note
	description: "[
					Object that represents a delayed domain used in Eiffel query language
		
					 A delayed domain means that `content' of the domain is not defined until a certain time.
					 For example, in query:
					     from "base" select class as c where (count feature from c > 10)
					 in this query, c is a delayed domain. Content of this delayed domain
					 is only meaningful when this query is executed. To be more detailed, when this query
					 executes, it will iterate all classes in group "base", and for every class, c
					 defines a domain which has one item which is the current iterated class in it.
				]"
	legal: "See notice at end of class."
	status: "See notice at end of class."
	date: "$Date$"
	revision: "$Revision$"

deferred class
	QL_DELAYED_DOMAIN

inherit
	QL_DOMAIN
		redefine
			is_delayed
		end

	QL_OBSERVER

feature -- Status report

	is_delayed: BOOLEAN = True
			-- Is `Current' a delayed domain?
			-- A delayed domain means that `content' of the domain is not defined until a certain time.
			-- For example, in query:
			--     from "base" select class as current_class where (count feature from current_class > 10)
			-- in this query, current_class is a delayed domain. Content of this delayed domain
			-- is only meaningful when this query is executed. To be more detailed, when this query
			-- executes, it will iterate all classes in group "base", and for every class, current_class
			-- defines a domain which has one item which is the current iterated class in it.			

feature -- Notification

	update (a_observable: QL_DOMAIN_GENERATOR; a_data: like item_type)
			-- Notification from `a_observable' indicating that `a_data' changed.
		do
			wipe_out
			if attached {like item_type} a_data.nearest_parent_with_scope (scope) as a_item then
				check a_item.is_valid_domain_item end
				content.extend (a_item)
			end
		end

note
	copyright: "Copyright (c) 1984-2018, Eiffel Software"
	license: "GPL version 2 (see http://www.eiffel.com/licensing/gpl.txt)"
	licensing_options: "http://www.eiffel.com/licensing"
	copying: "[
			This file is part of Eiffel Software's Eiffel Development Environment.
			
			Eiffel Software's Eiffel Development Environment is free
			software; you can redistribute it and/or modify it under
			the terms of the GNU General Public License as published
			by the Free Software Foundation, version 2 of the License
			(available at the URL listed under "license" above).
			
			Eiffel Software's Eiffel Development Environment is
			distributed in the hope that it will be useful, but
			WITHOUT ANY WARRANTY; without even the implied warranty
			of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
			See the GNU General Public License for more details.
			
			You should have received a copy of the GNU General Public
			License along with Eiffel Software's Eiffel Development
			Environment; if not, write to the Free Software Foundation,
			Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
		]"
	source: "[
			Eiffel Software
			5949 Hollister Ave., Goleta, CA 93117 USA
			Telephone 805-685-1006, Fax 805-685-6869
			Website http://www.eiffel.com
			Customer support http://support.eiffel.com
		]"

end