如何在 Drools DRL 运行时将事实添加到工作 memory 并在无状态 session 的执行结果中检索它们？

Question

背景：

我正在开发一个应用程序，该应用程序根据一组 drools 规则将输入 object 转换为两个 output 对象之一。 output object 直到运行时才知道，它是在第一个要执行的规则中创建的。

以下是创建 output object 的规则和示例转换规则：

rule "Initialization"
    dialect "java"
    salience 1000
    no-loop true
    when
        t : Trade()
    then 
        if(t.getTran().getInsType().equalsIgnoreCase("EEO") ||
           t.getTran().getInsType().equalsIgnoreCase("EEF"))
        {
            insert(new Option());
        }
        else
        {
            insert(new Swap());
        }
end

rule "Example Rule"
    dialect "java"
    when
        t : Trade()
        opt : Option()
    then
        opt.setCounterpartyName(t.getTran().getCParty());
end

这是调用规则的代码：

private void test(){
    for(File xmlFile : getXmlFilesFromDirectory(XML_DIRECTORY))
    {
        Trade trade = (Trade)unmarshall(xmlFile, Trade.class);

        KnowledgeBase kbase = readKnowledgeBase();

        StatelessKnowledgeSession ksession = kbase.newStatelessKnowledgeSession();
        KnowledgeRuntimeLogger logger = KnowledgeRuntimeLoggerFactory.newConsoleLogger(ksession);

        List<Command> commands = new ArrayList<Command>();
        commands.add(CommandFactory.newInsert(trade, "trade"));
        commands.add(CommandFactory.newFireAllRules());

        ExecutionResults results = ksession.execute(CommandFactory.newBatchExecution(commands));
        logger.close();
    }
 }

private static KnowledgeBase readKnowledgeBase() throws Exception 
{
    KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
    kbuilder.add(ResourceFactory.newClassPathResource("security-transformation.drl"), ResourceType.DRL);
    KnowledgeBuilderErrors errors = kbuilder.getErrors();
    if (errors.size() > 0) 
    {
        for (KnowledgeBuilderError error: errors) 
        {
            System.err.println(error);
        }

        throw new IllegalArgumentException("Could not parse knowledge.");
    }

    KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase();
    kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());
    return kbase;
}

问题：

当我执行规则时，我在返回的事实中没有收到 output object。 我收到交易 object 回来，但我没有取回选项或交换 object，这取决于第一条规则添加到工作 memory 中。

问题：

如何在运行时在 drl 中将事实添加到工作 memory 并在无状态 session 的执行结果中检索它们？

编辑：我需要使用流口水查询吗？

Answer 1

我继续使用drools 查询。 我会为其他出现的人发布代码。

查询添加到上述规则（对象扩展BaseTrade ）：

query "GetOutputObj"
    baseTrade: BaseTrade()
end

从执行结果中检索查询结果的代码：

    StatelessKnowledgeSession ksession = this.kbase.newStatelessKnowledgeSession();

    KnowledgeRuntimeLogger klogger = configureKnowledgeRuntimeLogger(ksession);

    List<Command> commands = new ArrayList<Command>();
    commands.add(CommandFactory.newInsert(inputObj, "inputObj"));
    commands.add(CommandFactory.newFireAllRules());
    commands.add(CommandFactory.newQuery("outputObj", "GetOutputObj"));

    ExecutionResults results = ksession.execute(CommandFactory.newBatchExecution(commands));

    QueryResults queryResults = ((NativeQueryResults)results.getValue("baseTrade")).getResults();

    try
    {
        Iterator iter = queryResults.iterator();
        while(iter.hasNext())
        {
            QueryResult result = iter.next();

            //There can be only one... just like Highlander
            //Could switch this up and return a list, but we only expect one thing from here.
            return (BaseTrade) result.get("baseTrade");
        }
    }
    finally
    {
        if(klogger != null)
        {
            klogger.close();
        }
    }