Delegate config map of lists

[kevhender]

Hi,

I'm trying to use a map of lists inside of an ActionHandler, but I am not able to correctly configure the list; I get an error saying that it cannot convert a String to a List. Here is the config:

...
<action name="my-action" class="com.sample.action.MyActionHandler">
 <fields>
 <entry>
 <key>one</key>
 <value>
 <list>
 <element>one-1</element>
 <element>one-2</element>
 </list>
 </value>
 </entry>
 <entry>
 <key>two</key>
 <value>
 <list>
 <element>two-1</element>
 <element>two-2</element>
 </list>
 </value>
 </entry>
 </fields>
</action>
...

public class MyActionHandler implements ActionHandler {

 private Map<String, List<String>> fields;

 @Override
 public void execute(ExecutionContext context) throws Exception {
 ...
 }

 public Map<String, List<String>> getFields() {
 return fields;
 }

 public void setFields(Map<String, List<String>> fields) {
 this.fields = fields;
 }

}

Here is the stack trace:

16:52:38,732 [main] ERROR GraphElement : action threw exception: java.lang.String cannot be cast to java.util.List
java.lang.ClassCastException: java.lang.String cannot be cast to java.util.List
 at com.sample.action.MysActionHandler.execute(CheckRequiredFieldsActionHandler.java:17)
 at org.jbpm.graph.def.Action.execute(Action.java:122)
 at org.jbpm.graph.def.GraphElement.executeAction(GraphElement.java:259)
 at org.jbpm.graph.def.GraphElement.executeActions(GraphElement.java:215)
 at org.jbpm.graph.def.GraphElement.fireAndPropagateEvent(GraphElement.java:185)
 at org.jbpm.graph.def.GraphElement.fireEvent(GraphElement.java:169)
 at org.jbpm.taskmgmt.exe.TaskInstance.end(TaskInstance.java:452)
 at org.jbpm.taskmgmt.exe.TaskInstance.end(TaskInstance.java:393)
 at com.sample.SimpleProcessTest.executeTask(SimpleProcessTest.java:103)

Does anyone know why this won't work? Thanks...

[kukeltje]

correct. afaik, the 'value' can only contain Strings, or the likes, no maps, lists etc...

[kevhender]

Can you clarify what this part of the documentation means?

maps. In this case, each element of the field-element is expected to have one subelement key and one element value. The key and element are both parsed using the conversion rules recursively. Just the same as with collections, a conversion to java.lang.String is assumed if no type attribute is specified.

(from http://docs.jboss.org/jbpm/v3/userguide/jpdl.html#configtypefield)

I would have figured that parsing the elements recursively meant that the elements could any type, and that they'd be parsed like a base element. Maybe I'm misinterpreting what the docs are saying?

Thanks again....

[kukeltje]

Yes, you are 'misinterpreting' the docs. You can pass in maps, collections etc, but each value can only be a simple type (String, Integer etc, but no map, list, collection)

You *can* pass in arbitrary complex XML structures that will be converted to Document if you use that as the type in your class