org.eclipse.viatra.query.runtime.api

## Interface ViatraQueryModelUpdateListener

-     public interface ViatraQueryModelUpdateListener

  Listener interface for model changes affecting different levels of the VIATRA Query architecture.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Interface and Description
    --- | ---
    `static class` | `ViatraQueryModelUpdateListener.ChangeLevel` Possible notification levels for changes

  - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `ViatraQueryModelUpdateListener.ChangeLevel` | `getLevel()` This may be queried only ONCE (!!!) at the registration of the listener.
    `void` | `notifyChanged(ViatraQueryModelUpdateListener.ChangeLevel changeLevel)` Called after each change with also sending the level of change.

- - ### Method Detail

    - #### notifyChanged

          void notifyChanged(ViatraQueryModelUpdateListener.ChangeLevel changeLevel)

      Called after each change with also sending the level of change. Only called if the change level is at least at the level returned by getLevel().
      Parameters:
        `changeLevel` -

    - #### getLevel

          ViatraQueryModelUpdateListener.ChangeLevel getLevel()

      This may be queried only ONCE (!!!) at the registration of the listener. NOTE: this allows us to only create engine level change providers if there is someone who needs it.
      Returns:
        the change level where you want notifications