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From Joseph Senecal <sene...@apple.com>
Subject Re: Configuring listener for all db Classes
Date Wed, 03 Aug 2011 20:04:37 GMT
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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