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https://issues.apache.org/jira/browse/DERBY-5872?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Knut Anders Hatlen updated DERBY-5872:
--------------------------------------

    Issue & fix info: Patch Available
    
> 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
>         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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