[DERBY-1615] Rewrite the Clob implementation in the client driver

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Later
• Fix Version/s: 11.0.0.0
• Component/s: JDBC, Network Client
• Labels: LOB
• Assignee: Unassigned
• Reporter: Kristian Waagan
• Created: 31/Jul/06 13:58
• Updated: 25/May/10 13:41
• Resolved: 08/May/09 12:47

Description

The implementation of java.sql.Clob in the client driver is cracking up, and should be rewritten.
A number of bugs have been discovered, and the implementation has traces of old and/or deprecated features. Further, several mandatory methods (JDBC 3 & 4) have not yet been implemented and could benefit from a fresh start.
I think maintainability for this piece of code has dropped to an unacceptable level.

It seems the implementation is based on an assumption that no longer holds; that a Clob object used for input to the database is never passed to the user. The consequence of this, is that the internal state of the Clob object is not valid [at all times], which causes exceptions when the user invokes methods on it.

A number of related Jira issues have been linked to this issue to aid the reimplementation process.

Issue Links

• relates to: DERBY-1599 Clob.getSubString() throws NullPointerException when created by updatable result set
• relates to: DERBY-253 Client should throw not implemented exception for depricated setUnicodeStream/getUnicodeStream
• relates to: DERBY-1516 Inconsistent behavior for getBytes and getSubString for embedded versus network
• relates to: DERBY-684 Improve performance of Clob objects (ClobOutputStream#write,ClobWriter#write) on the client
• relates to: DERBY-1286 Fill in Clob methods required for JDBC3 compliance
• relates to: DERBY-1341 LOB set method(s) are currently no supported, but part of the Java 1.4 JDBC interface
• relates to: DERBY-1417 Add new, lengthless overloads to the streaming api