new_name_server.erl

%% ---
%%  Excerpted from "Programming Erlang",
%%  published by The Pragmatic Bookshelf.
%%  Copyrights apply to this code. It may not be used to create training material, 
%%  courses, books, articles, and the like. Contact us if you are in doubt.
%%  We make no guarantees that this code is fit for any purpose. 
%%  Visit http://www.pragmaticprogrammer.com/titles/jaerlang for more book information.
%%---
-module(new_name_server).
-export([init/0, add/2, all_names/0, delete/1, whereis/1, handle/2]).
-import(server3, [rpc/2]).

%% interface
all_names()      -> rpc(name_server, allNames).
add(Name, Place) -> rpc(name_server, {add, Name, Place}).
delete(Name)     -> rpc(name_server, {delete, Name}).
whereis(Name)    -> rpc(name_server, {whereis, Name}).

%% callback routines
init() -> dict:new().
    
handle({add, Name, Place}, Dict) -> {ok, dict:store(Name, Place, Dict)};
handle(allNames, Dict)           -> {dict:fetch_keys(Dict), Dict};
handle({delete, Name}, Dict)     -> {ok, dict:erase(Name, Dict)};
handle({whereis, Name}, Dict)    -> {dict:find(Name, Dict), Dict}.