CHAPTER 11: MODEL TRANSFORMATION Transformation Definition - - PowerPoint PPT Presentation

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CHAPTER 11: MODEL TRANSFORMATION Transformation Definition - - PowerPoint PPT Presentation

Aug 29, 2023 384 likes •987 views

Architecture and Modelling of Information Systems (D0I71A) Prof. dr. Monique Snoeck CHAPTER 11: MODEL TRANSFORMATION Transformation Definition Transformation Tool 2 Agenda Model Transformations General approach Transformation

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Transformation Tool

Transformation Definition

CHAPTER 11: MODEL TRANSFORMATION

Architecture and Modelling

  • f Information Systems (D0I71A)
  • Prof. dr. Monique Snoeck
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SLIDE 2

Transformation Tool

Transformation Definition

Agenda

  • Model Transformations
  • General approach
  • Transformation Rule Examples
  • General Architecture
  • The Enterprise Layer
  • The Event Handling Layer
  • Transformation Technology Example

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Transformation Tool

Transformation Definition

General Approach

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models models

  • r

code transformation engine transformation definition

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Transformation Tool

Transformation Definition

General approach to transformations

  • Develop software manually
  • Look for patterns that are best practices
  • Define Transformations based on patterns
  • = Pushing patterns "below the water line"

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Transformation Tool

Transformation Definition

Pushing Best Practices “below the line”

  • FLAT FILE (198x)
  • Application
  • record insertion
  • record deletion
  • record search
  • sorting
  • indexing
  • storage

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  • DATABASE MGT SYSTEM (20xx)
  • Application
  • Record insertion
  • record deletion
  • record search
  • sorting
  • indexing
  • storage
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Transformation Tool

Transformation Definition

Specifications

Pushing Best Practices “below the line”

  • Traditional
  • MDA

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Code

Specifications Object Interaction Pattern OO –relational Storage Pattern

Code

Object Interaction Pattern OO –relational Storage Pattern Other Architectural Pattern Other Architectural Pattern

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Transformation Tool

Transformation Definition

Agenda

  • Model Transformations
  • General approach
  • Transformation Rule Examples
  • General Architecture
  • The Enterprise Layer
  • The Event Handling Layer
  • Transformation Technology Example

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Transformation Tool

Transformation Definition

General Transformation Architecture

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Domain Model Information System Services Enterprise Layer Persistence + Business Logic Event Handling Layer User Interface Transactions Queries Business Process Models Business Process Engine

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Transformation Tool

Transformation Definition

Agenda

  • Model Transformations
  • General approach
  • Transformation Rule Examples
  • General Architecture
  • The Enterprise Layer
  • The Event Handling Layer
  • Transformation Technology Example

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SLIDE 10

Transformation Tool

Transformation Definition

The Enterprise Layer

  • The Database Schema
  • Associations
  • Navigability: one way or both ways ?
  • Cardinality of ‘one’  transform to ‘many’ ?
  • Optimisations

 Merge classes for ‘mandatory-one’ dependencies ?  Merge classes for ‘optional-one’ dependencies ?

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Domain Model Enterprise Layer Persistence + Business Logic

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Transformation Tool

Transformation Definition

The Enterprise Layer

  • The Database Schema = PSM for the EDG (=PIM)

Class Project private Department owningDept Class Department private SET(Project) projects Class Employee private SET(DeptAssignment) assmtHistory Class Employee private Department mydepartement

  • Foreign Key from Dependent to Master
  • Navigation from master to dependent too ?
  • Transform cardinality of ‘one’ to ‘many ‘?
  • Merge Employee and DeptAssignment into
  • ne database class ?

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Transformation Tool

Transformation Definition

The Enterprise Layer

  • The Business Logic

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Domain Model Enterprise Layer Persistence + Business Logic

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Transformation Tool

Transformation Definition

The Enterprise Layer (Business Logic)

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Attribute of Object Type Association Object Type participates in Attribute in Implementation Class Association Attribute in Implementation Class Object Type Implementation Class Factory 1 method per event type the object type participates in + 1 method for checking the corresponding preconditions Abstract Class

Database Layer Business Logic

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Transformation Tool

Transformation Definition

The Enterprise Layer (Business Logic)

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Object Type's FSM Abstract state class (associated with mapped class) For each State of the FSM, a State subclass of the mapped Abstract state class Per mapped State subclass, methods for checking state con- ditions for each event in of the mapped Abstract state class Database Layer Business Logic

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Transformation Tool

Transformation Definition

The Enterprise Layer (Business Logic)

  • Preconditions
  • Code can be injected in different places
  • In a check-event method in business layer or in the event handling layer
  • Example:
  • checking a precondition for a returnDate to be later than today

Public boolean isValidReturnDate (Date d){ return d.compareTo(today) > 0 } … if isValidReturnDate(input_returnDate) { this.returnDate = input_returnDate; } else { throw new RuntimeException("return date is not valid.");}

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Transformation Tool

Transformation Definition

Agenda

  • Model Transformations
  • General approach
  • Transformation Rule Examples
  • General Architecture
  • The Enterprise Layer
  • The Event Handling Layer
  • Transformation Technology Example

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Domain Model Event Handling Layer

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Transformation Tool

Transformation Definition

(Recap) A Business Event is ...

  • A request to perform an activity to register something that happens or that you would

like to happen in the real world.

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Transformation Tool

Transformation Definition

(Recap)The Object Event Table

  • identifies Business Event Types
  • identifies Object Types
  • models participation of Object

Types to Business Event Types with an Object-Event-table

  • (Decide on notification & coordination pattern later at implementation time)

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Transformation Tool

Transformation Definition

(Recap)The Object Event Table

  • In Merode, a business event is a request + an activity
  • request can be refused
  •  When filled, a cell specifies what preconditions are

imposed on a business event by a business object type

  • Activity is distributed across participants
  • (assuming that the request has been accepted)
  •  when filled, cell specifies what the effect is of that

business event on the participating business object type (modified attributes, operation to call),

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Transformation Tool

Transformation Definition

Transforming the OET to code

  • OET-table (PIM)
  • No immediate transformation to code ...
  • Transform to UML-PSM
  • Define collaboration diagram
  • Transform Collaboration Diagram to code
  •  1 pattern, applicable to all event types !
  • Transparent
  • Maintenance easier
  • Transformation tot non-OO platforms possible as well

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MERODE OET UML Collaboration Diagram PSM/ Code

Messaging Pattern ?

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Transformation Tool

Transformation Definition

Business Event Handling

1. Tasks Event Dispatcher

  • Check Preconditions of all participants
  • By Event Dispatcher
  • By rule engine
  • By Objects/Components
  • Notify Event (broadcast) to participants
  • Co-ordinate answers
  • Check first – do then
  • Do & compensate

2. How many Event Dispatchers ?

  • Centralised versus Distributed
  • ne event handler for all events (maximally centralised)
  • ne event handler per event (maximally distributed)

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Transformation Tool

Transformation Definition

Mapping

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Platform Independent Model

Business Event Object

Object/Event Involvement

Mapping

Mapping Rules for

  • Event Triggering
  • Precondition verification
  • Event Notification
  • Coordination of Event

Execution

Platform Specific Model Platform Choice

  • Programming Languages
  • EAI Middleware
  • Web Service Technology
  • - ...
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Transformation Tool

Transformation Definition

Sample Event Handling Patterns

  • Messaging Pattern should take care of:
  • Event Notification to participants, precondition checking, Coordination of Event Execution
  • Scheme 1: Forwarding
  • Not standardised ⇒ Must be designed for each event type separately
  • More difficult to maintain
  • E.g. take inspiration from OO-SSADM (UK)
  • co-ordination of method invocation starts at home-entity
  • Merode
  • Forwarding can start in event owner
  • Scheme 2: Broadcasting
  • one event handler per event (event class)
  • (option chosen in code-generator)
  • one event handler for all events of one type (C/M/E event dispatchers)
  • (option chosen in JMermaid)

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1 2

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Transformation Tool

Transformation Definition

Event Forwarding

  • In MERODE all receiving objects are connected with ED-relationship

 Initiate forwarding in Owner of Event  Forward to Masters

Questions

  • How to ensure atomicity ?
  • What if more than one Owner for an Event ?
  • What with Event-preconditions ?

(= preconditions for event in general, not for a method in a class)

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Transformation Tool

Transformation Definition

Event Forwarding: example scheme

  • General outline:

Check first Do then

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PRODUCT TYPE PRODUCT ORDER ORDER LINE

(2) Check modify_quantity (3) Check modify_quantity (4) Checkmodify_quantity (1) modify_quantity OK OK OK Done Done Done Done (1) Check modify_quantity (2) modify_quantity (3) modify_quantity (4) modify_quantity

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Transformation Tool

Transformation Definition

Event forwarding

Questions

  • How to ensure atomicity ?
  • What if more than one Owner for an Event ?
  • What with Event-preconditions ?

(= preconditions for event in general, not for a method in a class)

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BOOK MEMBER LOAN RESERVATION fetch loan.member = reservation.member loan.book = reservation.book

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Transformation Tool

Transformation Definition

Event Broadcasting: example scheme 2

  • One class per 1-many Event(s)

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Event

PRODUCT TYPE PRODUCT ORDER ORDER LINE

modify_quantity

Modify Quantity

Check modify quantity

Done Done Done Done

modify quantity

Done Ok Ok Ok Ok

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Transformation Tool

Transformation Definition

e:Event Handler

  • 1

:Object Type s :StateClass checkEvent() OK_prec = checkEvent() getCurrentState() s = getCurrentState() checkEvent() IS1 :InputService handleEvent(o1) OK_state = checkEvent() Result = handleEvent() event() 1 2 event() 3 4

Event broadcasting pattern in Prototype

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Transformation Tool

Transformation Definition

Event broadcasting pattern in Prototype

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1 1 2 2 3 4 3 4

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Transformation Tool

Transformation Definition

Event Broadcasting: example scheme 2bis

  • One class per 1-many Event(s)

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Event

PRODUCT TYPE PRODUCT ORDER ORDER LINE

modify_quantity

Modify Quantity

Check modify quantity

Done Done Done Done

modify quantity

Done

Check done by Event Handler

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Transformation Tool

Transformation Definition

Event Broadcasting: example scheme 2ter

  • One class per 1-many Event(s)

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Event

PRODUCT TYPE PRODUCT ORDER ORDER LINE

modify_quantity

Modify Quantity

Check modify quantity

Done Done Done Done

modify quantity

Done

Check done by Rules Engine Rules Engine OK

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Transformation Tool

Transformation Definition

Event Broadcasting: example scheme 2

  • 2 main Options:
  • hard coded
  • for example one method per event
  • Using OET as look-up table
  • allows for dynamic subscription

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Transformation Tool

Transformation Definition

Hard coded EventDispatcher

Member Book Loan Borrow A/M A/M O/C

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Class Eventhandler borrow (m:member, b: book) is local new_loan : LOAN require do lock m lock b check Preconditions loan check preconditions member check preconditions book if OK then create new_loan.borrow(db.loans.new_id, book, member) db.loans.extend(new_loan) – stores new loan in database b.borrow(new_loan) m.borrow(new_loan) unlock member unlock copy end

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Transformation Tool

Transformation Definition

Event Dispatcher with look-up table

Member Book Loan Borrow A/M A/M O/C

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MEMBER LOAN BOOK

borrow

borrow

Done Done Done

Borrow

Done

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Transformation Tool

Transformation Definition

Patterns for Event Handling

  • Choice of transformation depends on aspects not yet captured in EL, ISL, BL
  • Non-functional Requirements (Qualities)
  • single platform vs multi-platform
  • confidentiality of rules
  • variability of participating services
  • technical capabilities of participating services
  • performance
  • Technical Design Choices
  • hard-coded or with subscription manager
  • coordination protocol
  • two-phase commit
  • compensation-based
  • rules private and checked decentrally
  • rules shared and checked centrally

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Transformation Tool

Transformation Definition

Agenda

  • Model Transformations
  • General approach
  • Transformation Rule Examples
  • General Architecture
  • The Enterprise Layer
  • The Event Handling Layer
  • Transformation Technology Example

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Transformation Tool

Transformation Definition

Generator Engine

Template-based transformation

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Transformation Tool

Transformation Definition

MXP to Java via Apache Velocity

  • Apache Generator engine

1.

Defines a data structure consisting of Java meta-object classes as structured data collections

2.

Uses an XML parser to extract data from MXP file and populate the Java meta-object classes

3.

Distributes properties collected from XML into velocity template contexts

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Transformation Tool

Transformation Definition

Starting point = Merode MXP

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  • Merode model = XML file
  • XML = Extensible Markup Language
  • was created to structure, store, and transport information
  • most common tool for data transmissions between all sorts of

applications

  • uses tags which are not predefined => user can define any tag
  • Information is stored between opening and closing tags, e.g.

<note> <to>Tove</to> <from>Jani</from> <heading>Reminder</heading> <body>Don't forget me this weekend!</body> </note>

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Transformation Tool

Transformation Definition

Merode MXP

  • Object types, attributes, events, methods

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String name String nr

<mxp:metamodel lastid="13"> <mxp:datatypes /> <mxp:metaobjects> <mxp:metaobject id="1" name="a" abstract="false"> <mxp:metadescription /> <mxp:metaconstraints /> <mxp:metamultiplepropagationconstraints /> <mxp:metaattributes> <mxp:metaattribute id="12" name="name" type="String" type-id="1"> <mxp:description /> <mxp:validation /> <mxp:implementation /> </mxp:metaattribute> <mxp:metaattribute id="13" name="nr" type="String" type-id="1"> <mxp:description /> <mxp:validation /> <mxp:implementation /> </mxp:metaattribute> / t tt ib t

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Transformation Tool

Transformation Definition

Merode MXP

  • Object types, attributes, events, methods

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<mxp:metaevents> <mxp:metaevent id="2" name="cr_a"> <mxp:metadescription /> <mxp:metaattributes /> </mxp:metaevent> <mxp:metaevent id="3" name="end_a"> <mxp:metadescription /> <mxp:metaattributes /> </mxp:metaevent> </mxp:metaevents>

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Transformation Tool

Transformation Definition

Merode MXP

  • Object types, attributes, events, methods

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<mxp:metamethods> <mxp:metamethod id="4" name="cr_a" provenance="OWNED" type="CREATE" ownerobjectid="1" ownereventid="2"> <mxp:metaprecondition /> <mxp:metaimplementation /> <mxp:metapostcondition /> <mxp:metaattributes /> </mxp:metamethod> <mxp:metamethod id="5" name="end_a" provenance="OWNED" type="END" ownerobjectid="1" ownereventid="3"> <mxp:metaprecondition /> <mxp:metaimplementation /> <mxp:metapostcondition /> <mxp:metaattributes /> </mxp:metamethod> </mxp:metamethods>

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Transformation Tool

Transformation Definition

Generation of Java-Code

  • Template for mapping a business object type defined in the

MERODE-model into a Java class

public abstract class $object.objName { // ---------------- attributes -------------------- #foreach ($attribute in $object.attributes.entrySet()) private $attribute.attributeType $attribute.attributeName; #end // ---------------- dependencies -------------------- #foreach ($master in $object.masters.entrySet()) private $master.masterName $master.masterName.toLowerCase(); #end ... }

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Transformation Tool

Transformation Definition

Generation of Java-Code

  • Template applied to LOAN

public abstract class Loan { // ---------------- attributes -------------------- private int loanID; private Date loanDate; private Date returnDate; // ---------------- dependencies -------------------- private Member member; private Copy copy;

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Transformation Tool

Transformation Definition

Generation of Java Code

  • Template for checking referential integrity precondition

#foreach ( $method in $object.ownedMethods ) .... #if ($method.isEndingMethod) if(hasLivingDependents()) throw new MerodeException ("Precondition violation in ending method \"${method.methodName}\" in class ${object.objectName}:\nObject has living dependents"); .... #end

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Transformation Tool

Transformation Definition

Generation of Java code

  • Result after applying to class A:

public class Aimpl extends A { ... public void check_end_a() throws MerodeException { if(hasLivingDependents()) throw new MerodeException ("Precondition violation in ending method \"end_a\" in class A:\nObject has living dependents"); } .... }

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Transformation Tool

Transformation Definition

Other examples of MDE

  • Previous JMermaid code generator (Raf Haesen)
  • Extension to UI generation (Jenny Ruiz)
  • Event-based Distributed Business Processes (Pieter Hens)
  • Service composition (Geert Monsieur)
  • Current JMermaid code generator (Gayane Sedrakyan)

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Transformation Tool

Transformation Definition

Case: Previous JMermaid code generator

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  • Used XMI-based generator “Andro MDA”
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Transformation Tool

Transformation Definition

UML: MXP to XMI via XSLT

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XMI: <UML:Class visibility="public" isSpecification="false" isRoot="false" isLeaf="false" isAbstract="false" isActive="false" stereotype="sentity" xmi.id="484" name="A"> <UML:Classifier.feature> <UML:Attribute visibility="private" isSpecification="false" ownerScope="instance" xmi.id="485" name="naam" type="987654321"/> <UML:Attribute visibility="private" isSpecification="false" ownerScope="instance" xmi.id="487" name="nr" type="987654321"/> <UML:Operation visibility="public" isSpecification="false" ownerScope="instance" isQuery="false" concurrency="sequential" isRoot="false" isLeaf="false" isAbstract="false" xmi.id="490" name="cr_a" stereotype="soc"> <UML:BehavioralFeature.parameter> <UML:Parameter kind="return" type="dvoid" xmi.id="mp490"/> </UML:BehavioralFeature.parameter> </UML:Operation> <UML:Operation visibility="public" isSpecification="false" ownerScope="instance" isQuery="false" concurrency="sequential" isRoot="false" isLeaf="false" isAbstract="false" xmi.id="491" name="end_a" stereotype="soe"> <UML:BehavioralFeature.parameter> <UML:Parameter kind="return" type="dvoid" xmi.id="mp491"/> </UML:BehavioralFeature.parameter> </UML:Operation> </UML:Classifier.feature> </UML:Class>

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Transformation Tool

Transformation Definition

Case: Extension with UI design

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Transformation Tool

Transformation Definition

Presentation model

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Transformation Tool

Transformation Definition

Case: Extension with UI design

  • UI generated according to UI design choices recorded in presentation model.

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Transformation Tool

Transformation Definition

Case: Using MDA to improve load balancing in business process execution

  • Model2Model transformation to split a global process into multiple smaller –lightweight-

processes

  • Takes advantage of existing event-based architectures (publish –subscribe)

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PIM

Split BPMN Model Split BPMN Model Split BPMN Model

Decentralization Algorithm

PSM PSM PSM

Business Process Modeler Deploy and distribute

Process Engine

Code Code Code

Process Engine Process Engine

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Transformation Tool

Transformation Definition

PIM2PSM Transformation (1)

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  • Each task in the original process

becomes a process on its own

  • For each new process, start rules are

calculated

  • A start rules depicts when a split

process can start its execution

  • The split processes are also in BPMN-

notation

  • The start rules are transcribed with

the use of bpmn-start-events

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Transformation Tool

Transformation Definition

PIM2PSM Transformation (2)

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  • Realized with the Atlas Transformation Language
  • Declarative language to define transformation rules from objects in the source meta-model to objects in the

target meta-model

  • Available as an Eclipse Plugin

rule Task2Process { from s: BPMN20!Task to newTask: BPMN20!Task ( id <- s.id, name <- s.name ), endev: BPMN20!EndEvent ( id <- 'EndEvent' + s.id, eventDefinitions <- outputDef ),

  • utputDef: BPMN20!SignalEventDefinition (

id <- 'outputDef' + s.id, signalRef <- outputSignal ),

  • utputSignal: BPMN20!Signal (

id <- 'Signal' + s.id), ), process: BPMN20!Process ( id <- 'sid-Process' + s.id, flowElements <- Sequence{newTask}, flowElements <- Sequence{outputSeqFlow}, flowElements <- Sequence{endev}, flowElements <- s.getEventRule()

  • > collect(e | thisModule.createStartEvents(e))

)

Ecore MetaMetaModel ATL BPMN2.0 BPMN2.0 BPMN2EventBPMN Source Model Target Model

Conforms to Conforms to Conforms to Conforms to Transformation Conforms to

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Transformation Tool

Transformation Definition

Coordination in service compositions

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Business Process as blueprint Coordination = Control Flow + Data Flow

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Transformation Tool

Transformation Definition

Using MDA to automate the design of service interactions

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BPMN Model

PIM

BPEL + WSDL File BPEL + WSDL File BPEL + WSDL File

Pattern-based coordination

PSM PSM PSM

Business Process Modeler Deploy and distribute

BPEL Engine

Code Code Code

BPEL Engine BPEL Engine

Configurable transformation ! Choose a pattern, then transform

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Transformation Tool

Transformation Definition

PIM2PSM transformation

  • Transformation rules implemented in Java
  • PIM (input):
  • BPMN 2.0 (XML)
  • Service and Data Providers (WSDL files)
  • Transformation configuration:
  • Coordination Model (XML)

= selection of patterns

  • PSM (output):
  • BPEL (and WSDL) files for each participating

service in the service composition

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Arrange
  • nline
payment Book flight Send tickets to customer Book car Book hotel Register payment Process customer’s request Notify Customer Overview
  • n unpaid
invoices Processed customer request Customer’s address The ‘overview on unpaid invoices’ data
  • bject can be retrieved from the
Finance Data Service and is required to make the decision that is modeld in this data-based gateway The ‘processed customer request’ data
  • bject which is a result from the
‘process customer’s request’ task is required to make the decision that is modeled in this data-based gateway Customer wants a hotel Customer wants a flight Customer wants a car The ‘customer’s address’ data
  • bject is available at the
Customer Data Service One or more unpaid invoices No unpaid invoices

Java

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Transformation Tool

Transformation Definition

Lessons Learned about MDE

  • Productivity ?
  • Development of code generation transformation: approximately 6-8 PM work
  • Intensive testing required
  • bug-free after +/- 1 year of use
  • Yearly used to generate hundred’s of applications
  • Template-based approach + JAVA are easy-to-use technologies for transformations
  • Documentation
  • PIM requires its own documentation
  • Documentation of transformation is essential

Maintenance of transformation is harder than maintenance of “normal” code

  •  the need for documentation does not disappear
  • Portability & Interoperability
  • Yes, but new transformations need to be defined

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