seresye.erl

%%%  SERESYE, a Swarm oriented ERlang Expert SYstem Engine
%%%
%%% Copyright (c) 2005-2010, Francesca Gangemi, Corrado Santoro
%%% All rights reserved.
%%%
%%% You may use this file under the terms of the BSD License. See the
%%% license distributed with this project or
%%% http://www.opensource.org/licenses/bsd-license.php
-module(seresye).

%%====================================================================
%% External exports
%%====================================================================

-export([start/0, start/1, start/2, stop/1, get_engine/1,
         add_rules/2, add_rule/2, add_rule/3, assert/2, get_kb/1,
         get_rules_fired/1, get_client_state/1,
         set_client_state/2, query_kb/2, remove_rule/2, retract/2]).

%% gen_server callbacks
-export([start_link/0, start_link/1, start_link/2, init/1, handle_call/3,
         handle_cast/2, handle_info/2, terminate/2, code_change/3]).

%%====================================================================
%% External functions
%%====================================================================
start() ->
    seresye_sup:start_engine().
    
start(Name) ->
    seresye_sup:start_engine(Name).

start(Name, ClientState) ->
    seresye_sup:start_engine(Name, ClientState).

set_client_state(Name, NewState) ->
    gen_server:cast(Name, {set_client_state, NewState}).

get_client_state(Name) ->
    gen_server:call(Name, get_client_state).

stop (EngineName) ->
  gen_server:call(EngineName, {stop}).

get_engine(EngineName) ->
    gen_server:call(EngineName, get_engine).

%% @doc Insert a fact in the KB.
%% It also checks if the fact verifies any condition,
%% if this is the case the fact is also inserted in the alpha-memory
assert(Name, Facts) ->
    gen_server:call(Name, {assert, Facts}).

%% @doc removes a 'fact' in the Knowledge Base and if something occurs
%% Condition is also deleted from the corresponding alpha-memory
retract(Name, Facts) ->
    gen_server:call(Name, {retract, Facts}).

add_rules(Name, RuleList)
  when is_list(RuleList) orelse is_atom(RuleList) ->
    gen_server:call(Name, {add_rules, RuleList}).

add_rule(Name, Fun) ->
    gen_server:call(Name, {add_rule, Fun}).

add_rule(Name, Rule, Salience) ->
    gen_server:call(Name, {add_rule, Rule, Salience}).

remove_rule(Name, Rule) ->
    gen_server:call(Name, {remove_rule, Rule}).

get_rules_fired(Name) ->
    gen_server:call(Name, get_rules_fired).

get_kb(Name) ->
    gen_server:call(Name, get_kb).

query_kb(Name, Pattern) ->
    gen_server:call(Name, {query_kb, Pattern}).


%%%===================================================================
%%% gen_server callbacks
%%%===================================================================
start_link() ->
    gen_server:start_link(?MODULE, [], []).

start_link(Name) when is_atom(Name) ->
    gen_server:start_link({local, Name}, ?MODULE, [], []).

start_link(ClientState, Name) when is_atom(Name) ->
    gen_server:start_link({local, Name}, ?MODULE, [ClientState], []).


init([]) ->
    {ok, seresye_engine:new()};
init([ClientState]) ->
    {ok, seresye_engine:new(ClientState)}.


handle_call(get_client_state, _From, State) ->
    Reply =
        try
            {ok, seresye_engine:get_client_state(State)}
        catch
            Type:Reason ->
                {error, {Type, Reason}}
        end,
    {reply, Reply, State};
handle_call(stop, _From, State) ->
    {stop, normal, State};
handle_call({assert, Facts}, _From, State0) ->
    {Reply, State1} =
        try
            {ok, seresye_engine:assert(State0, Facts)}
        catch
            Type:Reason ->
                {{error, {Type, Reason}}, State0}
        end,
    {reply, Reply, State1};
handle_call({retract, Facts}, _From, State0) ->
    {Reply, State1} =
        try
            {ok, seresye_engine:retract(State0, Facts)}
        catch
            Type:Reason ->
                {{error, {Type, Reason}}, State0}
        end,
    {reply, Reply, State1};
handle_call({add_rules, Rules}, _From, State0) ->
    {Reply, State1} =
        try
            {ok, seresye_engine:add_rules(State0, Rules)}
        catch
            Type:Reason ->
                {{error, {Type, Reason}}, State0}
        end,
    {reply, Reply, State1};
handle_call({add_rule, Rule}, _From, State0) ->
    {Reply, State1} =
        try
            {ok, seresye_engine:add_rule(State0, Rule)}
        catch
            Type:Reason ->
                {{error, {Type, Reason}}, State0}
        end,
    {reply, Reply, State1};
handle_call({add_rule, Rule, Salience}, _From, State0) ->
    {Reply, State1} =
        try
            {ok, seresye_engine:add_rule(State0, Rule, Salience)}
        catch
            Type:Reason ->
                {{error, {Type, Reason}}, State0}
        end,
    {reply, Reply, State1};
handle_call({remove_rule, Rule}, _From, State0) ->
    {Reply, State1} =
        try
            {ok, seresye_engine:remove_rule(State0, Rule)}
        catch
            Type:Reason ->
                {{error, {Type, Reason}}, State0}
        end,
    {reply, Reply, State1};
handle_call(get_rules_fired, _From, State0) ->
    Reply =
        try
            seresye_engine:get_rules_fired(State0)
        catch
            Type:Reason ->
                {error, {Type, Reason}}
        end,
    {reply, Reply, State0};
handle_call(get_engine, _From, State0) ->
    {reply, State0, State0};
handle_call(get_kb, _From, State0) ->
    Reply =
        try
            seresye_engine:get_kb(State0)
        catch
            Type:Reason ->
                {error, {Type, Reason}}
        end,
    {reply, Reply, State0};
handle_call({query_kb, Pattern}, _From, State0) ->
    Reply =
        try
            seresye_engine:query_kb(State0, Pattern)
        catch
            Type:Reason ->
                {error, {Type, Reason}}
        end,
    {reply, Reply, State0}.

handle_cast({set_client_state, CS}, State) ->
    {noreply, seresye_engine:set_client_state(State, CS)}.

handle_info(_Info, State) ->
    {noreply, State}.

terminate(_Reason, _State) ->
    ok.

code_change(_OldVsn, State, _Extra) ->
    {ok, State}.