# * George Moschovitis  <gm@navel.gr>
# (c) 2004-2005 Navel, all rights reserved.
# $Id: og.rb 270 2005-03-07 17:52:16Z gmosx $

require 'glue'
require 'glue/logger'
require 'glue/attribute'
require 'glue/property'
require 'glue/array'
require 'glue/hash'
require 'glue/time'
require 'glue/pool'
require 'glue/validation'

# Og (ObjectGraph) is an efficient, yet simple Object-Relational 
# mapping library. 
#
# === Features
#
# The library provides the following features:
#
# + Object-Relational mapping.
# + Absolutely no configuration files.
# + Multiple backends (PostgreSQL, MySQL, SQLite).
# + ActiveRecord-style meta language and db aware methods.
# + Deserialize to Ruby Objects.
# + Deserialize sql join queries to Ruby Objects (temporarily dissabled).
# + Serialize arbitrary ruby object graphs through YAML.
# + Connection pooling.
# + Thread safety.
# + SQL transactions.
# + Lifecycle callbacks.
# + Lifecycle observers.
# + Transparent support for cascading deletes for all backends.
# + Hierarchical structures (preorder traversal, materialized paths)
# + Works safely as part of distributed application.
# + Simple implementation.
#
# === Meta language
#
# primary_key :pid (NOT IMPLEMENTED)
# name_key :name (NOT IMPLEMENTED)
# prop_accessor Fixnum, :pid, :sql => "smallint DEFAULT 1"
# has_many Child, :children
# many_to_many Role, :roles
# sql_index :pid
#
# === Property Metadata
#
# Og defines, reserves and uses the following property 
# metadata types:
#
# [+:sql_index+]
#		Create an sql index for this property.
#
# [+:unique+]
#		This value of the property must be unique.
#
# [+:name_key+] 
#		This property is used as name-key.
#
# === Design
#
# Keep the main classes backend agnostic. 
#
# For class ids we use the name instead of a hash. Class ids are
# typically not used in querys, they are stored for completeness.
# If we store a hash we cannot reclaim the class thus invalidating
# the point. Instead of .name(), to_s() is used so the methods
# are more flexible (they accept class names too!!)
#
# Og allows the serialization of arbitrary Ruby objects. Just
# mark them as Object (or Array or Hash) in the prop_accessor
# and the engine will serialize a YAML dump of the object.
# Arbitrary object graphs are supported too.
#
# This is NOT a singleton, an application may access multiple
# databases.
#
# The og.xxx methods are more flexible and allow you to use
# multiple databases for example.
# 
# === Managed Objects Lifecycle Callbacks
#
# * og_pre_read
# * og_post_read
# * og_pre_insert
# * og_post_insert
#	* og_pre_update
# * og_post_update
# * og_pre_insert_update
# * og_post_insert_update
# * self.og_pre_delete
#
# A class level callback is used for delete because typically you call
# delete with an oid and not an object to avoid a deserialization.
#
# === Future 
# 
# * Support prepared statements (pgsql)
# * Support stored procedures (pgsql)
# * Support caching.
# * Deserialize to OpenStruct.
# * Better documentation.

module Og

	# The name.

	Name = 'ObjectGraph'

	# The version.

	Version = '0.12.0'

	# Library path.

	LibPath = File.dirname(__FILE__)

	# If true, only allow reading from the database. Usefull
	# for maintainance.
	
	mattr_accessor :read_only_mode, false

	# If true, the library automatically 'enchants' managed classes.
	# In enchant mode, special db aware methods are added to 
	# managed classes and instances.
	# If false, Og enchants only classes that define properties.
	
	mattr_accessor :enchant_managed_classes, true
	
	# If true, use Ruby's advanced introspection capabilities to 
	# automatically manage classes tha define properties.
	
	mattr_accessor :auto_manage_classes, true

	# If true, automatically include the Og meta-language into Module. 
	# If false, the polution of the Module object is avoided. However 
	# if you include a prop_accessor or a managed Mixin in your
	# object MetaLanguage gets automatically extended in the class.
	
	mattr_accessor :include_meta_language, true
	
	# Attach the following prefix to all generated SQL table names.
	# Usefull on hosting scenarios where you have to run multiple
	# web applications/sites on a single database.
	
	mattr_accessor :table_prefix, nil

	# If true, Og tries to create/update the schema in the
	# data store. For production/live environments set this to false
	# and only set to true when the object model is upadated.
	# For debug/development environments this should stay true
	# for convienience.
	
	mattr_accessor :create_schema, true
	
	# The active database. Og allows you to access multiple
	# databases from a single application.
	
	mattr_accessor :db

	# Set the active database.

	def self.use(db)
		@@db = db
		@@db.get_connection
	end

	# The adapter of the active database.

	def self.adapter
		@@db.adapter
	end

	# Marker module. If included this in a class, the Og automanager
	# ignores this class.

	module Unmanageable; end

end

# gmosx: leave this here.

require 'og/database'