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module Moneta
# Adapter base class
# @api public
class Adapter
include Defaults
include Config
attr_reader :backend
class << self
# Define a block used to build this adapter's backend. The block will
# receive as keyword arguments any options passed to the adapter during
# initialization that are not config settings.
#
# If the adapter is initialized with a `:backend` option, this will be used
# instead, and the block won't be called.
#
# @param [Boolean] required
# @yield [**options] options passed to the adapter's initialize method
# @yieldreturn [Object] The backend to use
def backend(required: true, &block)
raise "backend block already set" if class_variables(false).include?(:@@backend_block)
class_variable_set(:@@backend_block, block)
class_variable_set(:@@backend_required, true) if required
end
def backend_block
class_variable_get(:@@backend_block) if class_variable_defined?(:@@backend_block)
end
def backend_required?
class_variable_defined?(:@@backend_required)
end
end
# @param [Hash] options
def initialize(options = {})
set_backend(**configure(**options))
end
private
def set_backend(backend: nil, **options)
@backend = backend ||
if backend_block = self.class.backend_block
instance_exec(**options, &backend_block)
end
raise ArgumentError, 'backend needs to be set - refer to adapter documentation' if !@backend && self.class.backend_required?
end
end
end
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