On Mon, Jun 24, 2013 at 4:02 AM, Ian Boston <i...@tfd.co.uk> wrote:
> Hi Dishara,
> Yes. 1 resource == 1 row.
> The columns within that row represent the properties of the resource.
> I suggest that you use standard property names where appropriate (eg
> sling:resourceType is the Resource.resourceType etc)
>
> The Resource itself should be adaptable to a generic CassandraResource
> (which will probably implement Resource) which will have a map of
> properties containing all the columns of the cassandra row. (optimise
> later) A CassandraResource might look and feel like a Map<String, Object>
> or it might have a Map<String, Object> getProperties() method, or better
> still be adaptable to a Map. The essential think is dont hard code the
> property names in the interface of CassandraResource for the moment. ie no
> getContentType() and no getMimeType(), as we dont really know what a
> CassandraResource will store.
>
> ResourceMetadata should be built from a subset of the CassandraResource
> properties.
>
> You won't need to implement a ResourceResolver, only a ResourceProvider
> (and Factory). I would use CQL in preference to other API methods.
>
> There is one thing that hasnt been mentioned, and thats the URL ->
> Cassandra Row mapping.
> There are several ways of doing this.
>
> eg:
> URL = /content/cassandra/<columnFamily>/<rowID>
> Cassandra Column Family = columnFamily
> Cassandra RowID = rowID
> or
> URL = /content/cassandra/<columnFamilySelector>/remainder/of/the/path
> Cassandra Cassandra Column Family =
> mapOfColumnFamilies.get(columnFamilySelector)
> Cassandra RowID = function(/remainder/of/the/path)
>
> or to take that one stage further
>
> public interface CassandraMapper {
> String getCQL(String columnFamilySelector, String path);
> }
>
Hi Ian
Thank you for the detailed explanation.
OK. +1 for this approach with the mentioned flexibility.But I need a small
clarification. With this approach,
URL = /content/cassandra/<columnFamilySelector>ROW-ID
ROW-ID - function(/remainder/of/the/path).
So you mean ROW-ID is something we have to programatically uniquely create
right ? like a UUID.
What is this "/remainder/of/the/path" means ? Can you give an example with
real values in the context of a user who want to obtain a resource from
cassandra.
This is just for my understanding.
>
> URL = /content/cassandra/<columnFamilySelector>/<remainderOfPath>
>
> String cqlQuery =
>
> mapOfCassandraMappers.get(columnFamilySelector).getCQL(columnFamilySelector,
> remainderOfPath);
>
> Which would allow us provided one or more implementations of
> CassandraMapper to map between URL and CQL.
>
>
> HTH
> Ian
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> On 23 June 2013 19:29, Dishara Wijewardana <ddwijeward...@gmail.com>
> wrote:
>
> > Hi Ian,
> >
> > What is the data mapping should be between Cassandra and Sling resource.
> I
> > mean is a Sling Resource maps to a Cassandra Column ? Or Column Family ?
> >
> > Because to get this Cassandra and Sling story correct we need to finalize
> > this.
> > For an example what we eventually returns is a Sling resource. Everything
> > that needs to fill in to create Sling resource should be stored in
> > Cassandra.
> > In a Sling resource,
> >
> > - Path - direct sling resource path
> > - ResourceType - nt:cassandra
> > - ResourceSuperType - ?
> > - ResourceMetadata - we can create this on the fly with the data from
> > the corresponding column. At insertion, those need to be stored.
> > Following
> > are the ones which I thought might be useful by default to be set for
> > any
> > node. Please add if we need anything more.
> > - ContentType
> > - ContentLength
> > - CreationTime
> > - ModificationTime
> > - ResourceResolver - Do we need a resolver in this case ?
> >
> >
> > So I believe in CQL context, one ROW should represent a Sling resource.
> If
> > that is the case for ResourceMetadata we might need a separate column to
> > store it since it has multiple values. I am not sure whether we can do it
> > with CQL, but it should be possible with hector APIs may be.
> >
> > Appreciate your thoughts ?
> >
> >
> > On Wed, Jun 19, 2013 at 1:19 AM, Dishara Wijewardana <
> > ddwijeward...@gmail.com> wrote:
> >
> > > Hi Ian,
> > > I am starting this thread to keep track on things related to the GSoC
> > > project related milestone status updates and related discussions.
> > > So the first task over view will be as follows as per GSoC proposal
> > > provided.
> > >
> > > 1. Implementing a CassandraResourceProvider to READ from Cassandra.
> > > Implementation Details [1]
> > >
> > >
> > >
> > > [1] : Implementation Details:
> > >
> > > 1.A) Write a CassanrdaResourceProviderUtil which is basically a
> > > cassendra client which will facilitate all cassandra related operations
> > > required by other modules (CassandraResourceProvider and
> > > CassandraResourceResolver).
> > >
> > > 1.B) Implementation of CassandraResourceProvider
> > >
> > > 1.C) Implementation of CassandraResourceResolver
> > >
> > > 1.D) Implementation of CassandraResource
> > >
> > >
> > > And I will start writing the CassanrdaResourceProviderUtil class which
> > > will do basic add and get using hector API. Please provide any feedback
> > > that will be useful to accomplish this task.
> > > So for this how does path mapping should be done. Because for example,
> > the
> > > path of the cassendra node will not be same as the jcr node path. i.e
> > > provider will ask a node path /system/myapps/test/foo and where should
> we
> > > return it from Cassandra. Aren't we have to first consider the WRITE
> > aspect
> > > to Cassandra ?
> > >
> > >
> > > --
> > > Thanks
> > > /Dishara
> > >
> >
> >
> >
> > --
> > Thanks
> > /Dishara
> >
>
--
Thanks
/Dishara
