Refine null-safety for additional Assert methods

Closes gh-33530

Author: sdeleuze

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -58,6 +58,7 @@
  * @author Sam Brannen
  * @author Colin Sampaleanu
  * @author Rob Harrop
+ * @author Sebastien Deleuze
  * @since 1.1.2
  */
 public abstract class Assert {
@@ -209,6 +210,7 @@ public static void notNull(@Nullable Object object, Supplier<String> messageSupp
 	 * @throws IllegalArgumentException if the text is empty
 	 * @see StringUtils#hasLength
 	 */
+	@Contract("null, _ -> fail")
 	public static void hasLength(@Nullable String text, String message) {
 		if (!StringUtils.hasLength(text)) {
 			throw new IllegalArgumentException(message);
@@ -229,6 +231,7 @@ public static void hasLength(@Nullable String text, String message) {
 	 * @since 5.0
 	 * @see StringUtils#hasLength
 	 */
+	@Contract("null, _ -> fail")
 	public static void hasLength(@Nullable String text, Supplier<String> messageSupplier) {
 		if (!StringUtils.hasLength(text)) {
 			throw new IllegalArgumentException(nullSafeGet(messageSupplier));
@@ -244,6 +247,7 @@ public static void hasLength(@Nullable String text, Supplier<String> messageSupp
 	 * @throws IllegalArgumentException if the text does not contain valid text content
 	 * @see StringUtils#hasText
 	 */
+	@Contract("null, _ -> fail")
 	public static void hasText(@Nullable String text, String message) {
 		if (!StringUtils.hasText(text)) {
 			throw new IllegalArgumentException(message);
@@ -264,6 +268,7 @@ public static void hasText(@Nullable String text, String message) {
 	 * @since 5.0
 	 * @see StringUtils#hasText
 	 */
+	@Contract("null, _ -> fail")
 	public static void hasText(@Nullable String text, Supplier<String> messageSupplier) {
 		if (!StringUtils.hasText(text)) {
 			throw new IllegalArgumentException(nullSafeGet(messageSupplier));
@@ -387,6 +392,7 @@ public static void noNullElements(@Nullable Object[] array, Supplier<String> mes
 	 * @throws IllegalArgumentException if the collection is {@code null} or
 	 * contains no elements
 	 */
+	@Contract("null, _ -> fail")
 	public static void notEmpty(@Nullable Collection<?> collection, String message) {
 		if (CollectionUtils.isEmpty(collection)) {
 			throw new IllegalArgumentException(message);
@@ -406,6 +412,7 @@ public static void notEmpty(@Nullable Collection<?> collection, String message)
 	 * contains no elements
 	 * @since 5.0
 	 */
+	@Contract("null, _ -> fail")
 	public static void notEmpty(@Nullable Collection<?> collection, Supplier<String> messageSupplier) {
 		if (CollectionUtils.isEmpty(collection)) {
 			throw new IllegalArgumentException(nullSafeGet(messageSupplier));
@@ -461,6 +468,7 @@ public static void noNullElements(@Nullable Collection<?> collection, Supplier<S
 	 * @param message the exception message to use if the assertion fails
 	 * @throws IllegalArgumentException if the map is {@code null} or contains no entries
 	 */
+	@Contract("null, _ -> fail")
 	public static void notEmpty(@Nullable Map<?, ?> map, String message) {
 		if (CollectionUtils.isEmpty(map)) {
 			throw new IllegalArgumentException(message);
@@ -479,6 +487,7 @@ public static void notEmpty(@Nullable Map<?, ?> map, String message) {
 	 * @throws IllegalArgumentException if the map is {@code null} or contains no entries
 	 * @since 5.0
 	 */
+	@Contract("null, _ -> fail")
 	public static void notEmpty(@Nullable Map<?, ?> map, Supplier<String> messageSupplier) {
 		if (CollectionUtils.isEmpty(map)) {
 			throw new IllegalArgumentException(nullSafeGet(messageSupplier));
@@ -497,6 +506,7 @@ public static void notEmpty(@Nullable Map<?, ?> map, Supplier<String> messageSup
 	 * of the offending object's type will be appended.
 	 * @throws IllegalArgumentException if the object is not an instance of type
 	 */
+	@Contract("_, null, _ -> fail")
 	public static void isInstanceOf(Class<?> type, @Nullable Object obj, String message) {
 		notNull(type, "Type to check against must not be null");
 		if (!type.isInstance(obj)) {
@@ -516,6 +526,7 @@ public static void isInstanceOf(Class<?> type, @Nullable Object obj, String mess
 	 * @throws IllegalArgumentException if the object is not an instance of type
 	 * @since 5.0
 	 */
+	@Contract("_, null, _ -> fail")
 	public static void isInstanceOf(Class<?> type, @Nullable Object obj, Supplier<String> messageSupplier) {
 		notNull(type, "Type to check against must not be null");
 		if (!type.isInstance(obj)) {
@@ -530,6 +541,7 @@ public static void isInstanceOf(Class<?> type, @Nullable Object obj, Supplier<St
 	 * @param obj the object to check
 	 * @throws IllegalArgumentException if the object is not an instance of type
 	 */
+	@Contract("_, null -> fail")
 	public static void isInstanceOf(Class<?> type, @Nullable Object obj) {
 		isInstanceOf(type, obj, "");
 	}
@@ -546,6 +558,7 @@ public static void isInstanceOf(Class<?> type, @Nullable Object obj) {
 	 * offending subtype will be appended.
 	 * @throws IllegalArgumentException if the classes are not assignable
 	 */
+	@Contract("_, null, _ -> fail")
 	public static void isAssignable(Class<?> superType, @Nullable Class<?> subType, String message) {
 		notNull(superType, "Supertype to check against must not be null");
 		if (subType == null || !superType.isAssignableFrom(subType)) {
@@ -565,6 +578,7 @@ public static void isAssignable(Class<?> superType, @Nullable Class<?> subType,
 	 * @throws IllegalArgumentException if the classes are not assignable
 	 * @since 5.0
 	 */
+	@Contract("_, null, _ -> fail")
 	public static void isAssignable(Class<?> superType, @Nullable Class<?> subType, Supplier<String> messageSupplier) {
 		notNull(superType, "Supertype to check against must not be null");
 		if (subType == null || !superType.isAssignableFrom(subType)) {
@@ -579,7 +593,8 @@ public static void isAssignable(Class<?> superType, @Nullable Class<?> subType,
 	 * @param subType the subtype to check
 	 * @throws IllegalArgumentException if the classes are not assignable
 	 */
-	public static void isAssignable(Class<?> superType, Class<?> subType) {
+	@Contract("_, null -> fail")
+	public static void isAssignable(Class<?> superType, @Nullable Class<?> subType) {
 		isAssignable(superType, subType, "");
 	}