[hibernate-dev] implement criteria query collection-of-component and collection-of-value against latest 3.5.0-Beta-3

[David Mansfield]

Hi All,

Attached is a series of patches which implements the missing
functionality for Criteria queries, namely being able to use Criteria
queries for collections of components or scalars.

The patch series includes documentation changes and test cases.

I'd love for this to get into the project, and would appreciate any
feedback or questions and will work to resolve any issues.

The first two patches are necessary groundwork and bugfixes for the real
code.  

This code (against 3.3.1 and previous) has been in production for a long
time here and has no known issues.

Here's some info about the patches as a series:

Patch 0001: In the JoinWalker, we assemble an SQL select list fragment
from a list of Joinables.  Reading the existing code, we see it's
possible for the fragment generated to be empty.  However if the LAST
joinable generates an empty fragment, we put a spurious comma into the
fragment.  Fix this by only prepending a comma when necessary.

Patch 0002: In the CriteriaQueryTranslator, we process the path given by
a SubCriteria object looking for the entity name for the property.  If
the SubCriteria was mistakenly created on a component type, we will exit
the loop using the owning entity, and will eventually end up failing
(throwing an exception) trying to lookup up the restricted property
against the entity, instead of against the component.  Fix this by
throwing a more informative exception, and modify the documentation to
be explicit about how to do this properly.

Patch 0003: Implement the enhancement named.  This includes the
documentation changes.  The general approach is:
- create an interface called the CriteriaInfoProvider which abstracts
the operations that are different for the different types of Criteria
targets.
- change the getPathEntityName method to be a factory method for
creating the proper implementation of the interface
- change the rest of CriteriaQueryTranslator to use the interface
instead of using the previous entity-only implementation
- implementations of the interface exist for
  Entity: this implements the same code as currently exists
  ComponentCollection: for collection-of-component
  ScalarCollection: for collection-of-value
  Component: for components
- update the logic in CriteriaJoinWalker which has to be very careful
about how it works since the walker walks certain property paths twice.

Patch 0004: the test case for collection-of-value

Patch 0005: the test case for collection-of-component

Thanks,
David Mansfield
Cobite INC.