???????????? Techniques and Applications of COTS Software Reuse

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????????????Techniques and Applications of COTS
Software Reuse

• ???
• ?????????
• ??????
• jimmy_at_thmu.edu.tw

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Outlines

• Introduction
• COTS-Based Systems
• Distributed Software Integration System (DSIS)
• DSIS Examples
• MultiAgent Distributed Scripting System (MADSS)
• Conclusions
• MADSS Demo

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INTRODUCTION
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Motivation

• Building a house
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• ?????

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Motivation (Cont.)

• Find a parking space in a large parking lot
• gt How to build a Graphic Parking Lot ?Management
  System?
• design from scratch (higher cost, longer
  development time, suitable for popular software)
• design by reusing existing software (lower cost,
  shorter development time, suitable for
  customizing software)

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CAR RECORD Name Jim-Min
Lin Car_ID RD-9681 Parking space
105 Check-in-date 04/12/2002 Check-in-time
130657 PM Check-out-date 04/12/2002 Check-out-t
ime 155103 PM Parking fee NT 90.00
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Software Reuse

• Why software reuse?
• Time and money saving
• Diverse tools/functions support
• Revaluing existing software
• Ensuring software reliability
• Evolving software easily
• Software reuse approaches
• software reuse with source codes
• software reuse without source codes

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Software Reuse

• Levels of software reuse
• Functions
• Modules or objects
• Subsystems
• Application systems

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Software Reuse (cont)

• Problems with reuse
• Increased maintenance costs
• Lack of tool support
• Maintaining a component library
• Finding and adapting reusable components
• gt Component-based Software Engineering is a
  currently feasible and more and more important
  solution to software reuse

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Component Based Software Development (CBSD or
CBSE)?

• CBSD focuses on building large software systems
  by integrating previously-existing software
  components.
• gt Buy, dont build
• Component-based systems encompass both COTS
  products and components through other means

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Software components

• Components with a specific interface protocol
• CORBA objects
• COM/DCOM objects
• JavaBeans
• EJB ..
• Components without specific interface protocol
• off-the-shelf applications with source codes
• Commercial-Off-The-Shelf (COTS) products without
  source codes lt Focus of our works

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COTS component

• COTS component
• A component that is
• Sold, leased, or licensed to the general public
• Offered by a vendor trying to profit from it
• Supported and evolved by the vendor, who retains
  the intellectual property rights
• Available in multiple, identical copies used
  without modification of the internals

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CBS COTS BASED SYSTEMS
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Software development changes in COTS Based
Systems (CBS)
TraditionalApproach
Required ITSEP Approach
Stakeholder needs/Business Process
Requirements
SimultaneousDefinitionand Tradeoffs
Architecture Design
Architecture/Design
Marketplace
Programmatics/Risk
Implementation
ITSEPInformation Technology Solutions Evolution,
2002, CMU SEI
Adapted from COTS-Based Systems for Program
Managers
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Activities of CBS development
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Physical View of COTS-Based System

• A set of reusable COTS components
• Software architecture
• Glueware

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Architecture

• Software Architecture
• A high level design that provides decisions made
  about the problem(s) that the component will
  solve, component descriptions, relationships
  between components, and dynamic operation
  description.
• A sub-system design made up of a collection of
  components

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Architecture (cont)

• Class of architecture
• System infrastructure
• Support the development of system infrastructure
• Middleware integration
• Support component communication and information
  exchange
• Example CORBA, COM, DCOM
• Enterprise application
• Support the development of end-user application

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Glueware

• Glueware supports a physical methodology to
  integrate components
• Types of Glueware
• Custom codes
• System tools, ex Unix pipe filter
• Scripting language
• Unix shell
• Visual Basic
• TCL/TK(Tool Command Language/Tool Kit)

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COTS product reuse

• Benefits with COTS system integration
• Diverse functionality
• To reduce costs and delivery times
• Reduce risks
• Adaptable alone with system evolution

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COTS product reuse(cont)

• Problems with COTS system integration
• Lack of source codes and the control over
  functionality and performance
• Problems with COTS system interoperability
• Lack of support from COTS vendors

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COTS product reuse(cont)

• Issues of COTS-based System development
• Which technologies and COTS products are most
  appropriate?
• How can COTS product mismatches be rectified in
  our system?
• How can we engineer system attributes such as
  reliability, security, and performance in spite
  of decreasing control over individual system
  components?
• How do we integrate COTS products with the custom
  code that continues to provide the core of many
  systems?
• How do we take advantage of COTS while delivering
  a system that can evolve over a long lifetime?

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Reuse of COTS Products

• Our works focused on the CBS integration
  techniques and applications

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COTS product Integration

• Integration technique of COTS products
• Adaptation through Wrapper technique
• Wrapper
• A piece of codes that encapsulate the underlying
  components and bridge the components with their
  clients
• Wrapping COTS as another component with specific
  interface

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COTS product Integration(cont)
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Wrapper technique

• Purposes and usage of a wrapper
• enhancing the functionality or performance of
  the wrapped software
• gluing a software with other (independent)
  software so that they can work together

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Distributed Software Integration System (DSIS)
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Conceptual View of DSIS
network
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CORBA-based DSIS

• Objectives
• gt Migrating DOS, Windows, and UNIX applications
  to CORBA server objects

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Overall structure of CORBA-based DSIS
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Wrapper for CORBA DSIS

• a program that consists of a CORBA interface
  module and an I/O redirector module
• gt the former part is responsible for accepting
  requests from CORBA clients and then rescheduling
  the transactions to PC applications if necessary
• gt the latter part is to intercept I/O data of PC
  applications and support multithreading (or
  multi-instance) for increasing system throughput

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Wrapper Operation Scenario
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Implementation of Wrappers

• DOS Wrapper
• Windows Wrapper
• UNIX Wrapper

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DOS Wrapper

• Using DOS VM to intercept and redirect DOS I/O
  channels

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WINDOWS Wrapper

• Hooking system message queue and clip board

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Windows Input Redirection
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Windows Output Redirection
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UNIX Wrapper

• A sandwich-structure wrapper

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DSIS Examples
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DSIS Example 1

• Graphical Parking Lot Management System (GPLMS)

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Integration Web Server??
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GPLMS??????????
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DSIS Example 2

• A MultiAgent-based Distributed Scripting System
  (MADSS)
• Agent-based DSIS scripting mechanism

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MADSS Overview
USER
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MADSS System Structure
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MADSS

• The benefits
• More intelligent abilities to deal with tasks
• Component integration with speech acts
  communication
• Load balance
• Adopting existing technologies
• Java
• KQML (Agent Communication Language, ACL)

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MADSS(cont)

• Roles of MADSS
• Users
• Client Agent
• Slave Agent
• Facilitator
• Service Agent

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MADSS(cont)

• MADSS Users
• Responsible for writing MADSS scripts

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MADSS(cont)

• Client Agent
• A stationary agent
• Interpret an MADSS script program as the
  corresponding agents commands and KQML messages
• Delegate tasks to slave agents for users
• Delegate sub-tasks to mobile slave agents

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MADSS(cont)

• Slave Agent
• A mobile agent
• Get delegated tasks from a client agent
• Directed/driven by an MADSS script program
• Bring the requests to a service agent through
  KQML and take the results back to another service
  agent respectively

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MADSS(cont)

• Service Agent
• Advertising services on facilitator
• Forward messages and method calls to
  corresponding COTS components (COTSwrapper) for
  slave agents
• Service management

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MADSS(cont)

• Facilitator
• Record agent information for newly created agents
• Assist an agent to look for an appropriate
  service agent.
• Assist an agent to deliver messages to the
  corresponding agents.

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MADSS(cont)

• Distributed Scripting Language
• Instruction types
• Agent execution
• Identify target agent
• Task delegation
• Delegate tasks to target agent
• Scripting scenarios
• Circular trip
• Parallel execution
• Forth and back

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Instruction types

• Agent execution
• astart agent_name task1, task2
• Start an agent and specify the associated tasks
• dispose
• Terminate an agent
• execute agent_name
• Execute an agent
• pexecute agent1, agent2,
• Parallel execute several agents

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Instruction types(cont)

• Task delegation
• delegate parameter value
• d (destination)
• Destinations address defaultlocal site
• s (service)
• Target service defaultnull
• n (name)
• Service Agents name
• t (expire time)
• Expire time to dispose an agent

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Instruction types(cont)

• Task delegation
• delegate parameter value
• -c (message content)
• Message contents for communicating with remote
  service agents.
• -fn (nth file name)
• The nth file containing data carried by a mobile
  slave agent to a destination site
• -r (file name)
• the file containing the service results back to
  origin

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Scripting scenarios

• Circular trip

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Scripting scenarios (cont)

• Example of circular trip
• astart AgentA //140.134.26.58, default agent
  transfer protocol (atp) port 4434
• delegate -d atp//140.134.26.56 -n
  Calculator_agent1 -s Math -c (13) -r result1
  -f null
• delegate -d atp//140.134.26.65 -n
  Calculator_agent2 -s Math -c (result14) -r
  result2 -f null
• delegate -d atp//140.134.26.58 -n
  client_agent -s Home -c result1,result2 -r null
  -f null
• dispose
• execute AgentA

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Scripting scenarios (cont)

• Parallel execution

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Scripting scenarios (cont)

• Example of parallel execution
• astart AgentB //140.134.26.58
• delegate -d atp//140.134.26.56 -n KqmlMedia -s
  Media -c c\abc.mpg -r null -f file_B
• astart AgentC //140.134.26.58
• delegate -d atp//140.134.26.65 -n KqmlMedia -s
  Media c C\song.mp3 -r null -f file_c
• pexecute AgentB,AgentC

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Scripting scenarios (cont)

• Forth and back

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Scripting scenarios (cont)

• Example of forth and back
• astart AgentD // 140.134.26.58 Aglet 2.0.2 port
  4434
• delegate -d atp//140.134.26.65 -n Calculator_1
  -s Math -c (13) -r result1 f null
• delegate -d atp//140.134.26.56 -n Calculator_2
  -s Math -c (32) -r result2 -f null
• delegate -d atp//140.134.26.65 -n Calculator_1
  -s Math -c (result1result2) -r result3 -f
  null
• delegate -d atp//140.134.26.58 -n agent_jimmy
  -s print_result -c result1,result2,result3 -r
  null -f null
• dispose
• execute AgentA

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????MADSS

• Environment
• 3 PCs
• Windows 2000/98
• Java 2 Standard Version
• IBM Aglet

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CONCLUSIONS
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Summary

• The Internet is a repository of countless COTS
  products.
• CBS is highly possibly an economic and fast way
  to building a software system
• DSIS provides a feasible solution to constructing
  a CBS. MADSS is for integrating heterogeneous
  software through a scripting programming.
• We have successfully implemented an experimental
  MADSS based on IBM Aglet package

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Future Works

• Interface specification mechanism for COTS based
  software components
• Software architecture for COTS based systems
• Agent-based CBS component searching system
• KQML -gt XML
• MADSS Programmatic interface

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Important Source of references

• International Conference on COTS Based System
  (ICCBS) --- initiated by CMU SEI
• Web Site www.sei.cmu.edu

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Q A
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THANK YOU VERY MUCH!

• ???
• 1.????????? ??????,????
• 2.???? ??????,???
• Jimmy_at_thmu.edu.tw