Package org.gcube.common.health.api

Interface ContextPreparation

public interface ContextPreparation
How an application prepares itself in one of its Contexts (e.g. reads or creates its configuration there and reaches what it needs) and reports its state there. It is optional: an application without it is active in every Context. The class is annotated ContextPreparer.

Both methods work in the Context of the token of the caller, which SmartGears sets before calling them. An exception thrown by either makes the Context unavailable, with a generic reason.

  • Method Summary

    Modifier and Type
    Method
    Description
    ContextState
    prepare()
    Prepares the application in the Context of the caller.
    default Duration
    refresh()
    Returns how often SmartGears prepares the application again in the Contexts where it is already active, e.g. to notice a configuration changed in the Context.
    default void
    removed(String context)
    Tells the application that the node has left a Context, so that it drops what it keeps for it.
    ContextState
    state()
    Returns the state of the application in the Context of the caller, without preparing it.

  • Method Details

    • prepare

      ContextState prepare()
      Prepares the application in the Context of the caller. It does nothing when the application is already active there. It may be called at the same time in the same Context (the start-up thread, a request, the check of the health), so it must be safe under concurrent calls.
      Returns:
      the state of the application in the Context after the attempt

    • state

      ContextState state()
      Returns the state of the application in the Context of the caller, without preparing it.
      Returns:
      the state

    • refresh

      default Duration refresh()
      Returns how often SmartGears prepares the application again in the Contexts where it is already active, e.g. to notice a configuration changed in the Context. The Contexts where it is not active are prepared again every 20 minutes in any case.
      Returns:
      the interval, or null (unless the application says otherwise) to prepare an active Context only once

    • removed

      default void removed(String context)
      Tells the application that the node has left a Context, so that it drops what it keeps for it. It is called with no secret: the token of the Context is gone.
      Parameters:
      context - the Context the node has left