From a74fbb8da44fb7c07cdaafb877315c5805d5edb0 Mon Sep 17 00:00:00 2001
From: Benedikt Waldvogel <benedikt.waldvogel@cronn.de>
Date: Fri, 15 Nov 2024 09:21:08 +0100
Subject: [PATCH] Add SetUtils for creating ordered sets

---
 README.md                                     | 17 +++++++++++++++++
 .../java/de/cronn/commons/lang/SetUtils.java  | 17 +++++++++++++++++
 .../de/cronn/commons/lang/SetUtilsTest.java   | 19 +++++++++++++++++++
 3 files changed, 53 insertions(+)
 create mode 100644 src/main/java/de/cronn/commons/lang/SetUtils.java
 create mode 100644 src/test/java/de/cronn/commons/lang/SetUtilsTest.java

diff --git a/README.md b/README.md
index 029c023..5e72f28 100644
--- a/README.md
+++ b/README.md
@@ -64,6 +64,23 @@ Set<Object> numbers = Stream.of(1, 2, 3, 2, 3)
     .collect(StreamUtil.toLinkedHashSet());
 ```
 
+### SetUtils
+
+`SetUtils` provides utility methods for creating ordered sets in Java.
+
+Unlike `Set.of(…)`, `SetUtils.orderedSet(…)` maintains the order of elements as they are added.
+
+#### Example Usage
+
+```java
+Set<String> ordered = SetUtils.orderedSet("abc", "def", "ghi");
+// Output: [abc, def, ghi]
+
+Set<Integer> numbers = SetUtils.orderedSet(3, 1, 2, 1);
+// Output: [3, 1, 2]
+```
+
+> **Key Difference**: `SetUtils.orderedSet(…)` uses `LinkedHashSet`, ensuring insertion order is preserved.
 
 ## AlphanumericComparator
 
diff --git a/src/main/java/de/cronn/commons/lang/SetUtils.java b/src/main/java/de/cronn/commons/lang/SetUtils.java
new file mode 100644
index 0000000..5bb055f
--- /dev/null
+++ b/src/main/java/de/cronn/commons/lang/SetUtils.java
@@ -0,0 +1,17 @@
+package de.cronn.commons.lang;
+
+import java.util.Arrays;
+import java.util.LinkedHashSet;
+import java.util.Set;
+
+public final class SetUtils {
+
+	private SetUtils() {
+	}
+
+	@SafeVarargs
+	@SuppressWarnings("varargs")
+	public static <E> Set<E> orderedSet(E... elements) {
+		return new LinkedHashSet<>(Arrays.asList(elements));
+	}
+}
diff --git a/src/test/java/de/cronn/commons/lang/SetUtilsTest.java b/src/test/java/de/cronn/commons/lang/SetUtilsTest.java
new file mode 100644
index 0000000..f780536
--- /dev/null
+++ b/src/test/java/de/cronn/commons/lang/SetUtilsTest.java
@@ -0,0 +1,19 @@
+package de.cronn.commons.lang;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class SetUtilsTest {
+
+	@Test
+	void testOrderedSet() {
+		assertThat(SetUtils.orderedSet("abc")).containsExactly("abc");
+		assertThat(SetUtils.orderedSet("abc", "def", "ghi")).containsExactly("abc", "def", "ghi");
+		assertThat(SetUtils.orderedSet(2, 1, 3)).containsExactly(2, 1, 3);
+		assertThat(SetUtils.orderedSet(2, 1, 3, 1)).containsExactly(2, 1, 3);
+		assertThat(SetUtils.orderedSet(null, "abc")).containsExactly(null, "abc");
+		assertThat(SetUtils.orderedSet((Object) null)).singleElement().isNull();
+	}
+
+}