Diagram is not generated when using expression in CallActivity

[spawnrider]

Hi,

I created a simple working process with a CallActivity at the end. See the workflow below :
[img]data:image/jpeg;base64,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[/img]

Depending of the router task (Businnes Rule task) return value, I execute a specific process. This process is defined at the runtime, so the CallActivity calledElement contains an expression like this :

<callActivity id="callActivity" name="Call Activity" calledElement="${execution.getVariable('result').get(0).get('processKey')}">‍

When I deploy my process into Activiti, the diagram is not generated. See below : 
[img]http://s3.kkloud.com.s3.amazonaws.com/gett/1YtSuZE2/process.png.client.x675.png?AWSAccessKeyId=AKIAI...[/img]

The associated stacktrace is :

SEVERE: Servlet.service() for servlet [dispatcher] in context with path [/activiti-explorer] threw exception [Request processing failed; nested exception is org.activiti.engine.ActivitiIllegalArgumentException: key is null] with root cause
org.activiti.engine.ActivitiIllegalArgumentException: key is null
   at org.activiti.engine.impl.ProcessDefinitionQueryImpl.processDefinitionKey(ProcessDefinitionQueryImpl.java:129)
   at org.activiti.engine.impl.ProcessDefinitionQueryImpl.processDefinitionKey(ProcessDefinitionQueryImpl.java:36)
   at org.activiti.rest.diagram.services.BaseProcessDefinitionDiagramLayoutResource.getActivity(BaseProcessDefinitionDiagramLayoutResource.java:441)
   at org.activiti.rest.diagram.services.BaseProcessDefinitionDiagramLayoutResource.getDiagramNode(BaseProcessDefinitionDiagramLayoutResource.java:211)
   at org.activiti.rest.diagram.services.ProcessDefinitionDiagramLayoutResource.getDiagram(ProcessDefinitionDiagramLayoutResource.java:28)
   at sun.reflect.GeneratedMethodAccessor121.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
   at java.lang.reflect.Method.invoke(Method.java:606)
   at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
   at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
   at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
   at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:749)
   at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:689)
   at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
   at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:938)
   at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
   at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
   at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
   at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
   at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
   at org.activiti.explorer.servlet.JsonpCallbackFilter.doFilter(JsonpCallbackFilter.java:40)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
   at org.activiti.explorer.filter.ExplorerFilter.doFilter(ExplorerFilter.java:42)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
   at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
   at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
   at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
   at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
   at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
   at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
   at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
   at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
   at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1074)
   at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
   at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
   at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
   at java.lang.Thread.run(Thread.java:745)
‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

By browsing the source code, I found that the diagam definition/generator (BaseProcessDefinitionDiagramLayoutResource) is looking for the subprocess called by CallActivity using the ProcessDefinitionKey :

 // Get last definition by key
          ProcessDefinition lastProcessDefinition = repositoryService
              .createProcessDefinitionQuery()
              .processDefinitionKey(callActivityBehavior.getProcessDefinitonKey())
              .latestVersion().singleResult();‍‍‍‍‍

But the ProcessDefinitionKey is not defined on the CallActivity when processDefinitionExpression is setted (An expression is passed into the calledElement field).

How can we generate a diagram :

1. For the "Deployed process definitions" view. When the process is not yet executed?
2. For the "My instances" view. When a process has been started?

I think this require a source code modification in CallActivityBehavior or another class…

[martin_grofcik]

Hi Yohann,

I would say you have found
- an issue,
- the cause

(next step could be to create pull request. 🙂 )
Regards
Martin

[jean-guillaume_]

https://jira.codehaus.org/browse/ACT-2244 opened w/ a proposed fix solution