Towards a Common Metamodel for the Development of Web Applications

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UML-BASED WEB ENGINEERING UML-BASED WEB ENGINEERING

Towards a Common Metamodel

for the Development of

Web Applications

Nora Koch and Andreas Kraus Ludwig-Maximilians-Universität

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Motivation

Overwhelming

diversity

of Web

methodologies

n Different views (models) and modeling elements n Different notations

Goal:

Unification

at high

level

of

abstraction

⇓

Common

metamodel

for

Web

methodologies

n Better comparison and integration

n Fundamental for tool support and code generation n Allows different development processes

n Allows use of subsets of modeling elements (like UML)

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Overview

n

About UWE

n

A Step Towards the Common Metamodel: UWE Metamodel

n

Mapping to the Notation

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UML-BASED WEB ENGINEERING UML-BASED WEB

ENGINEERING

About UWE

n UML-based Web Engineering (UWE) is an object-oriented approach

based on UML and the Unified Process

n Main focus of UWE is the systematic design followed by a

semi-automatic generation of Web applications

n Systematic design supported by

CASE-tool ArgoUWE – an extension of ArgoUML

n Semi-automatic generation supported

by UWEXML – a model-driven Code Generator for deployment to an XML publishing framework OpenUWE development environment UWE metamodel

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UML-BASED WEB ENGINEERING UML-BASED WEB ENGINEERING ApplicationModel UWE MOF UML M3 M2 M1

UWE Metamodel

n

Definition of concepts and relationships

among concepts

n

Compatibility with the OMG metamodeling

architecture

n MOF meta-metamodel

n XMI interchange format → tool compatibility

n

Conservative extension of the UML

metamodel

n

Static semantics given by OCL constraints

(Well-formedness rules)

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ENGINEERING

Conservative Extension

n

UML modeling elements

n are not modified, e.g. by adding additional features

n are extended by inheritance

n

Valid UML model

⇒

valid UWE model

NavigationClass Class

Not allowed for conservative extensions!

ConceptualClass

NavigationClass Class

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UML-BASED WEB ENGINEERING UML-BASED WEB ENGINEERING = UML Metamodel Foundation Model Management Behavioral Elements UWE Foundation Behavioral Elements Model Management Foundation Model Management Behavioral Elements = UWE Metamodel

Package Structure

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UML-BASED WEB ENGINEERING UML-BASED WEB ENGINEERING Foundation Context User Environment Core Navigation Conceptual Presentation Model Management Behavioral Elements Task Adaptation

Package Structure

(cont.)

Foundation Context User Environment Core Navigation Conceptual Presentation Model Management Behavioral Elements Task Adaptation „Separation of Concerns“

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UML-BASED WEB ENGINEERING UML-BASED WEB ENGINEERING = UML Metamodel Attribute (Foundation.Core) Association (Foundation.Core) AssociationEnd (Foundation.Core) Class (Foundation.Core) Operation (Foundation.Core) BehavioralFeature (Foundation.Core) Feature (Foundation.Core) Classifier (Foundation.Core) StructuralFeature (Foundation.Core) 1 2..* {ordered} +connection 0..1 +owner * {ordered} +feature 1 +participant * +association

Conceptual Package

Attribute (Foundation.Core) Association (Foundation.Core) ConceptualAssociation AssociationEnd (Foundation.Core) ConceptualOperation Operation (Foundation.Core) BehavioralFeature (Foundation.Core) Feature (Foundation.Core) Class (Foundation.Core) ConceptualClass Classifier (Foundation.Core) ConceptualAttribute StructuralFeature (Foundation.Core) 1 2..* {ordered} +connection 0..1 +owner * {ordered} +feature 1 +participant * +association = UWE Metamodel

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UML-BASED WEB ENGINEERING UML-BASED WEB ENGINEERING Class (Foundation.Core) Association (Foundation.Core)

Navigation Package

Link isAutomatic : Boolean Association (Foundation.Core) NavigationNode isLandmark : Boolean Class (Foundation.Core) {derived} +target 1..* +inLinks * {derived} +source 1 +outLinks * NavigationNode isLandmark : Boolean Association (Foundation.Core) Link isAutomatic : Boolean Class (Foundation.Core) ExternalNode url : String Menu NavigationClass * 1..* {derived} +target 1..* +inLinks * {derived} +source 1 +outLinks * 0..1 * NavigationNode isLandmark : Boolean Association (Foundation.Core) Link isAutomatic : Boolean Class (Foundation.Core) ExternalNode url : String TaskLink Menu

NavigationClass ExternalLink NavigationLink

* 1..* {derived} +target 1..* +inLinks * {derived} +source 1 +outLinks * 0..1 *

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Example of a well-formedness rule:

“Navigation attributes are derived from from conceptual attributes. These navigation attributes have to be reachable by navigation through the model“

Same example constraint in OCL:

context NavigationClass

inv: self.feature->select( oclIsKindOf(NavigationAttribute) ).derivedFromAttributes-> forAll( f | self.derivedFrom.transitiveClosure->exists( feature = f ) )

Navigation Package

(cont.)

ConceptualAttribute (UWE.Foundation.Core.Conceptual) ConceptualClass (UWE.Foundation.Core.Conceptual) NavigationNode Attribute (Foundation.Core) NavigationAttribute NavigationClass * +derivedFromAttributes * * +derivedFrom 1 * <<implicit>>

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Mapping to the Notation

n

Mapping to extended UML syntax in a non-standard way

n i.e. not using extension mechanisms of the UML

n Standard UML CASE tools can not be used

n Good documentation required

notation MyNavigationClass isLandmark abstract syntax NavigationClass NavigationNode isLandmark : Boolean Example:

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n

Mapping to a UML Profile

n Mapping uses standard extension mechanisms like stereotypes,

tagged values and OCL constraints

n Standard UML CASE tools can be used

n Compatibility with the UML XMI interchange format

n Profile support

n Active: by plug-ins, tool extensions

n Passive: by an external tool

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§ Classes → Elements with stereotype

notation

<<navigation class>>

MyNavigationClass

§ Attributes → Tagged values

{isLandmark}

Mapping Rules

Systematic rules for mapping a metamodel to a UML profile:

abstract syntax

NavigationClass

NavigationNode isLandmark : Boolean

§ Inheritance → Inheritance among stereotypes

Repeated mapping of attributes and associations

«navigation node»

«navigation class»

§ Associations → Tagged values or associations (for Classifiers)

{isLandmark, derivedFrom=MyCClass}

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Example UWE Model

<<navigation class>> Conference {isLandmark, derivedFrom=Conference} reviewDeadline : Date{derivedFromAttributes=reviewDeadline} submissionDeadline : Date{derivedFromAttributes=submissionDeadline} title : String{derivedFromAttributes=title} <<navigation class>> Paper {derivedFrom=Paper} keywords[*] : String{derivedFromAttributes=keyword.key} title : String{derivedFromAttributes=title} <<navigation class>> Author {derivedFrom=Author} affilation : String{derivedFromAttributes=affilation} name : String{derivedFromAttributes=name} <<navigation link>> 1..* <<navigation link>> 1..* SubmittedPapers <<navigation link>> * <<navigation link>> * <<navigation class>> Author {derivedFrom=Author} affilation : String{derivedFromAttributes=affilation} name : String{derivedFromAttributes=name} i

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Conclusions / Future Work

n

Definition of the UWE metamodel

⇒

a first step towards a common metamodel for Web

applications

n

Systematic mapping to the UWE notation (UML profile)

Future Work

n Refinement of the UWE metamodel and unification with other

methodologies, especially concerning dynamic aspects

n Meta tool suite OpenUWE

n CASE tool ArgoUWE

n Code generators n Model checking

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Thank you for your attention

Further questions?

Nora Koch [email protected]