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From Joseph Senecal <sene...@apple.com>
Subject Re: Configuring listener for all db Classes
Date Thu, 04 Aug 2011 17:21:40 GMT
Thanks. It looks like I was doing it right, but it just wasn't working for me using Cayenne
3.1M2. 

For now I'm generating code in the validation methods. Which given the operations I'm doing,
might actually be a better place. What I'm doing is automatically setting or updating fields
used internally but in the external business logic: creationDate, lastModDate, and modCount.
The more I think about it the more putting these specific operations into the generated superclass
template makes sense.

Joe

On Aug 4, 2011, at 5:03 AM, Dzmitry Kazimirchyk wrote:

> Hi Joe,
> 
> Behaviour that you've described seems little bit strange to me. Trying to reproduce it
I've written following:
> 
> ObjEntity in my map.xml:
> 
> <obj-entity name="Artist" className="org.test.cayenne.persistent.Artist" dbEntityName="Artist">
> <obj-attribute name="name" type="java.lang.String" db-attribute-path="NAME"/>
> <entity-listener class="org.test.cayenne.listen.TestListener">
> <pre-persist method-name="onPrePersist"/>
> <pre-update method-name="onPreUpdate"/>
> </entity-listener>
> </obj-entity>
> 
> Also I registered same listener for DataMap.
> 
> <entity-listener class="org.test.cayenne.listen.TestListener">
> <pre-persist method-name="onPrePersist"/>
> <pre-update method-name="onPreUpdate"/>
> </entity-listener>
> 
> The listener class itself:
> 
> public class TestListener {
> 
>    void onPrePersist (Object object) {
>        System.out.println("pre-persist");
>    }
> 
>    void onPreUpdate (Object object) {
>        System.out.println("pre-update");
>    }
> }
> 
> Place where events are actually triggered:
> 
>        ServerRuntime cayenneRuntime = new ServerRuntime("cayenne-testDomain.xml");
> 
>        ObjectContext context = cayenneRuntime.getContext();
> 
>        // testing persist events
>        Artist a = context.newObject(Artist.class);
>        context.commitChanges();
> 
>        //testing update events
>        a.setName("name");
>        context.commitChanges();
> 
> Both pre-persist and pre-update events were triggered correctly calling corresponding
listener methods. I've tried this also for other events but got the same result.
> Am I missing something important in your particular case?
> 
> On 08/03/2011 11:04 PM, Joseph Senecal wrote:
>> Perhaps I'm just missing something simple. I've tried using individual listener configurations,
and they don't work either.
>> 
>> Here is a sample entry:
>> 		<entity-listener class="com.apple.mqm.db.PDCAListener">
>> 			<pre-persist method-name="onPrePersist"/>
>> 			<pre-update method-name="onPreUpdate"/>
>> 		</entity-listener>
>> 
>> 
>> And here is my listener class:
>> package com.apple.mqm.db;
>> 
>> import java.util.Date;
>> 
>> import org.apache.cayenne.CayenneDataObject;
>> 
>> public class PDCAListener {
>> 
>> 	void onPrePersist (Object object) {
>> 		CayenneDataObject dataObject = (CayenneDataObject) object;
>> 		if (dataObject.readProperty(Product.CREATION_DATE_PROPERTY) == null) {
>> 			dataObject.writeProperty(Product.CREATION_DATE_PROPERTY, new Date());
>> 		}
>> 		if (dataObject.readProperty(Product.LAST_MOD_DATE_PROPERTY) == null) {
>> 			dataObject.writeProperty(Product.LAST_MOD_DATE_PROPERTY, new Date());
>> 		}
>> 		dataObject.writeProperty(Product.MOD_COUNT_PROPERTY, 1);
>> 	}
>> 
>> 	void onPreUpdate (Object object) {
>> 		CayenneDataObject dataObject = (CayenneDataObject) object;
>> 		dataObject.writeProperty(Product.LAST_MOD_DATE_PROPERTY, new Date());
>> 		dataObject.writeProperty(Product.MOD_COUNT_PROPERTY, ((Integer)dataObject.readProperty(Product.LAST_MOD_DATE_PROPERTY))+1);
>> 	}
>> }
>> 
>> 
>> I don't have any code to activate the listeners. When testing I'm getting a validation
error that for a field that this listener sets onPrePersist. And I never reach a breakpoint
in the listener code.
>> 
>> Joe
>> 
>> 
>> On Aug 3, 2011, at 11:12 AM, Andrus Adamchik wrote:
>> 
>>> Ok, we'll need to re-test this case, and implement the missing registration API.
>>> 
>>> On Aug 3, 2011, at 9:09 PM, Joseph Senecal wrote:
>>>> Andrus,
>>>> 
>>>> Yes, I was using a per DataMap listener.
>>>> 
>>>> I'll try using individual class listeners for the prototype and see how that
works.
>>>> 
>>>> These listeners are really part of the basic operation of the DB interface,
so they are common to all programs using the database. Currently I'm considering having the
template generate the listener methods in each class, along with code that will install the
listener for that class the first time the class is referenced (probably using a static initializer).
This will allow the listener methods to be customized for each class instead of having to
check the model. Annotations will help there.
>>>> 
>>>> Joe
>>>> 
>>>> On Aug 3, 2011, at 10:50 AM, Andrus Adamchik wrote:
>>>> 
>>>>> Hi Joe,
>>>>> 
>>>>> On Aug 3, 2011, at 10:29 AM, Joseph Senecal wrote:
>>>>> 
>>>>>> I'm trying to configure a single listener object to listen to a couple
of events for all objects. This is to update modCounts and lastModTimes just before the commit.
>>>>>> 
>>>>>> The documentation says this is configured in the Cayenne modeler,
but doesn't explain how. I found how to specify a class and methods, but it doesn't seem to
be getting called.
>>>>> This is odd. This certainly works for me. Here is an example from one
of my map.xml files (created by the Modeler) :
>>>>> 
>>>>> This part is a listener within<obj-enntity>  tags:
>>>>> 
>>>>> 	<entity-listener class="com.foo.listener.MyListener">
>>>>> 		<post-persist method-name="objectPostPersistCallback"/>
>>>>> 	</entity-listener>
>>>>> 
>>>>> This part is callbacks on persistent objects themselves:
>>>>> 
>>>>> 	<post-add method-name="onPostAdd"/>
>>>>> 	<pre-update method-name="onPreUpdate"/>
>>>>> 
>>>>> These are per-entity callbacks/listeners. Are you setting a listener
per DataMap? (I personally haven't used "global" listeners, but those should work too). Could
you confirm - we'll re-test this case then.
>>>>> 
>>>>>> I can see how to do it programmatically, but is there a cleaner solution
that I'm missing?
>>>>> Personally I am moving to setting everything programmatically, as it
allows me to have different listeners for the same shared entities in different Java projects.
So my preferred method is the latest 3.1M2 API based on annotations:
>>>>> 
>>>>> runtime.getChannel().getEntityResolver().getCallbackRegistry().addListener(listener)
>>>>> 
>>>>> But again - this is for per-entity listeners. Not per-DataMap. (Which
reminds me - we need to support this flavor in per-DataMap case).
>>>>> 
>>>>> Cheers,
>>>>> Andrus
>>>> 
> 


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