TSID.diff

TSID.diff

diff --git a/src/main/java/io/hypersistence/tsid/TSID.java b/src/main/java/io/hypersistence/tsid/TSID.java
index 1ca20ca..665f081 100644
--- a/src/main/java/io/hypersistence/tsid/TSID.java
+++ b/src/main/java/io/hypersistence/tsid/TSID.java
@@ -36,6 +36,7 @@ import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.IntFunction;
 import java.util.function.IntSupplier;
+import java.util.function.Supplier;
 
 /**
  * A value object that represents a Time-Sorted Unique Identifier (TSID).
@@ -790,17 +791,14 @@ public final class TSID implements Serializable, Comparable<TSID> {
 	 * and reuse a single instance of {@link Factory} per node in your
 	 * distributed system.
 	 */
-	public static final class Factory {
+	public static class Factory {
 
 		private static final ReentrantLock LOCK = new ReentrantLock();
 
-		public static final Factory INSTANCE = new Factory();
-
-		public static final Factory INSTANCE_256 = newInstance256();
-
-		public static final Factory INSTANCE_1024 = newInstance1024();
-
-		public static final Factory INSTANCE_4096 = newInstance4096();
+		public static final Factory INSTANCE = new Proxy(Factory::new);
+		public static final Factory INSTANCE_256 = new Proxy(Factory::newInstance256);
+		public static final Factory INSTANCE_1024 = new Proxy(Factory::newInstance1024);
+		public static final Factory INSTANCE_4096 = new Proxy(Factory::newInstance4096);
 
 		public static final IntSupplier THREAD_LOCAL_RANDOM_FUNCTION = () -> ThreadLocalRandom.current().nextInt();
 
@@ -1543,4 +1541,37 @@ public final class TSID implements Serializable, Comparable<TSID> {
 			return INSTANCE_4096.generate();
 		}
 	}
+	
+	private static class Proxy extends Factory {
+
+		private Factory factory = null;
+		private Supplier<Factory> supplier;
+		private static final ReentrantLock LOCK = new ReentrantLock();
+
+		public Proxy(Supplier<Factory> supplier) {
+			this.supplier = supplier;
+		}
+
+		private Factory get() {
+
+			if (factory != null) {
+				return factory;
+			}
+
+			try {
+				LOCK.lock();
+				if (factory == null) {
+					this.factory = supplier.get();
+				}
+				return this.factory;
+			} finally {
+				LOCK.unlock();
+			}
+		}
+
+		@Override
+		public TSID generate() {
+			return get().generate();
+		}
+	}
 }