xpath-splitter and empty xpath result

[Alexey Pomelov]

Hello.

My goal is to process some XML like

  <items>
    <item>value1</item>
    <item>value2</item>
    <item>value3</item>
  </items>

And convert it to a List of my beans that could be created with static MyBean.create(String).
Here is a context fragment:

    <int:chain input-channel="..." output-channel="...">
        <int-xml:xpath-splitter>
            <int-xml:xpath-expression expression="/items/item" />
        </int-xml:xpath-splitter>
        <int-xml:xpath-transformer evaluation-type="STRING_RESULT" xpath-expression="/" />
        <int:transformer expression="T(MyBean).create(payload)" />
        <int:aggregator />        
    </int:chain>

It works quite well when the input message contains some items. But I'm failed to get an empty list when the message doesn't contains any items.
As far as I understand from code, XPathMessageSplitter throws an exception when the result collection is empty. Is there any way to work around that?

Regards,
-- Alexey

[Gary Russell]

Add an xpath-filter upstream of the splitter...

    <int:chain input-channel="..." output-channel="...">
        <int-xml:xpath-filter>
            <int-xml:xpath-expression expression="/items/item" />
        </int-xml:xpath-filter>
        <int-xml:xpath-splitter>
            <int-xml:xpath-expression expression="/items/item" />
        </int-xml:xpath-splitter>
        <int-xml:xpath-transformer evaluation-type="STRING_RESULT" xpath-expression="/" />
        <int:transformer expression="T(MyBean).create(payload)" />
        <int:aggregator />        
    </int:chain>

[Alexey Pomelov]

I'm using a gateway around that chain and it is not happy, when filter gobbles the request. I've added an xpath-router to check if there are any items or not. If no, I manually generate an empty list.