Interface Configurable

public interface Configurable
A configurable Exonum service. Allows services to update their configuration through the supervisor service during their operation.

The configuration update process includes the following steps: a proposal of a new configuration; verification of its correctness; approval of the proposal; and application of the new configuration. The protocol of the proposal and approval steps is determined by the installed supervisor service. The verification and application of the parameters are implemented by the service with verifyConfiguration(ExecutionContext, Configuration) and applyConfiguration(ExecutionContext, Configuration) methods.

Services may use the same configuration parameters as in Service.initialize(ExecutionContext, Configuration), or different.

  • Method Details

    • verifyConfiguration

      void verifyConfiguration​(ExecutionContext context, Configuration configuration)
      Verifies the correctness of the proposed configuration.

      This method is called when a new configuration is proposed. If the proposed configuration is correct, this method shall return with no changes to the service data. If it is not valid, this method shall throw an exception.

      context - a read-only execution context object, providing access to the current database state
      configuration - a proposed configuration
      ExecutionException - if the proposed configuration is not valid to prevent the configuration application
    • applyConfiguration

      void applyConfiguration​(ExecutionContext context, Configuration configuration)
      Applies the given configuration to this service. The configuration is guaranteed to be valid according to verifyConfiguration(ExecutionContext, Configuration).

      The implementation shall make any changes to the service persistent state to apply the new configuration, because the supervisor does not store them for later retrieval.

      context - an execution context for this service
      configuration - a new valid configuration