Re: Listening for changes on an EO
Re: Listening for changes on an EO
- Subject: Re: Listening for changes on an EO
- From: Lon Varscsak <email@hidden>
- Date: Thu, 9 Jul 2009 12:43:41 -0700
Thanks for the tips!
-Lon
On Thu, Jul 9, 2009 at 12:34 PM, Chuck Hill<email@hidden> wrote:
>
> On Jul 9, 2009, at 12:26 PM, Lon Varscsak wrote:
>
>> Thanks. I figured there was nothing built to do exactly what I
>> needed, but I figured I would ask.
>>
>> Do you know if there is much overhead if I implemented this in my EO
>> superclass even if there were no observers?
>
> EOF makes heavy use of notification. I would not expect there to be much
> overhead. You will probably want to qualify the notification with the EC
> (depending on what it is you are trying to do) to limit the number of
> observers. And then keep the method receiving the notification fast. The
> notifications are synchronous, so you don't want anything slow in this
> method.
>
>
> Chuck
>
>
>
>>
>> -Lon
>>
>> On Thu, Jul 9, 2009 at 11:50 AM, Simon McLean<email@hidden> wrote:
>>>
>>> also, if you are using wonder, check out
>>> hasKeyChangedFromCommittedSnapshot in ERXGenericRecord. maybe listen
>>> for the notification mentioned by chuck, then use
>>> hasKeyChangedFromCommittedSnapshot to check the particular key you are
>>> looking at.
>>>
>>> simon
>>>
>>> 2009/7/9 Chuck Hill <email@hidden>:
>>>>
>>>> On Jul 9, 2009, at 10:24 AM, Lon Varscsak wrote:
>>>>
>>>>> Is there a way for a controller object to listen for changes to an EO
>>>>> (and a specific key)?
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Lon
>>>>
>>>> EOEditingContext has ObjectsChangedInEditingContextNotification, but it
>>>> is
>>>> on an object by object basis, not a key by key one.
>>>>
>>>> You could implement this in your EO super class.
>>>>
>>>>
>>>> Chuck
>>>>
>>>> --
>>>> Chuck Hill Senior Consultant / VP Development
>>>>
>>>> Practical WebObjects - for developers who want to increase their overall
>>>> knowledge of WebObjects or who are trying to solve specific problems.
>>>> http://www.global-village.net/products/practical_webobjects
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
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>>
>
> --
> Chuck Hill Senior Consultant / VP Development
>
> Practical WebObjects - for developers who want to increase their overall
> knowledge of WebObjects or who are trying to solve specific problems.
> http://www.global-village.net/products/practical_webobjects
>
>
>
>
>
>
>
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