Package com.launchdarkly.sdk.android.subsystems

Interface DataSource

public interface DataSource
Interface for an object that receives updates to feature flags from LaunchDarkly.

This component uses a push model. When it is created, the SDK will provide a reference to a DataSourceUpdateSink component (as part of ClientContext, which is a write-only abstraction of the SDK state. The SDK never requests feature flag data from the DataSource-- it only looks at the last known data that was pushed into the state.

Each LDClient instance maintains exactly one active data source instance. It stops and discards the active data source whenever it needs to create a new one due to a significant state change, such as if the evaluation context is changed with identify(), or if the SDK goes online after previously being offline, or if the foreground/background state changes.

Since:
3.3.0
See Also:

  • Method Summary

    Modifier and Type
    Method
    Description
    default boolean
    needsRefresh(boolean newInBackground, LDContext newEvaluationContext)
    The SDK calls this method to determine whether it needs to stop the current data source and start a new one after a state transition.
    void
    start(Callback<Boolean> resultCallback)
    Initializes the data source.
    void
    stop(Callback<Void> completionCallback)
    Tells the data source to stop.

  • Method Details

    • start

      void start(@NonNull Callback<Boolean> resultCallback)
      Initializes the data source. This is called only once per instance.
      Parameters:
      resultCallback - called when the data source has successfully acquired the initial data, or if an error has occurred

    • stop

      void stop(@NonNull Callback<Void> completionCallback)
      Tells the data source to stop.
      Parameters:
      completionCallback - called once it has completely stopped (this is allowed to be asynchronous because it might involve network operations that can't be done on the main thread)

    • needsRefresh

      default boolean needsRefresh(boolean newInBackground, LDContext newEvaluationContext)
      The SDK calls this method to determine whether it needs to stop the current data source and start a new one after a state transition.

      State transitions include going from foreground to background or vice versa, or changing the evaluation context. The SDK will not call this method unless at least one of those types of transitions has happened.

      If this method returns true, the SDK considers the current data source to be no longer valid, stops it, and asks the ComponentConfigurer to create a new one.

      If this method returns false, the SDK retains the current data source.

      Parameters:
      newInBackground - true if the application is now in the background
      newEvaluationContext - the new evaluation context
      Returns:
      true if the data source should be recreated
      Since:
      4.1.0