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@ryuone
Last active November 29, 2015 14:03
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gen_fsm sample(すごいErlangゆかいに学ぼう! 15章)
-module(stupid_dog_fsm).
-author('ryuone<[email protected]>').
-behaviour(gen_fsm).
-export([start_link/0]).
-export([init/1, handle_event/3, handle_sync_event/4, handle_info/3, terminate/3, code_change/4]).
-export([sit/3, bark/3, wag_tail/3]).
-export([get_sync_state/1]).
-export([test/0]).
-record(state, {name}).
start_link() ->
{ok, proc_lib:spawn_link(?MODULE, init, [self()])}.
init(_Args) ->
process_flag(trap_exit, true),
State = #state{name = ryuone},
gen_fsm:enter_loop(?MODULE, [], sit, State).
handle_event(stop, _StateName, State) ->
{stop, normal, State}.
handle_sync_event(get_state, _From, StateName, State) ->
{reply, StateName, StateName, State};
handle_sync_event(stop, _From, _StateName, State) ->
{stop, normal, error, State};
handle_sync_event(Event, _From, StateName, State) ->
io:format("Event : ~p~n", [Event]),
{reply, StateName, StateName, State}.
handle_info(_Info, StateName, State) ->
{next_state, StateName, State}.
code_change(iOldVsn, StateName, State, _) ->
{ok, StateName, State}.
terminate(Reason, _StateName, _State) ->
io:format("terminate called with ~p~n", [Reason]),
ok.
%%
%% State
%%
sit(Event=see_squirrel, From, State) ->
io:format("Current state is sit. Event is ~p~n", [Event]),
gen_fsm:reply(From, " State will change to bark."),
{next_state, bark, State}.
bark(Event=get_petted, From, State) ->
io:format("Current state is bark. Event is ~p~n", [Event]),
gen_fsm:reply(From, " State will change to get_petted."),
{next_state, wag_tail, State}.
wag_tail(Event=wait, From, State) ->
io:format("Current state is wag_tail. Event is ~p~n", [Event]),
gen_fsm:reply(From, " State will change to bark."),
{next_state, bark, State};
wag_tail(Event=get_petted, From, State) ->
io:format("Current state is wag_tail. Event is ~p~n", [Event]),
gen_fsm:reply(From, " State will change to sit."),
{next_state, sit, State}.
%%
%% stupid_dog_fsm functins.
%%
get_sync_state(Pid) ->
gen_fsm:sync_send_all_state_event(Pid, get_state).
%%
%% Test function.
%%
test() ->
{ok, Pid} = start_link(),
Res = gen_fsm:sync_send_all_state_event(Pid, get_state),
% * Current state : sit
io:format("* Current state : ~p~n", [Res]),
Ret1 = gen_fsm:sync_send_event(Pid, see_squirrel),
% Current state is sit. Event is see_squirrel
% State will change to bark.
io:format("~s~n", [Ret1]),
Ret2 = gen_fsm:sync_send_event(Pid, get_petted),
% Current state is bark. Event is get_petted
% State will change to get_petted.
io:format("~s~n", [Ret2]),
Ret3 = gen_fsm:sync_send_event(Pid, get_petted),
% Current state is wag_tail. Event is get_petted
% State will change to sit.
io:format("~s~n", [Ret3]),
ok = gen_fsm:stop(Pid),
ok.
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