Managed Object

Arthur Foster

Hillman House, 4, Madeira Road,

Parkstone, Poole, Dorset BH14 9ET

Description of GDMO
Managed Object

e-mail:	arthur@arthurfoster.com
tel:	+44 (01202) 469468
fax:	+44 (01202) 469861

Managed Object Example
Create Operation
Delete Operation

The MANAGED OBJECT CLASS template defines the characteristics of the managed object. The managed object class consists of several packages. The packages are either mandatory, which means that these packages must be present in an instance of the managed object class, or conditional which means that these packages may or may not be present in an instance of the managed object depending on the condition.

A new managed object class can be derived directly from another existing managed object class. The new managed object class takes all the characteristics of the class from which it is derived plus the characteristics of the new class. This is an object-oriented technique.

The choice of use of derived managed object classes or use of packages is a design decision and will depend on the style of interface that required. The international standards have used a combination of both techniques in which conditional packages are used for optional features and derivation is used for specialisations.

        name  MANAGED OBJECT CLASS
                DERIVED FROM   class... ;
                CHARACTERISED BY
                        package  ... ;
                CONDITIONAL PACKAGES
                        package   
                    PRESENT IF condition, ... ;
        REGISTERED AS  object identifier;

The DERIVED FROM class references another managed object class by the name of that managed object class. All the characteristics of the derived from managed object class are 'inherited'. If the managed object class is specified in another document, a document reference precedes the name. This clause is optional.

The package in CHARACTERISED BY package references at least one package by name. If the package is specified in another document, a document reference precedes the name. The definitions specified in the package are mandatory characteristics of the managed managed and must be contained in any instance of the managed object class. Usually the package is defined in-line. This clause is optional.

The CONDITIONAL PACKAGES package references at least one package by the name of that package. It is always followed by a PRESENT IF clause. If the PRESENT IF condition is true for a particular instance of the managed object class then the definitions specified in the package are all present in the managed object instance. If package referenced is specified in another document, a document reference must precede the name. This clause is optional.

The PRESENT IF condition is some delimited text, usually delimited by quotes, that states the condition. It can be any text such as a formal expression, but is usually a single English sentence. There one PRESENT IF for each conditional package that is present.

The REGISTERED AS object identifier is a unique identity that is used in the protocol to identify this particular managed object class. This clause is mandatory.


Author: Arthur Foster 28 May 2002	Arthur Foster is a founder member of
Author: Arthur Foster 28 May 2002		Hosted by