[OpenLayers-Dev] OLON / context
tschaub at openplans.org
Tue Feb 5 15:01:51 EST 2008
Pierre GIRAUD wrote:
> Hi Tim Schaub and Lorenzo Becchi, and others,
> I'm really interested in the work you did in the context sandbox and
> specifically on the OLON format.
> Can you give clues on what its current state is ?
> Was it abandoned and replaced by the brand new WMC format ? I thought
> that this would be used for an history control but it doesn't seem to
The context stuff is pretty solid. I stopped working on it shortly
after the foss4g sprint, but I think it has good potential.
The idea is that any instance of an OL class is serializable if the
arguments to it's constructor are serializable. Arguments are
serializable if they are 1) objects that can be represented as json (no
circular references) or 2) instances of an OL class that meet the
condition in the first sentence.
The serialize/deserialize code is in place. You can call the static
OpenLayers.Class.serialize and OpenLayers.Class.deserialize methods on
any object. If a prototype has a serializable property (see the
HTTPRequest layer or others), then instances of a parent class or
subclass will be serialized as OLON (OpenLayers Object Notation).
The work left to be done is to 1) go around the library adding
serializable properties to prototypes (there is a bit of magic with
inheritance of this property that deserves documentation), and 2) give
the write method of OpenLayers.Format.OLON a filter option so you can
specify what you want serialized.
Though I originally suggested that Lorenzo use OLON as an intermediate
structure for the WMC and OWS Context work, I ended up not using it for
the WMC work I did. (This was because I wanted to get the WMC format in
the trunk before having to completely finish the OLON work. Apologies
to Lorenzo.) The reason it did make sense to use OLON as an
intermediate structure is that it would be a structure that we could
agree on (the idea being that wmc.read(doc) should return a regular
structure that you can rely on).
> Would it be a good start point to build an application level context ?
Yeah, I think so.
I'm happy to discuss more on IRC.
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