Accepting Object[] as an acceptable input to setObject with Types.ARRAY?

From: Steven Schlansker <stevenschlansker(at)gmail(dot)com>
To: pgsql-jdbc(at)postgresql(dot)org
Subject: Accepting Object[] as an acceptable input to setObject with Types.ARRAY?
Date: 2011-06-03 20:04:58
Message-ID: AFD63DD9-2CDD-41E5-AB5D-AA6D8A33A59F@gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-jdbc

Hi all,

First off, the environment -
PostgreSQL 9.0, driver 9.0-801.jdbc4
C3P0 0.9.1.2
H2 1.3.154

Here's my dilemma. I am attempting to use SQL Arrays (a JDBC 4 feature) but all the JDBC pools I have had good success with (to date, only C3P0) do not support JDBC 4. Specifically, if you try to call Connection.createArrayOf, the pool intercepts it and fails with an AbstractMethodError as the Connection did not specify that interface method when C3P0 was compiled (against the JDBC 2 API). It is possible to break through this barrier with reflective magic, but I don't like this as a long term solution.

This means that it is not possible to create the java.sql.Array instance that would be required to call setArray to set an array argument on a prepared statement in a portable way.

H2 (http://www.h2database.com) supports a nifty workaround - if you call setObject with a Object[] it will "do the right thing" and internally convert this into the SQL Array. This means that the driver does the work so client code does not have to hack around the lack of createArrayOf.

(ref: http://www.h2database.com/html/datatypes.html#array_type )

It looks like adding support for such a fix to the Postgres driver would be extremely easy. In particular looking around AbstractJdbc2Statement.java:1732

case Types.ARRAY:
if (in instanceof Array)
setArray(parameterIndex, (Array)in);
else
throw new PSQLException(GT.tr("Cannot cast an instance of {0} to type {1}", new Object[]{in.getClass().getName(),"Types.ARRAY"}), PSQLState.INVALID_PARAMETER_TYPE);
break;

it could check if in is an array type and if so synthesize the Array object necessary.

Does this sound like a reasonable feature request? Did I miss an easier way to do this? It is probably outside of the JDBC spec but it at least has some traction with H2...

If this is a reasonable approach I would be happy to contribute a patch, although I am sure an actual PG JDBC developer could do it much faster than I.

Thanks much for any input,
Steven

Responses

Browse pgsql-jdbc by date

  From Date Subject
Next Message Radosław Smogura 2011-06-03 20:59:28 Re: Accepting Object[] as an acceptable input to setObject with Types.ARRAY?
Previous Message Johnny Luong 2011-06-03 18:40:50 SELECT statement_timeout(integer) in lieu of setQueryTimeout at the statement level