[FLINK-3469] Improve documentation for grouping keys

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.0.0
• Fix Version/s: 1.0.1, 1.1.0
• Component/s: Documentation
• Assignee: Greg Hogan
• Reporter: Greg Hogan
• Created: 22/Feb/16 17:52
• Updated: 11/Apr/16 12:24
• Resolved: 11/Apr/16 12:24

Description

The transformation documentation for "Reduce on DataSet Grouped by KeySelector Function" uses a field expression in the Java example.

There are four ways to specify keys and only two have named examples in the documentation. Expand the documentation to cover all cases.