# File lib/active_record/connection_adapters/abstract/connection_specification.rb, line 116
    def self.connection=(spec)
      if spec.kind_of?(ActiveRecord::ConnectionAdapters::AbstractAdapter)
        active_connections[self] = spec
      elsif spec.kind_of?(ConnectionSpecification)
        self.connection = self.send(spec.adapter_method, spec.config)
      elsif spec.nil?
        raise ConnectionNotEstablished
      else
        establish_connection spec
      end
    end