add ObjectUtils.getNonNull/getIfNull/getIfEmpty

Signed-off-by: Vincent Potucek <vpotucek@me.com>

Author: Vincent Potucek

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

@@ -118,46 +118,47 @@ public static boolean isEmpty(@Nullable Object @Nullable [] array) {
 		return (array == null || array.length == 0);
 	}
 
+
 	/**
-	 * Returns the object if it is not {@code null}; otherwise, returns the default value.
+	 * Returns the first non-null element from the provided varargs.
 	 *
-	 * <pre>
-	 * ObjectUtils.getIfNull(null, null)      = null
-	 * ObjectUtils.getIfNull(null, "")        = ""
-	 * ObjectUtils.getIfNull(null, "zz")      = "zz"
-	 * ObjectUtils.getIfNull("abc", *)        = "abc"
-	 * ObjectUtils.getIfNull(Boolean.TRUE, *) = Boolean.TRUE
-	 * </pre>
+	 * @param objects 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.
+	 */
+	@SafeVarargs
+	public static <T> Optional<T> getNonNull(@Nullable final T... objects) {
+		return Optional.ofNullable(objects)
+				.map(arr -> Arrays.stream(arr).filter(Objects::nonNull).findFirst())
+				.orElse(Optional.empty());
+	}
+
+	/**
+	 * Returns the object if it is not {@code null}; otherwise, returns the default value.
 	 *
-	 * @param <T>          the type of the object
 	 * @param object       the object to test, may be {@code null}
 	 * @param defaultValue the default value to return if the object is {@code null}, may be {@code null}
-	 * @return {@code object} if it is not {@code null}; otherwise, {@code defaultValue}
+	 * @param <T>          the type of the object
+	 * @return An Optional containing either the object if not null, or the default value wrapped in an Optional.
 	 */
-	@Nullable
-	public static <T> T getIfNull(@Nullable final T object, @Nullable final T defaultValue) {
-		return Objects.nonNull(object) ? object : defaultValue;
+	public static <T> Optional<T> getIfNull(@Nullable final T object, @Nullable final T defaultValue) {
+		return Optional.ofNullable(object).or(() -> Optional.ofNullable(defaultValue));
 	}
 
 	/**
 	 * Returns the collection if it is not {@code null} and not empty; otherwise, returns the default value.
 	 *
-	 * <pre>
-	 * ObjectUtils.getIfEmpty(List.of("a"), List.of("b"))     			= List.of("a")
-	 * ObjectUtils.getIfEmpty(null, List.of("b"))            			= List.of("b")
-	 * ObjectUtils.getIfEmpty(Collections.emptyList(), List.of("b")) 	= List.of("b")
-	 * ObjectUtils.getIfEmpty(null, null)                    			= null
-	 * </pre>
-	 *
-	 * @param <T>          the type of elements in the collection
 	 * @param object       the collection to test, may be {@code null}
 	 * @param defaultValue the default value to return if the collection is {@code null} or empty, may be {@code null}
-	 * @return {@code object} if it is not {@code null} and not empty; otherwise, {@code defaultValue}
-	 */
-	@Nullable
-	public static <T> Collection<T> getIfEmpty(@Nullable final Collection<T> object,
-											   @Nullable final Collection<T> defaultValue) {
-		return Objects.nonNull(object) && !object.isEmpty() ? object : defaultValue;
+	 * @param <T>          the type of elements in the collection
+	 * @return An Optional containing the collection if not null and not empty, otherwise an Optional of the default
+	 * value.
+	 */
+	public static <T> Optional<Collection<T>> getIfEmpty(@Nullable final Collection<T> object,
+														 @Nullable final Collection<T> defaultValue) {
+		return Optional.ofNullable(object)
+				.filter(collection -> !collection.isEmpty())
+				.or(() -> Optional.ofNullable(defaultValue));
 	}
 
 	/**

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

@@ -55,6 +55,7 @@
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.springframework.util.ObjectUtils.getIfEmpty;
 import static org.springframework.util.ObjectUtils.getIfNull;
+import static org.springframework.util.ObjectUtils.getNonNull;
 import static org.springframework.util.ObjectUtils.isEmpty;
 
 /**
@@ -118,29 +119,49 @@ void isCompatibleWithThrowsClause() {
 	void getIfNullObject() {
 		String value = UUID.randomUUID().toString();
 		String backup = UUID.randomUUID().toString();
-		assertThat(getIfNull(value, backup)).isEqualTo(value);
-		assertThat(getIfNull(value, value)).isEqualTo(value);
-		assertThat(getIfNull(backup, backup)).isEqualTo(backup);
-		assertThat(getIfNull(null, value)).isEqualTo(value);
-		assertThat(getIfNull(null, backup)).isEqualTo(backup);
-		assertThat(getIfNull("null", backup)).isEqualTo("null");
-		assertThat(Optional.ofNullable(getIfNull(null, null))).isEmpty();
+
+		assertThat(getIfNull(value, backup)).contains(value);
+		assertThat(getIfNull(value, backup)).contains(value);
+		assertThat(getIfNull(value, value)).contains(value);
+		assertThat(getIfNull(backup, backup)).contains(backup);
+		assertThat(getIfNull(null, value)).contains(value);
+		assertThat(getIfNull(null, backup)).contains(backup);
+		assertThat(getIfNull("null", backup)).contains("null");
+		assertThat(getIfNull(null, null)).isEmpty();
 	}
 
 	@Test
 	void getIfEmptyObject() {
 		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)).isEqualTo(value);
-		assertThat(getIfEmpty(null, backup)).isEqualTo(backup);
-		assertThat(getIfEmpty(empty, backup)).isEqualTo(backup);
-		assertThat(getIfEmpty(value, empty)).isEqualTo(value);
-		assertThat(getIfEmpty(empty, empty)).isEqualTo(empty);
-		assertThat(getIfEmpty(backup, backup)).isEqualTo(backup);
-		assertThat(getIfEmpty(null, empty)).isEqualTo(empty);
-		assertThat(getIfEmpty(null, backup)).isEqualTo(backup);
-		assertThat(Optional.ofNullable(getIfEmpty(null, null))).isEmpty();
+
+		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)).contains(empty);
+		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 getNonNullObject() {
+		String value = UUID.randomUUID().toString();
+		String backup = UUID.randomUUID().toString();
+
+		assertThat(getNonNull(backup, value, value)).contains(backup);
+		assertThat(getNonNull(value, null, backup)).contains(value);
+		assertThat(getNonNull(backup, value, null)).contains(backup);
+		assertThat(getNonNull(value, backup)).contains(value);
+		assertThat(getNonNull(null, null, value)).contains(value);
+
+		String _null = null;
+		assertThat(getNonNull(null, null, _null)).isEmpty();
+		assertThat(getNonNull(null, "null", backup)).contains("null");
+		assertThat(getNonNull(null, null)).isEmpty();
 	}
 
 	@Test