Replace instanceof check and cast with pattern matching (#3979)

Signed-off-by: Mengqi Xu <[email protected]>

Author: remeio

spring-ai-model/src/main/java/org/springframework/ai/chat/prompt/PromptTemplate.java

@@ -111,8 +111,8 @@ public String render() {
 		// Process internal variables to handle Resources before rendering
 		Map<String, Object> processedVariables = new HashMap<>();
 		for (Entry<String, Object> entry : this.variables.entrySet()) {
-			if (entry.getValue() instanceof Resource) {
-				processedVariables.put(entry.getKey(), renderResource((Resource) entry.getValue()));
+			if (entry.getValue() instanceof Resource resource) {
+				processedVariables.put(entry.getKey(), renderResource(resource));
 			}
 			else {
 				processedVariables.put(entry.getKey(), entry.getValue());
@@ -126,8 +126,8 @@ public String render(Map<String, Object> additionalVariables) {
 		Map<String, Object> combinedVariables = new HashMap<>(this.variables);
 
 		for (Entry<String, Object> entry : additionalVariables.entrySet()) {
-			if (entry.getValue() instanceof Resource) {
-				combinedVariables.put(entry.getKey(), renderResource((Resource) entry.getValue()));
+			if (entry.getValue() instanceof Resource resource) {
+				combinedVariables.put(entry.getKey(), renderResource(resource));
 			}
 			else {
 				combinedVariables.put(entry.getKey(), entry.getValue());

spring-ai-model/src/main/java/org/springframework/ai/util/json/JsonParser.java

@@ -116,8 +116,8 @@ private static boolean isValidJson(String input) {
 	 * Converts a Java object to a JSON string if it's not already a valid JSON string.
 	 */
 	public static String toJson(@Nullable Object object) {
-		if (object instanceof String && isValidJson((String) object)) {
-			return (String) object;
+		if (object instanceof String str && isValidJson(str)) {
+			return str;
 		}
 		try {
 			return OBJECT_MAPPER.writeValueAsString(object);