[infinispan-dev] HotRodMarshaller interface

[Mircea Markus]

On 8 Jul 2010, at 14:57, Manik Surtani wrote:

> Guys,
> 
> I just created ISPN-532 (HotRodMarshaller needs cleaning up) targeted for Radegast CR2 and Final.  I know it is late in the day to be making API changes in an interface, but I would much rather this is done right prior to being baked into Final and hence eternity.  :)
> 
> 	http://fisheye.jboss.org/browse/Infinispan/trunk/client/hotrod-client/src/main/java/org/infinispan/client/hotrod/HotRodMarshaller.java?r=1850
> 
> So I have 3 issues to address with this interface.
> 
> 1.  Methods on the interface
> 
> The purpose of this is simple: the 2 methods, readObject() and marshallObject() are meant to perform diametrically opposed tasks (byte[] -> object in one case, object -> byte[] in the other) but the names are far from that.
> 
> I propose either of the following:
> 
> 	1) readObject() and writeObject()
> 	2) Simply, read() and write()
> 	3) Or if we want to follow org.infinispan.marshall.Marshaller conventions, objectFromByteBuffer(), objectToByteBuffer()
> 
> My preference would be (3).
> 
> 
> 2.  Interface name and package
> 
> Further, any reason why we call this HotRodMarshaller?  Isn't it just a marshaller that serializes arbitrary objects <--> byte[] and should contain no HotRod-specific logic?  I can see why we did not use the org.infinispan.marshall.Marshaller interface for this (too complex?) but perhaps we could create a org.infinispan.marshall.BasicMarshaller which just contains objectFromByteBuffer() and objectToByteBuffer(), and Marshaller can extend BasicMarshaller for Infinispan's internals and HotRod clients can directly implement BasicMarshaller?
> 
> This would allow people who write custom marshallers to reuse them for both the HotRod client as well as for Infinispan's internal marshalling.
+1
We can reuse the optimised marshalling logic from core this way, so that makes a lot of sense.
I'm thinking a better name would be ByteArrayMarshaller/BitesMarshaller (vs BasicMarshaller) - but obviously I'm not good with the names (see 1).
> 
> 3.  isKeyHint parameter on marshallObject()
> 
> What is this for?  
Here is the kind of application that would benefit from this: small keys with large values (e.g. an mp3 files kept in the grid, where file name is the key and the file is the value, or the gridFS). 
You are allowed to specify an default size for ExposedByteArrayOutputStream's underlaying byte[]. When this is exceeded the byte[] "doubles".
So for the above example specifying an 128bytes default value would be optimal for key serialization, but rather bad for values serialization: underlying byte[] would be created several times.
Also setting an value of e.g. 4MB for the default value would be not good for the keys, for same reasons.
> And surely there is a more elegant/generic way to achieve this?  
Perhaps overloading objectToByteBuffer(byte[] estimatedSize) ?
> 
> Cheers
> Manik
> 
> --
> Manik Surtani
> manik at jboss.org
> Lead, Infinispan
> Lead, JBoss Cache
> http://www.infinispan.org
> http://www.jbosscache.org
> 
> 
> 
> 
> 
> _______________________________________________
> infinispan-dev mailing list
> infinispan-dev at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/infinispan-dev