Add OutputParser

spring-ai-core/src/main/java/org/springframework/ai/parser/AbstractConversionServiceOutputParser.java

@@ -0,0 +1,17 @@
+package org.springframework.ai.parser;
+
+import org.springframework.core.convert.support.DefaultConversionService;
+
+public abstract class AbstractConversionServiceOutputParser<T> implements OutputParser<T> {
+
+	private final DefaultConversionService conversionService;
+
+	public AbstractConversionServiceOutputParser(DefaultConversionService conversionService) {
+		this.conversionService = conversionService;
+	}
+
+	public DefaultConversionService getConversionService() {
+		return conversionService;
+	}
+
+}

spring-ai-core/src/main/java/org/springframework/ai/parser/ListOutputParser.java

@@ -0,0 +1,29 @@
+package org.springframework.ai.parser;
+
+import org.springframework.core.convert.support.DefaultConversionService;
+
+import java.util.List;
+
+/**
+ * Parse out a List from a formatting request to convert a
+ */
+public class ListOutputParser extends AbstractConversionServiceOutputParser<List<String>> {
+
+	public ListOutputParser(DefaultConversionService defaultConversionService) {
+		super(defaultConversionService);
+	}
+
+	@Override
+	public String getFormat() {
+		return """
+				Your response should be a list of comma separated values
+				eg: `foo, bar, baz`
+				""";
+	}
+
+	@Override
+	public List<String> parse(String text) {
+		return getConversionService().convert(text, List.class);
+	}
+
+}

spring-ai-core/src/main/java/org/springframework/ai/parser/OutputParser.java

@@ -1,11 +1,23 @@
-package org.springframework.ai.parser;
-
-import org.springframework.ai.client.Generation;
+/*
+ * Copyright 2023 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.
+ */
 
-import java.util.List;
+package org.springframework.ai.parser;
 
-public interface OutputParser<T> {
+import org.springframework.ai.prompt.FormatProvider;
 
-	T parse(List<Generation> output);
+public interface OutputParser<T> extends Parser<T>, FormatProvider {
 
 }

spring-ai-core/src/main/java/org/springframework/ai/parser/Parser.java

@@ -0,0 +1,10 @@
+package org.springframework.ai.parser;
+
+import java.util.Locale;
+
+@FunctionalInterface
+public interface Parser<T> {
+
+	T parse(String text);
+
+}

spring-ai-core/src/main/java/org/springframework/ai/prompt/FormatProvider.java

@@ -0,0 +1,7 @@
+package org.springframework.ai.prompt;
+
+public interface FormatProvider {
+
+	String getFormat();
+
+}

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

@@ -18,6 +18,7 @@
 
 import org.antlr.runtime.Token;
 import org.antlr.runtime.TokenStream;
+import org.springframework.ai.parser.OutputParser;
 import org.springframework.ai.prompt.messages.Message;
 import org.springframework.ai.prompt.messages.UserMessage;
 import org.springframework.core.io.Resource;

spring-ai-core/src/test/java/org/springframework/ai/prompt/parsers/ListOutputParserTest.java

@@ -0,0 +1,21 @@
+package org.springframework.ai.prompt.parsers;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.ai.parser.ListOutputParser;
+import org.springframework.core.convert.support.DefaultConversionService;
+
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ListOutputParserTest {
+
+	@Test
+	void csv() {
+		String csvAsString = "foo, bar, baz";
+		ListOutputParser listOutputParser = new ListOutputParser(new DefaultConversionService());
+		List<String> list = listOutputParser.parse(csvAsString);
+		assertThat(list).containsExactlyElementsOf(List.of("foo", "bar", "baz"));
+	}
+
+}

spring-ai-openai/src/test/java/org/springframework/ai/openai/client/ClientIntegrationTests.java

@@ -1,7 +1,10 @@
 package org.springframework.ai.openai.client;
 
 import org.junit.jupiter.api.Test;
+import org.springframework.ai.client.AiClient;
 import org.springframework.ai.client.Generation;
+import org.springframework.ai.parser.OutputParser;
+import org.springframework.ai.parser.ListOutputParser;
 import org.springframework.ai.prompt.Prompt;
 import org.springframework.ai.prompt.PromptTemplate;
 import org.springframework.ai.prompt.SystemPromptTemplate;
@@ -11,6 +14,7 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.core.io.Resource;
 
 import java.util.List;
@@ -47,7 +51,6 @@ void roleTest() {
 		assertThat(response).isNotNull();
 
 		evaluateQuestionAndAnswer(request, response.getText());
-
 	}
 
 	private void evaluateQuestionAndAnswer(String question, String answer) {
@@ -61,4 +64,25 @@ private void evaluateQuestionAndAnswer(String question, String answer) {
 		assertThat(response.getText()).isEqualTo("YES");
 	}
 
+	@Test
+	void outputParser() {
+		DefaultConversionService conversionService = new DefaultConversionService();
+		ListOutputParser outputParser = new ListOutputParser(conversionService);
+
+		String format = outputParser.getFormat();
+		String template = """
+				List five {subject}
+				{format}
+				""";
+		PromptTemplate promptTemplate = new PromptTemplate(template,
+				Map.of("subject", "ice cream flavors", "format", format));
+		Prompt prompt = new Prompt(promptTemplate.createMessage());
+		Generation generation = openAiClient.generate(prompt).getGeneration();
+
+		List<String> list = outputParser.parse(generation.getText());
+		System.out.println(list);
+		assertThat(list).hasSize(5);
+
+	}
+
 }