Introduce EnumMapUtil

service/src/main/java/org/whispersystems/textsecuregcm/util/EnumMapUtil.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2024 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.textsecuregcm.util;
+
+import java.util.Arrays;
+import java.util.EnumMap;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+public class EnumMapUtil {
+
+  private EnumMapUtil() {}
+
+  public static <E extends Enum<E>, V> EnumMap<E, V> toEnumMap(final Class<E> enumClass, final Function<E, V> valueMapper) {
+    return Arrays.stream(enumClass.getEnumConstants())
+        .collect(Collectors.toMap(Function.identity(), valueMapper, (a, b) -> {
+              throw new AssertionError("Duplicate enumeration key");
+            },
+            () -> new EnumMap<>(enumClass)));
+  }
+}