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Generating Time Based UUIDs (#13668) 

* time-based UUIDs

* review

* review
This commit is contained in:
Alexandru Borza 2023-04-11 21:21:36 +03:00 committed by GitHub
parent 0ac00ad389
commit 67d6b1533b
5 changed files with 126 additions and 1 deletions
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15
core-java-modules/core-java-uuid/pom.xml
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@ -24,6 +24,21 @@
<artifactId>log4j-over-slf4j</artifactId>
<version>${org.slf4j.version}</version>
</dependency>
<dependency>
<groupId>com.github.f4b6a3</groupId>
<artifactId>uuid-creator</artifactId>
<version>5.2.0</version>
</dependency>
<dependency>
<groupId>com.fasterxml.uuid</groupId>
<artifactId>java-uuid-generator</artifactId>
<version>4.1.0</version>
</dependency>
<dependency>
<groupId>com.github.f4b6a3</groupId>
<artifactId>tsid-creator</artifactId>
<version>5.2.3</version>
</dependency>
</dependencies>
<build>

42
core-java-modules/core-java-uuid/src/main/java/com/baeldung/timebaseduuid/JavaUUIDCreatorBenchmark.java Normal file
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@ -0,0 +1,42 @@
package com.baeldung.timebaseduuid;
import com.fasterxml.uuid.Generators;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
public class JavaUUIDCreatorBenchmark {
public static void main(String[] args) throws InterruptedException {
int threadCount = 128;
int iterationCount = 100_000;
Map<UUID, Long> uuidMap = new ConcurrentHashMap<>();
AtomicLong collisionCount = new AtomicLong();
long startNanos = System.nanoTime();
CountDownLatch endLatch = new CountDownLatch(threadCount);
for (long i = 0; i < threadCount; i++) {
long threadId = i;
new Thread(() -> {
for (long j = 0; j < iterationCount; j++) {
UUID uuid = Generators.timeBasedGenerator().generate();
Long existingUUID = uuidMap.put(uuid, (threadId * iterationCount) + j);
if(existingUUID != null) {
collisionCount.incrementAndGet();
}
}
endLatch.countDown();
}).start();
}
endLatch.await();
System.out.println(threadCount * iterationCount + " UUIDs generated, " + collisionCount + " collisions in "
+ TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startNanos) + "ms");
}
}

13
core-java-modules/core-java-uuid/src/main/java/com/baeldung/timebaseduuid/JavaUUIDCreatorExample.java Normal file
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@ -0,0 +1,13 @@
package com.baeldung.timebaseduuid;
import com.fasterxml.uuid.Generators;
public class JavaUUIDCreatorExample {
public static void main(String[] args) {
System.out.println("UUID Version 1: " + Generators.timeBasedGenerator().generate());
System.out.println("UUID Version 6: " + Generators.timeBasedReorderedGenerator().generate());
System.out.println("UUID Version 7: " + Generators.timeBasedEpochGenerator().generate());
}
}

42
core-java-modules/core-java-uuid/src/main/java/com/baeldung/timebaseduuid/UUIDCreatorBenchmark.java Normal file
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@ -0,0 +1,42 @@
package com.baeldung.timebaseduuid;
import com.github.f4b6a3.uuid.UuidCreator;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
public class UUIDCreatorBenchmark {
public static void main(String[] args) throws InterruptedException {
int threadCount = 128;
int iterationCount = 100_000;
Map<UUID, Long> uuidMap = new ConcurrentHashMap<>();
AtomicLong collisionCount = new AtomicLong();
long startNanos = System.nanoTime();
CountDownLatch endLatch = new CountDownLatch(threadCount);
for (long i = 0; i < threadCount; i++) {
long threadId = i;
new Thread(() -> {
for (long j = 0; j < iterationCount; j++) {
UUID uuid = UuidCreator.getTimeBased();
Long existingUUID = uuidMap.put(uuid, (threadId * iterationCount) + j);
if(existingUUID != null) {
collisionCount.incrementAndGet();
}
}
endLatch.countDown();
}).start();
}
endLatch.await();
System.out.println(threadCount * iterationCount + " UUIDs generated, " + collisionCount + " collisions in "
+ TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startNanos) + "ms");
}
}

13
core-java-modules/core-java-uuid/src/main/java/com/baeldung/timebaseduuid/UUIDCreatorExample.java Normal file
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@ -0,0 +1,13 @@
package com.baeldung.timebaseduuid;
import com.github.f4b6a3.uuid.UuidCreator;
public class UUIDCreatorExample {
public static void main(String[] args) {
System.out.println("UUID Version 1: " + UuidCreator.getTimeBased());
System.out.println("UUID Version 6: " + UuidCreator.getTimeOrdered());
System.out.println("UUID Version 7: " + UuidCreator.getTimeOrderedEpoch());
}
}