Hi Peter,
Great question. With the current implementation, all CFCs that compose
a given CFC are serialized along with that CFC. That is, all CFCs that
are referenced within the "this" or "variables" scope of a CFC are
serialized along with that CFC. If you want to avoid this behavior,
you'll have to code around it manually (for example, by removing CFCs
from the "this" or "variables" scope before writing to the datastore,
and then restoring them when reading). As we get more experience and
develop a set of use-cases, we can figure out the right way to handle
this automatically.
A technique that I'm using while porting BlogCFC is to store the
Google keys of referenced CFCs rather than the CFCs themselves within
the composed CFCs. For example, a blog category--represented by
blogCategory.cfc--contains references to blog entries--represented by
blogEntry.cfc. One way to implement this would be for blogCategory.cfc
to keep an array of blogEntry.cfc instances. But, the problem with
that solution is that blogEntry.cfc instances would get serialized to
the datastore whenever you write a blogCategory.cfc instance, which is
undesirable because a blog entry can belong to multiple categories,
which would result in the blogEntry.cfc instances getting serialized
multiple times (once with each category).
Instead, I store the Google keys for the blogEntry.cfc instances
within the blogCategory.cfc and read the blogEntry.cfc instances only
when needed. Within the blogCategory.cfc pseudo-constructor I create
an array to hold the Google keys of the blogEntry.cfc instances (I
call the keys "ids" to be consistent with existing blogCFC
terminology):
<cfset variables.entryIdArray = arrayNew( 1 )>
Then I declare an "addEntry" function within blogCategory.cfc that
looks like this:
<cffunction name="addEntry" access="public" returntype="void"
output="false">
<cfargument name="entryId" type="string" required="true">
<cfset arrayAppend( variables.entryIdArray, arguments.entryId )>
<cfset googleWrite( this )>
</cffunction>
The "getEntries" function can be used to retrieve all entries for a
category (note that the GoogleRead function allows you to do a "batch
read" by passing an array of keys, returning an array of CFC
instances):
<cffunction name="getEntries" access="public" returntype="array"
output="false">
<cfreturn googleRead( variables.entryIdArray )>
</cffunction>
Again, as we gain experience and develop a set of use-cases, we may be
able to provide a way to automate this technique.
Vince
On Jun 2, 3:12 am, "Peter J. Farrell" <[email protected]> wrote:
>
> This is cool stuff Baz. I'm sure Vince will response on your question. I
> have an additional question.
>
> How is / does Open BD handle the object graph of a CFC (basically a CFC
> has that other CFCs via composition) and deserializing it to the Google
> Datastore? Is that something that will be handled via cfproperty? I'm
> asking because I'm sure there are some CFCs where you want to
> deserialize some, but all not all CFCs via composition (for instance an
> application wide CFC that you an inject after serialization).
>
> Thanks in advance,
> .Peter
>
--~--~---------~--~----~------------~-------~--~----~
Open BlueDragon Public Mailing List
http://groups.google.com/group/openbd?hl=en
official site @ http://www.openbluedragon.org/
!! save a network - trim replies before posting !!
-~----------~----~----~----~------~----~------~--~---
