org.voltdb.task

Interface ActionGenerator

public interface ActionGenerator

Interface which generates actions to be be performed as part of a task on a schedule

Method Summary

Modifier and Type	Method and Description
Action	getFirstAction() This method is invoked only once to obtain the first action.
default boolean	isReadOnly() Return false unless it is guaranteed that all procedures are also read only.
default boolean	restrictProcedureByScope() If this method returns true that means the type of procedure which this scheduler can run is restricted based upon the scope type.

Methods inherited from interface org.voltdb.task.Initializable

getDependencies

Method Detail

getFirstAction

Action getFirstAction()

This method is invoked only once to obtain the first action. The first action will be performed after a time interval has elapsed. After the action has been performed callback will be invoked with the result of this action. The return of the callback will be used as the next action.

If this method throws an exception or returns null the task instance will halted and put into an error state.

Returns:

Action to perform

restrictProcedureByScope

default boolean restrictProcedureByScope()

If this method returns true that means the type of procedure which this scheduler can run is restricted based upon the scope type.

• SYSTEM - Cannot run single partition procedures
• HOSTS - Only NT procedures are allowed
• PARTITIONS - Only partitioned procedures are allowed

Default return is false

Returns:

true if the type of procedure this scheduler can run should be restricted based upon scope

isReadOnly

default boolean isReadOnly()

Return false unless it is guaranteed that all procedures are also read only.

Returns:

true if all procedures returned by this instance are read only