path: root/lib/orber/doc/src/Module_Interface.xml

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<!DOCTYPE erlref SYSTEM "erlref.dtd">

<erlref>
  <header>
    <copyright>
      <year>1999</year>
      <year>2016</year>
      <holder>Ericsson AB, All Rights Reserved</holder>
    </copyright>
    <legalnotice>
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
 
      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

  The Initial Developer of the Original Code is Ericsson AB.
    </legalnotice>

    <title>Module_Interface</title>
    <prepared></prepared>
    <docno></docno>
    <checked></checked>
    <date>1999-09-03</date>
    <rev>A</rev>
  </header>
  <module>Module_Interface</module>
  <modulesummary>Orber generated stubs/skeletons.</modulesummary>
  <description>
    <p>This module contains the stub/skeleton functions generated by IC.</p>
    <p>Starting a Orber server can be done in three ways:</p>
    <list type="bulleted">
      <item>Normal - when the server dies Orber forgets all knowledge of the server.</item>
      <item>Supervisor child - adding the configuration parameter <c>{sup_child, true}</c>
       the <c>oe_create_link/2</c> function returns <c>{ok, Pid, ObjRef}</c> which
       can be handled by the application <em>supervisor/stdlib-1.7</em> or later. </item>
      <item>Persistent object reference - adding the configuration parameters <c>{persistent, true}</c>
       and <c>{regname, {global, term()}}</c> Orber will remember the object reference until the
       server terminates with reason <em>normal</em> or <em>shutdown</em>. Hence,
       if the server is started as a <em>transient</em> supervisor child we do not
       receive a 'OBJECT_NOT_EXIST' exception when it has crashed and is being restarted.</item>
    </list>
    <p>The Orber stub can be used to start a <c>pseudo object</c>, which will create a non-server implementation.
      A pseudo object introduce some limitations:</p>
    <list type="bulleted">
      <item>The functions <c>oe_create_link/2</c> is equal to <c>oe_create/2</c>, i.e.,
       no link can or will be created.</item>
      <item>The <c>BIF:s self()</c> and <c>process_flag(trap_exit,true)</c> behaves incorrectly.</item>
      <item>The <c>IC</c> option <c>{{impl, "M::I"}, "other_impl"}</c> has no effect. The call-back
       functions must be implemented in a file called <c>M_I_impl.erl</c></item>
      <item>The <c>IC</c> option <c>from</c> has no effect. </item>
      <item>The call-back functions must be implemented as if the <c>IC</c> option 
      <c>{this, "M::I"}</c> was used.</item>
      <item>Server <c>State</c> changes have no effect. The user can provide information via
       the <c>Env</c> start parameter and the State returned from <c>init/2</c> will be the State
       passed in following invocations.</item>
      <item>If a call-back function replies with the <c>Timeout</c> parameter set it have no effect.</item>
      <item>Operations defined as <c>oneway</c> are blocking until the operation replies.</item>
      <item>The option <c>{pseudo, true}</c> overrides all other start options.</item>
      <item>Only the functions, besides own definitions, <c>init/2</c> (called via oe_create*/2) and 
      <c>terminate/2</c> (called via corba:dispose/1) must be implemented.</item>
    </list>
    <p>By adopting the rules for <c>pseudo</c> objects described above we can use <c>oe_create/2</c>
      to create <c>server</c> or <c>pseudo</c> objects, by excluding or including the 
      option <c>{pseudo, true}</c>, without changing the call-back module.
      </p>
    <p>If you start a object without <c>{regname, RegName}</c> it can only be accessed through the returned object key. 
      Started with a <c>{regname, RegName}</c> the name is registered locally or globally. 
      </p>
    <warning>
      <p>To avoid flooding Orber with old object references start erlang using the flag 
        <em>-orber objectkeys_gc_time Time</em>, which will remove all object references
        related to servers being dead for Time seconds. To avoid extra overhead, i.e., performing
        garbage collect if no persistent objects are started, the objectkeys_gc_time default value 
        is <em>infinity</em>. For more information, see the orber and corba documentation.</p>
    </warning>
  </description>
  <funcs>
    <func>
      <name>Module_Interface:typeID() -> TypeId</name>
      <fsummary>Return the Type ID related to this stub/skeleton</fsummary>
      <type>
        <v>TypeId = string(), e.g., "IDL:Module/Interface:1.0"</v>
      </type>
      <desc>
        <p>Returns the Type ID related to this stub/skeleton</p>
      </desc>
    </func>
    <func>
      <name>Module_Interface:oe_create() -> ObjRef</name>
      <fsummary>Start a Orber server.</fsummary>
      <type>
        <v>ObjRef = #object reference</v>
      </type>
      <desc>
        <p>Start a Orber server.</p>
      </desc>
    </func>
    <func>
      <name>Module_Interface:oe_create_link() -> ObjRef</name>
      <fsummary>Start a linked Orber server.</fsummary>
      <type>
        <v>ObjRef = #object reference</v>
      </type>
      <desc>
        <p>Start a linked Orber server.</p>
      </desc>
    </func>
    <func>
      <name>Module_Interface:oe_create(Env) -> ObjRef</name>
      <fsummary>Start a Orber server.</fsummary>
      <type>
        <v>Env = term()</v>
        <v>ObjRef = #object reference</v>
      </type>
      <desc>
        <p>Start a Orber server passing Env to <c>init/1</c>.</p>
      </desc>
    </func>
    <func>
      <name>Module_Interface:oe_create_link(Env) -> ObjRef</name>
      <fsummary>Start a linked Orber server.</fsummary>
      <type>
        <v>Env = term()</v>
        <v>ObjRef = #object reference</v>
      </type>
      <desc>
        <p>Start a linked Orber server passing Env to <c>init/1</c>.</p>
      </desc>
    </func>
    <func>
      <name>Module_Interface:oe_create(Env, Options) -> ObjRef</name>
      <fsummary>Start a Orber stub/skeleton</fsummary>
      <type>
        <v>Env = term()</v>
        <v>ObjRef = #object reference</v>
        <v>Options = [{sup_child, false} | {persistent, Bool} | {regname, RegName} |  {pseudo, Bool} | {local_typecheck, Bool} | {survive_exit, Bool} | {create_options, [CreateOpts]}]</v>
        <v>Bool = true | false</v>
        <v>RegName = {global, term()} | {local, atom()}</v>
        <v>CreateOpts = {debug, [Dbg]} | {timeout, Time}</v>
        <v>Dbg = trace | log | statistics | {log_to_file, FileName}</v>
      </type>
      <desc>
        <p>Start a Orber server passing Env to <c>init/1</c>.</p>
        <p>If the option <c>{pseudo, true}</c> is used, all other options are overridden.
          As default, this option is set to false.</p>
        <p>This function cannot be used for starting a server as supervisor child.
          If started as <c>persistent</c>, the options <c>[{persistent, true}, {regname, {global, term()}}]</c> must be used and
          Orber will only forget the object reference if it terminates with reason <em>normal</em> or <em>shutdown</em>.</p>
        <p>The option <c>{local_typecheck, boolean()}</c>, which overrides the
          <seealso marker="ch_install#flags">Local Typechecking</seealso>
          environment flag, turns on or off typechecking. If activated,
          parameters, replies and raised exceptions will be checked to ensure that
          the data is correct, when invoking operations on CORBA Objects within
          the same Orber domain. Due to the extra overhead, this option 
          <em>MAY ONLY</em> be used during testing and development.</p>
        <p><c>{survive_exit, boolean()}</c> overrides the
          <seealso marker="ch_install#flags">EXIT Tolerance</seealso>
          environment flag. If activated, the server will not terminate, even though
          the call-back module returns EXIT.</p>
        <p><c>Time</c> specifies how long time, in milliseconds, the server is allowed to
          spend initializing. For more information about the <c>Dbg</c> options,
          see the <c>sys</c> module.</p>
      </desc>
    </func>
    <func>
      <name>Module_Interface:oe_create_link(Env, Options) -> Return</name>
      <fsummary>Start a Orber stub/skeleton</fsummary>
      <type>
        <v>Env = term()</v>
        <v>Return = ObjRef | {ok, Pid, ObjRef}</v>
        <v>ObjRef = #object reference</v>
        <v>Options = [{sup_child, Bool} | {persistent, Bool} | {regname, RegName} | {pseudo, Bool} | {local_typecheck, Bool} | {survive_exit, Bool} |  {create_options, [CreateOpts]}]</v>
        <v>Bool = true | false</v>
        <v>RegName = {global, term()} | {local, atom()}</v>
        <v>CreateOpts = {debug, [Dbg]} | {timeout, Time}</v>
        <v>Dbg = trace | log | statistics | {log_to_file, FileName}</v>
        <v></v>
        <v></v>
        <v></v>
      </type>
      <desc>
        <p>Start a linked Orber server passing Env to <c>init/1</c>.</p>
        <p>If the option <c>{pseudo, true}</c> is used, all other options are overridden and no link will be created.
          As default, this option is set to false.</p>
        <p>This function can be used for starting a server as persistent or supervisor child. At the moment
          <c>[{persistent, true}, {regname, {global, term()}}]</c> must be used to start
          a server as persistent, i.e., if a server died and is in the process of being restarted
          a call to the server will not raise <c>'OBJECT_NOT_EXIST'</c> exception.
          Orber will only forget the object reference if it terminates with reason <em>normal</em> or <em>shutdown</em>,
          hence, the server must be started as <em>transient</em> (for more information see the
          supervisor documentation).</p>
        <p>The options <c>{local_typecheck, boolean()}</c> and <c>{survive_exit, boolean()}</c> 
          behaves in the same way as for <c>oe_create/2</c>.</p>
        <p><c>Time</c> specifies how long time, in milliseconds, the server is allowed to
          spend initializing. For more information about the <c>Dbg</c> options,
          see the <c>sys</c> module.</p>
      </desc>
    </func>
    <func>
      <name>Module_Interface:own_functions(ObjRef, Arg1, ..., ArgN) -> Reply</name>
      <name>Module_Interface:own_functions(ObjRef, Options, Arg1, ..., ArgN) -> Reply</name>
      <fsummary>User defined function which is not a part of Orber</fsummary>
      <type>
        <v>ObjRef = #object reference</v>
        <v>Options = [Option] | Timeout</v>
        <v>Option = {timeout, Timeout} | {context, [Context]}</v>
        <v>Timeout = infinity | integer(milliseconds)</v>
        <v>Context = #'IOP_ServiceContext'{context_id = CtxId, context_data = CtxData}</v>
        <v>CtxId = ?ORBER_GENERIC_CTX_ID</v>
        <v>CtxData = {interface, Interface} | {userspecific, term()} | {configuration, Options}</v>
        <v>Interface = string()</v>
        <v>Options = [{Key, Value}]</v>
        <v>Key = ssl_client_verify | ssl_client_depth | ssl_client_certfile | ssl_client_cacertfile |
                 ssl_client_password | ssl_client_keyfile | ssl_client_ciphers | ssl_client_cachetimeout</v>
        <v>Value = allowed value associated with the given key</v>
        <v>ArgX = specified in the IDL-code.</v>
        <v>Reply = specified in the IDL-code.</v>
      </type>
      <desc>
        <p>The default value for the <c>Timeout</c> option is <c>infinity</c>.
          IPv4 or IPv6 addresses are accepted as local Interface.</p>
        <p>The <em>configuration</em> context is used to override the global
           SSL client side 
           <seealso marker="ch_install#config">configuration</seealso>.</p>
        <p>To gain access to <c>#'IOP_ServiceContext'{}</c> record and the 
          <c>?ORBER_GENERIC_CTX_ID</c> macro, you must add 
          <c>-include_lib("orber/include/corba.hrl").</c> to your module.</p>
      </desc>
    </func>
  </funcs>

  <section>
    <title>CALLBACK FUNCTIONS</title>
    <p>The following functions should be exported from a <c>CORBA</c>
      callback module. Note, a complete template of the call-back module can
      be generated automatically by compiling the IDL-file with the IC option 
      <c>{be,erl_template}</c>. One should also add
      the same compile options, for example <c>this</c> or <c>from</c>,
      used when generating the stub/skeleton modules.</p>
  </section>
  <funcs>
    <func>
      <name>Module_Interface_impl:init(Env) -> CallReply</name>
      <fsummary>User defined function which is not a part of Orber</fsummary>
      <type>
        <v>Env = term()</v>
        <v>CallReply = {ok, State} | {ok, State, Timeout} | ignore | {stop, StopReason}</v>
        <v>State = term()</v>
        <v>Timeout = int() >= 0 | infinity</v>
        <v>StopReason = term()</v>
      </type>
      <desc>
        <p>Whenever a new server is started, <em>init/1</em> is the first function called in the specified call-back module.</p>
      </desc>
    </func>
    <func>
      <name>Module_Interface_impl:terminate(Reason, State) -> ok</name>
      <fsummary>User defined function which is not a part of Orber</fsummary>
      <type>
        <v>Reason = term()</v>
        <v>State = term()</v>
      </type>
      <desc>
        <p>This call-back function is called whenever the server is about to terminate.</p>
      </desc>
    </func>
    <func>
      <name>Module_Interface_impl:code_change(OldVsn, State, Extra) -> CallReply</name>
      <fsummary>User defined function which is not a part of Orber</fsummary>
      <type>
        <v>OldVsn = undefined | term()</v>
        <v>State = term()</v>
        <v>Extra = term()</v>
        <v>CallReply = {ok, NewState}</v>
        <v>NewState = term()</v>
      </type>
      <desc>
        <p>Update the internal <c>State</c>.</p>
      </desc>
    </func>
    <func>
      <name>Module_Interface_impl:handle_info(Info, State) -> CallReply</name>
      <fsummary>User defined function which is not a part of Orber</fsummary>
      <type>
        <v>Info = term()</v>
        <v>State = term()</v>
        <v>CallReply = {noreply, State} | {noreply, State, Timeout} | {stop, StopReason, State}</v>
        <v>Timeout = int() >= 0 | infinity</v>
        <v>StopReason = normal | shutdown | term()</v>
      </type>
      <desc>
        <p>If the configuration parameter <em>{{handle_info, "Module::Interface"}, true}</em>
          is passed to IC and <em>process_flag(trap_exit,true)</em> is set in the <em>init()</em> 
          call-back this function must be exported. </p>
        <note>
          <p>To be able to handle the <c>Timeout</c> option in <c>CallReply</c> in the call-back
            module the configuration parameter <em>{{handle_info, "Module::Interface"}, true}</em> must
            be passed to IC. </p>
        </note>
      </desc>
    </func>
    <func>
      <name>Module_Interface_impl:own_functions(State, Arg1, ..., ArgN) -> CallReply</name>
      <name>Module_Interface_impl:own_functions(This, State, Arg1, ..., ArgN) -> CallReply</name>
      <name>Module_Interface_impl:own_functions(This, From, State, Arg1, ..., ArgN) -> ExtCallReply</name>
      <name>Module_Interface_impl:own_functions(From, State, Arg1, ..., ArgN) -> ExtCallReply</name>
      <fsummary>User defined function which is not a part of Orber</fsummary>
      <type>
        <v>This = the servers #object reference</v>
        <v>State = term()</v>
        <v>ArgX = specified in the IDL-code.</v>
        <v>CallReply = {reply, Reply, State} | {reply, Reply, State, Timeout} |  {stop, StopReason, Reply, State} | {stop, StopReason, State} |  corba:raise(Exception)</v>
        <v>ExtCallReply = CallReply | corba:reply(From, Reply), {noreply, State} | corba:reply(From, Reply), {noreply, State, Timeout}</v>
        <v>Reply = specified in the IDL-code.</v>
        <v>Timeout = int() >= 0 | infinity</v>
        <v>StopReason = normal | shutdown | term()</v>
      </type>
      <desc>
        <p>All two-way functions must return one of the listed replies or raise any of
          the exceptions listed in the IDL code (i.e. raises(...)). 
          If the IC compile options <em>this</em> and/or <em>from</em> are used,
          the implementation must accept the <em>This</em> and/or <em>From</em> 
          parameters.</p>
      </desc>
    </func>
    <func>
      <name>Module_Interface_impl:own_functions(State, Arg1, ..., ArgN) -> CastReply</name>
      <name>Module_Interface_impl:own_functions(This, State, Arg1, ..., ArgN) -> CastReply</name>
      <fsummary>User defined function which is not a part of Orber</fsummary>
      <type>
        <v>This = the servers #object reference</v>
        <v>State = term()</v>
        <v>CastReply = {noreply, State} | {noreply, State, Timeout} | {stop, StopReason, State}</v>
        <v>ArgX = specified in the IDL-code.</v>
        <v>Reply = specified in the IDL-code.</v>
        <v>Timeout = int() >= 0 | infinity</v>
        <v>StopReason = normal | shutdown | term()</v>
      </type>
      <desc>
        <p>All one-way functions must return one of the listed replies. 
          If the IC compile option <em>this</em> is used,
          the implementation must accept the <em>This</em> parameter.</p>
      </desc>
    </func>
  </funcs>
  
</erlref>