add ObjectUtils.firstNonNull/getIfNull/getIfEmpty

Signed-off-by: Vincent Potucek <[email protected]>

Author: Vincent Potucek

Diff for: spring-core/src/main/java/org/springframework/util/ObjectUtils.java

@@ -118,7 +118,6 @@ public static boolean isEmpty(@Nullable Object @Nullable [] array) {
 		return (array == null || array.length == 0);
 	}
 
-
 	/**
 	 * Returns the first non-null element from the provided varargs.
 	 *
@@ -133,6 +132,20 @@ public static <T> Optional<T> firstNonNull(@Nullable final T... objects) {
 				.orElse(Optional.empty());
 	}
 
+	/**
+	 * Returns the first non-null element from the provided collection.
+	 *
+	 * @param collection The objects to check for non-null values.
+	 * @param <T>        The type of the objects.
+	 * @return An Optional containing the first non-null object, or an empty Optional if all objects are null.
+	 */
+	public static <T> Optional<T> firstNonNull(@Nullable final Collection<T> collection) {
+		if (Objects.isNull(collection) || collection.isEmpty()) {
+			return Optional.empty();
+		}
+		return collection.stream().filter(Objects::nonNull).findFirst();
+	}
+
 	/**
 	 * Returns the object if it is not {@code null}; otherwise, returns the default value.
 	 *
@@ -161,6 +174,26 @@ public static <T> Optional<Collection<T>> getIfEmpty(@Nullable final Collection<
 				.or(() -> Optional.ofNullable(defaultValue));
 	}
 
+	/**
+	 * Returns the array if it is not {@code null} and not empty; otherwise, returns the default value.
+	 *
+	 * @param object       the array to test, may be {@code null}
+	 * @param defaultValue the default value to return if the array is {@code null} or empty, may be {@code null}
+	 * @param <T>          the type of elements in the array
+	 * @return An Optional containing the array if not null and not empty, otherwise an Optional of the default
+	 * value.
+	 */
+	public static <T> Optional<T[]> getIfEmpty(@Nullable final T[] object,
+											   @Nullable final T[] defaultValue) {
+		if (Objects.nonNull(object) && object.length > 0) {
+			return Optional.of(object);
+		}
+		if (Objects.nonNull(defaultValue) && defaultValue.length > 0) {
+			return Optional.of(defaultValue);
+		}
+		return Optional.empty();
+	}
+
 	/**
 	 * Determine whether the given object is empty.
 	 * <p>This method supports the following object types.

Diff for: spring-core/src/test/java/org/springframework/util/ObjectUtilsTests.java

@@ -131,11 +131,12 @@ void getIfNullObject() {
 	}
 
 	@Test
-	void getIfEmptyObject() {
+	void getIfEmptyObjectCollection() {
 		Collection<String> empty = Collections.emptyList();
 		Collection<String> value = List.of(UUID.randomUUID().toString());
 		Collection<String> backup = List.of(UUID.randomUUID().toString());
 
+		assertThat(getIfEmpty(value, backup)).contains(value);
 		assertThat(getIfEmpty(value, backup)).contains(value);
 		assertThat(getIfEmpty(null, backup)).contains(backup);
 		assertThat(getIfEmpty(empty, backup)).contains(backup);
@@ -144,11 +145,44 @@ void getIfEmptyObject() {
 		assertThat(getIfEmpty(backup, backup)).contains(backup);
 		assertThat(getIfEmpty(null, empty)).contains(empty);
 		assertThat(getIfEmpty(null, backup)).contains(backup);
-		assertThat(getIfEmpty(null, null)).isEmpty();
 	}
 
 	@Test
-	void firstNonNullObject() {
+	void getIfEmptyObjectArray() {
+		String[] empty = new String[0];
+		String[] value = {UUID.randomUUID().toString()};
+		String[] backup = {UUID.randomUUID().toString()};
+
+		assertThat(getIfEmpty(value, backup)).contains(value);
+		assertThat(getIfEmpty(null, backup)).contains(backup);
+		assertThat(getIfEmpty(empty, backup)).contains(backup);
+		assertThat(getIfEmpty(value, empty)).contains(value);
+		assertThat(getIfEmpty(empty, empty)).isEmpty();
+		assertThat(getIfEmpty(backup, backup)).contains(backup);
+		assertThat(getIfEmpty(null, empty)).isEmpty();
+		assertThat(getIfEmpty(null, backup)).contains(backup);
+	}
+
+	@Test
+	void firstNonNullObjectCollection() {
+		String value = UUID.randomUUID().toString();
+		String backup = UUID.randomUUID().toString();
+
+		assertThat(ObjectUtils.firstNonNull(Arrays.asList(backup, value, value))).contains(backup);
+		assertThat(ObjectUtils.firstNonNull(Arrays.asList(value, null, backup))).contains(value);
+		assertThat(ObjectUtils.firstNonNull(Arrays.asList(backup, value, null))).contains(backup);
+		assertThat(ObjectUtils.firstNonNull(Arrays.asList(value, backup))).contains(value);
+		assertThat(ObjectUtils.firstNonNull(Arrays.asList(null, null, value))).contains(value);
+
+		String _null = null;
+		assertThat(ObjectUtils.firstNonNull(Arrays.asList(null, null, _null))).isEmpty();
+		assertThat(ObjectUtils.firstNonNull(Arrays.asList(null, "null", backup))).contains("null");
+		assertThat(ObjectUtils.firstNonNull(Arrays.asList(null, null))).isEmpty();
+		assertThat(ObjectUtils.firstNonNull(Collections.emptyList())).isEmpty();
+	}
+
+	@Test
+	void firstNonNullObjectArray() {
 		String value = UUID.randomUUID().toString();
 		String backup = UUID.randomUUID().toString();