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159 | -----------------------------------------------------------------------
-- awa-events-services -- AWA Event Manager
-- Copyright (C) 2012, 2016, 2020 Stephane Carrez
-- Written by Stephane Carrez (Stephane.Carrez@gmail.com)
--
-- Licensed under the Apache License, Version 2.0 (the "License");
-- you may not use this file except in compliance with the License.
-- You may obtain a copy of the License at
--
-- http://www.apache.org/licenses/LICENSE-2.0
--
-- Unless required by applicable law or agreed to in writing, software
-- distributed under the License is distributed on an "AS IS" BASIS,
-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-- See the License for the specific language governing permissions and
-- limitations under the License.
-----------------------------------------------------------------------
with Ada.Finalization;
with Ada.Containers.Doubly_Linked_Lists;
with Util.Strings;
with EL.Expressions;
with EL.Beans;
with AWA.Events.Models;
with AWA.Events.Queues;
with AWA.Events.Queues.Maps;
with AWA.Events.Dispatchers;
limited with AWA.Applications;
package AWA.Events.Services is
-- ------------------------------
-- Event manager
-- ------------------------------
-- The `Event_Manager` manages the dispatch of event to the right event queue
-- or to the event action. The event manager holds a list of actions that
-- must be triggered for a particular event/queue pair. Such list is created
-- and initialized when the application is configured. It never changes.
type Event_Manager is tagged limited private;
type Event_Manager_Access is access all Event_Manager'Class;
-- Find the event queue identified by the given name.
function Find_Queue (Manager : in Event_Manager;
Name : in String) return AWA.Events.Queues.Queue_Ref;
-- Add the event queue in the registry.
procedure Add_Queue (Manager : in out Event_Manager;
Queue : in AWA.Events.Queues.Queue_Ref);
-- Send the event to the modules that subscribed to it.
-- The event is sent on each event queue. Event queues will dispatch the event
-- by invoking immediately or later on the `Dispatch`> operation.
-- The synchronous or asynchronous reception of the event depends
-- on the event queue.
procedure Send (Manager : in Event_Manager;
Event : in Module_Event'Class);
-- Set the event message type which correspond to the `Kind` event index.
procedure Set_Message_Type (Manager : in Event_Manager;
Event : in out AWA.Events.Models.Message_Ref;
Kind : in Event_Index);
-- Set the event queue associated with the event message.
-- The event queue identified by `Name` is searched to find the
-- `Queue_Ref` instance.
procedure Set_Event_Queue (Manager : in Event_Manager;
Event : in out AWA.Events.Models.Message_Ref;
Name : in String);
-- Dispatch the event identified by `Event` and associated with the event
-- queue `Queue`. The event actions which are associated with the event are
-- executed synchronously.
procedure Dispatch (Manager : in Event_Manager;
Queue : in AWA.Events.Queues.Queue_Ref;
Event : in Module_Event'Class);
-- Add an action invoked when the event identified by `Event` is sent.
-- The event is posted on the queue identified by `Queue`.
-- When the event queue dispatches the event, the Ada bean identified
-- by the method action represented by `Action` is created and initialized
-- by evaluating and setting the parameters defined in `Params`.
-- The action method is then invoked.
procedure Add_Action (Manager : in out Event_Manager;
Event : in String;
Queue : in AWA.Events.Queues.Queue_Ref;
Action : in EL.Expressions.Method_Expression;
Params : in EL.Beans.Param_Vectors.Vector);
-- Add a dispatcher to process the event queues matching the `Match` string.
-- The dispatcher can create up to `Count` tasks running at the priority
-- `Priority`.
procedure Add_Dispatcher (Manager : in out Event_Manager;
Match : in String;
Count : in Positive;
Priority : in Positive);
type Application_Access is access all AWA.Applications.Application'Class;
-- Initialize the event manager.
procedure Initialize (Manager : in out Event_Manager;
App : in Application_Access);
-- Start the event manager. The dispatchers are configured to dispatch
-- the event queues and tasks are started to process asynchronous events.
procedure Start (Manager : in out Event_Manager);
-- Stop the event manager.
procedure Stop (Manager : in out Event_Manager);
-- Get the application associated with the event manager.
function Get_Application (Manager : in Event_Manager) return Application_Access;
private
use AWA.Events.Queues;
-- An event queue associated with a dispatcher.
type Queue_Dispatcher is record
Queue : AWA.Events.Queues.Queue_Ref;
Dispatcher : AWA.Events.Dispatchers.Dispatcher_Access := null;
Model : AWA.Events.Models.Queue_Ref;
end record;
-- Finalize the queue dispatcher releasing the dispatcher memory.
procedure Finalize (Object : in out Queue_Dispatcher);
-- A list of event queue dispatcher.
package Queue_Dispatcher_Lists is
new Ada.Containers.Doubly_Linked_Lists (Element_Type => Queue_Dispatcher);
-- A list of event queues for a given event.
type Event_Queues is record
Queues : Queue_Dispatcher_Lists.List;
Name : Util.Strings.Name_Access;
Event : AWA.Events.Models.Message_Type_Ref;
end record;
-- Finalize the event queues and the dispatchers.
procedure Finalize (Object : in out Event_Queues);
-- An array of event queue actions.
type Event_Queues_Array is array (Event_Index range <>) of Event_Queues;
type Event_Queues_Array_Access is access all Event_Queues_Array;
type Event_Manager is new Ada.Finalization.Limited_Controlled with record
Actions : Event_Queues_Array_Access := null;
Queues : AWA.Events.Queues.Maps.Map;
Application : Application_Access := null;
Dispatchers : Events.Dispatchers.Dispatcher_Access_Array := (others => null);
end record;
-- Finalize the event manager by releasing the allocated storage.
overriding
procedure Finalize (Manager : in out Event_Manager);
end AWA.Events.Services;
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