~michaelforrest/use-case-mapper/trunk

module ActiveRecord

  class Base

    class ConnectionSpecification #:nodoc:

      attr_reader :config, :adapter_method

      def initialize (config, adapter_method)

        @config, @adapter_method = config, adapter_method

      end

    end

 

    ##

    # :singleton-method:

    # The connection handler

    cattr_accessor :connection_handler, :instance_writer => false

    @@connection_handler = ConnectionAdapters::ConnectionHandler.new

 

    # Returns the connection currently associated with the class. This can

    # also be used to "borrow" the connection to do database work that isn't

    # easily done without going straight to SQL.

    def connection

      self.class.connection

    end

 

    # Establishes the connection to the database. Accepts a hash as input where

    # the <tt>:adapter</tt> key must be specified with the name of a database adapter (in lower-case)

    # example for regular databases (MySQL, Postgresql, etc):

    #

    #   ActiveRecord::Base.establish_connection(

    #     :adapter  => "mysql",

    #     :host     => "localhost",

    #     :username => "myuser",

    #     :password => "mypass",

    #     :database => "somedatabase"

    #   )

    #

    # Example for SQLite database:

    #

    #   ActiveRecord::Base.establish_connection(

    #     :adapter => "sqlite",

    #     :database  => "path/to/dbfile"

    #   )

    #

    # Also accepts keys as strings (for parsing from YAML for example):

    #

    #   ActiveRecord::Base.establish_connection(

    #     "adapter" => "sqlite",

    #     "database"  => "path/to/dbfile"

    #   )

    #

    # The exceptions AdapterNotSpecified, AdapterNotFound and ArgumentError

    # may be returned on an error.

    def self.establish_connection(spec = nil)

      case spec

        when nil

          raise AdapterNotSpecified unless defined? RAILS_ENV

          establish_connection(RAILS_ENV)

        when ConnectionSpecification

          @@connection_handler.establish_connection(name, spec)

        when Symbol, String

          if configuration = configurations[spec.to_s]

            establish_connection(configuration)

          else

            raise AdapterNotSpecified, "#{spec} database is not configured"

          end

        else

          spec = spec.symbolize_keys

          unless spec.key?(:adapter) then raise AdapterNotSpecified, "database configuration does not specify adapter" end

 

          begin

            require 'rubygems'

            gem "activerecord-#{spec[:adapter]}-adapter"

            require "active_record/connection_adapters/#{spec[:adapter]}_adapter"

          rescue LoadError

            begin

              require "active_record/connection_adapters/#{spec[:adapter]}_adapter"

            rescue LoadError

              raise "Please install the #{spec[:adapter]} adapter: `gem install activerecord-#{spec[:adapter]}-adapter` (#{$!})"

            end

          end

 

          adapter_method = "#{spec[:adapter]}_connection"

          if !respond_to?(adapter_method)

            raise AdapterNotFound, "database configuration specifies nonexistent #{spec[:adapter]} adapter"

          end

 

          remove_connection

          establish_connection(ConnectionSpecification.new(spec, adapter_method))

      end

    end

 

    class << self

      # Deprecated and no longer has any effect.

      def allow_concurrency

        ActiveSupport::Deprecation.warn("ActiveRecord::Base.allow_concurrency has been deprecated and no longer has any effect. Please remove all references to allow_concurrency.")

      end

 

      # Deprecated and no longer has any effect.

      def allow_concurrency=(flag)

        ActiveSupport::Deprecation.warn("ActiveRecord::Base.allow_concurrency= has been deprecated and no longer has any effect. Please remove all references to allow_concurrency=.")

      end

 

      # Deprecated and no longer has any effect.

      def verification_timeout

        ActiveSupport::Deprecation.warn("ActiveRecord::Base.verification_timeout has been deprecated and no longer has any effect. Please remove all references to verification_timeout.")

      end

 

      # Deprecated and no longer has any effect.

      def verification_timeout=(flag)

        ActiveSupport::Deprecation.warn("ActiveRecord::Base.verification_timeout= has been deprecated and no longer has any effect. Please remove all references to verification_timeout=.")

      end

 

      # Returns the connection currently associated with the class. This can

      # also be used to "borrow" the connection to do database work unrelated

      # to any of the specific Active Records.

      def connection

        retrieve_connection

      end

 

      def connection_pool

        connection_handler.retrieve_connection_pool(self)

      end

 

      def retrieve_connection

        connection_handler.retrieve_connection(self)

      end

 

      # Returns true if +ActiveRecord+ is connected.

      def connected?

        connection_handler.connected?(self)

      end

 

      def remove_connection(klass = self)

        connection_handler.remove_connection(klass)

      end

 

      delegate :clear_active_connections!, :clear_reloadable_connections!,

        :clear_all_connections!,:verify_active_connections!, :to => :connection_handler

    end

  end

end