Mule 从组件返回 MessageCollection

Question

我在从组件返回 MuleMessage 实例集合时遇到了困难。

骡子 3.3.1.

以下代码有效（即，在组件之后，带有记录器的 foreach 组件按照我的预期转储出“abc”和“def”）。

public Object onCall( MuleEventContext eventContext ) throws Exception 
{
    MuleMessage message = eventContext.getMessage();

    MuleMessageCollection collection = new DefaultMessageCollection( message.getMuleContext() );

    String s1 = "abc";
    String s2 = "def";
    DefaultMuleMessage m1 = new DefaultMuleMessage( s1, message.getMuleContext() );
    DefaultMuleMessage m2 = new DefaultMuleMessage( s2, message.getMuleContext() );
    List<MuleMessage> list = new ArrayList<MuleMessage>();
    list.add( m1 );
    list.add( m2 );

    collection.addMessages( list );

    return collection;
}

但是，如果我用我自己的类代替字符串，如下所示：

public Object onCall( MuleEventContext eventContext ) throws Exception 
{
    MuleMessage message = eventContext.getMessage();

    MuleMessageCollection collection = new DefaultMessageCollection( message.getMuleContext() );

    LicenseRequest s1 = new LicenseRequest();
    LicenseRequest s2 = new LicenseRequest();
    DefaultMuleMessage m1 = new DefaultMuleMessage( s1, message.getMuleContext() );
    DefaultMuleMessage m2 = new DefaultMuleMessage( s2, message.getMuleContext() );
    List<MuleMessage> list = new ArrayList<MuleMessage>();
    list.add( m1 );
    list.add( m2 );

    collection.addMessages( list );

    return collection;
}

我得到一个例外：

org.mule.transport.http.HttpsConnector Work caused exception on 'workCompleted'. Work being executed was: org.mule.transport.http.HttpsMessageReceiver$HttpsWorker@7b921c57
org.mule.exception.DefaultSystemExceptionStrategy Caught exception in Exception Strategy: Payload was invalidated calling setPayload and the message is not collection anymore.
java.lang.IllegalStateException: Payload was invalidated calling setPayload and the message is not collection anymore.
    at org.mule.DefaultMessageCollection.checkValidPayload(DefaultMessageCollection.java:107)
    at org.mule.DefaultMessageCollection.newThreadCopy(DefaultMessageCollection.java:312)
    at org.mule.DefaultMuleEvent.newThreadCopy(DefaultMuleEvent.java:779)
    at org.mule.RequestContext.newEvent(RequestContext.java:140)
    at org.mule.RequestContext.setExceptionPayload(RequestContext.java:121)
    at org.mule.exception.AbstractSystemExceptionStrategy.handleException(AbstractSystemExceptionStrategy.java:54)
    at org.mule.exception.AbstractSystemExceptionStrategy.handleException(AbstractSystemExceptionStrategy.java:77)
    at org.mule.transport.http.HttpMessageReceiver$HttpWorker.run(HttpMessageReceiver.java:220)
    at org.mule.work.WorkerContext.run(WorkerContext.java:311)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)
Exception in thread "[license-generation].HTTPSConnector.receiver.02" java.lang.IllegalStateException: Payload was invalidated calling setPayload and the message is not collection anymore.
    at org.mule.DefaultMessageCollection.checkValidPayload(DefaultMessageCollection.java:107)
    at org.mule.DefaultMessageCollection.newThreadCopy(DefaultMessageCollection.java:312)
    at org.mule.DefaultMuleEvent.newThreadCopy(DefaultMuleEvent.java:779)
    at org.mule.RequestContext.newEvent(RequestContext.java:140)
    at org.mule.RequestContext.setExceptionPayload(RequestContext.java:121)
    at org.mule.exception.AbstractSystemExceptionStrategy.handleException(AbstractSystemExceptionStrategy.java:54)
    at org.mule.exception.AbstractSystemExceptionStrategy.handleException(AbstractSystemExceptionStrategy.java:77)
    at org.mule.transport.AbstractConnector.handleWorkException(AbstractConnector.java:2099)
    at org.mule.transport.AbstractConnector.workCompleted(AbstractConnector.java:2067)
    at org.mule.work.WorkerContext.run(WorkerContext.java:338)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)

在我的测试中，LicenseRequest 只是一个空类，其 toString() 方法返回“ghi”。

我做错了什么？

我应该补充一点，我的目标是返回从传入有效负载创建的对象集合。然后，我可以在调用流程中迭代这些对象并为每个对象采取适当的操作。

编辑：看来我可以在变压器中做我想做的事，而不是一个组件。这是为什么呢？

Answer 1

我想不需要将每个 LicenseRequest 对象包装到 mule 消息中并将其添加到集合中。直接做一个集合，从onCall方法中返回。

public Object onCall( MuleEventContext eventContext ) throws Exception 
{
    MuleMessage message = eventContext.getMessage();

    LicenseRequest s1 = new LicenseRequest();
    LicenseRequest s2 = new LicenseRequest();

    List<LicenseRequest> list = new ArrayList<LicenseRequest>();
    list.add( s1 );
    list.add( s2 );

    return list;
}

希望这会有所帮助。