public static final class VoltCompoundProcedure.Stage
extends java.lang.Object
VoltCompoundProcedure.
A Stage can only be constructed using one of the methods
of VoltCompoundProcedure.StageListBuilder. The compound procedure does not interact
directly with Stage objects; they provide a description
of how the compound procedure is to be executed.
Each stage is a method of the procedure. The stages are declared
in the initial run method of procedure execution.
A stage may execute any desired computation, and optionally issue one or more procedure calls, prior to returning. The next stage will be called with an array of the responses from the calls issued by the previous stage, when they have been received. The first stage will have an empty response array.
Stages execute sequentially. Each stage executes on an arbitrary thread from a dedicated thread pool, potentially a different thread for each stage.
Intermediate results and working values must be saved in member variables.