Add Builder for FactCheckingEvaluator (#4652)

Signed-off-by: guanxu <[email protected]>

Signed-off-by: Eric Bottard <[email protected]>

Author: guanxuc

spring-ai-client-chat/src/main/java/org/springframework/ai/chat/evaluation/FactCheckingEvaluator.java

@@ -22,6 +22,8 @@
 import org.springframework.ai.evaluation.EvaluationRequest;
 import org.springframework.ai.evaluation.EvaluationResponse;
 import org.springframework.ai.evaluation.Evaluator;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 
 /**
  * Implementation of {@link Evaluator} used to evaluate the factual accuracy of Large
@@ -59,6 +61,7 @@
  *
  * @author Eddú Meléndez
  * @author Mark Pollack
+ * @author guan xu
  * @see Evaluator
  * @see EvaluationRequest
  * @see EvaluationResponse
@@ -69,13 +72,20 @@ public class FactCheckingEvaluator implements Evaluator {
 	private static final String DEFAULT_EVALUATION_PROMPT_TEXT = """
 				Evaluate whether or not the following claim is supported by the provided document.
 				Respond with "yes" if the claim is supported, or "no" if it is not.
-				Document: \\n {document}\\n
-				Claim: \\n {claim}
+
+				Document:
+				{document}
+
+				Claim:
+				{claim}
 			""";
 
 	private static final String BESPOKE_EVALUATION_PROMPT_TEXT = """
-				Document: \\n {document}\\n
-				Claim: \\n {claim}
+				Document:
+				{document}
+
+				Claim:
+				{claim}
 			""";
 
 	private final ChatClient.Builder chatClientBuilder;
@@ -89,7 +99,7 @@ public class FactCheckingEvaluator implements Evaluator {
 	 * evaluation
 	 */
 	public FactCheckingEvaluator(ChatClient.Builder chatClientBuilder) {
-		this(chatClientBuilder, DEFAULT_EVALUATION_PROMPT_TEXT);
+		this(chatClientBuilder, null);
 	}
 
 	/**
@@ -99,9 +109,10 @@ public FactCheckingEvaluator(ChatClient.Builder chatClientBuilder) {
 	 * evaluation
 	 * @param evaluationPrompt The prompt text to use for evaluation
 	 */
-	public FactCheckingEvaluator(ChatClient.Builder chatClientBuilder, String evaluationPrompt) {
+	public FactCheckingEvaluator(ChatClient.Builder chatClientBuilder, @Nullable String evaluationPrompt) {
+		Assert.notNull(chatClientBuilder, "chatClientBuilder cannot be null");
 		this.chatClientBuilder = chatClientBuilder;
-		this.evaluationPrompt = evaluationPrompt;
+		this.evaluationPrompt = evaluationPrompt != null ? evaluationPrompt : DEFAULT_EVALUATION_PROMPT_TEXT;
 	}
 
 	/**
@@ -138,4 +149,33 @@ public EvaluationResponse evaluate(EvaluationRequest evaluationRequest) {
 		return new EvaluationResponse(passing, "", Collections.emptyMap());
 	}
 
+	public static FactCheckingEvaluator.Builder builder() {
+		return new FactCheckingEvaluator.Builder();
+	}
+
+	public static final class Builder {
+
+		private ChatClient.Builder chatClientBuilder;
+
+		private String evaluationPrompt;
+
+		private Builder() {
+		}
+
+		public FactCheckingEvaluator.Builder chatClientBuilder(ChatClient.Builder chatClientBuilder) {
+			this.chatClientBuilder = chatClientBuilder;
+			return this;
+		}
+
+		public FactCheckingEvaluator.Builder evaluationPrompt(String evaluationPrompt) {
+			this.evaluationPrompt = evaluationPrompt;
+			return this;
+		}
+
+		public FactCheckingEvaluator build() {
+			return new FactCheckingEvaluator(this.chatClientBuilder, this.evaluationPrompt);
+		}
+
+	}
+
 }

spring-ai-client-chat/src/test/java/org/springframework/ai/chat/evaluation/FactCheckingEvaluatorTests.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2023-2025 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.ai.chat.evaluation;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.ai.chat.client.ChatClient;
+import org.springframework.ai.chat.model.ChatModel;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Unit tests for {@link FactCheckingEvaluator}.
+ *
+ * @author guan xu
+ */
+class FactCheckingEvaluatorTests {
+
+	@Test
+	void whenChatClientBuilderIsNullThenThrow() {
+		assertThatThrownBy(() -> new FactCheckingEvaluator(null)).isInstanceOf(IllegalArgumentException.class)
+			.hasMessageContaining("chatClientBuilder cannot be null");
+
+		assertThatThrownBy(() -> FactCheckingEvaluator.builder().chatClientBuilder(null).build())
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessageContaining("chatClientBuilder cannot be null");
+	}
+
+	@Test
+	void whenEvaluationPromptIsNullThenUseDefaultEvaluationPromptText() {
+		FactCheckingEvaluator evaluator = new FactCheckingEvaluator(ChatClient.builder(mock(ChatModel.class)));
+		assertThat(evaluator).isNotNull();
+
+		evaluator = FactCheckingEvaluator.builder()
+			.chatClientBuilder(ChatClient.builder(mock(ChatModel.class)))
+			.build();
+		assertThat(evaluator).isNotNull();
+	}
+
+	@Test
+	void whenForBespokeMinicheckThenUseBespokeEvaluationPromptText() {
+		FactCheckingEvaluator evaluator = FactCheckingEvaluator
+			.forBespokeMinicheck(ChatClient.builder(mock(ChatModel.class)));
+		assertThat(evaluator).isNotNull();
+	}
+
+}