Nested Callbacks Fail

[He Yuan Huang]

Hi,

I created a simple SCA application, which involves an order process. Below
is the composite file of the application. Note that, the callback method of
Supplier will invoke the callback interface of Customer. Thus, there are
nested callbacks.

<?xml version="1.0" encoding="UTF-8"?>
<composite xmlns="http://www.osoa.org/xmlns/sca/1.0";
      targetNamespace="http://orderprocess";
      xmlns:cb="http://orderprocess";
      name="orderprocess">

      <component name="Customer">
            <implementation.java class="orderprocess.CustomerImpl"/>
            <reference name="supplier" target="Supplier/Order">
                  <interface.java interface="orderprocess.Order"
callbackInterface="orderprocess.OrderNotification"/>
            </reference>
      </component>

    <component name="Supplier">
      <service name="Order">
                  <interface.java interface="orderprocess.Order"
callbackInterface="orderprocess.OrderNotification"/>
      </service>
        <implementation.java class="orderprocess.SupplierImpl"/>
        <reference name="railway" target="RailwayTransport/Shipment">
                  <interface.java interface="orderprocess.Shipment"
callbackInterface="orderprocess.ShipmentNotification"/>
        </reference>
        <reference name="highway" target="HighwayTransport">
                  <interface.java interface="orderprocess.Shipment"
callbackInterface="orderprocess.ShipmentNotification"/>
        </reference>
    </component>

    <component name="HighwayTransport">
        <service name="Shipment">
                  <interface.java interface="orderprocess.Shipment"
callbackInterface="orderprocess.ShipmentNotification"/>
      </service>
        <implementation.java class="orderprocess.HighwayTransport"/>
        <property name="period">5000</property>
    </component>

    <component name="RailwayTransport">
        <service name="Shipment">
                  <interface.java interface="orderprocess.Shipment"
callbackInterface="orderprocess.ShipmentNotification"/>
      </service>
        <implementation.java class="orderprocess.RaiwayTransport"/>
        <property name="period">1000</property>
    </component>

</composite>

However, the application fails on both SCA Java 0.90 and trunk. Below is
the error message. When I debugged the application, I found that it might
be caused by wrong "from" info in ThreadMessageContext.

java.lang.NullPointerException
      at
org.apache.tuscany.sca.core.invocation.JDKCallbackInvocationHandler.invoke(
JDKCallbackInvocationHandler.java:77)
      at $Proxy11.notify(Unknown Source)
      at orderprocess.SupplierImpl.notify(SupplierImpl.java:70)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(
NativeMethodAccessorImpl.java:39)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(
DelegatingMethodAccessorImpl.java:25)
      at java.lang.reflect.Method.invoke(Method.java:585)
      at
org.apache.tuscany.sca.implementation.java.invocation.JavaTargetInvoker.invokeTarget(
JavaTargetInvoker.java:112)
      at
org.apache.tuscany.sca.implementation.java.invocation.JavaTargetInvoker.invoke(
JavaTargetInvoker.java:134)
      at
org.apache.tuscany.sca.implementation.java.invocation.TargetInvokerInvoker.invoke(
TargetInvokerInvoker.java:46)
      at
org.apache.tuscany.sca.core.invocation.AbstractInvocationHandler.invoke(
AbstractInvocationHandler.java:84)
      at
org.apache.tuscany.sca.core.invocation.JDKCallbackInvocationHandler.invoke(
JDKCallbackInvocationHandler.java:85)
      at $Proxy13.notify(Unknown Source)
      at orderprocess.RaiwayTransport.doShipping(RaiwayTransport.java:56)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(
NativeMethodAccessorImpl.java:39)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(
DelegatingMethodAccessorImpl.java:25)
      at java.lang.reflect.Method.invoke(Method.java:585)
      at
org.apache.tuscany.sca.implementation.java.invocation.JavaTargetInvoker.invokeTarget(
JavaTargetInvoker.java:112)
      at
org.apache.tuscany.sca.implementation.java.invocation.JavaTargetInvoker.invoke(
JavaTargetInvoker.java:134)RuntimeException invoking receiveResult:
java.lang.NullPointerException

      at
org.apache.tuscany.sca.implementation.java.invocation.TargetInvokerInvoker.invoke(
TargetInvokerInvoker.java:46)
      at
org.apache.tuscany.sca.core.invocation.NonBlockingInterceptor$1.run(
NonBlockingInterceptor.java:68)
      at org.apache.tuscany.sca.core.work.Jsr237Work.run(Jsr237Work.java:61
)
      at
org.apache.tuscany.sca.core.work.ThreadPoolWorkManager$DecoratingWork.run(
ThreadPoolWorkManager.java:206)
      at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(
ThreadPoolExecutor.java:650)
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(
ThreadPoolExecutor.java:675)
      at java.lang.Thread.run(Thread.java:595)

Best Regards,
York