 4 & 0xFFFF_FFFF_FFFF_0000L
// MSB bits 48-51 - version = 6
| 0x6000L
// MSB bits 52-63 - least significant 12 bits from the 60-bit starting timestamp
// MSB bits 52-63 - the least significant 12 bits from the 60-bit starting timestamp
| state.lastTimestamp & 0x0FFFL,
// LSB bits 0-1 - variant = 4
0x8000_0000_0000_0000L
// LSB bits 2-15 - clock sequence
| (long) state.lastSequence << 48
// LSB bits 16-63 - pseudorandom data, least significant bit of the first octet is set to 1
// LSB bits 16-63 - pseudorandom data, the least significant bit of the first octet is set to 1
| randomNode()
);
}
Expand Down
23 changes: 12 additions & 11 deletions hibernate-core/src/main/java/org/hibernate/id/uuid/UuidVersion7Strategy.java
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Original file line number Diff line number Diff line change
Expand Up @@ -42,7 +42,6 @@ public class UuidVersion7Strategy implements UUIDGenerationStrategy, UuidValueGe
@Internal
public static class Holder {
private static final SecureRandom numberGenerator = new SecureRandom();

}

public record State(Instant lastTimestamp, long lastSequence, long nanos) {
Expand All @@ -60,20 +59,23 @@ private static long nanos(Instant timestamp) {
}

public State getNextState() {
final Instant now = Instant.now();
if ( lastTimestamp.toEpochMilli() < now.toEpochMilli() ||
lastTimestamp.toEpochMilli() == now.toEpochMilli() && nanos < nanos( now ) ) {
final var now = Instant.now();
if ( lastTimestampEarlierThan( now ) ) {
return new State( now, randomSequence() );
}
final long nextSequence = lastSequence + Holder.numberGenerator.nextLong( 0xFFFF_FFFFL );
if ( nextSequence > MAX_RANDOM_SEQUENCE ) {
return new State( lastTimestamp.plusNanos( 250 ), randomSequence() );
}
else {
return new State( lastTimestamp, nextSequence );
final long nextSequence = lastSequence + Holder.numberGenerator.nextLong( 0xFFFF_FFFFL );
return nextSequence > MAX_RANDOM_SEQUENCE
? new State( lastTimestamp.plusNanos( 250 ), randomSequence() )
: new State( lastTimestamp, nextSequence );
}
}

private boolean lastTimestampEarlierThan(Instant now) {
return lastTimestamp.toEpochMilli() < now.toEpochMilli()
|| lastTimestamp.toEpochMilli() == now.toEpochMilli() && nanos < nanos( now );
}

private static long randomSequence() {
return Holder.numberGenerator.nextLong( MAX_RANDOM_SEQUENCE );
}
Expand Down Expand Up @@ -106,8 +108,7 @@ public UUID generateUUID(final SharedSessionContractImplementor session) {

@Override
public UUID generateUuid(final SharedSessionContractImplementor session) {
final State state = lastState.updateAndGet( State::getNextState );

final var state = lastState.updateAndGet( State::getNextState );
return new UUID(
// MSB bits 0-47 - 48-bit big-endian unsigned number of the Unix Epoch timestamp in milliseconds
state.millis() << 16 & 0xFFFF_FFFF_FFFF_0000L
Expand Down