feat: kata/adapter-to-java-dot-util-dot-list-dot-of

kata/beta/adapter-to-java-dot-util-dot-list-dot-of/README.md

@@ -0,0 +1,17 @@
+# [Adapter to java.util.List.of](https://www.codewars.com/kata/adapter-to-java-dot-util-dot-list-dot-of "https://www.codewars.com/kata/65e5ef770a978e003e36f16a")
+
+If you're an experienced Java programmer, you've likely come across `List.of`, but it often frustrates newcomers since the returned list is
+immutable and doesn’t allow adding, removing, or modifying elements. This happens because the object implements the `java.util.List`
+interface but delegates its method calls to another implementation behind the scenes, demonstrating the Adapter pattern that allows
+different interfaces
+to work together by translating method calls.
+
+Your task is to create a method that takes an array (or varargs) and returns a `List` structure that keeps the data immutable, similar to
+how `List.of` works.
+
+You cannot use:
+ - List.of
+ - any method named .of
+ - the new operator, except when creating Exceptions
+
+You can find more info on [List.of()](https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/util/List.html#of()) in the Java docs.

kata/beta/adapter-to-java-dot-util-dot-list-dot-of/main/InmutableList.java

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+import static java.util.Arrays.stream;
+
+import java.util.List;
+
+interface InmutableList {
+  static <E> List<E> alternativeOf(E... varargs) {
+    return stream(varargs).toList();
+  }
+}

kata/beta/adapter-to-java-dot-util-dot-list-dot-of/test/ExampleTest.java

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+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class ExampleTest {
+  @Test
+  void createListWithSingleElement() {
+    List<Integer> singleElementList = InmutableList.alternativeOf(42);
+    assertEquals(1, singleElementList.size());
+    assertEquals(42, singleElementList.get(0));
+  }
+
+  @Test
+  void createListWithMultipleElements() {
+    List<String> multiElementList = InmutableList.alternativeOf("apple", "banana", "cherry");
+    assertEquals(3, multiElementList.size());
+    assertEquals("banana", multiElementList.get(1));
+  }
+
+  @Test
+  void createListWithVarargs() {
+    List<Integer> varargsList = InmutableList.alternativeOf(1, 2, 3, 4, 5);
+    assertEquals(5, varargsList.size());
+    assertEquals(4, varargsList.get(3));
+  }
+
+  @Test
+  void checkImmutability() {
+    List<String> immutableList = InmutableList.alternativeOf("one", "two", "three");
+    assertThrows(UnsupportedOperationException.class, () -> immutableList.add("four"));
+  }
+}

kata/beta/index.md

@@ -1,4 +1,5 @@
 - [02. Sum of array's elements](02-sum-of-arrays-elements "58f475735e78fde4a2000011")
+- [Adapter to java.util.List.of](adapter-to-java-dot-util-dot-list-dot-of "65e5ef770a978e003e36f16a")
 - [¡Arrest the cardiac!](arrest-the-cardiac "660af4c7fe0da42cceb4af56")
 - [Average of Even Numbers in a List](average-of-even-numbers-in-a-list "685a10c62388b0a0220ac88d")
 - [Bad Collection?](bad-collection "5e36fb0ffc5a260001e65a5b")