From 02d6c286f11b21247ba477209d590ac890834443 Mon Sep 17 00:00:00 2001
From: Fabio Lima <fabiolimace@gmail.com>
Date: Sun, 7 Jul 2024 01:41:23 -0300
Subject: [PATCH] Refactor UUIDv7 factory method with an instant parameter

---
 .../com/github/f4b6a3/uuid/UuidCreator.java   |  8 +----
 .../f4b6a3/uuid/factory/UuidFactory.java      | 27 ++++++++++++++++
 .../standard/TimeOrderedEpochFactory.java     | 31 ++++++++++++++++---
 3 files changed, 55 insertions(+), 11 deletions(-)

diff --git a/src/main/java/com/github/f4b6a3/uuid/UuidCreator.java b/src/main/java/com/github/f4b6a3/uuid/UuidCreator.java
index c781c78e..98575d9b 100644
--- a/src/main/java/com/github/f4b6a3/uuid/UuidCreator.java
+++ b/src/main/java/com/github/f4b6a3/uuid/UuidCreator.java
@@ -24,7 +24,6 @@
 
 package com.github.f4b6a3.uuid;
 
-import java.security.SecureRandom;
 import java.time.Instant;
 import java.util.Objects;
 import java.util.UUID;
@@ -605,12 +604,7 @@ public static UUID getTimeOrderedEpochPlusN() {
 	 * @since 5.3.3
 	 */
 	public static UUID getTimeOrderedEpoch(Instant instant) {
-		Objects.requireNonNull(instant, "Null instant");
-		final long time = instant.toEpochMilli();
-		SecureRandom random = new SecureRandom();
-		final long msb = (time << 16) | (random.nextLong() & 0x0fffL) | 0x7000L;
-		final long lsb = (random.nextLong() & 0x3fffffffffffffffL) | 0x8000000000000000L;
-		return new UUID(msb, lsb);
+		return UUID7.create(Parameters.builder().withInstant(instant).build());
 	}
 
 	/**
diff --git a/src/main/java/com/github/f4b6a3/uuid/factory/UuidFactory.java b/src/main/java/com/github/f4b6a3/uuid/factory/UuidFactory.java
index eff1bfb4..b56c9c83 100644
--- a/src/main/java/com/github/f4b6a3/uuid/factory/UuidFactory.java
+++ b/src/main/java/com/github/f4b6a3/uuid/factory/UuidFactory.java
@@ -25,6 +25,7 @@
 package com.github.f4b6a3.uuid.factory;
 
 import java.nio.charset.StandardCharsets;
+import java.time.Instant;
 import java.util.Arrays;
 import java.util.Objects;
 import java.util.UUID;
@@ -100,6 +101,11 @@ public UuidVersion getVersion() {
 	 */
 	public static class Parameters {
 
+		/**
+		 * Instant to be used.
+		 */
+		private final Instant instant;
+
 		/**
 		 * Name space byte array.
 		 */
@@ -127,12 +133,17 @@ public static class Parameters {
 		 */
 		public Parameters(Builder builder) {
 			Objects.requireNonNull(builder);
+			this.instant = builder.instant;
 			this.namespace = builder.namespace;
 			this.name = builder.name;
 			this.localDomain = builder.localDomain;
 			this.localIdentifier = builder.localIdentifier;
 		}
 
+		public Instant getInstant() {
+			return this.instant;
+		}
+
 		/**
 		 * Get the name space bytes.
 		 * 
@@ -183,6 +194,11 @@ public static Builder builder() {
 		 */
 		public static class Builder {
 
+			/**
+			 * Instant to be used.
+			 */
+			private Instant instant;
+
 			/**
 			 * Name space byte array.
 			 */
@@ -206,6 +222,17 @@ public static class Builder {
 			private Builder() {
 			}
 
+			/**
+			 * Use the instant provided.
+			 * 
+			 * @param instant an instant
+			 * @return the builder
+			 */
+			public Builder withInstant(Instant instant) {
+				this.instant = instant;
+				return this;
+			}
+
 			/**
 			 * Use the name space UUID.
 			 * 
diff --git a/src/main/java/com/github/f4b6a3/uuid/factory/standard/TimeOrderedEpochFactory.java b/src/main/java/com/github/f4b6a3/uuid/factory/standard/TimeOrderedEpochFactory.java
index 23c50d4d..7c0aabaa 100644
--- a/src/main/java/com/github/f4b6a3/uuid/factory/standard/TimeOrderedEpochFactory.java
+++ b/src/main/java/com/github/f4b6a3/uuid/factory/standard/TimeOrderedEpochFactory.java
@@ -25,11 +25,13 @@
 package com.github.f4b6a3.uuid.factory.standard;
 
 import java.time.Clock;
+import java.time.Instant;
+import java.util.Objects;
 import java.util.Random;
 import java.util.UUID;
 import java.util.concurrent.locks.ReentrantLock;
+import java.util.function.Function;
 import java.util.function.LongSupplier;
-import java.util.function.Supplier;
 
 import com.github.f4b6a3.uuid.enums.UuidVersion;
 import com.github.f4b6a3.uuid.factory.AbstCombFactory;
@@ -251,11 +253,26 @@ public static Builder builder() {
 	 */
 	@Override
 	public UUID create() {
-		UUID uuid = this.uuidFunction.get();
+		UUID uuid = this.uuidFunction.apply(null);
 		return toUuid(uuid.getMostSignificantBits(), uuid.getLeastSignificantBits());
 	}
 
-	static abstract class UuidFunction implements Supplier<UUID> {
+	/**
+	 * Returns a time-ordered unique identifier (UUIDv7) for a given instant.
+	 * <p>
+	 * The random component is generated with each method invocation.
+	 * 
+	 * @return a UUIDv7
+	 * @param instant a given instant
+	 */
+	@Override
+	public UUID create(Parameters parameters) {
+		Objects.requireNonNull(parameters.getInstant(), "Null instant");
+		UUID uuid = this.uuidFunction.apply(parameters.getInstant());
+		return toUuid(uuid.getMostSignificantBits(), uuid.getLeastSignificantBits());
+	}
+
+	static abstract class UuidFunction implements Function<Instant, UUID> {
 
 		protected long msb = 0L; // most significant bits
 		protected long lsb = 0L; // least significant bits
@@ -276,10 +293,16 @@ public UuidFunction(IRandom random, LongSupplier timeFunction) {
 		}
 
 		@Override
-		public UUID get() {
+		public UUID apply(Instant instant) {
 			lock.lock();
 			try {
 
+				if (instant != null) {
+					// The user provided the time.
+					reset(instant.toEpochMilli());
+					return new UUID(this.msb, this.lsb);
+				}
+
 				final long lastTime = this.time();
 				final long time = timeFunction.getAsLong();