indexing description: "[ A utility for clients accessing a service (globally or locally via a service provider) and determining a service's existence. ]" doc: "wiki://Service Consumers" legal: "See notice at end of class." status: "See notice at end of class."; date: "$date$"; revision: "$revision$" class SERVICE_CONSUMER [G -> SERVICE_I] inherit ANY SHARED_SERVICE_PROVIDER rename service_provider as global_service_provider export {NONE} all end create default_create, make_with_provider feature {NONE} -- Initialization make_with_provider (a_provider: ?like service_provider) -- Initialize a service consumer using an alternative (local) service provider. -- -- `a_provider': A service provider to use when querying for a service, instead of the global -- one. indexing doc: "wiki://Service Consumers:Using Local Service Providers" require a_provider_attached: a_provider /= Void do internal_service_provider := a_provider ensure service_provider_set: service_provider = a_provider end feature -- Access service: !G -- Access to the service require is_service_available: is_service_available local l_service: ?G do if {l_internal_service: G} internal_service then Result := l_internal_service else if {l_other_service: G} service_provider.service ({G}) then l_service := l_other_service else check False end end check l_service_attached: l_service /= Void end Result := l_service internal_service := Result end end feature {NONE} -- Access service_provider: !SERVICE_PROVIDER_I -- Access to the set service provider, or global service provider if no local provider was set. do if {l_provider :like internal_service_provider} internal_service_provider then Result := l_provider else Result := global_service_provider end end feature -- Status report is_service_available: BOOLEAN -- Indicates if the service is available indexing doc: "wiki://Service Consumers:Services Are Tentative" do Result := internal_service /= Void or else (service_provider.service ({G}) /= Void) ensure has_service: Result implies (internal_service /= Void) or else service_provider.service ({G}) /= Void end feature {NONE} -- Implementation: Internal cache internal_service: ?G -- Cached version of `service'. -- Note: Do not use directly! internal_service_provider: ?like service_provider -- Cached version of `service_provider' -- Note: Do not use directly! ;indexing copyright: "Copyright (c) 1984-2008, 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 356 Storke Road, Goleta, CA 93117 USA Telephone 805-685-1006, Fax 805-685-6869 Website http://www.eiffel.com Customer support http://support.eiffel.com ]" end