New features in CORBA 3.0

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New features in CORBA 3.0

• Niall Stapley, CERN
• email niall.stapley_at_cern.ch

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Overview

• What exactly is CORBA3?
• Objects passed by value
• CORBA Component Model
• Asynchronous Messaging
• Minimum CORBA
• Fault Tolerant CORBA
• Other new specifications

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What exactly is CORBA 3.0?

• Actually a suite of specifications.
• Conceptual difference between 2 and 3
• CORBA 2 tried to preserve network transparency.
• CORBA 3 provides features that help with the
  network.
• Divided into 3 main areas
• Java and internet integration.
• Quality of Service Control.
• CORBA Components.

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Objects by value

• A struct with added value
• They can have state and behaviour
• Not CORBA objects
• Can inherit from other valuetypes and support
  interfaces
• Supports the CORBA Component Model and Java to
  IDL reverse mapping.
• New keywords valuetype, public, private,
  abstract
• Uses a value factory to create local object
• Since CORBA 2.3

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Objects by value
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CORBA Component Model

• Framework for designing, implementing and
  deploying CORBA components.
• Purpose is to simplify and reduce effort by using
  a container that
• manages lifecycle
• provides CORBA services
• allows clean separation between application logic
  and CORBA
• Support for ready made components

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CORBA Component Model

• Two levels of component
• Basic - fully compatible with EJB
• Extended - components expose ports
• Component categories
• Session, Service, Entity, Process
• More extra keywords like component, home,
  supports
• Implementations?
• K2 Component Server
• MicoCCM
• OpenCCM

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Quality of Service

• Provides policy-based QoS Framework
• No standard defaults ORB Vendor sets them
• Policy areas
• Rebind Support
• Request / Reply Priority
• Request / Reply Timeout
• Synchronization Scope
• Routing

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Asynchronous Messaging

• Brings flexible asynchronous communication to
  Static Invocations.
• Asynchronous Method Invocation (AMI)
• Callback mode
• Similar to providing a callback handler object
• Polling mode
• Returns a valuetype object for client to check
• From CORBA 2.4

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Minimum CORBA

• Designed systems with limited resources
• Do not need everything that CORBA provides
• Has size and space limits
• Some operations are omitted from Object, ORB
• Other omissions
• Dynamic Invocation Interface
• Dynamic Skeleton interface
• Dynamic any
• Interface Repository

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Minimum CORBA

• The POA
• Default policies only for
• create_thread_policy
• create_implicit_activation_policy
• create_servant_retention_policy
• create_request_processing_policy
• No dynamic activation of POAs
• No ServantManagers
• Implementations
• Tatankas gibralter
• Sankhyas Varadi

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Fault Tolerant CORBA

• Aims to provide robust support for high
  reliability
• Defines a Fault Tolerance Infrastructure
• Provides reliability by
• entity redundancy
• object replication (passive and active)
• request retry and redirection
• fault detection and recovery
• Multiple profiles in IOR
• Example of a FT corbaloc URL
• corbaloc1.2_at_hostA683,1.2_at_hostB683/myObj

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Other New Specifications

• Data Parallel Processing
• Defines Architecture for parallel programming
• Data is typically divided and redistributed
• Unreliable Multicast (MIOP)
• Deliver messages to many objects at once
• Takes advantage of network ability
• IDL operations would require oneway
• Clients join a multicast group with a group IOR
• Domain CORBAfacilities
• IDL is a great way to define standard interfaces
  for standard objects that every company in an
  industry can share.

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And Finally...

• For more information
• http//www.omg.org/technology/corba/corba3releasei
  nfo.htm
• http//www.omg.org/technology/documents/specialize
  d_corba.htm
• CORBA 3 Fundamentals and Programming by Jon
  Siegel
• Any questions?
• Thanks ESRF for a great workshop!