[ACCUMULO-3181] VolumeChooser usage doesn't always comply with implied API contract

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.6.0, 1.6.1
• Fix Version/s: 1.6.2, 1.7.0
• Labels: api interface plugin
• Assignee: Jenna Huston
• Reporter: Christopher Tubbs
• Created: 26/Sep/14 20:24
• Updated: 02/Dec/14 00:59
• Resolved: 29/Oct/14 08:00

Description

The VolumeChooser interface accepts a String array of "options" to choose from. This method has no javadoc to explicitly declare what "options" mean, but given the name of the class, and its intended purpose, derived from its usage, it appears that the Strings it receives should represent volumes.

However, some of the current usage is a bit lax in its parameter passing. In some cases, what is passed are not volumes at all, but volumes concatenated with some path. This works for the RandomVolumeChooser provided, but it should not be expected to work for any arbitrary implementation.

The use of this API should consider the parameter to strictly be an array of volumes (or Strings, representing volumes), since it's not a "PathChooser". Any concatenation of path elements should be done outside the chooser, so we can define the API contract explicitly. That means that some of the current usage should be altered to concatenate path elements after the choose method returns.

Issue Links

• breaks: ACCUMULO-3312 IllegalArgumentException in master and gc during randomwalk
• is related to: ACCUMULO-3178 Create example preferred volumes chooser
• is related to: ACCUMULO-3089 Create a volume chooser that makes decisions based on table attributes
• is related to: ACCUMULO-3376 VolumeChooser API: replace String[] with Set<Volume>
• links to: Review Board