diff --git a/release-notes/VERSION b/release-notes/VERSION index 64add4f..f621b53 100644 --- a/release-notes/VERSION +++ b/release-notes/VERSION @@ -7,6 +7,10 @@ Releases 5.0.0 (not yet released) #53: Increase JDK baseline to JDK 8 +#81: Add `UUIDUtil.extractTimestamp()` for extracting 64-bit timestamp for + all timestamp-based versions + (requested by @gabrielbalan) + (contributed by @magdel) #85: Fix `LazyRandom` for native code generation tools (contributed by @Maia-Everett) diff --git a/src/main/java/com/fasterxml/uuid/impl/UUIDUtil.java b/src/main/java/com/fasterxml/uuid/impl/UUIDUtil.java index 41c8984..60ce671 100644 --- a/src/main/java/com/fasterxml/uuid/impl/UUIDUtil.java +++ b/src/main/java/com/fasterxml/uuid/impl/UUIDUtil.java @@ -353,4 +353,66 @@ private final static void _checkUUIDByteArray(byte[] bytes, int offset) throw new IllegalArgumentException("Invalid offset ("+offset+") passed: not enough room in byte array (need 16 bytes)"); } } + + /** + * Extract 64-bit timestamp from time-based UUIDs (if time-based type); + * returns 0 for other types. + * + * @param uuid uuid timestamp to extract from + * + * @return timestamp in milliseconds (since Epoch), or 0 if type does not support timestamps + * + * @since 5.0.0 + */ + public static long extractTimestamp(UUID uuid) + { + UUIDType type = typeOf(uuid); + if (type == null) { + // Likely null UUID: + return 0L; + } + switch (type) { + case NAME_BASED_SHA1: + case UNKNOWN: + case DCE: + case RANDOM_BASED: + case FREE_FORM: + case NAME_BASED_MD5: + return 0L; + case TIME_BASED: + return _getTimestampFromUuidV1(uuid); + case TIME_BASED_REORDERED: + return _getTimestampFromUuidV6(uuid); + case TIME_BASED_EPOCH: + return _getTimestampFromUuidV7(uuid); + default: + throw new IllegalArgumentException("Invalid `UUID`: unexpected type " + type); + } + } + + private static long _getTimestampFromUuidV1(UUID uuid) { + long mostSignificantBits = uuid.getMostSignificantBits(); + mostSignificantBits = mostSignificantBits & 0b1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1110_1111_1111_1111L; + long low = mostSignificantBits >>> 32; + long lowOfHigher = mostSignificantBits & 0xFFFF0000L; + lowOfHigher = lowOfHigher >>> 16; + long highOfHigher = mostSignificantBits & 0xFFFFL; + return highOfHigher << 48 | lowOfHigher << 32 | low; + } + + private static long _getTimestampFromUuidV6(UUID uuid) { + long mostSignificantBits = uuid.getMostSignificantBits(); + mostSignificantBits = mostSignificantBits & 0b1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1001_1111_1111_1111L; + long lowL = mostSignificantBits & 0xFFFL; + long lowH = mostSignificantBits & 0xFFFF0000L; + lowH = lowH >>> 16; + long high = mostSignificantBits & 0xFFFFFFFF00000000L; + return high >>> 4 | lowH << 12 | lowL; + } + + private static long _getTimestampFromUuidV7(UUID uuid) { + long mostSignificantBits = uuid.getMostSignificantBits(); + mostSignificantBits = mostSignificantBits & 0b1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1001_1111_1111_1111L; + return mostSignificantBits >>> 16; + } } diff --git a/src/test/java/com/fasterxml/uuid/impl/UUIDUtilTest.java b/src/test/java/com/fasterxml/uuid/impl/UUIDUtilTest.java index 2e43517..bcf972f 100644 --- a/src/test/java/com/fasterxml/uuid/impl/UUIDUtilTest.java +++ b/src/test/java/com/fasterxml/uuid/impl/UUIDUtilTest.java @@ -1,7 +1,9 @@ package com.fasterxml.uuid.impl; +import java.util.Random; import java.util.UUID; +import com.fasterxml.uuid.Generators; import junit.framework.TestCase; /** @@ -13,6 +15,8 @@ */ public class UUIDUtilTest extends TestCase { + final static int TEST_REPS = 1_000_000; + public void testNilUUID() { UUID nil = UUIDUtil.nilUUID(); // Should be all zeroes: @@ -26,4 +30,41 @@ public void testMaxUUID() { assertEquals(~0, max.getMostSignificantBits()); assertEquals(~0, max.getLeastSignificantBits()); } + + public void testExtractTimestampUUIDTimeBased() { + TimeBasedGenerator generator = Generators.timeBasedGenerator(); + final Random rnd = new Random(1); + for (int i = 0; i < TEST_REPS; i++) { + long rawTimestamp = rnd.nextLong() >>> 4; + UUID uuid = generator.construct(rawTimestamp); + assertEquals(rawTimestamp, UUIDUtil.extractTimestamp(uuid)); + } + } + + public void testExtractTimestampUUIDTimeBasedReordered() { + TimeBasedReorderedGenerator generator = Generators.timeBasedReorderedGenerator(); + final Random rnd = new Random(2); + for (int i = 0; i < TEST_REPS; i++) { + long rawTimestamp = rnd.nextLong() >>> 4; + UUID uuid = generator.construct(rawTimestamp); + assertEquals(rawTimestamp, UUIDUtil.extractTimestamp(uuid)); + } + } + + public void testExtractTimestampUUIDEpochBased() { + TimeBasedEpochGenerator generator = Generators.timeBasedEpochGenerator(); + final Random rnd = new Random(3); + for (int i = 0; i < TEST_REPS; i++) { + long rawTimestamp = rnd.nextLong() >>> 16; + UUID uuid = generator.construct(rawTimestamp); + assertEquals(rawTimestamp, UUIDUtil.extractTimestamp(uuid)); + } + } + + public void testExtractTimestampUUIDOnOtherValues() { + assertEquals(0L, UUIDUtil.extractTimestamp(null)); + assertEquals(0L, UUIDUtil.extractTimestamp(UUID.fromString("00000000-0000-0000-0000-000000000000"))); + assertEquals(0L, UUIDUtil.extractTimestamp(UUIDUtil.nilUUID())); + assertEquals(0L, UUIDUtil.extractTimestamp(UUIDUtil.maxUUID())); + } }