can't inject TaskInstance with @In, causes Exception

[cali85]

Hi,

I'm working with Seam and jBPM.

I start a task and I want to get the name of the TaskInstance. So I try to inject the TaskInstance:

@In TaskInstance task;

This causes the folowing exception:

org.jboss.seam.RequiredException: @In attribute requires non-null value: pasis_offen.task
     org.jboss.seam.Component.getValueToInject(Component.java:2297)
     org.jboss.seam.Component.injectAttributes(Component.java:1703)
     org.jboss.seam.Component.inject(Component.java:1521)
     org.jboss.seam.core.BijectionInterceptor.aroundInvoke(BijectionInterceptor.java:61)
     org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
     org.jboss.seam.core.ConversationInterceptor.aroundInvoke(ConversationInterceptor.java:65)
     org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
     org.jboss.seam.bpm.BusinessProcessInterceptor.aroundInvoke(BusinessProcessInterceptor.java:51)
     org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
     org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:44)
     org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
     org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
     org.jboss.seam.intercept.JavaBeanInterceptor.interceptInvocation(JavaBeanInterceptor.java:185)
     org.jboss.seam.intercept.JavaBeanInterceptor.invoke(JavaBeanInterceptor.java:103)
     org.jboss.seam.example.todo.Pasis_Offen_$$_javassist_4.getThema(Pasis_Offen_$$_javassist_4.java)
     sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     java.lang.reflect.Method.invoke(Method.java:597)
     javax.el.BeanELResolver.getValue(BeanELResolver.java:62)
     javax.el.CompositeELResolver.getValue(CompositeELResolver.java:53)
     com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:72)
     org.apache.el.parser.AstValue.getValue(AstValue.java:118)
     org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)
     org.apache.jasper.el.JspValueExpression.getValue(JspValueExpression.java:101)
     javax.faces.component.UIOutput.getValue(UIOutput.java:184)
     com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getValue(HtmlBasicInputRenderer.java:201)
     com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.getCurrentValue(HtmlBasicRenderer.java:284)
     com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeEnd(HtmlBasicRenderer.java:154)
     javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:861)
     javax.faces.component.UIComponent.encodeAll(UIComponent.java:937)
     javax.faces.render.Renderer.encodeChildren(Renderer.java:148)
     javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:837)
     javax.faces.component.UIComponent.encodeAll(UIComponent.java:930)
     javax.faces.component.UIComponent.encodeAll(UIComponent.java:933)
     com.sun.faces.application.ViewHandlerImpl.doRenderView(ViewHandlerImpl.java:266)
     com.sun.faces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:197)
     org.jboss.seam.jsf.SeamViewHandler.renderView(SeamViewHandler.java:87)
     com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:110)
     com.sun.faces.lifecycle.Phase.doPhase(Phase.java:100)
     com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
     javax.faces.webapp.FacesServlet.service(FacesServlet.java:266)
     org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83)
     org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:58)
     org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
     org.jboss.seam.web.IdentityFilter.doFilter(IdentityFilter.java:40)
     org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
     org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:90)
     org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
     org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64)
     org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
     org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45)
     org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
     org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158)
     org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)

What could be the reason that the @In attribute has a null value? I guess the task is already started. I don't understand that....

Your help would be appreciated!!!

Best Regards

[mwohlf]

try:

 @In
 TaskInstance taskInstance;

or:

 @In(value="taskInstance")
 TaskInstance task;

[cali85]

Thank you, I think I just understood something new....

BTW:
It only works with:

import org.jbpm.taskmgmt.exe.TaskInstance;

not with:

import org.jboss.seam.bpm.TaskInstance;

But since this works I have a new problem:

My button, which ends the current task doesn't work anymore, when I inject the taskInstance:

@EndTask(transition="next")
public String next() {
     return "pasis_todo";
}

There is no Exception but I get no redirection to pasis_todo.jsp and in the task overview I can see that the task wasn't ended.

As soon as I comment out the injection of taskInstance, the button works again. What could be the reason for this?

[mwohlf]

Just a guess:
Are you sure the right taskInstance is injected, maybe there is no transition next for the injected taskInstance?
Try using the default transition on whatever task is injected by using just @EndTask, or print some debug info about the injected taskInstance...

[cali85]

The right taskInstance is injected. I checked the name of it and I tried @EndTask without (transition="next") but it doesn't help.

What kind of debug info could you need?

[mwohlf]

I am clueless here, I was thinking along the line of printing stuff like this:

         @EndTask(transition="next")
        public String next() {
           System.err.println(taskInstance.getAvailableTransitions());
           System.err.println(taskInstance.isSignalling());
           System.err.println(taskInstance.isOpen());
           return "pasis_todo";
        }

or doing a manual

         taskInstance.end("next");

just to see if the code is doing what you think it is doing...

I only use the <end-task transition="next" /> Syntax in xxx.page.xml for my Project atm, so I am not sure what problems there might be with the annotations...