Developing.NET Web Service- based Architectures with Aspect-Oriented Component Engineering Santokh Singh 1, Professor John Grundy 1,2 and Professor John Hosking 1 1 Department of Computer Science 2 Department of Electrical and Computer Engineering, University of Auckland, New Zealand

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking Outline Introduction & Motivation Aspect-oriented Component Engineering AO Components & Aspect Details AOCE – web services architecture AOCE.NET AOUDDI and AOWSDL Current and Future Work Conclusions

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking Introduction Present component-based systems engineering focuses on low level software component interface design and implementation. Great setbacks –  Often results in development of components whose services are hard to understand and combine.  Makes too many assumptions about other components related to it.  Component documentation is too low level which is again hard to understand at higher levels.

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking Motivation Low-level software component interface design and implementation - cumbersome and difficult to comprehend. The larger the software system, the more prevalent and critical this problem becomes. Problem even in industries producing or refactoring the code for commercial software tools and systems. Leads to tremendous wastage in terms of time, effort and resources. A solution need to be found, real fast!

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking Aspect-oriented Component Engineering AOCE - a new component based software engineering technique. Aims at enabling software engineers develop efficient, better and more reusable software components. AO-Components are better characterised and categorised.

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking AOCE AO Components will vertically slice the application Data processing comp. Event HistoryProcess Views Distribution related services Software application built using AOCE techniques Process Users User Interface related services Persistency related services Performance related services Aspects will horizontally slice the Components

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking Aspects in AOCE Aspects horizontally slice the overall software system that was vertically componentised. Aspects characterize specific cross-cutting functional and non-functional properties of the components. Examples of Aspects: security, persistency, configuration, collaboration, transaction processing, distribution, user interface, performance and resource utilization.

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking Aspect-oriented web services architecture Find, using aspectual queries & responses AO-Discovery Agencies (AOUDDI) AO-Discovery Agencies (AOUDDI) AO- Service Providers AO- Service Requestors AO- Service Requestors Interact/bind Publish AO-Service Description (AOWSDL) Aspect- oriented Clients Aspect- oriented Services AO-Service Description (AOWSDL) Validating agents/ Adaptors Runtime Validation and Adapting

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking AOCE.NET Overview of using AOCE to develop.NET web service-based software systems

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking AOCE design for travel planner components

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking Travel planner's AO-web service-based architecture.

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking Travel Planner: simplified version AOUDDI Registry Web services repository Flights Services AOWSDL Payment Services AOWSDL Hotels Services AOWSDL Car Rentals Services AOWSDL Booking Adaptor AOWSDL Pay & Book Composite Pay & Book Composite Testing Agents Travel Planner Client

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking Example of using the AO-UDDI registry AOUDDI – Aspect- Oriented Universal Description, Discovery and Integration business registry for locating and integrating ao-web services. AODDI can also handle multiple queries. Aspect details can be ascertained from the AOUDDI.

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking AOUDDI & AOWSDL (continued) ………… ………… …….. …… ….. AOWSDL - Aspect-Oriented Web Services Description Language for describing ao-web services. A sample of the component element in the AOWSDL document is shown on the left.

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking Current/Future work Further AOUDDI, AOWSDL development Investigating automated AO-WS component discovery Automatic validation and integration/ adaptation Tool support

AWSA '04 Presentation (c) Santokh, John Grundy & John Hosking Conclusions Time, effort and resources unnecessarily expanded to understand low-level software component designs and implementations. The bigger the system, the greater is the wastage. These losses can be minimised or even prevented. Aspect-Oriented Component Engineering proposes a better way to characterise and categorise components in system architectures. Hopefully it can address other issues like reducing outsourcing…