Transforming Legacy Web Applications To The MVC Architecture

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Transforming Legacy Web Applications To The MVC
Architecture

• Yu Ping and Kostas Kontogiannis
• Electrical and Computer Engineering
• University of Waterloo

Terence C. Lau IBM Centre for Advanced
Studies IBM Toronto Laboratory
SDM-DS Workshop, STEP 2003 Amsterdam, The
Netherlands September 20, 2003
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TABLE OF CONTENT

• Introduction
• Design Rational
• Migration Framework
• JSP Refactorying Process
• Conclusion

Transforming Legacy Web Applications to the MVC
Architecture
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INTRODUCTION Problem Description

• Legacy Web Applications
• Designed by inflexible or less flexible
  architectures and implemented by older
  technologies
• Maintainability 2-tier design
• Scalability Process-based
• Portability Server-dependent
• Some Examples
• CGI application (PERL, C, Python)
• Web Server APIs (ISAPI, NSAPI)
• Traditional JSP-based Web sites

Transforming Legacy Web Applications to the MVC
Architecture
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INTRODUCTION Migration to Network-centric
Platform

• Modern Web Applications
• Designed by component-based architectures and
  supported by open standards and technologies
• Maintainability 2-tier design ? Multi-tier
  design
• Scalability Process-based ? Thread-based
• Portability Server-dependent ?
  Server-independent
• Some Examples
• J2EE

Transforming Legacy Web Applications to the MVC
Architecture
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DESIGN RATIONAL MVC

• 1. Model-View-Controller (MVC) Design Pattern
• MVC separates the data persistence/business rule
  (model), user interface (view), and application
  control (controller)
• The new system will adopt the MVC architecture in
  an enterprise Java environment

Controller
(Servlet)
Model
Data
Client
(JavaBeans/EJB)
Base
View
(JSP)
Transforming Legacy Web Applications to the MVC
Architecture
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DESIGN RATIONAL Data Bean Architecture
2. Data Bean Compliant Architecture

• Query Command Bean
• Execute SQL statements through JDBC
• Data Bean
• Populate data in JSP pages
• Data Access Bean
• Carry data from query command beans to data beans

JSP Pages
Data Base
Activate
JDBC
Set input parameters
Query Command Bean
Data Bean
Invoke Query Command
Data Access Bean
Set output parameters
Get output parameters
Transforming Legacy Web Applications to the MVC
Architecture
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MIGRATION FRAMEWORK Transformation Methodology

Phase 1 Separating data base access (model) from
presentation logic (view) Phase 2 Making
transition to JSP Phase 3 Making the migrant
system extensible
Transforming Legacy Web Applications to the MVC
Architecture
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MIGRATION FRAMEWORK Transformation
Architecture
Source Code
JSP Application
Transforming Legacy Web Applications to the MVC
Architecture
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JSP Refactorying Process JSP Web Site
Reengineering
A Web site is a hyper-linked network environment,
usually without an engineering architecture.
We present an approach that aims to restructure
an existing JSP-based Web site by adopting a
controller-centric structure.
Transforming Legacy Web Applications to the MVC
Architecture
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CONCLUSION

• We present a reengineering framework for the
  transformation of legacy Web applications to
  enterprise Java environments based on the MVC
  design pattern
• Future extensions may focus on following
  directions
• Investigating the use of the wrapping technology
  or Java connector architecture in order to
  integrate the legacy Web applications
• Examining the usage of a software clustering
  technique with the purpose of identifying
  cohesive groups of Web pages
• Developing the technique for automatic
  implementation of analyzing dynamic Web
  components

Transforming Legacy Web Applications to the MVC
Architecture
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Transforming Legacy Web Applications To The MVC
Architecture

• Yu Ping and Kostas Kontogiannis
• Electrical and Computer Engineering
• University of Waterloo

Terence C. Lau IBM Centre for Advanced
Studies IBM Toronto Laboratory
EAI Workshop, STEP 2003 Amsterdam, The
Netherlands September 20, 2003