Bug #33823 public interface ResultSetInternalMethods with nonpublic CachedResultSetMetaData
Submitted: 11 Jan 2008 18:11 Modified: 1 Mar 2008 13:30
Reporter: Eric Jensen
Status: Closed
Category:Connector/J Severity:S3 (Non-critical)
Version:5.1.5 OS:Any
Assigned to: Target Version:
Tags: StatementInterceptor, interface, CachedResultSetMetaData, ResultSetInternalMethods

[11 Jan 2008 18:11] Eric Jensen 
Description:
ResultSetInternalMethods is a public interface, but it requires implementing the
following two methods that depend on CachedResultSetMetaData, which is a package-private
class:

populateCachedMetaData(CachedResultSetMetaData cachedMetaData)
initializeFromCachedMetaData(CachedResultSetMetaData cachedMetaData)

This effectively makes it impossible to implement that interface outside the
com.mysql.jdbc package, voiding its utility as a public interface.  This is a problem
when implementing StatementInterceptors because as the comments of
ResultSetInternalMethods say, it is "intended to be used by implementors of statement
interceptors so that implementors can create static ... proxy instances of ResultSets". 
This is not actually possible without introducing a class into the com.mysql.jdbc
package.

How to repeat:
Implementing the ResultSetInternalMethods interface in a package other than
com.mysql.jdbc will cause these compiler errors:

- The type com.mysql.jdbc.CachedResultSetMetaData is not visible
- The type ExampleResultSetInternalMethodsImpl must implement the 
	 inherited abstract method 
ResultSetInternalMethods.initializeFromCachedMetaData(CachedResultSetMeta
	 Data)
- The type ExampleResultSetInternalMethodsImpl must implement the 
	 inherited abstract method 
	ResultSetInternalMethods.populateCachedMetaData(CachedResultSetMetaData)

Suggested fix:
make CachedResultSetMetaData a public class
[20 Jan 2008 4:53] Bugs System 
A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/41075
[31 Jan 2008 6:10] Bugs System 
A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/41474
[1 Mar 2008 13:30] MC Brown 
A note has been added to the 5.1.6 changelog: 

The internal class ResultSetInternalMethods referenced the non-public class
com.mysql.jdbc.CachedResultSetMetaData.