An Adaptive Application Framework Facilitating Information Grid

1
An Adaptive Application Framework Facilitating
Information Grid

• Li Gang Lv Qing-zhong Han Yan-bo
• Institute of Computing Technology
• Chinese Academy of Sciences

2
Overview

• Background
• State of the Art
• Adaptive Architecture Model and the Framework
  Thereof
• Framework Implementation
• Framework Application
• Conclusion

3
Background

• Computing Trends
• Computing is moving to grid
• Computing Environment
• Grid environments are subject to a higher degree
  of heterogeneity and dynamism
• Features of Application
• Grid applications are composed of heterogeneous
  resources across dynamic environment, changes are
  very unpredictable in nature
• Changes of user requirements, grid resources etc.
  cause changes of applications

4
State of the Art

• Much work has been done, focusing on grid
  infrastructure, application development method
  etc.
• How to make applications adapt to environmental
  changes and evolve smoothly is still an open
  issue
• Related work
• Architectural reflection--Walter Cazzola etc.
• Service-oriented application construction--eFlow
• Component mark language--CXML

5
Diagrammatic Representation of Our Solution
Designer Power User
6
An Adaptive Architecture Model
CRAM

• Why we bring forward the model?
• There is a great gap between business domain and
  software domain
• Classic reflection itself is not enough for
  making application adaptable to business and
  resource changes in information grid
• There are requirement for a model that is to
  enable adaptation caused by changes in business
  domain and resources
• The Convergent and Reflective Architecture Model
  (CRAM)
• Keeping business model, architecture model and
  software as a whole, which enable change mapping
  between different domain
• Realizing extended reflection, which make
  adaptation easily

7
Structure of CRAM
Business Processes and Entities
Executable Application
8
Three Levels of CRAM

• Convergent and Reflective Base Level
• Focusing on implementation of users requirements
  and completes computing tasks that user submits
• Corresponding to the executable grid application
  that offers functionalities user needs
• Convergent and Reflective Meta Level
• Focusing on architecture aspect of grid
  application
• Depicting static and dynamic architecture
  features
• Convergent and Reflective Meta-meta Level
• Focusing on business view of software and catches
  changes in grid resources
• depicting software architecture aspects from
  business domain

9
A Convergent Architecture Description Language
CADEL

• Why do we bring forward the language?
• To explicitly describe application architecture
  and enable adaptation
• Features of the Language
• Convergent
• Executable
• XML-based

10
Core of CADEL Service Description

• A service is defined as a specific capability
  provided by one or more network-enabled
  components
• A service can be identified in terms of the
  protocol that the service uses to interact with
  others and the service behavior responding to
  protocol messages
• Capability of a service is described with
• Operations
• Attributes
• Behavior protocols

11
Core of CADEL Coordination Description

• Coordination rules depict the interaction
  relations among components of grid application
• Coordination rules specify the data flows,
  control flows and event flows among resources,
  and activities fulfilled by resources
• Coordination rule are specified by
• Initiation node
• Finish node
• And-in node
• And-out node
• Or-in node
• Or-out node
• Activity node etc.

12
Framework Implementation Considerations in
Implementation

• Change-aware requirements
• Adaptation requires tools to capture changes in
  business domain and materialize those changes in
  software easily
• Smooth Adaptation
• Those tools should offer automatic support to
  some extent for adaptation.
• Mini-kernel of the framework
• The framework should be adaptive also, must be
  implemented as a mini-kernel, and can be extended
  by plug-ins
• When adaptation begins
• The framework should support adaptation at
  runtime dynamically

13
Framework Implementation
Architecture View
14
Framework Implementation Key
Components (1)

• Application Composer
• It is used to capture the business view in
  graphic manner and associate data object and
  processing object with architecture component of
  the meta level
• Resource manager
• It is used to store and manage service
  information and data objects
• Resource Explorer
• With the responsibility for discovering and
  inspecting service, Resource Explorer finds
  services in term of the instruction of power
  user, gets meta data of those services and stores
  it into repository
• Interpreter
• It interprets the specification, making it run

15
Framework Implementation Key
Components (2)

• Runtime Monitor
• It is used to watch the runtime state of
  application, in order to provide information for
  making adjustment decision
• Meta-level Controller
• It enables one to change application based on the
  framework at runtime
• User Proxy
• User Proxy is the provider of access control
• ServProxyPool
• It is used to access service
• Event Facility
• It provides support to asynchronous service

16
Target Users of the Framework

• There are two kinds user of the framework
• Designer
• To construct a new application
• To modifying a application
• Power user
• To adapt a application at runtime or non-runtime

17
Framework Application Application Background

• Vega Railway Information Grid (Vega-RIG) is
  currently being developed by ICT Chinese Academy
  of Science
• Several large and distributed information systems
  have been constructed to support railway
  management
• They work independently and form heterogeneous
  virtual organizations
• Typical problems Vega-RIG has to solve are
• How can users share information among legacy
  systems and draw information from them
  dynamically and synthetically?
• How can information systems transparently adapt
  to changes of data resources and business rules,
  which take place in business evolution?

18
Framework Application
A CASE

• Railage Statistics Management Information System
  (RS-MIS) is an application in Vega-RIG
• Changes in RS-MIS are following

Category
Line ID
Category
Line ID
19
Framework Application Our Solution to the
Problem (1)

• Use the framework to construct application
• Constructing business model
• Generating specification in CADEL
• Assigning user account
• Interpreting the specification and run

20
Framework Application Our Solution to the
Problem (2)

• Use the framework to adapt the application
• Adaptation at runtime
• Watching the states and architecture by runtime
  monitor
• Modifying the application by meta-level
  controller
• Adaptation at non-runtime
• Reconstructing the application by application
  composer

21
Conclusions

• In this paper, we present
• An adaptation-enabled convergent architecture
  model named CRAM
• A convergent architecture description language
  CADEL which enables application adaptation with
  fewer efforts by reconfiguration of resources and
  adjustment of coordination rules.
• An adaptive application framework facilitating
  information grid