[TINKERPOP-1162] Add VertexProgram.getTransientComputeKeys() for removing scratch-data.

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Implemented
• Affects Version/s: 3.1.0-incubating
• Fix Version/s: 3.2.0-incubating
• Component/s: process
• Labels: breaking
• Assignee: Marko A. Rodriguez
• Reporter: Marko A. Rodriguez
• Created: 17/Feb/16 22:34
• Updated: 01/Mar/16 14:30
• Resolved: 01/Mar/16 14:30

Description

When you run a PageRankVertexProgram or a PeerPressureVertexProgram, you have an edgeCount property which is used for determining the weight distribution. This is just some "scratch pad data." We need a way to tell the GraphComputer which properties are "scratch pad" and thus, delete them before outputting the `ComputerResult`.

I propose:

Set<String> VertexProgram.getTransientComputeKeys()

We can have a default that returns Collections.emptySet(). This would be breaking as the GraphComputer provider will need to handle dropping such properties. This, of course, will be verified in a GraphComputerTest.shouldSupportTransientProperties().