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      $Id$


This example shows how pre and post condition can be used for a Corba server object.


The example consists of three files;

ex.idl        - the interface specification
m_i_impl.erl  - the server implementation
tracer.erl    - a module which contains a pre and a post condition


The IDL file can for example be compiled with the following options:

ic:gen(ex, [{precond, {tracer, pre}},{{postcond, "m::i::f"}, {tracer, post}}]).

The result is that the function m::i::f gets both a pre and post condition call while 
the function m::i::g just get a pre condition call.


A pre/post condition function should always return the atom ok and if something is wrong
it should raise an exception ( ex: corba:raise(#userexception{}) ).




Compile all erlang files and test the application.

First start an erlang node, then type the following commands in the erlang shell.

1> mnesia:create_schema([]).
2> orber:install([]).
3> orber:start().
3>
3> X = m_i:oe_create().
4> catch m_i:f(X, 17).
Precond called in process <0.139.0>: m_i:f() [[],17]
f working ....
Postcond called in process <0.139.0>: m_i:f() [[],17] {reply,{17,17},[]}
17
5> 
5> catch m_i:f(X, q).
6> {'EXCEPTION',{m_NotAnInteger,"IDL:m/NotAnInteger:1.0"}}
7>
7>m_i:g(X, 17).
Precond called in process <0.139.0>: m_i:g() [[],17]
ok
g working ....
8> 
8>corba_boa:dispose(X).
9> orber:stop().
10>