Can't find non-public callback methods with superclass or interface parameters
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Key: OPENJPA-133
URL: https://issues.apache.org/jira/browse/OPENJPA-133
Project: OpenJPA
Issue Type: Bug
Components: jpa
Reporter: Kevin Sutter
Assigned To: Kevin Sutter
Using xml to define my listener callback methods (doesn't make any difference
whether we're using MappedSuperclass or Entity):
<mapped-superclass
class="com.ibm.ws.persistence.tests.callbacks.CallbackSuperclass">
<entity-listeners>
<entity-listener
class="com.ibm.ws.persistence.tests.callbacks.CallbackListener">
<!--
<pre-persist
method-name="prePersistXML" />
-->
<post-persist
method-name="postPersistXML" />
<!--
<pre-remove method-name="preRemove" />
<post-remove method-name="postRemove"
/>
<pre-update method-name="preUpdate" />
<post-update method-name="postUpdate"
/>
<post-load method-name="postLoad" />
-->
</entity-listener>
</entity-listeners>
</mapped-superclass>
My Entity heirarchy is defined as follows:
public interface CallbackMarker { }
@MappedSuperclass
public class CallbackSuperclass implements CallbackMarker { .. }
@Entity
public class CallbackEntity extends CallbackSuperclass { .. }
My listener method is defined as follows:
public class CallbackListener {
:
private void postPersistXML(CallbackMarker cbm) {
System.out.println("PostPersist (ListenerXML) on CallbackMarker: " +
cbm);
((CallbackEntity)cbm).postSuccessful = true;
}
:
}
I'm probably clouding the issue with all of these details, but the real problem
is that we're not properly finding the postPersistXML(CallbackMarker cbm)
method. When I run the example, I am getting the following exception. The
original
call stack is huge, so I will just include the "caused by":
Caused by: java.lang.NoSuchMethodException:
com.ibm.ws.persistence.tests.callbacks.CallbackListener.postPersistXML(com.ibm.ws.persistence.tests.callbacks.CallbackSuperclass)
at java.lang.Class.throwNoSuchMethodException(Class.java:271)
at java.lang.Class.getMethod(Class.java:748)
at
org.apache.openjpa.event.MethodLifecycleCallbacks.getMethod(MethodLifecycleCallbacks.java:123)
Digging through the problem, I am finding that we're not properly reflecting on
the Class to find the appropriate Method. First, we
do a getMethods(), which only returns the public methods. Of course, nothing
matches up, so we end up in the catch {} block. Here,
we attempt a getDeclaredMethod() passing in the specific type for the argument.
This doesn't work in this case since the specific
type (CallbackSuperclass) isn't on the Method signature (the interface
CallbackMarker is). Also, calling getDeclaredMethod only looks in the specific
Class and does not go up the heirarchy (like getMethods() does). So, we have a
couple of problems with this
method.
My proposed change is to use the getDeclaredMethods() invocation and manually
go up the heirarchy (if necessary). If we go all the way up the tree without
finding the method, then we throw the exception. This seems to clear up the
processing and makes the code
more readable (no try/catch is required). You could argue that this approach
might take more processing since we might have to get the Superclass and make
additional getDeclaredMethods() invocations. But, my guess is that most of the
methods being requested will be on the base class and no additional invocations
will be necessary.
FYI, this problem only exists with the XML configuration since the annotated
version doesn't do this parameter checking. Annotated callback methods just
register the method and assume that it will work. If it doesn't, then we get a
runtime exception with IllegalArgumentException. Whether we should do this
type checking for the annotated callbacks is a topic for a separate JIRA
report...
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