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<cell align="left" valign="middle">The operation was invoked on the target object but an error occurred after the object replied. This occur, for example, if a server replies but Orber is not able to marshal and send the reply to the client ORB.</cell>

</row>

<row>

<cell align="left" valign="middle">'COMPLETED_NO'</cell>

<cell align="left" valign="middle">Orber failed to invoke the operation on the target object. This occur, for example, if the object no longer exists.</cell>

</row>

<row>

<cell align="left" valign="middle">'COMPLETED_MAYBE'</cell>

<cell align="left" valign="middle">Orber invoked the operation on the target object but an error occurred and it is impossible to decide if the request really reached the object or not.</cell>

</row>

<tcaption>Table 1: System Exceptions Status</tcaption>

</table>

</section>

<title>Minor Field</title>

The minor field contains an integer (VMCID), which is related to a more

specific reason why an invocation failed. The function

<c>orber:exception_info/1</c> can be used to map the minor code to a string.

Note, for VMCID:s not assigned by the OMG or Orber, the documentation

for that particular ORB must be consulted.

</section>

<title>Supported System Exceptions</title>

The OMG CORBA specification defines the following exceptions:

<item>'BAD_CONTEXT' - if a request does not contain a correct

context this exception is raised.</item>

<item>'BAD_INV_ORDER' - this exception indicates that operations

has been invoked operations in the wrong order, which would cause,

for example, a dead-lock.</item>

<item>'BAD_OPERATION' - raised if the target object exists, but

that the invoked operation is not supported.</item>

<item>'BAD_PARAM' - is thrown if, for example, a parameter is out

of range or otherwise considered illegal.</item>

<item>'BAD_TYPECODE' - if illegal type code is passed, for example,

encapsulated in an any data type the <c>'BAD_TYPECODE'</c> exception

will be raised.</item>

<item>'BAD_QOS' - raised whenever an object cannot support the

required quality of service.</item>

<item>'CODESET_INCOMPATIBLE' - raised if two ORB's cannot

communicate due to different representation of, for example,

<c>char</c> and/or <c>wchar</c>.</item>

<item>'COMM_FAILURE' - raised if an ORB is unable to setup

communication or it is lost while an operation is in progress.</item>

<item>'DATA_CONVERSION' - raised if an ORB cannot convert data

received to the native representation. See also the

<c>'CODESET_INCOMPATIBLE'</c> exception.</item>

<item>'FREE_MEM' - the ORB failed to free dynamic memory and

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failed.</item>

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<item>'IMP_LIMIT' - an implementation limit was exceeded in the

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ORB at run time. A object factory may, for example, limit the

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number of object clients are allowed to create.</item>

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<item>'INTERNAL' - an internal failure occurred in an ORB, which

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is unrecognized. You may consider contacting the ORB providers

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support.</item>

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<item>'INTF_REPOS' - the ORB was not able to reach the interface

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repository, or some other failure relating to the interface

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repository is detected.</item>

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<item>'INITIALIZE' - the ORB initialization failed due to, for

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example, network or configuration error.</item>

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<item>'INVALID_TRANSACTION' - is raised if the request carried an

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invalid transaction context.</item>

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<item>'INV_FLAG' - an invalid flag was passed to an operation,

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which caused, for example, a connection to be closed.</item>

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<item>'INV_IDENT' - this exception indicates that an IDL

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identifier is incorrect.</item>

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<item>'INV_OBJREF' - this exception is raised if an objet

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reference is malformed or a nil reference (see

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also corba:create_nil_objref/0).</item>

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<item>'INV_POLICY' - the invocation cannot be made due to an

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incompatibility between policy overrides that apply to the

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particular invocation.</item>

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<item>'MARSHAL' - this exception may be raised by the client- or

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server-side when either ORB is unable to marshal/unmarshal requests or

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replies.</item>

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<item>'NO_IMPLEMENT' - if the operation exists but no implementation

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exists, this exception is raised.</item>

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<item>'NO_MEMORY' - the ORB has run out of memory.</item>

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<item>'NO_PERMISSION' - the caller has insufficient privileges,

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such as, for example, bad <c>SSL</c> certificate.</item>

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<item>'NO_RESOURCES' - a general platform resource limit

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exceeded.</item>

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<item>'NO_RESPONSE' - no response available of a deferred

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synchronous request.</item>

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<item>'OBJ_ADAPTER' - indicates administrative mismatch; the object

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adapter is not able to associate an object with the implementation

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repository.</item>

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<item>'OBJECT_NOT_EXIST' - the object have been disposed or

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terminated; clients should remove all copies of the object reference

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and initiate desired recovery process.</item>

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<item>'PERSIST_STORE' - the ORB was not able to establish a

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connection to its persistent storage or data contained in the

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the storage is corrupted.</item>

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<item>'REBIND' - a request resulted in, for example, a

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<c>'LOCATION_FORWARD'</c> message; if the policies are incompatible

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this exception is raised.</item>

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<item>'TIMEOUT' - raised if a request fail to complete within the

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given time-limit.</item>

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<item>'TRANSACTION_MODE' - a transaction policy mismatch detected.</item>

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<item>'TRANSACTION_REQUIRED' - a transaction is required for the

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invoked operation but the request contained no transaction context.</item>

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<item>'TRANSACTION_ROLLEDBACK' - the transaction associated with

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the request has already been rolled back or will be.</item>

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<item>'TRANSACTION_UNAVAILABLE' - no transaction context can be

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supplied since the ORB is unable to contact the Transaction

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Service.</item>

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<item>'TRANSIENT' - the ORB could not determine the current status

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of an object since it could not be reached. The error may be

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temporary.</item>

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<item>'UNKNOWN' - is thrown if an implementation throws a

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non-CORBA, or unrecognized, exception.</item>

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</list>

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</section>

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</section>

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<title>User Defined Exceptions</title>

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User exceptions is defined in IDL-files and is listed in operations raises

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exception listing. For example, if we have the following IDL code:

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module MyModule {

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exception MyException {};

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exception MyExceptionMsg { string ExtraInfo; };

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interface MyInterface {

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void foo()

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raises(MyException);

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void bar()

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raises(MyException, MyExceptionMsg);

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void baz();

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};

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};

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</code>

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</section>

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<title>Throwing Exceptions</title>

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To be able to raise <c>MyException</c> or <c>MyExceptionMsg</c> exceptions,

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the generated <c>MyModule.hrl</c> must be included, and typical usage is:

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-module('MyModule_MyInterface_impl').

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-include("MyModule.hrl").

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bar(State) ->

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case TestingSomething of

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ok ->

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{reply, ok, State};

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{error, Reason} when list(Reason) ->

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corba:raise(#'MyModule_MyExceptionMsg'{'ExtraInfo' = Reason});

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error ->

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corba:raise(#'MyModule_MyException'{})

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end.

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</code>

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</section>

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<title>Catching Exceptions</title>

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Depending on which operation we invoke we must be able to handle:

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<item>foo - <c>MyException</c> or a system exception.</item>

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<item>bar - <c>MyException</c>, <c>MyExceptionMsg</c> or a system

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exception.</item>

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<item>baz - a system exception.</item>

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</list>

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Catching and matching exceptions can bee done in different ways:

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case catch 'MyModule_MyInterface':bar(MIReference) of

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ok ->

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%% The operation raised no exception.

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ok;

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{'EXCEPTION', #'MyModule_MyExceptionMsg'{'ExtraInfo' = Reason}} ->

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%% If we want to log the Reason we must extract 'ExtraInfo'.

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error_logger:error_msg("Operation 'bar' raised: ~p~n", [Reason]),

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... do something ...;

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{'EXCEPTION', E} when record(E, 'OBJECT_NOT_EXIST') ->

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... do something ...;

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{'EXCEPTION', E} ->

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... do something ...

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end.

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</code>

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</section>

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</chapter>

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