Enhance SafeGuardAdvisor with customizable failure response

 - Add customizable failure response instead of empty result
 - Add order parameter for advisor prioritization
 - Implement default values for failure response and order
 - Introduce builder pattern for flexible configuration

 Resolves #1393

Author: tzolov

spring-ai-core/src/main/java/org/springframework/ai/chat/client/advisor/SafeGuardAdvisor.java

@@ -19,11 +19,14 @@
 
 import org.springframework.ai.chat.client.advisor.api.AdvisedRequest;
 import org.springframework.ai.chat.client.advisor.api.AdvisedResponse;
-import org.springframework.ai.chat.client.advisor.api.CallAroundAdvisorChain;
 import org.springframework.ai.chat.client.advisor.api.CallAroundAdvisor;
+import org.springframework.ai.chat.client.advisor.api.CallAroundAdvisorChain;
 import org.springframework.ai.chat.client.advisor.api.StreamAroundAdvisor;
 import org.springframework.ai.chat.client.advisor.api.StreamAroundAdvisorChain;
+import org.springframework.ai.chat.messages.AssistantMessage;
 import org.springframework.ai.chat.model.ChatResponse;
+import org.springframework.ai.chat.model.Generation;
+import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
 
 import reactor.core.publisher.Flux;
@@ -37,10 +40,26 @@
  */
 public class SafeGuardAdvisor implements CallAroundAdvisor, StreamAroundAdvisor {
 
+	private final static String DEFAULT_FAILURE_RESPONSE = "I'm unable to respond to that due to sensitive content. Could we rephrase or discuss something else?";
+
+	private final static int DEFAULT_ORDER = 0;
+
+	private final String failureResponse;
+
 	private final List<String> sensitiveWords;
 
+	private final int order;
+
 	public SafeGuardAdvisor(List<String> sensitiveWords) {
+		this(sensitiveWords, DEFAULT_FAILURE_RESPONSE, DEFAULT_ORDER);
+	}
+
+	public SafeGuardAdvisor(List<String> sensitiveWords, String failureResponse, int order) {
+		Assert.notNull(sensitiveWords, "Sensitive words must not be null!");
+		Assert.notNull(failureResponse, "Failure response must not be null!");
 		this.sensitiveWords = sensitiveWords;
+		this.failureResponse = failureResponse;
+		this.order = order;
 	}
 
 	public String getName() {
@@ -51,9 +70,9 @@ public String getName() {
 	public AdvisedResponse aroundCall(AdvisedRequest advisedRequest, CallAroundAdvisorChain chain) {
 
 		if (!CollectionUtils.isEmpty(this.sensitiveWords)
-				&& sensitiveWords.stream().anyMatch(w -> advisedRequest.userText().contains(w))) {
-			return new AdvisedResponse(ChatResponse.builder().withGenerations(List.of()).build(),
-					advisedRequest.adviseContext());
+				&& this.sensitiveWords.stream().anyMatch(w -> advisedRequest.userText().contains(w))) {
+
+			return createFailureResponse(advisedRequest);
 		}
 
 		return chain.nextAroundCall(advisedRequest);
@@ -64,16 +83,57 @@ public Flux<AdvisedResponse> aroundStream(AdvisedRequest advisedRequest, StreamA
 
 		if (!CollectionUtils.isEmpty(this.sensitiveWords)
 				&& sensitiveWords.stream().anyMatch(w -> advisedRequest.userText().contains(w))) {
-			return Flux.empty();
+			return Flux.just(createFailureResponse(advisedRequest));
 		}
 
 		return chain.nextAroundStream(advisedRequest);
+	}
 
+	private AdvisedResponse createFailureResponse(AdvisedRequest advisedRequest) {
+		return new AdvisedResponse(ChatResponse.builder()
+			.withGenerations(List.of(new Generation(new AssistantMessage(this.failureResponse))))
+			.build(), advisedRequest.adviseContext());
 	}
 
 	@Override
 	public int getOrder() {
-		return 0;
+		return this.order;
+	}
+
+	public static Builder builder() {
+		return new Builder();
+	}
+
+	public static class Builder {
+
+		private List<String> sensitiveWords;
+
+		private String failureResponse = DEFAULT_FAILURE_RESPONSE;
+
+		private int order = DEFAULT_ORDER;
+
+		private Builder() {
+		}
+
+		public Builder withSensitiveWords(List<String> sensitiveWords) {
+			this.sensitiveWords = sensitiveWords;
+			return this;
+		}
+
+		public Builder withFailureResponse(String failureResponse) {
+			this.failureResponse = failureResponse;
+			return this;
+		}
+
+		public Builder withOrder(int order) {
+			this.order = order;
+			return this;
+		}
+
+		public SafeGuardAdvisor build() {
+			return new SafeGuardAdvisor(this.sensitiveWords, this.failureResponse, this.order);
+		}
+
 	}
 
 }