ByteBufferStoreHashMap

[Karl Wettin <ka...@apache.org>]

Hello forum,

I'm in need of object storage for Mahout. BDB would be perfect but their 
license is not compatible with ASF.

So I'm thinking I should clone your HashMap, make all access to element 
data abstract and run it on ByteBuffers.

It would be used as a Map<K, DataFileEntry> pointing at where in the 
object data file the current value is located.

Updaing values would mean to mark the old instance deleted, add a new 
one to the end of the object data file and update the position in the index.

It would use Hadoops Writable to serialize keys and values.

It would initially be transactionless.


Any comments to this? Perhaps something similar already exists ASLed?



     karl

Re: ByteBufferStoreHashMap

[Tim Ellison <t....@gmail.com>]

Karl Wettin wrote:
> Hello forum,

Hello.

> I'm in need of object storage for Mahout. BDB would be perfect but their 
> license is not compatible with ASF.
> 
> So I'm thinking I should clone your HashMap, make all access to element 
> data abstract and run it on ByteBuffers.
> 
> It would be used as a Map<K, DataFileEntry> pointing at where in the 
> object data file the current value is located.
> 
> Updaing values would mean to mark the old instance deleted, add a new 
> one to the end of the object data file and update the position in the 
> index.
> 
> It would use Hadoops Writable to serialize keys and values.
> 
> It would initially be transactionless.
> 
> 
> Any comments to this? Perhaps something similar already exists ASLed?

Can't think of anything in the Java platform area that would be 
immediately useful to you.  Have you tried asking in the db.apache.org 
space?  Maybe something in Derby or JDO space would be more suitable?

Regards,
Tim