Fahmi & Shamira

Perkhidmatan-perkhidmatan CORBA

Notification Services.

1.  Memanjangkan pertukaran mesej ‘Event Service’ tidak segerak

• Membolehkan ‘multiple event suppliers’ untuk hantar events ke ‘multiple event consumers’

• Menyokong ‘pull’ dan ‘push’ bagi model-model

• Membolehkan ‘event channel’ menjadi bersekutu

• Membolehkan pelanggan untuk melampirkan penapis kepada setiap proksi dalam ‘event channel’

2.  Ciri-ciri QoS:

• Per-saluran, per-proksi, per-event

3.  ‘CORBA Notification Service’ menggunakan:

• StructuredEvent, EventChannel, kelas-kelas EventType

• StructuredPushConsumer, kelas-kelas StructuredPushSupplier

Trader Services.

1.  Konteks ‘Market Trading’

• Objek yang menghuraikan perkhidmatan yang ditawarkan kepada sistem

• Pelanggan ‘request’ isu perkhidmatan yang dikehendaki

• Melaksanakan ‘matching’

2.  Antaramuka

• Antaramuka ‘Lookup’untuk mengiklan keperluan pengimport

• Antaramuka ‘Register’ untuk mengiklan ciri-ciri suatu servis

• OfferIterator untuk ‘iterate’ melalui pelbagai tawaran (hits)

• Antaramuka ‘Admin’ untuk ‘query’ untuk semua tunggakan pertanyaan dan tawaran untuk mengawal proses ‘matching’

Collections Services. 

1.  Kumpulan objek

• Sets, queues, sequences

• ‘Iterators’ untuk koleksi ini

• Kelas ‘Factory’ untuk penciptaan objek

2.  Antaramuka koleksi

• Set, Heap, Stack, Queue, SortedSet adalah kelas-kelas sub

3.  Antaramuka ‘iterator’

• EqualityIterator, SequentialIterator adalah kelas-kelas sub

4.  Antaramuka operasi

• Kelas asas untuk operasi terhadap objek

Siti Khadijah Korai & Norhafidah Ishak

Externalization Service.

Description: Defines protocols and conventions for externalizing (recording the object’s state in a stream of data) and internalizing objects.

This service defines the means for converting objects into a form suitable for export over general media, such as network streams or disk storage, and then re-constituting this data back into object references, potentially in a different ORB and/or process. The service allows for pluggable data formats for externalized objects, but a standard serialized format for objects is provided, to ensure that a baseline protocol can be shared among users of the service. The Externalization Service uses a Stream object for externalizing and internalizing objects. A StreamFactory creates Stream objects. Specific sources or destinations for streams can be supported by subclasses of the StreamFactory (e.g., FileStreamFactory). Objects that are to be externalized must extend the Streamable interface. This service uses the Life Cycle Service to create and destroy Stream and StreamFactory objects. The Relationship Service manages the externalization of graphs of related objects.

Query Service.

Description: Provides query operations on collections of objects.

The Query Service provides a general object query mechanism for distributed objects. With this service, collections of objects can be searched to generate subcollections, or subsets of objects within a collection can be deleted or updated through a query. The facilities defined in the Query Service can be mapped to, but are not limited to, persistent storage facilities, such as relational or object databases. Collections of objects are represented by Collection objects, which are created using a CollectionFactory. You iterate through a Collection of objects using an Iterator. QueryEvaluator objects issue a Query against a given Collection. The result of evaluating a Query can be of any type, but typically it is a Collection of some kind. A QueryManager is a type of QueryEvaluator that allows you to create queries.

Licensing Service.

Description: Defines the interfaces that support management of software licenses.

The Licensing Service is a protocol for controlled access to objects and services under a licensing model. Conceptually, you can think of it as an extension of the Security Service, with some additional access semantics having to do with consumable and expirable access. A license gives a user certain limited rights to use a particular remote object or set of objects. In the License Service model, a client makes a request for a licensed service from a service provider, giving the provider some proof of ownership of a license. The provider then turns to a license manager to acquire a license service, which it uses to verify the existence of a license and check its policy against the proposed usage. The producer can then ask to be notified of license expiration during its use, or it can poll the license service for changes in the license state. The LicenseServiceManager provides access to license services specific to certain producers. The ProducerSpecificLicenseService provides a producer with the methods needed to check on license validity, and start and end license usage sessions. The License Service depends on the Security Service for license verification and secure communications and on the Event Service for asynchonous notification of license events to producers. Some implementations may also use the Relationship,
Property, and Query Services.