6 OMG IDL到Erlang映射

// DB IDL
#ifndef _DB_IDL_
#define _DB_IDL_
// A module is simply a container
module DB {

  // An interface maps to a CORBA::Object.
  interface CommonUser {

  };

  // Inherit the Consumer interface
  interface Administrator : CommonUser {

  };

  interface Access {

  };

};
#endif    

// Null terminated
typedef string myString;
typedef wstring myWString;
// Maximum length 10 
typedef string<10> myString10;
typedef wstring<10> myWString10;
      

const string  SwedensBestSoccerTeam = "\101" "\x49" "\u004B";
const wstring SwedensBestHockeyTeam = L"\101\x49\u004B";
const char  aChar  = '\u004B';  
const wchar aWchar = L'\u004C';
      

typedef sequence <short, 1> aShortSequence;
typedef sequence <long> aLongSequence;
typedef sequence <aLongSequence> anEvenLongerSequence;
      

typedef long myMatrix[2][3];
      

const fixed myFixed1 = 3.14D;
const fixed myFixed2 = .14D;
const fixed myFixed3 = 0.14D;
const fixed myFixed4 = 3.D;
const fixed myFixed5 = 3D;
      

const fixed myFixed6 = 3D + 0.14D;
const fixed myFixed7 = -3.14D;
      

typedef fixed<5,3> myFixed53;
const myFixed53 myFixed53constant = 03.140d;
typedef fixed<3,2> myFixed32;
const myFixed32 myFixed32constant = 3.14d;

myFixed53 foo(in myFixed32 MF // OK
void bar(in fixed<5,3> MF // Illegal
      

// DB IDL
#ifndef _DB_IDL_
#define _DB_IDL_
module DB {

  typedef unsigned long EmployeeNo;

  interface CommonUser {

     any lookup(in EmployeeNo ENo

  };

  interface Administrator : CommonUser {

     void delete(in EmployeeNo ENo

  };

  interface Access {

      typedef string<10> UserID;
      typedef string<10> Password;

      CommonUser logon(in UserID ID, in Password PW

  };

};
#endif    

struct myStruct; // Forward declaration
typedef sequence<myStruct> myStructSeq;
struct myStruct {
    myStructSeq chain;
};

// Deprecated definition (anonymous) not supported by IC
struct myStruct {
    sequence<myStruct> chain;
};
      

// Illegal default; all cases covered by 
// non-default cases.
union BooleanUnion switch(boolean) {
  case TRUE:  long TrueValue;
  case FALSE: long FalseValue;
  default: long DefaultValue; 
};
// OK
union BooleanUnion2 switch(boolean) {
  case TRUE:  long TrueValue;
  default: long DefaultValue; 
};
      

// If the discriminator equals 1 or 2 the value 
// is a long. Otherwise, the atom undefined.
union LongUnion switch(long) {
  case 1:
  case 2:  long TrueValue;
};
// If the discriminator equals 1 or 2 the value 
// is a long. Otherwise, a boolean.
union LongUnion2 switch(long) {
  case 1:
  case 2:  long TrueValue;
  default: boolean DefaultValue; 
};
      

// Forward declaration
union myUnion;
typedef sequence<myUnion>myUnionSeq;
union myUnion switch (long) {
    case 1 : myUnionSeq chain;
    default: boolean DefaultValue;
};
      

// DB IDL
#ifndef _DB_IDL_
#define _DB_IDL_
module DB {

  typedef unsigned long EmployeeNo;

  enum Department {Department1, Department2};

  struct employee {
        EmployeeNo No;
        string Name; 
        string Address; 
        Department Dpt;
  };

  typedef employee EmployeeData;

  interface CommonUser {

     EmployeeData lookup(in EmployeeNo ENo

  };

  interface Administrator : CommonUser {

     void delete(in EmployeeNo ENo

  };

  interface Access {

      typedef string<10> UserID;
      typedef string<10> Password;

      // Since Administrator inherits from CommonUser
      // the returned Object can be of either type.
      CommonUser logon(in UserID ID, in Password PW

  };

};
#endif    

$ erlc DB.idl
    

$ erl
Erlang (BEAM) emulator version 5.1.1 [threads:0]

Eshell V5.1.1  (abort with ^G)
1> ic:gen('DB').
ok
2> halt().
    

module MyModule {
     // 'two' is not unique
     enum MyEnum {one, two};
     enum MyOtherEnum {two, three};
};
      

// DB IDL
#ifndef _DB_IDL_
#define _DB_IDL_
// ++ topmost scope ++ 
// IC generates oe_XX.erl and oe_XX.hrl.
// XX is equal to the name of the IDL-file.
// Tips: create one IDL-file for each top module
// and give the file the same name (DB.idl).
// The oe_XX.erl module is used to register data
// in the IFR.
module DB {

  // ++ Module scope ++
  // To access 'EmployeeNo' from another scope, use:
  // DB::EmployeeNo, DB::Access etc.
  typedef unsigned long EmployeeNo;

  enum Department {Department1, Department2};

  // Definitions of this struct is contained in:
  // DB.hrl
  // Access functions exported by:
  // DB_employee.erl
  struct employee {
     ... CUT ...
  };

  typedef employee EmployeeData;

  ... CUT ...

  // If this interface should inherit an interface
  // in another module (e.g. OtherModule) use:
  // interface Access : OtherModule::OtherInterface
  interface Access {

      // ++ interface scope ++
      // Types within this scope is accessible via:
      // DB::Access::UserID
      // The Stub/Skeleton for this interface is
      // placed in the module:
      // DB_Access.erl
      typedef string<10> UserID;
      typedef string<10> Password;

      // Since Administrator inherits from CommonUser
      // the returned Object can be of either type.
      // This operation is exported from:
      // DB_Access.erl
      CommonUser logon(in UserID ID, in Password PW

  };

};
#endif      

module x {

    struct y_z {
    ...
    };

    interface y {

    struct z {
        ...
    };
    };
};
      

%% Erlang code
....
AnEmployee = #'DB_employee'{'No'      = 1,
                            'Name'    = "Adam Ivan Kendall",
                            'Address' = "Rasunda, Solna",
                            'Dpt'     = 'Department1'},
EmployeeTC = 'DB_employee':tc(),
EmployeeAny = any:create(EmployeeTC, AnEmployee),
....
    

// m.idl
module m {
    const float pi = 3.14;

    interface i {
    const float pi = 3.1415;
    };
};
    

$ erlc m.idl
$ erlc m.erl
$ erl
Erlang (BEAM) emulator version 5.1.1 [threads:0]

Eshell V5.1.1  (abort with ^G)
1> m:pi().
3.14
2> m_i:pi().
3.1415
3> halt().
    

readonly attribute long RAttribute;
attribute long RWAttribute;
    

// IDL
module m {
  interface i {
      readonly attribute long RAttribute;
      attribute long RWAttribute;
      long foo(in short a
      long bar(in char c, inout string s, out long count
      void baz(out long Id
  };
};
    

%% Erlang code
....
Obj = ...    %% get object reference
RAttr  = m_i:'_get_RAttribute'(Obj),
RWAttr = m_i:'_get_RWAttribute'(Obj),
ok = m_i:'_set_RWAttribute'(Obj, Long),
R1 = m_i:foo(Obj, 55),
{R2, S, Count} = m_i:bar(Obj, $a, "hello"),
....
    

'_set_RWAttribute'(State, Long) ->
    {reply, ok, State}.

'_get_RWAttribute'(State) ->
    {reply, Long, State}.

'_get_RAttribute'(State) ->
    {reply, Long, State}.

foo(State, AShort) ->
    {reply, ALong, State}.
 
bar(State, AShort, AString) ->
    {reply, {ALong, "MyString", ALong}, State}.
 
baz(State) ->
    {reply, {ok, AId}, State}.
    

$> erlc +"{be,erl_template}" DB.idl
    

%%----------------------------------------------------------------------
%% <LICENSE>
%% 
%%     $Id$
%%
%%----------------------------------------------------------------------
%% Module       : DB_Access_impl.erl
%% 
%% Source       : /home/user/example/DB.idl
%% 
%% Description  : 
%% 
%% Creation date: 2005-05-20
%%
%%----------------------------------------------------------------------
-module('DB_Access_impl').

-export([logon/3]).

%%----------------------------------------------------------------------
%% Internal Exports
%%----------------------------------------------------------------------
-export([init/1,
         terminate/2,
         code_change/3,
         handle_info/2]).

%%----------------------------------------------------------------------
%% Include Files
%%----------------------------------------------------------------------


%%----------------------------------------------------------------------
%% Macros
%%----------------------------------------------------------------------


%%----------------------------------------------------------------------
%% Records
%%----------------------------------------------------------------------
-record(state, {}).

%%======================================================================
%% API Functions
%%======================================================================
%%----------------------------------------------------------------------
%% Function   : logon/3
%% Arguments  : State - term()
%%              ID = String()
%%              PW = String()
%% Returns    : ReturnValue = OE_Reply
%%              OE_Reply = Object_Ref()
%% Raises     : 
%% Description: 
%%----------------------------------------------------------------------
logon(State, ID, PW) ->
    %% Check if the ID/PW is valid and what 
    %% type of user it is (Common or Administrator).
    OE_Reply
            = case check_user(ID, PW) of
             {ok, administrator} ->
                'DB_Administrator':oe_create(
             {ok, common} ->
                'DB_CommonUser':oe_create(
             error ->
                %% Here we should throw an exception              
                corba:raise(....)
        end,
    {reply, OE_Reply, State}.

%%======================================================================
%% Internal Functions
%%======================================================================
%%----------------------------------------------------------------------
%% Function   : init/1
%% Arguments  : Env = term()
%% Returns    : {ok, State}          |
%%              {ok, State, Timeout} |
%%              ignore               |
%%              {stop, Reason}
%% Raises     : -
%% Description: Initiates the server
%%----------------------------------------------------------------------
init(_Env) ->
    {ok, #state{}}.


%%----------------------------------------------------------------------
%% Function   : terminate/2
%% Arguments  : Reason = normal | shutdown | term()
%%              State = term()
%% Returns    : ok
%% Raises     : -
%% Description: Invoked when the object is terminating.
%%----------------------------------------------------------------------
terminate(_Reason, _State) ->
    ok.


%%----------------------------------------------------------------------
%% Function   : code_change/3
%% Arguments  : OldVsn = undefined | term()
%%              State = NewState = term()
%%              Extra = term()
%% Returns    : {ok, NewState}
%% Raises     : -
%% Description: Invoked when the object should update its internal state
%%              due to code replacement.
%%----------------------------------------------------------------------
code_change(_OldVsn, State, _Extra) ->
    {ok, State}.


%%----------------------------------------------------------------------
%% Function   : handle_info/2
%% Arguments  : Info = normal | shutdown | term()
%%              State = NewState = term()
%% Returns    : {noreply, NewState}          |
%%              {noreply, NewState, Timeout} |
%%              {stop, Reason, NewState}
%% Raises     : -
%% Description: Invoked when, for example, the server traps exits.
%%----------------------------------------------------------------------
handle_info(_Info, State) ->
    {noreply, State}.
    

$ erlc +'{{impl, "DB::CommonUser"}, "DBUser_impl"}'\ +'{{impl, "DB::Administrator"}, "DBUser_impl"}' DB.idl
$ erlc *.erl
    

%%======================================================================
%% API Functions
%%======================================================================
%%----------------------------------------------------------------------
%% Function   : delete/2
%% Arguments  : State - term()
%%              ENo = unsigned_Long()
%% Returns    : ReturnValue = ok
%% Raises     : 
%% Description: 
%%----------------------------------------------------------------------
delete(State, ENo) ->
        %% How we access the DB, for example mnesia, is not shown here.
        case delete_employee(No) of
            ok ->
                {reply, ok, State};
            error ->
                %% Here we should throw an exception if
                %% there is no match.
                corba:raise(....)
        end.

%%----------------------------------------------------------------------
%% Function   : lookup/2
%% Arguments  : State - term()
%%              ENo = unsigned_Long()
%% Returns    : ReturnValue = OE_Reply
%%              OE_Reply = #'DB_employee'{No,Name,Address,Dpt}
%%              No = unsigned_Long()
%%              Name = String()
%%              Address = String()
%%              Dpt = Department
%%              Department = 'Department1' | 'Department2' 
%% Raises     : 
%% Description: 
%%----------------------------------------------------------------------
lookup(State, ENo) ->
        %% How we access the DB, for example mnesia, is not shown here.
        case lookup_employee(ENo) of
            %% We assume that we receive a 'DB_employee' struct
            {ok, Employee} ->
                OE_Reply = Employee,
                {reply, OE_Reply, State};
            error ->
                %% Here we should throw an exception if
                %% there is no match.
                corba:raise(....)
        end.
    

%% Erlang code
....
%% Create an Access object
Acc = 'DB_Access':oe_create(),

%% Login is Common user and Administrator
Adm = 'DB_Access':logon(A, "admin", "pw"),
Com = 'DB_Access':logon(A, "comm", "pw"),

%% Lookup existing employee
Employee = 'DB_Administrator':lookup(Adm, 1),
Employee = 'DB_CommonUser':lookup(Adm, 1),

%% If we try the same using the DB_CommonUser interface 
%% it result in an exit since that operation is not exported.
{'EXIT', _} = (catch 'DB_CommonUser':delete(Adm, 1)),

%% Try to delete the employee via the CommonUser Object
{'EXCEPTION', _} = (catch 'DB_Administrator':delete(Com, 1)),

%% Invoke delete operation on the Administrator object
ok = 'DB_Administrator':delete(Adm, 1),
....
    

typedef string native;
interface i {
   void foo(in native Arg
   };
};
    

typedef string _native;
interface i {
   void foo(in _native Arg
   };
};