onExisting<TCommand extends Object> method

void onExisting<TCommand extends Object>(AggregateIdResolver<TCommand, TId> toId, AggregateCommandHandler<TCommand, TEvent, TValue, TId, TState, TAggregate> action)

Register an asynchronous handler for a command, which is expected to use an existing aggregate instance. Use parameter toId to get the AggregateId from give command. Use parameter action to performed actions on the aggregate, given the aggregate instance and the command

• Type parameter TCommand - Command type

Implementation

void onExisting<TCommand extends Object>(
    AggregateIdResolver<TCommand, TId> toId,
    AggregateCommandHandler<TCommand, TEvent, TValue, TId, TState, TAggregate>
        action) {
  assert(!isFrozen, 'Aggregate handlers has been frozen');

  _handlers.putIfAbsent(
    typeOf<TCommand>(),
    () => RegisteredAggregateCommandHandler<TCommand, TEvent, TValue, TId,
        TState, TAggregate>(
      ExpectedState.exists,
      action,
    ),
  );

  _resolvers.putIfAbsent(
    typeOf<TCommand>(),
    () => (command) => toId(command as TCommand),
  );
}