# File lib/active_record/connection_adapters/seamless_database_pool_adapter.rb, line 41
      def establish_adapter(adapter)
        raise AdapterNotSpecified.new("database configuration does not specify adapter") unless adapter
        raise AdapterNotFound.new("database pool must specify adapters") if adapter == 'seamless_database_pool'
      
        begin
          require 'rubygems'
          gem "activerecord-#{adapter}-adapter"
          require "active_record/connection_adapters/#{adapter}_adapter"
        rescue LoadError
          begin
            require "active_record/connection_adapters/#{adapter}_adapter"
          rescue LoadError
            raise "Please install the #{adapter} adapter: `gem install activerecord-#{adapter}-adapter` (#{$!})"
          end
        end

        adapter_method = "#{adapter}_connection"
        if !respond_to?(adapter_method)
          raise AdapterNotFound, "database configuration specifies nonexistent #{adapter} adapter"
        end
      end