[Registry-dev] extensible searching API

[Chathura C. Ekanayake]

There is a problem in returning a ResultSet object in executeQuery(...) 
method.
ResultSets cannot be accessed after the jdbc connection used for 
retrieving the ResultSet is closed.

AFAIK although we use pooled connections, we can't guarantee that the 
connections will not be closed.
Connection pool implementations may close connections after it has 
reached some threshold connection count.

The solution for disconnected database result access is CachedRowSet 
interface, which is only available in java 1.5.
And even in java 1.5, there is no standard impl of that interface.

I think there are two solutions for this problem.

1) Add a java.sql.Connection object as a parameter to the executeQuery 
method. Then the caller of the method is
responsible for closing the connection (or giving the connection back to 
the pool).

2) Create an in-memory table to hold the data of the ResultSet and 
return it.

Comments ...

Thanks,
Chathura

Sanjiva Weerawarana wrote:
> Here's a proposal for adding extensible searching to the registry:
>
> void defineQuery (String name, String query)
> ResultSet executeQuery (String name, Object[] params)
>
> So one can define a query and then later execute it.
>
> Obviously the person writing the query needs to understand the 
> relational data model that we're using; thus effectively we need 
> document that as part of the "API" of the registry.
>
> Thoughts?
>
> Sanjiva.