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Posted to derby-dev@db.apache.org by "Mamta A. Satoor (JIRA)" <ji...@apache.org> on 2013/07/26 19:33:48 UTC
[jira] [Commented] (DERBY-5872) Inconsistency between
isWrapperFor() and unwrap() in logical statements
[ https://issues.apache.org/jira/browse/DERBY-5872?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13720973#comment-13720973 ]
Mamta A. Satoor commented on DERBY-5872:
----------------------------------------
Knut, I was wondering if it would be ok to backport this to 10.9 and 10.8. It is on the list of jiras to backport.
> Inconsistency between isWrapperFor() and unwrap() in logical statements
> -----------------------------------------------------------------------
>
> Key: DERBY-5872
> URL: https://issues.apache.org/jira/browse/DERBY-5872
> Project: Derby
> Issue Type: Bug
> Components: JDBC
> Affects Versions: 10.4.1.3, 10.5.1.1, 10.6.1.0, 10.7.1.1, 10.8.1.2, 10.9.1.0
> Reporter: Knut Anders Hatlen
> Assignee: Knut Anders Hatlen
> Fix For: 10.10.1.1
>
> Attachments: derby-5872-1a.diff
>
>
> I noticed this when I refactored the logical statement classes in DERBY-5868. The isWrapperFor() method forwards calls to the underlying physical statement, but the unwrap() method works purely at the logical level.
> For example, if you produce a LogicalPreparedStatement40 instance with this code
> ClientConnectionPoolDataSource ds = new ClientConnectionPoolDataSource();
> ds.setDatabaseName("testdb");
> ds.setCreateDatabase("create");
> ds.setMaxStatements(10);
> PooledConnection pc = ds.getPooledConnection();
> Connection c = pc.getConnection();
> PreparedStatement ps = c.prepareStatement("values 1");
> you'll see that
> System.out.println(ps.isWrapperFor(LogicalPreparedStatement40.class));
> prints false, telling that ps is not a wrapper for LogicalPreparedStatement40. However, trying to unwrap ps as a LogicalPreparedStatement succeeds:
> LogicalPreparedStatement40 lps = ps.unwrap(LogicalPreparedStatement40.class);
> On the other hand
> System.out.println(ps.isWrapperFor(PreparedStatement40.class));
> prints true, indicating that ps is a wrapper for PreparedStatement40, but trying to unwrap it as one, fails:
> PreparedStatement40 ps4 = ps.unwrap(PreparedStatement40.class);
> Exception in thread "main" java.sql.SQLException: Unable to unwrap for 'class org.apache.derby.client.am.PreparedStatement40'
> at org.apache.derby.client.am.SQLExceptionFactory40.getSQLException(SQLExceptionFactory40.java:108)
> at org.apache.derby.client.am.SqlException.getSQLException(SqlException.java:364)
> at org.apache.derby.client.am.LogicalStatementEntity.unwrap(LogicalStatementEntity.java:258)
> at org.apache.derby.client.am.LogicalPreparedStatement.unwrap(LogicalPreparedStatement.java:57)
> at Test.main(Test.java:37)
> Caused by: org.apache.derby.client.am.SqlException: Unable to unwrap for 'class org.apache.derby.client.am.PreparedStatement40'
> ... 3 more
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