Skip to content

Commit

Permalink
JENA-1882: UUID time in microseconds
Browse files Browse the repository at this point in the history
  • Loading branch information
@afs
afs committed Apr 16, 2020
1 parent cbdba5e commit 50eac4a
Showing 1 changed file with 24 additions and 25 deletions.
49 changes: 24 additions & 25 deletions jena-core/src/main/java/org/apache/jena/shared/uuid/UUID_V1_Gen.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,7 @@
ftp://ftp.rfc-editor.org/in-notes/rfc4122.txt
Originally: http://www.opengroup.org/onlinepubs/009629399/apdxa.htm
http://en.wikipedia.org/wiki/Universally_unique_identifier
Version 1: hardware address and timebased:
60 bits of time
48 bits of nodeId
Expand Down Expand Up @@ -67,13 +67,13 @@
Least significant long:
0xC000000000000000 variant C = 1100 (base 2)
0xC000000000000000 variant C = 1100 (base 2)
0x3FFF000000000000 clock_seq 3 = 0011 (base 2)
0x0000FFFFFFFFFFFF node
Note on variant: despite the javadoc document, the variant is defined as the
top 3 bits of octet 8. But the low bit is a "don't care" in this variant
and is used by the clock.
and is used by the clock.
*/

Expand All @@ -89,29 +89,29 @@ public class UUID_V1_Gen implements UUIDFactory
// Constants
static final int versionHere = 1 ; // Version 1: time-based. This is one character hex string.
static final int variantHere = 2 ; // DCE varient

static final long maskTimeLow = 0xFFFFFFFF00000000L ;
static final long maskTimeMid = 0x00000000FFFF0000L ;
static final long maskTimeHigh = 0x0000000000000FFFL ;
static final long maskVersion = 0x000000000000F000L ;

static final long maskVariant = 0xC000000000000000L ;
static final long maskClockSeq = 0x3FFF000000000000L ;
static final long maskNode = 0x0000FFFFFFFFFFFFL ;

// Generator variables.
long gregorianTime = 0 ;
long gregorianTime = 0 ; // Called uuid_time in RFC
static final long UUIDS_PER_TICK = 100 ;
long uuids_this_tick = UUIDS_PER_TICK+1 ; // Force reset first time.

// Generator initial state
int clockSeq = 0 ;
private static final int CLOCK_BITS = 8 ;
private static final int CLOCK_BITS = 8 ;
long node = 0 ;

// Time control
private long lastTime = 0 ;
private long DELAY = 10 ; // Milliseconds
private long lastTime = 0 ; // Microseconds
private long DELAY = 10 ; // Milliseconds

public UUID_V1_Gen() {
reset() ;
Expand All @@ -128,7 +128,7 @@ public void reset() {
@Override
public JenaUUID generate()
{ return generateV1() ; }

public UUID_V1 generateV1() {
long timestamp = 0 ;
synchronized (this) {
Expand All @@ -139,7 +139,7 @@ public UUID_V1 generateV1() {
}
return generate(timestamp) ;
}

/* 8-4-4-4-12 = 32+4 dashes = 36 chars
UUID = <time_low> "-" <time_mid> "-"
Expand Down Expand Up @@ -175,7 +175,7 @@ public JenaUUID parse(String s) throws UUIDFormatException {
static UUID_V1 parse$(String s) {
// The UUID broken up into parts.
// 00000000-0000-0000-0000-000000000000
// ^ ^ ^ ^ ^
// ^ ^ ^ ^ ^
// Byte: 0 4 6 8 10
// Char: 0 9 14 19 24 including hyphens
int x = (int)BitsLong.unpack(s, 19, 23) ;
Expand All @@ -190,7 +190,7 @@ public JenaUUID parse(String s) throws UUIDFormatException {
int version = (int)BitsLong.unpack(s, 14, 15) ;
return generate(version, variant, timeHigh, timeMid, timeLow, clockSeq, node) ;
}

// See LibUUID.toString(JenaUUID)
// The code here works on the specific fields and is kept for reference only.
private static String unparse(UUID_V1 uuid) {
Expand Down Expand Up @@ -224,7 +224,7 @@ private UUID_V1 generate(long timestamp) {
// Testing.
/*package*/ static UUID_V1 generate(int version, int variant, long timestamp, long clockSeq, long node) {
long timeHigh = timestamp >>> (60 - 12) ; // Top 12 bits of 60 bit number.
long timeMid = (timestamp >>> 32) & 0xFFFFL ; // 16 bits, bits 32-47
long timeMid = (timestamp >>> 32) & 0xFFFFL ; // 16 bits, bits 32-47
long timeLow = timestamp & 0xFFFFFFFFL ; // Low 32 bits

return generate(version, variant, timeHigh, timeMid, timeLow, clockSeq, node) ;
Expand All @@ -237,17 +237,17 @@ private static UUID_V1 generate(int version, int variant, long timeHigh, long ti
}

private void setTime() {
long time = 0 ;
long time = 0 ; // Time, in microseconds (as best we can in Java8).

// Wait for a clock tick.
synchronized (this) {
if ( lastTime == 0 )
lastTime = System.currentTimeMillis() ;
lastTime = 1000*System.currentTimeMillis() ;

boolean done = false ;
while (!done) {
time = System.currentTimeMillis() ;
if ( time < lastTime + DELAY ) {
time = 1000*System.currentTimeMillis() ;
if ( time < lastTime + 1000*DELAY ) {
// pause for a while to wait for time to change
try {
Thread.sleep(DELAY) ;
Expand All @@ -259,9 +259,10 @@ private void setTime() {
}
}

// We claim this tick just passed! 1 UUID per 100ns so ...
// UUIDS_PER_TICK = (time-lastTime)*10 ;
lastTime = time ;

// We claim this tick just passed!
// Reset the ticks counter.
uuids_this_tick = 0 ;

// Convert to the UUID base time (00:00:00.00, 15 October 1582)
Expand All @@ -282,7 +283,7 @@ private void setInitialState() {
// The loopback I/F does not have a MAC address.
try {
Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces() ;

byte[] hwAddr = null ;
while(en.hasMoreElements()) {
NetworkInterface ni = en.nextElement() ;
Expand All @@ -301,8 +302,6 @@ private void setInitialState() {
}
} catch (Exception ex) { } // Failed in some way. Fallback.



node = BitsLong.unpack(random, 0, 47) ; // Low 48bits, except groups address bit
node = BitsLong.set(node, 47) ; // Set group address bit

Expand Down

0 comments on commit 50eac4a

Please sign in to comment.