WEB BUSINESS PLATFORMS ON

THE ‘CLOUD’ – AN ENGINEERING

PERSPECTIVE

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Harshavardhan “Harsh” Jegadeesan

Business Suite Core

SAP Labs, India

CONTEXT

Web-Business Platforms

Platform Strategy

“Opening-up” of the platforms using SOA-based webAPIs

Platform Adoption and Creation of an ecosystem – ofdevelopers, partners and entrepreneurs – around theplatform

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So what are the Engineering Challengesfaced by platform owners while adoptinga Platform Strategy?

Multi-tenancy

…

Handling heterogeneity in the serviceecosystem

Evolving Standards Problem#1

XML / JSON

OASIS / W3C …

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Issues with automated service consumption

Inadequate service descriptions

Lean Service MetadataProblem

#2

Service Differentiationin a Services marketplace

#3

“Unintrusive” Service Differentiation

Service

Capability on-offer

Terms of Offer

Creation and Maintenance ofConsumption APIs

#4

Catering to heterogeneous service consumers

Browsers

Mash-ups

Support for Customizing and ExtendingService Offerings

#5

How can customers extend the services?

Support for Visual Syntax forService Specification

#6

Business users prefer visualparadigms for specifying service artifacts

How can platform owners address thesechallenges?

How would a solution approach looklike?

What criteria would any solution satisfy?

CRITERIA FOR SOLUTION (1)

Criterion #1: A solution must support ServiceRepresentation at a conceptual and technologyagnostic level

Criterion #2: The Service Representation must beeasily convertible to executable servicespecifications

Criterion #3: The Service Representation musthave minimal concepts supporting maximalexpressiveness

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CRITERIA FOR SOLUTION (2)

Criterion #4: The Service Representation mustsupport different roles involved in thedevelopment of the service

Criterion #5: The Service Representation musthave strong underpinnings in the applicationdomain

Criterion #6: The Service Representation must beopen-standards compliant and must leverageexisting tools

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CRITERIA FOR SOLUTION (3)

Criterion #7: The solution must supportunintrusive changes to commissioned services tosupport differentiation

Criterion #8: The solution must support creationof language-specific Web APIs to support aheterogeneous platform audience

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WHAT DOES A ‘SERVICE’ REPRESENT?

A Service represents:

Capability on-offer Represents the underlying business function or capability

Terms of Offer Represent the terms at which this capability is offered.

E.g. SHIPPINGSERVICE

Capability on-offer: to ship an item from one place toanother

Terms of Offer: Cost, Delivery time, Payment Options

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SOLUTION CONTEXT

- REFERENCE ARCHITECTURE

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OUR SOLUTION APPROACH

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Our solution approach is based on Model-Drivendevelopment.

Metamodels

Six Model Views

We have developed Six Model Views to addressdifferent facets of coarse services development

Domain-DrivenDesign Metamodel

ResourcesMetamodel

ServicesMetamodel

MODEL VIEWS & VIEW POINTS

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Model View Viewpoint addresses

ServiceDescription View

Description and classification ofServices based on ownership domain

ServiceCapability View

Defines the capability on-offer. Description of Service,Service Properties, Interfaces, Operations, Messages andmessage-exchange pattern.

Service PolicyView

Defines the term of offer of a service. Definition of ServicePolicies.

ServiceRealization View

Defining the service provisioning approach, either serviceimplementation from underlying IT assets or throughcomposition of constituent services

ServiceMediation View

Defining how existing services could be re-purposed toaddress different consumer goals using process or datamediation.

ServiceDeploymentView

Describes service interaction points and serviceinvocation mechanisms

METAMODELS, MODELS & TRANSFORMATIONS

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(MOF 2) UMLInfrastructure

DDDMetamodel

ResourcesMetamodel

ServicesMetamodel

Metamodels

DomainModel

ResourceModel

ServiceDescription Model

ServiceCapability Model

ServicePolicy Model

ServiceRealization Model

ServiceMediation Model Service

Deployment Model

Model-to-ModelTransformation

Models

ExecutableSpecifications

ProvisioningCode

(Java, .NET)

SOAP /REST

Interfaces

ServiceDescriptions

(WSDL / WADL)

PolicyDescription(WS-Policy)

Model-to-TextTransformation Consumption

APIs

USING THE MODEL TO CREATE SERVICE

CONSUMPTION APIS

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Models

Technology Platforms(Programming Languages)

Domain Model ResourcesModel

Services Model(Service Capability

Model)

UML2 ModelClasses Diagram)

Model-to-ModelTransformation

Model-to-ModelTransformation Model-to-Model

Transformation

Model-to-TextTransformation

DLL Client-Library

.NET Platform

JAR FilesJava Platform

PHP, Ruby, Pearl,Python

CONCLUDING REMARKS

By abstracting service representations usingconceptual models we support:

Increased longevity of the solution

address the evolving standards problem, lean servicemetadata problem

By defining “terms of offer” as policies, wesupport unintrusive change of terms of offer tomake service offering attractive

Using model-to-model and model-to-texttransformations we support easy creation andevolution of service consumption APIs

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QUESTIONS

&DISCUSSIONS

ABSTRACT

Web businesses such as eBay®, Amazon® and a whole lot of others havelong seized to be mere websites; they have morphed into web businessplatforms on the "cloud". By adopting a platform strategy, they arebuilding an ecosystem of developers, partners and entrepreneurs to buildinnovative applications for customers. As platform owners, catering to hisheterogeneous ecosystem is a huge engineering challenge in itself. Thissession, we would discuss some of these challenges along with somerecipes to overcome them.

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Harsh currently works as a Project Manager in the SOA teamwithin the Business Suite organization in SAP Labs, India. Priorto this, he was working with the Research & BreakthroughInnovation group on SAP® ByDesign®. He follows his passion forteaching, as an adjunct faculty with BITS, Pilani, teachinggraduate courses is software engineering. He actively contributesto JournalServer.Org, a free library of scholarly articles. His areasof interest include service-oriented architectures, enterprisesystems and business process platforms. He can be reached at:harshavardhan.jegadeesan@sap.com

SPEAKER BIO