com.exonum.binding.core.service

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(Fork, Configuration) and applyConfiguration(Fork, Configuration) methods.

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

Method Summary

Modifier and Type	Method and Description
void	applyConfiguration(Fork fork, Configuration configuration) Applies the given configuration to this service.
void	verifyConfiguration(Fork fork, Configuration configuration) Verifies the correctness of the proposed configuration.

Method Detail

verifyConfiguration

void verifyConfiguration(Fork fork,
                         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.

Parameters:

fork - a view representing the current database state

configuration - a proposed configuration

Throws:

IllegalArgumentException - if the proposed configuration is not valid

applyConfiguration

void applyConfiguration(Fork fork,
                        Configuration configuration)

Applies the given configuration to this service. The configuration is guaranteed to be valid according to verifyConfiguration(Fork, 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.

Parameters:

fork - a fork to which to apply changes

configuration - a new valid configuration