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Overview
of CORBA Services
Life
Cycle Service
• The
Life Cycle Service defines conventions for creating, deleting, copying and
moving objects. Because CORBA-based environments support distributed objects,
life cycle services define services and conventions that allow clients to
perform life cycle operations on objects in different locations.
• The
client's model of creation is defined in terms of factory objects. A factory is
an object that creates another object. Factories are not special objects. As
with any object, factories have well-defined OMG IDL interfaces and
implementations in some programming language.
• The
Life Cycle Service defines an interface for a generic factory. This allows for
the definition of standard creation services.
• The
Life Cycle Service defines a LifeCycleObject interface. This interface defines
remove, copy and move operations.
• The
Life Cycle Service has been extended to support compound life cycle operations
on graphs of related objects. Compound objects (graphs of objects) rely on the
Relationship Service for the definition of object graphs.
Persistent
Object Service
• The
Persistent Object Service (POS) provides a set of common interfaces to the
mechanisms used for retaining and managing the persistent state of objects.
• The
object ultimately has the responsibility of managing its state, but can use or
delegate to the Persistent Object Service for the actual work. A major feature
of the Persistent Object Service is its openness. In this case, that means that
there can be a variety of different clients and implementations of the
Persistent Object Service,
and they can work together.
This is particularly important for storage, where mechanisms useful for
documents may not be appropriate for employee databases, or the mechanisms
appropriate for mobile computers do not apply to mainframes.
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