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Bread::Board::Service::WithDependencies - Services with dependencies


version 0.37


This is a sub-role of Bread::Board::Service, for services with dependencies. It provides the mechanism to recursively resolve dependencies.



Hashref, constrained by Bread::Board::Service::Dependencies. Values must be instances of Bread::Board::Dependency, but can be coerced from various other types, see the type's docs.




Adds a new dependency.


  my $dep = $service->get_dependency('name');

Gets a dependency by name.


  if ($service->has_dependency('name')) { ... }

Returns true if this service has a dependency with the given name.


  if ($service->has_dependencies) { ... }

Returns true if this service has any dependency.


  my %deps = $service->get_all_dependencies;

Returns all the dependencies for this service, as a key-value list.


Builder for the service parameters, augmented to inject all the resolved dependencies into the params attribute, so that get can use them.


After the get method, the params attribute is cleared, to make sure that dependencies will be resolved again on the next call (of course, if the service is using a singleton lifecycle, the whole "getting" only happens once).


  my %name_object_map = $self->resolve_dependencies;

For each element of "dependencies", calls its service method to retrieve the service we're dependent on, then tries to instantiate the value of the service. This can happen in a few different ways:

the service is not locked, and does not require any parameter

just call get on it

the service is not locked, requires parameters, but the dependency has values for them

call $service->get(%{$dependency->service_params})

the service is not locked, requires parameters, and we don't have values for them

we can't instantiate anything at this point, so we use a Bread::Board::Service::Deferred::Thunk instance, on which you can call the inflate method, passing it all the needed parameters, to get the actual instance

the service is locked

we return a Bread::Board::Service::Deferred that will proxy to the instance that the service will eventually return; yes, this means that in many cases circular dependencies can be resolved, at the cost of a proxy object


Stevan Little <>


Please report any bugs or feature requests on the bugtracker website

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.


This software is copyright (c) 2019, 2017, 2016, 2015, 2014, 2013, 2011, 2009 by Infinity Interactive.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.