Parallel Node Execution

In Graph, when the current node doesn’t depend on upstream node results, it can be processed in parallel

The practical code can be found at: spring-ai-alibaba-examples under the graph directory. This chapter is in the parallel-node module.

pom.xml

Here we use version 1.0.0.3-SNAPSHOT. There are some changes in StateGraph definition compared to 1.0.0.2

<properties>
    <spring-ai-alibaba.version>1.0.0.3-SNAPSHOT</spring-ai-alibaba.version>
</properties>

<dependencies>

    <dependency>
        <groupId>org.springframework.ai</groupId>
        <artifactId>spring-ai-autoconfigure-model-openai</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.ai</groupId>
        <artifactId>spring-ai-autoconfigure-model-chat-client</artifactId>
    </dependency>

    <dependency>
        <groupId>com.alibaba.cloud.ai</groupId>
        <artifactId>spring-ai-alibaba-graph-core</artifactId>
        <version>${spring-ai-alibaba.version}</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>

application.yml

server:
  port: 8080
spring:
  application:
    name: simple
  ai:
    openai:
      api-key: ${AIDASHSCOPEAPIKEY}
      base-url: https://dashscope.aliyuncs.com/compatible-mode
      chat:
        options:
          model: qwen-max

config

Fields stored in OverAllState:

query: user’s question
expandernumber: number of expansions
expandercontent: expansion content
translatelanguage: target language for translation
translatecontent: translated content
mergeresult: result after merging expansion node and translation node

Define ExpanderNode, TranslateNode, and internally define MergeResultsNode

The edges connect as follows:

START -> expander -> merge
START -> translate -> merge

merge -> END

package com.spring.ai.tutorial.graph.parallel.config;

import com.alibaba.cloud.ai.graph.GraphRepresentation;
import com.alibaba.cloud.ai.graph.KeyStrategy;
import com.alibaba.cloud.ai.graph.KeyStrategyFactory;
import com.alibaba.cloud.ai.graph.OverAllState;
import com.alibaba.cloud.ai.graph.StateGraph;
import com.alibaba.cloud.ai.graph.action.NodeAction;
import com.alibaba.cloud.ai.graph.exception.GraphStateException;
import com.alibaba.cloud.ai.graph.state.strategy.ReplaceStrategy;
import com.spring.ai.tutorial.graph.parallel.node.ExpanderNode;
import com.spring.ai.tutorial.graph.parallel.node.TranslateNode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.ai.chat.client.ChatClient;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.HashMap;
import java.util.Map;

import static com.alibaba.cloud.ai.graph.action.AsyncNodeAction.nodeasync;

/**
 * @author yingzi
 * @since 2025/6/13
 */
@Configuration
public class ParallelGraphConfiguration {

    private static final Logger logger = LoggerFactory.getLogger(ParallelGraphConfiguration.class);

    @Bean
    public StateGraph parallelGraph(ChatClient.Builder chatClientBuilder) throws GraphStateException {
        KeyStrategyFactory keyStrategyFactory = () -> {
            HashMap<String, KeyStrategy> keyStrategyHashMap = new HashMap<>();

            // User input
            keyStrategyHashMap.put("query", new ReplaceStrategy());

            keyStrategyHashMap.put("expandernumber", new ReplaceStrategy());
            keyStrategyHashMap.put("expandercontent", new ReplaceStrategy());

            keyStrategyHashMap.put("translatelanguage", new ReplaceStrategy());
            keyStrategyHashMap.put("translatecontent", new ReplaceStrategy());

            keyStrategyHashMap.put("mergeresult", new ReplaceStrategy());

            return keyStrategyHashMap;
        };

        StateGraph stateGraph = new StateGraph(keyStrategyFactory)
                .addNode("expander", nodeasync(new ExpanderNode(chatClientBuilder)))
                .addNode("translate", nodeasync(new TranslateNode(chatClientBuilder)))
                .addNode("merge", nodeasync(new MergeResultsNode()))

                .addEdge(StateGraph.START, "expander")
                .addEdge(StateGraph.START, "translate")
                .addEdge("translate", "merge")
                .addEdge("expander", "merge")

                .addEdge("merge", StateGraph.END);

        // Add PlantUML printing
        GraphRepresentation representation = stateGraph.getGraph(GraphRepresentation.Type.PLANTUML,
                "expander flow");
        logger.info("\n=== expander UML Flow ===");
        logger.info(representation.content());
        logger.info("==================================\n");

        return stateGraph;
    }

    private record MergeResultsNode() implements NodeAction {
        @Override
        public Map<String, Object> apply(OverAllState state) {
            Object expanderContent = state.value("expandercontent").orElse("unknown");
            String translateContent = (String) state.value("translatecontent").orElse("");

            return Map.of("mergeresult", Map.of("expandercontent", expanderContent,
                    "translatecontent", translateContent));
        }
    }
}

node

ExpanderNode

PromptTemplate DEFAULTPROMPTTEMPLATE: prompt for text expansion
ChatClient chatClient: client for calling the AI model
Integer NUMBER: default expansion of 3 similar questions

The response content from the AI model is finally returned to the expandercontent field

package com.spring.ai.tutorial.graph.node;

import com.alibaba.cloud.ai.graph.NodeOutput;
import com.alibaba.cloud.ai.graph.OverAllState;
import com.alibaba.cloud.ai.graph.action.NodeAction;
import com.alibaba.cloud.ai.graph.streaming.StreamingChatGenerator;
import org.bsc.async.AsyncGenerator;
import org.springframework.ai.chat.client.ChatClient;
import org.springframework.ai.chat.model.ChatResponse;
import org.springframework.ai.chat.prompt.PromptTemplate;
import reactor.core.publisher.Flux;

import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


public class ExpanderNode implements NodeAction {

    private static final PromptTemplate DEFAULTPROMPTTEMPLATE = new PromptTemplate("You are an expert at information retrieval and search optimization.\nYour task is to generate {number} different versions of the given query.\n\nEach variant must cover different perspectives or aspects of the topic,\nwhile maintaining the core intent of the original query. The goal is to\nexpand the search space and improve the chances of finding relevant information.\n\nDo not explain your choices or add any other text.\nProvide the query variants separated by newlines.\n\nOriginal query: {query}\n\nQuery variants:\n");

    private final ChatClient chatClient;

    private final Integer NUMBER = 3;

    public ExpanderNode(ChatClient.Builder chatClientBuilder) {
        this.chatClient = chatClientBuilder.build();
    }

    @Override
    public Map<String, Object> apply(OverAllState state) throws Exception {
        String query = state.value("query", "");
        Integer expanderNumber = state.value("expandernumber", this.NUMBER);


        Flux<String> streamResult = this.chatClient.prompt().user((user) -> user.text(DEFAULTPROMPTTEMPLATE.getTemplate()).param("number", expanderNumber).param("query", query)).stream().content();
        String result = streamResult.reduce("", (acc, item) -> acc + item).block();
        List<String> queryVariants = Arrays.asList(result.split("\n"));

        HashMap<String, Object> resultMap = new HashMap<>();
        resultMap.put("expandercontent", queryVariants);
        return resultMap;
    }
}

TranslateNode

PromptTemplate DEFAULTPROMPTTEMPLATE: prompt for text translation
ChatClient chatClient: client for calling the AI model
String TARGETLANGUAGE: default translation language is English

The response content from the AI model is finally returned to the translatecontent field

package com.spring.ai.tutorial.graph.parallel.node;

import com.alibaba.cloud.ai.graph.OverAllState;
import com.alibaba.cloud.ai.graph.action.NodeAction;
import org.springframework.ai.chat.client.ChatClient;
import org.springframework.ai.chat.prompt.PromptTemplate;
import reactor.core.publisher.Flux;

import java.util.HashMap;
import java.util.Map;


public class TranslateNode implements NodeAction {

    private static final PromptTemplate DEFAULTPROMPTTEMPLATE = new PromptTemplate("Given a user query, translate it to {targetLanguage}.\nIf the query is already in {targetLanguage}, return it unchanged.\nIf you don't know the language of the query, return it unchanged.\nDo not add explanations nor any other text.\n\nOriginal query: {query}\n\nTranslated query:\n");

    private final ChatClient chatClient;

    private final String  TARGETLANGUAGE= "English";

    public TranslateNode(ChatClient.Builder chatClientBuilder) {
        this.chatClient = chatClientBuilder.build();
    }

    @Override
    public Map<String, Object> apply(OverAllState state) throws Exception {
        String query = state.value("query", "");
        String targetLanguage = state.value("translatelanguage", TARGETLANGUAGE);

        Flux<String> streamResult = this.chatClient.prompt().user((user) -> user.text(DEFAULTPROMPTTEMPLATE.getTemplate()).param("targetLanguage", targetLanguage).param("query", query)).stream().content();
        String result = streamResult.reduce("", (acc, item) -> acc + item).block();

        HashMap<String, Object> resultMap = new HashMap<>();
        resultMap.put("translatecontent", result);
        return resultMap;
    }
}

MergeResultsNode

Places the results processed by ExpanderNode and TranslateNode into the mergeresult field

private record MergeResultsNode() implements NodeAction {
    @Override
    public Map<String, Object> apply(OverAllState state) {
        Object expanderContent = state.value("expandercontent").orElse("unknown");
        String translateContent = (String) state.value("translatecontent").orElse("");

        return Map.of("mergeresult", Map.of("expandercontent", expanderContent,
                "translatecontent", translateContent));
    }
}

controller

package com.spring.ai.tutorial.graph.parallel.controller;

import com.alibaba.cloud.ai.graph.CompiledGraph;
import com.alibaba.cloud.ai.graph.OverAllState;
import com.alibaba.cloud.ai.graph.RunnableConfig;
import com.alibaba.cloud.ai.graph.StateGraph;
import com.alibaba.cloud.ai.graph.exception.GraphStateException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;
import java.util.Map;
import java.util.Optional;

@RestController
@RequestMapping("/graph/parallel")
public class ParallelController {

    private static final Logger logger = LoggerFactory.getLogger(ParallelController.class);

    private final CompiledGraph compiledGraph;

    public ParallelController(@Qualifier("parallelGraph") StateGraph stateGraph) throws GraphStateException {
        this.compiledGraph = stateGraph.compile();
    }

    @GetMapping(value = "/expand-translate")
    public Map<String, Object> expandAndTranslate(@RequestParam(value = "query", defaultValue = "你好，很高兴认识你，能简单介绍一下自己吗？", required = false) String query,
                                      @RequestParam(value = "expandernumber", defaultValue = "3", required = false) Integer  expanderNumber,
                                      @RequestParam(value = "translatelanguage", defaultValue = "english", required = false) String translateLanguage,
                                      @RequestParam(value = "threadid", defaultValue = "yingzi", required = false) String threadId){
        RunnableConfig runnableConfig = RunnableConfig.builder().threadId(threadId).build();
        Map<String, Object> objectMap = new HashMap<>();
        objectMap.put("query", query);
        objectMap.put("expandernumber", expanderNumber);
        objectMap.put("translatelanguage", translateLanguage);

        Optional<OverAllState> invoke = this.compiledGraph.invoke(objectMap, runnableConfig);

        return invoke.map(OverAllState::data).orElse(new HashMap<>());
    }

}