java - Drools - 检索输出对象

Question

我是 Kie Workbench 和执行服务器的新手。我正在使用 Java Rest 调用在 kie 工作台中运行规则。请找到下面的代码:

private String kieServerUrl;
private String kieServerContainerId;
private String KieServerUsername;
private String kieServerPassword;

private RuleServicesClient ruleClient;

private static final String INPUT_OUT_IDENTIFIER = "Input";
private static final String SESSION_OBJECTS = "SessionObjects";
private static final String RUN_ALL_RULES = "RunAllRules";

public void init() {
    final KieServicesConfiguration config = KieServicesFactory.newRestConfiguration(kieServerUrl, KieServerUsername, kieServerPassword);
    config.setMarshallingFormat(MarshallingFormat.XSTREAM);     
    KieServicesClient kieServicesClient = KieServicesFactory.newKieServicesClient(config);
    ruleClient = kieServicesClient.getServicesClient(RuleServicesClient.class); 
}


@Override
public Output process(final Input input) {
    Output output = null;

    logger.debug("Running rules ..");

    BatchExecutionCommandImpl executionCommand = new BatchExecutionCommandImpl();

    executionCommand.getCommands().add(new InsertObjectCommand(input, INPUT_OUT_IDENTIFIER));
    executionCommand.getCommands().add(new FireAllRulesCommand(RUN_ALL_RULES));
    executionCommand.getCommands().add(new GetObjectsCommand(null, SESSION_OBJECTS));

    logger.debug("Sending commands to the server");

    ServiceResponse<ExecutionResults> response = ruleClient.executeCommandsWithResults(kieServerContainerId, executionCommand);

    if(response.getType().equals(ServiceResponse.ResponseType.SUCCESS)){
        logger.debug("Commands executed with success! Response: ");

        final ExecutionResultImpl result = (ExecutionResultImpl) response.getResult();  
        ArrayList<Object> values = (ArrayList<Object>)result.getValue(SESSION_OBJECTS);
    }else{
        logger.error("Error executing rules. Message: {}", response.getMsg());
    }

    logger.debug("...finished running rules.");

    return output;
}

规则被正确执行，并且输出对象在规则期间被实例化。一个问题是，当我再次调用此方法第二次执行规则时，我收到两个输出对象，并且对于每个后续调用，我都会获得一个附加对象。 session 中的对象似乎已被存储，并且每次调用都不会被清除。如何才能实现每次调用都只得到一个输出对象作为返回？

Answer 1

由于您是 Drools 的新手，您可能不知道 Drools 有两种 session 类型:无状态和有状态。验证 KIE 执行服务器 session 配置是否无状态，因为有状态会保留先前请求处理中的事实。

通过项目编辑器中的设置验证其是否为无状态:

Open Project Editor -> Knowledge bases and sessions

查看现有的或创建一个:

Add Knowledge Sessions -> and set the State to Stateless