Re: Synchronizing data displayed by two instances of my app
Re: Synchronizing data displayed by two instances of my app
- Subject: Re: Synchronizing data displayed by two instances of my app
- From: Denis Stanton <email@hidden>
- Date: Tue, 6 Apr 2004 22:31:01 +1200
Thanks a lot for the explanation.
On 06/04/2004, at 8:04 PM, Sam Hart wrote:
> Change notification basically allows you to cluster apps which share
> data without a common cache.
>
> When an app changes an object in the data store ( DB ) it then sends a
> message ( usually via JMS ) to listening apps.
I have found mention of change notification and posting a notification,
but so far I can't find how apps register to receive and respond. More
reading to do.
> In a single app it isn't needed, at least it shouldn't be, if it is
> you are in trouble.
In Cocoa there are notifications pasted and detected in a single app -
or at least there are in the one I have written, drawing on code
examples from Bill Cheeseman's books Cocoa Recipes for OS X.
Notifications are used to communicate between the data and view
segments of the program so that a change to the data store is reflected
in the screen display. It puzzled me for a while, as it would be
possible for the data storage procedure to call the display update
directly, but it does make the code simpler if the display section is
just told to wait for a notification to arrive.
Thanks for your help
Denis Stanton
email@hidden
Home: +64 9 533 0391
mobile: +64 21 1433622
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