From ebc145f52aa5fb1c01fbac4522a4e2aa1f06ce04 Mon Sep 17 00:00:00 2001
From: Fabio Lima <fabiolimace@gmail.com>
Date: Sat, 22 Oct 2022 15:01:18 -0300
Subject: [PATCH] Add a fast method to generate identifiers #22

---
 CHANGELOG.md                                  |  9 +++++--
 README.md                                     | 21 +++++++++++----
 .../src/main/java/benchmark/Throughput.java   | 12 ++++++++-
 .../java/com/github/f4b6a3/ulid/Ulid.java     | 26 +++++++++++++++++--
 .../java/com/github/f4b6a3/ulid/UlidTest.java | 19 +++++++++++++-
 5 files changed, 76 insertions(+), 11 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3d27b67..f6288c8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,10 @@ All notable changes to this project will be documented in this file.
 
 Nothing unreleased.
 
+## [5.1.0] - 2022-10-22
+
+Add a fast method to generate identifiers. #22
+
 ## [5.0.2] - 2022-09-17
 
 Rewrite docs. #21
@@ -298,8 +302,9 @@ Project created as an alternative Java implementation of [ULID spec](https://git
 -   Added `LICENSE`
 -   Added test cases
 
-[unreleased]: https://github.com/f4b6a3/ulid-creator/compare/ulid-creator-5.0.2...HEAD
-[5.0.2]: https://github.com/f4b6a3/ulid-creator/compare/ulid-creator-5.0.0...ulid-creator-5.0.2
+[unreleased]: https://github.com/f4b6a3/ulid-creator/compare/ulid-creator-5.1.0...HEAD
+[5.0.2]: https://github.com/f4b6a3/ulid-creator/compare/ulid-creator-5.0.2...ulid-creator-5.1.0
+[5.0.2]: https://github.com/f4b6a3/ulid-creator/compare/ulid-creator-5.0.1...ulid-creator-5.0.2
 [5.0.1]: https://github.com/f4b6a3/ulid-creator/compare/ulid-creator-5.0.0...ulid-creator-5.0.1
 [5.0.0]: https://github.com/f4b6a3/ulid-creator/compare/ulid-creator-4.2.1...ulid-creator-5.0.0
 [4.2.1]: https://github.com/f4b6a3/ulid-creator/compare/ulid-creator-4.2.0...ulid-creator-4.2.1
diff --git a/README.md b/README.md
index 9a187ec..e45b87e 100644
--- a/README.md
+++ b/README.md
@@ -43,7 +43,7 @@ Add these lines to your `pom.xml`.
 <dependency>
   <groupId>com.github.f4b6a3</groupId>
   <artifactId>ulid-creator</artifactId>
-  <version>5.0.2</version>
+  <version>5.1.0</version>
 </dependency>
 ```
 See more options in [maven.org](https://search.maven.org/artifact/com.github.f4b6a3/ulid-creator).
@@ -125,6 +125,14 @@ Sequence of Monotonic ULIDs:
 
 ### More Examples
 
+Create a quick ULID:
+
+```java
+Ulid ulid = Ulid.fast();
+```
+
+---
+
 Create a ULID from a canonical string (26 chars):
 
 ```java
@@ -253,16 +261,19 @@ This section shows benchmarks comparing `UlidCreator` to `UUID.randomUUID()`.
 --------------------------------------------------------------------------------
 THROUGHPUT (operations/msec)            Mode  Cnt      Score      Error   Units
 --------------------------------------------------------------------------------
-UUID_randomUUID                        thrpt    5   3459,889 ±   98,257  ops/ms
+UUID_randomUUID                        thrpt    5   3459,889 ±   98,257  ops/ms (1.00)
 UUID_randomUUID_toString               thrpt    5   3148,298 ±  159,507  ops/ms
 -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
-UlidCreator_getUlid                    thrpt    5   4276,614 ±   11,069  ops/ms
+Ulid_fast                              thrpt    5  34523,147 ± 1022,114  ops/ms (9.98)
+Ulid_fast_toString                     thrpt    5  19161,375 ±  662,563  ops/ms
+-  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
+UlidCreator_getUlid                    thrpt    5   4276,614 ±   11,069  ops/ms (1.23)
 UlidCreator_getUlid_toString           thrpt    5   3645,088 ±   85,478  ops/ms
 -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
-UlidCreator_getMonotonicUlid           thrpt    5  32921,698 ± 1286,983  ops/ms
+UlidCreator_getMonotonicUlid           thrpt    5  32921,698 ± 1286,983  ops/ms (9.51)
 UlidCreator_getMonotonicUlid_toString  thrpt    5  18541,252 ±  710,281  ops/ms
 --------------------------------------------------------------------------------
-Total time: 00:02:01
+Total time: 00:02:41
 --------------------------------------------------------------------------------
 ```
 
diff --git a/benchmark/src/main/java/benchmark/Throughput.java b/benchmark/src/main/java/benchmark/Throughput.java
index 3588c07..b29566d 100644
--- a/benchmark/src/main/java/benchmark/Throughput.java
+++ b/benchmark/src/main/java/benchmark/Throughput.java
@@ -37,6 +37,16 @@ public class Throughput {
 		return UUID.randomUUID().toString();
 	}
 
+	@Benchmark
+	public Ulid Ulid_fast() {
+		return Ulid.fast();
+	}
+
+	@Benchmark
+	public String Ulid_fast_toString() {
+		return Ulid.fast().toString();
+	}
+
 	@Benchmark
 	public Ulid UlidCreator_getUlid() {
 		return UlidCreator.getUlid();
@@ -46,7 +56,7 @@ public class Throughput {
 	public String UlidCreator_getUlid_toString() {
 		return UlidCreator.getUlid().toString();
 	}
-	
+
 	@Benchmark
 	public Ulid UlidCreator_getMonotonicUlid() {
 		return UlidCreator.getMonotonicUlid();
diff --git a/src/main/java/com/github/f4b6a3/ulid/Ulid.java b/src/main/java/com/github/f4b6a3/ulid/Ulid.java
index c9a3eea..e9ecc2b 100644
--- a/src/main/java/com/github/f4b6a3/ulid/Ulid.java
+++ b/src/main/java/com/github/f4b6a3/ulid/Ulid.java
@@ -26,12 +26,13 @@ package com.github.f4b6a3.ulid;
 
 import java.io.Serializable;
 import java.time.Instant;
+import java.util.SplittableRandom;
 import java.util.UUID;
 
 /**
  * A class that represents ULIDs.
  * <p>
- * ULID is 128-bit value that has two components:
+ * ULID is a 128-bit value that has two components:
  * <ul>
  * <li><b>Time component</b>: a number of milliseconds since 1970-01-01 (Unix
  * epoch).
@@ -237,6 +238,27 @@ public final class Ulid implements Serializable, Comparable<Ulid> {
 		this.lsb = long1;
 	}
 
+	/**
+	 * Returns a fast new ULID.
+	 * <p>
+	 * This static method is a quick alternative to {@link UlidCreator#getUlid()}.
+	 * <p>
+	 * It employs {@link SplittableRandom} which works very well, although not
+	 * cryptographically strong.
+	 * <p>
+	 * Security-sensitive applications that require a cryptographically secure
+	 * pseudo-random generator should use {@link UlidCreator#getUlid()}.
+	 * 
+	 * @return a ULID
+	 * @see {@link SplittableRandom}
+	 * @since 5.1.0
+	 */
+	public static Ulid fast() {
+		final long time = System.currentTimeMillis();
+		final SplittableRandom random = new SplittableRandom();
+		return new Ulid((time << 16) | (random.nextLong() & 0xffffL), random.nextLong());
+	}
+
 	/**
 	 * Converts a UUID into a ULID.
 	 * 
@@ -677,7 +699,7 @@ public final class Ulid implements Serializable, Comparable<Ulid> {
 	 * Compares two ULIDs as unsigned 128-bit integers.
 	 * <p>
 	 * The first of two ULIDs is greater than the second if the most significant
-	 * byte in which they differ is greater for the first UUID.
+	 * byte in which they differ is greater for the first ULID.
 	 * 
 	 * @param that a ULID to be compared with
 	 * @return -1, 0 or 1 as {@code this} is less than, equal to, or greater than
diff --git a/src/test/java/com/github/f4b6a3/ulid/UlidTest.java b/src/test/java/com/github/f4b6a3/ulid/UlidTest.java
index 109ae71..4a85e0f 100644
--- a/src/test/java/com/github/f4b6a3/ulid/UlidTest.java
+++ b/src/test/java/com/github/f4b6a3/ulid/UlidTest.java
@@ -15,7 +15,7 @@ import java.util.UUID;
 
 import org.junit.Test;
 
-public class UlidTest {
+public class UlidTest extends UlidFactoryTest {
 
 	private static final int DEFAULT_LOOP_MAX = 1_000;
 
@@ -577,6 +577,23 @@ public class UlidTest {
 		}
 	}
 
+	@Test
+	public void testUlidFast() {
+		Ulid[] list = new Ulid[DEFAULT_LOOP_MAX];
+
+		long startTime = System.currentTimeMillis();
+
+		for (int i = 0; i < DEFAULT_LOOP_MAX; i++) {
+			list[i] = Ulid.fast();
+		}
+
+		long endTime = System.currentTimeMillis();
+
+		checkNullOrInvalid(list);
+		checkUniqueness(list);
+		checkCreationTime(list, startTime, endTime);
+	}
+
 	public static Ulid fromString(String string) {
 
 		long time = 0;