[TAJO-1114] Improve ConfVars (SessionVar) to take a validator interface to check its input.

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.10.0
• Assignee: Jihun Kang
• Reporter: Hyunsik Choi
• Created: 12/Oct/14 20:11
• Updated: 28/Oct/14 06:42
• Resolved: 28/Oct/14 06:28

Description

Each task uses session variables from client or configs from tajo-site.xml. The session variables and configs are used in task during query processing.

If invalid configs or invalid session variables are used for a query, the error will be caused in a runtime instead of query init phase. It's bad situation. Invalid values must be detected at the initialization phase.

Because each session variable or config varies in its value type and value range, It would be great if each ConfigKey takes a validator for its value and Tajo uses validators for it.