For example, assuming that the interface Account is not a value type IDL type and is also not an abstract interface and has no abstract base interfaces, its AccountHelper class will look like this:

abstract public class AccountHelper
{
  private static String  _id = "IDL:Account:1.0";

  // inserts an Account object into an Any object
  public static void insert (org.omg.CORBA.Any a, Account that)
  {
    org.omg.CORBA.portable.OutputStream out = a.create_output_stream ();
    a.type (type ());
    write (out, that);
    a.read_value (out.create_input_stream (), type ());
  }

  // extracts an Account object from an Any object
  public static Account extract (org.omg.CORBA.Any a)
  {
    return read (a.create_input_stream ());
  }

  
  private static org.omg.CORBA.TypeCode __typeCode = null;
  // gets the typecode for this type
  synchronized public static org.omg.CORBA.TypeCode type ()
  {
    if (__typeCode == null)
    {
      __typeCode = org.omg.CORBA.ORB.init ().create_interface_tc (AccountHelper.id (), "Account");
    }
    return __typeCode;
  }

  // gets the repository id for this type
  public static String id ()
  {
    return _id;
  }

  // reads an Account object from an input stream
  public static Account read (org.omg.CORBA.portable.InputStream istream)
  {
    return narrow (istream.read_Object (_AccountStub.class));
  }

  // writes an Account object to an outputstream
  public static void write (org.omg.CORBA.portable.OutputStream ostream, Account value)
  {
    ostream.write_Object ((org.omg.CORBA.Object) value);
  }

  // converts (narrows) an Object to an Account object
  public static Account narrow (org.omg.CORBA.Object obj)
  {
    if (obj == null)
      return null;
    else if (obj instanceof Account)
      return (Account)obj;
    else if (!obj._is_a (id ()))
      throw new org.omg.CORBA.BAD_PARAM ();
    else
    {
      org.omg.CORBA.portable.Delegate delegate = ((org.omg.CORBA.portable.ObjectImpl)obj)._get_delegate ();
      _AccountStub stub = new _AccountStub ();
      stub._set_delegate(delegate);
      return stub;
    }
  }

}

Value Type Helper Classes A helper class for a value type includes different renderings of the same methods generated for non-value type methods. The main difference is that value types are types that can be passed by value as parameters or return values of a method, which means that they must be serializable.

Assuming that Address is a value type, the AddressHelper class will look like this:

abstract public class AddressHelper
{
  private static String  _id = "IDL:Address:1.0";

  // same as for non-value type
  public static void insert (org.omg.CORBA.Any a, Address that)
  {
    org.omg.CORBA.portable.OutputStream out = a.create_output_stream ();
    a.type (type ());
    write (out, that);
    a.read_value (out.create_input_stream (), type ());
  }

  // same as for non-value type
  public static Address extract (org.omg.CORBA.Any a)
  {
    return read (a.create_input_stream ());
  }

  private static org.omg.CORBA.TypeCode __typeCode = null;
  private static boolean __active = false;
  
  // getting the typecode for the type
  synchronized public static org.omg.CORBA.TypeCode type ()
  {
    if (__typeCode == null)
    {
      synchronized (org.omg.CORBA.TypeCode.class)
      {
        if (__typeCode == null)
        {
          if (__active)
          {
            return org.omg.CORBA.ORB.init().create_recursive_tc ( _id );
          }
          __active = true;
          org.omg.CORBA.ValueMember[] _members0 = new org.omg.CORBA.ValueMember[0];
          org.omg.CORBA.TypeCode _tcOf_members0 = null;
          __typeCode = org.omg.CORBA.ORB.init ().create_value_tc (_id, "Address", org.omg.CORBA.VM_NONE.value, null, _members0);
          __active = false;
        }
      }
    }
    return __typeCode;
  }

  // same as for non-value type
  public static String id ()
  {
    return _id;
  }

  // reads a serializable instance of Address from the given input stream
  public static Address read (org.omg.CORBA.portable.InputStream istream)
  {
    return (Address)((org.omg.CORBA_2_3.portable.InputStream) istream).read_value (id ());
  }

  // writes a serializable instance of Address to the given output stream
  public static void write (org.omg.CORBA.portable.OutputStream ostream, Address value)
  {
    ((org.omg.CORBA_2_3.portable.OutputStream) ostream).write_value (value, id ());
  }


}

The Helper classes defined in the package org.omg.CORBA are:

     AnySeqHelper
     BooleanSeqHelper
     CharSeqHelper
     CompletionStatusHelper
     CurrentHelper
     DefinitionKindHelper
     DoubleSeqHelper
     FieldNameHelper
     FloatSeqHelper
     IdentifierHelper
     IDLTypeHelper
     LongLongSeqHelper
     LongSeqHelper
     NameValuePairHelper
     ObjectHelper
     OctetSeqHelper
     ParameterModeHelper
     PolicyErrorCodeHelper
     PolicyErrorHelper
     PolicyHelper
     PolicyListHelper
     PolicyTypeHelper
     RepositoryIdHelper
     ServiceDetailHelper
     ServiceInformationHelper
     SetOverrideTypeHelper
     ShortSeqHelper
     StringSeqHelper
     StringValueHelper
     StructMemberHelper
     ULongLongSeqHelper
     ULongSeqHelper
     UnionMemberHelper
     UnknownUserExceptionHelper
     UShortSeqHelper
     ValueBaseHelper
     ValueMemberHelper
     VersionSpecHelper
     VisibilityHelper
     WCharSeqHelper
     WrongTransactionHelper
     WStringSeqHelper
     WStringValueHelper

Other Classes

Classes Created by an ORB

• TCKind -- indicates the kind (datatype) for a TypeCode object
• TypeCode -- indicates a datatype and possibly other information
• Any -- contains a value and its typecode
• NamedValue -- contains a name, an Any object, and an argument mode flag. NamedValue objects contain information about method arguments, method return values, or a context.
• ContextList -- a list of strings that describe the contexts that need to be resolved and sent with an invocation
• ExceptionList -- a list of TypeCodes for exceptions that may be thrown by a method
• Environment -- a container for the exception thrown during a method invocation
• Context -- a list of NamedValue objects used to pass auxiliary information from client to server
• NVList -- a list of NamedValue objects, used to pass arguments or get results

Classes That Deal with Requests

• Object -- the base class for all CORBA object references
• Request -- the main class in the DII, which contains methods for adding arguments to the request, for accessing information about the method being invoked (the method name, its arguments, exceptions it throws, and so on), and for making invocations on the request
• DynamicImplementation -- the base class for server implementations using the DSI. It has the method invoke, which is used by an implementation of this class to determine the state of a ServerRequest object and to set its result or exception
• ServerRequest -- captures the explicit state of a request for the Dynamic Skeleton Interface

Interfaces That Serve as Constants

This is why several interfaces in the org.omg.CORBA package consist of a single field, value, which is a short. This field is a constant used for such things as an error code or value modifier. For example, the value field of the interface BAD_POLICY is one of the possible reasons for the exception PolicyError to be thrown. To specify this error code, you would use BAD_POLICY.value.

The exception PolicyError uses the value field of the following interfaces as its possible error codes.

• BAD_POLICY
• BAD_POLICY_TYPE
• BAD_POLICY_VALUE
• UNSUPPORTED_POLICY
• UNSUPPORTED_POLICY_VALUE

• VM_NONE
• VM_ABSTRACT
• VM_CUSTOM
• VM_TRUNCATABLE

• PRIVATE_MEMBER
• PUBLIC_MEMBER

• ARG_IN
• ARG_INOUT
• ARG_OUT
• CTX_RESTRICT_SCOPE

Interface Repository Interfaces and Classes

An ORB does not require that there be an interface repository, and Java IDL does not include one. Even though this release does not include an implementation of an interface repository, the following IR classes and interfaces have been included for the purpose of creating typecodes (see create_value_tc, create_struct_tc, create_union_tc and create_exception_tc methods in interface org.omg.CORBA.ORB):
&nbs

• IRObject
• IDLType
• DefinitionKind
• StructMember
• UnionMember
• ValueMember

Related Documentation

• Java IDL home page

CORBA Features Not Implemented in Java IDL

Some of the API included in org.omg subpackages is provided for conformance with the current OMG CORBA specification but is not implemented in Sun's release of the JDK^TM. This enables other JDK licensees to provide implementations of this API in standard extensions and products.

Features That Throw NO_IMPLEMENT

Some of the API included in org.omg subpackages throw NO_IMPLEMENT exceptions for various reasons. Among these reasons are:

• In some cases, for example LocalObject, the complete implementation according to the specification indicates that these API should throw NO_IMPLEMENT.

• In most cases, for example methods in ORB.java, methods that throw NO_IMPLEMENT are actually implemented in subclasses elsewhere in the ORB code.

• In some cases, for example _get_interface_def() and _get_interface, API are really not yet implemented.

General Summary of Features or API Not Implemented in This Release:

• Interface Repository. An Interface Repository is not required for normal operation of Java IDL.
• Java IDL does not support long double.
• Policies (org.omg.CORBA.Policy) and methods for getting them are not implemented.
• Domain managers (org.omg.CORBA.DomainManager) and methods for getting them are not implemented.
• Service Information org.omg.CORBA.ServiceInformation and ORB method public boolean get_service_information(short service_type, ServiceInformationHolder service_info) are not implemented.
• ORB methods for supporting single-threading (perform_work, work_pending) are not implemented.
• IDL contexts.

Specific List of Unimplemented Features in Package org.omg.CORBA

Unimplemented Methods in package org.omg.CORBA:

• ORB
  • public org.omg.CORBA.Policy create_policy(int type, org.omg.CORBA.Any val)
  • public void perform_work()
  • public boolean work_pending()
  • public org.omg.CORBA.Current get_current()
  • create_operation_list
  • get_default_context
  • get_service_information
  • obsolete DynAnys (deprecated in favor of DynamicAny package)