dsl case study: state machine language - · pdf filecase study: state machine language runtime...

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TDT4250 - Model-driven Development of Information Systems, Autumn 2009

DSL case study:

State machine language

• Define a DSL language for state machines

• Create GMF- and Xtext-based editors

• Translate to the executable SCXML language

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Q

DSL with Eclipse

EMF provides platform for DSL

Ecore – (meta)model for design and runtime

EMF.Edit & Editor – edit support and tree-based editor

EMF.Codegen – generic code generation mechanism

GMF – graphical editor runtime and generator

builds on Ecore model of language concepts

domain-specific languages for (among others)

graphical syntax, i.e. structure of diagram symbols

mapping between conceptual language and graphical syntax

generates a complete graphical editor

palette and pop-up tools for editing

saves concepts and diagram elements in separate files

3


Q

DSL with Eclipse

Xtext – text editor runtime and generator

domain-specific language for

textual language grammar

implicitly defines Ecore language model

generates a complete textual editor

syntax coloring and highlighting

completion

navigation and find references

folding, outline and quick outline

syntax checking / error markers

4


Q

DSL with Eclipse

Model transformations

model to model (M2M) using ATL (QVT)

model to text (M2T) using JET or Xpand

5


Q

Case study: state machine language

Language with state machine concepts

states (hierarchy) with enter and exit actions

transitions with events, conditions and actions

Meta-levels

Specific state machine in example model

Model (type): State, Transition, Event, Condition, Action concepts

Meta-model: Ecore

Meta-meta-model: Ecore (!)

6


Q

Case study: state machine language

Runtime based on SCXML

XML-based language for Statecharts

Implemented by Apache project (library)

Steps:

GMF (and EMF) for building graphical editor

Xtext for building textual editor

Transform (alternatives)

to Ecore model of SCXML using ATL

to SCXML-objects using Java

to SCXML markup using Xpand

7


Q

GMF – Graphical Modeling Framework

Provides a DSL, runtime and tools for building

graphical editors

EMF is used for defining the language concepts

Other models cover:

graphical structure and syntax (gmfgraph)

editing tools (gmftool)

mapping from language concepts to graphical syntax

(gmfmap)

together these implicitly define the generator model (gmfgen)

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Q

Overview of GMF models

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Q

Language concepts

State

name

enterAction and exitAction

sub-states

Transition

event

condition

action

ExternalTransition

source and target states

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Q

Graphical syntax

State

node syntactical type

rounded rectangle

label

compartment for

substates

Transition

connection syntactical type

line with arrow

between source and target states

label combining event, condition and action

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Q

Graphical state syntax

Syntactical types

State node

Substates compartment

Figure

rounded rectangle

label

rectangle (invisible)

inset to provide target area along edges

border layout, with label @ north and compartment @ center

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Q

Graphical transition syntax

Syntactical type

Transition link

Figure

polyline

label

polyline decoration @ target

points defining the arrow head shape -1,-1

0,0

-1, 1

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Q

Tool palette structure

Tools

Create State tool

Create Transition tool

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Q

Mapping from concepts to syntax

Defines

how to traverse the object structure to generate the diagram

and keep it updated when the object structure changes

top-level diagram elements

contained elements

what information in the objects go where in the diagram

labels

Lot’s of details are necessary

a complete specification has to be detailed

the model has necessary details, while the (generated) code

has irrelevant and unnecessary details

15


Q

Mapping from concepts to syntax

Top level elements

state

State

node mapping: State class to state node

label mapping: State name attribute to label figure

child reference and compartment mapping: State subStates

reference to compartment

Transition

link mapping: ExternalTransition class to transition connection

Transitions are children of states

Transition source/target references to source and target

label mapping: Transition event, condition and action attributes

to label, with view and edit pattern (syntax)

16


Q

TMF Xtext – Textual Modeling Framework


textual editors

EMF is used as the underlying target language

Ecore model is implicitly defined by the grammar

Grammar covers:

lexical syntax (terminals)

rules for syntactical structures

relation between syntax and Ecore classes

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Q

Language concepts

State

name

sub-states

transitions

variables

definitions for script-based events, conditions and actions

Transition

internal, actions triggered by transitions or states

event, condition

initial, default transition when entering parent state

condition, action

external, between states

event, condition, action

18


Q

Language syntax

State

either just a name or content within braces { }

Transition

internal, actions triggered by transitions or states

action when event [ condition ]

initial, default transition when entering parent state

-> state when [ condition ] / action

external, between states

state -> state when event [ condition ] / action

Event

name!, event script reference, state -> state, state-> or ->state

Action

name! or action script reference

Condition

condition script reference

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Q

TMF Xtext – Textual Modeling Framework


textual editors

EMF is used as the underlying target language

Ecore model is implicitly defined by the grammar

Grammar covers:

lexical syntax (terminals)

rules for syntactical structures

relation between syntax and Ecore classes

dsl case study: state machine language - · pdf filecase study: state machine language runtime...

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