AW: [Objectbridge-jdo-dev] Introduction

[Mahler T. <tho...@it...>]

Hi Joel,

<ozone deficits>
ACK !

<snip db4o>

<snip>
> 
> Sounds good... What would be the quickest way for me to digest your
> PersistenceBroker API?
>
There is a tutorial on the PB API:
http://objectbridge.sourceforge.net/tutorial1.html
JavaDoc is here:
http://objectbridge.sourceforge.net/api/ojb/broker/package-summary.html

To get an impression how a JDO implementation could use PB Api internally
you might have a look at the OJB ODMG Implementation.
Interesting points to get started:

- ojb.odmg.TransactionImpl 
  Each transactionImpl holds a PB to do perform persistence Operations.
- ojb.odmg.oql.OQLQueryImpl
  the execute() method is most interesting. is shows how OQL Strings
  are parsed into OJB query objects. Than a PB is used to perform the
  query
- ojb.odmg.states.ModificationState and subclasses
  this is a part that I really like. This is the ODMG instance lifecyle.
  it combines State Pattern and command pattern.
  StatePattern is used to model the state transition between the lifecycle
states.
  (My ODMG impl follows closely the JDO spec. The only required JDO state
not present is the "Hollow" state)
  command pattern is used to perform appropiate operations
  on commit and rollback.
 
cu,

Thomas