Textual Modeling Framework Xtext

Textual Modeling Framework

Sven Efftinge, Sebastian Zarnekow
itemis

Donnerstag, 16. Juli 2009

Domain-Speciﬁc Language (DSL)


A DSL is a formal, processable language
targeting at a speciﬁc viewpoint or
aspect of a software system.


A DSL is a formal, processable language
targeting at a speciﬁc viewpoint or
aspect of a software system.
It’s semantics, ﬂexibility and notation is
designed in order to support working
with that viewpoint as good as possible.


Why DSLs?


Why DSLs?
• higher abstractions


Why DSLs?
• avoid redundancy


Why DSLs?
• separation of concerns


Why DSLs?
• separation of concerns
• use domain concepts
(Ubiquitous Language)


The challenge


Complicated

Complicated & Expensive ?

licensed by http://www.wordle.net/

How we address this with


Convenience

grammar org.xtext.workshop.DomainModel
with org.eclipse.xtext.common.Terminals

generate domainModel "http://www.xtext.org/DomainModel"

Model :
(types+=Type)+;

Type :
Class | DataType;

DataType :
'datatype' name=ID;

Class :
(abstract?='abstract')? 'class' name=ID '{'
(features+=Feature)*
'}';

Feature :
'attr' name=ID ':' type=[DataType];

9

Grammar grammar org.xtext.workshop.DomainModel
definition with org.eclipse.xtext.common.Terminals


Model :
(types+=Type)+;

Type :
Class | DataType;

DataType :
'datatype' name=ID;

Class :
'}';

Feature :

9

Grammar grammar org.xtext.workshop.DomainModel Grammar reuse
definition with org.eclipse.xtext.common.Terminals


Model :
(types+=Type)+;

Type :
Class | DataType;

DataType :
'datatype' name=ID;

Class :
'}';

Feature :

9


Derived generate domainModel "http://www.xtext.org/DomainModel"
metamodel
Model :
(types+=Type)+;

Type :
Class | DataType;

DataType :
'datatype' name=ID;

Class :
'}';

Feature :

9



Model :
(types+=Type)+;
Parser
rules Type :
Class | DataType;

DataType :
'datatype' name=ID;

Class :
'}';

Feature :

9



Model :
(types+=Type)+;
Parser
rules Type :
Class | DataType;

DataType :
'datatype' name=ID;

Class :
Keywords '}';

Feature :

9



Multivalue assignment
Model :
(types+=Type)+;

Type :
Class | DataType;
Simple assigment
DataType :
'datatype' name=ID;
Boolean assigment
Class :
'}';

Feature :

9



Model :
(types+=Type)+; Cardinality (one or more)

Type :
Class | DataType;

DataType :
'datatype' name=ID;

Class : Optional Element
(features+=Feature)* Cardinality (zero or more)
'}';

Feature :

9



Model :
(types+=Type)+; Cardinality (one or more)

Alternative
Type :
Class | DataType;

DataType :
'datatype' name=ID;

Class : Optional Element
(features+=Feature)* Cardinality (zero or more)
'}';

Feature :

9



Model :
(types+=Type)+;

Type :
Class | DataType;

DataType :
'datatype' name=ID; Assignment with rulecall

Class :
'}';

Feature :

9



Model :
(types+=Type)+;

Type :
Class | DataType; Unassigned rulecall

DataType :

Class :
'}';

Feature :

9



Model :
(types+=Type)+;

Type :

DataType :

Class :
'}'; Containment

Feature :

9



Model :
(types+=Type)+;

Type :

DataType :

Class :
'}'; Containment
Cross reference
Feature :

9

Metamodel Inference

generate domainModel
"http://www.xtext.org/workshop/DomainModel"

Model :
(types+=Type)+;

Type :
Class | DataType;

DataType :
'datatype' name=ID;

Class :
'}';

Feature :

10

Based on
the grammar and Ecore models,
Xtext provides you with sensible
default implementations.


Flexibility

Dependency management


MyCustomLabelProvider


Dependency Injection
with Google fGuice


with Google fGuice

‣No dependency to concrete implementation


with Google fGuice

‣No explicit construction


with Google fGuice

‣Easy testing


with Google fGuice

‣Easy testing
‣Easy composition

Configuration of
Components in Xtext
/**
* used to register components to be used within the IDE.
*/
public class DomainmodelUiModule
extends GeneratedDomainmodelUiModule {

@Override
public Class<? extends ILabelProvider> bindILabelProvider() {
return MySpecialLabelProvider.class;
}
}


Composable
Code Generator
‣ Generator is composed of “fragments”


Composable
Code Generator
‣ Fragments can contribute to:


Composable
Code Generator
‣ Manifest.MF


Composable
Code Generator
‣ Manifest.MF
‣ plugin.xml


Composable
Code Generator
‣ Manifest.MF
‣ plugin.xml
‣ Guice modules


Composable
Code Generator
‣ Manifest.MF
‣ plugin.xml
‣ Guice modules
‣ Add your own fragments

UseCase
Migrating existing Apps


Starting point

• DB-Application
• Oracle DB
• OracleForms

Target

• Oracle DB
• Java Rich Client
• JPA
• Spring
• Swing / JGoodies Forms

Quantities


Quantities
• 1700++ Tables


Quantities
• 1700++ Tables
• 19500++ Columns


Quantities
• 1700++ Tables
• 19500++ Columns
• 300++ Forms


Quantities
• 1700++ Tables
• 19500++ Columns
• 300++ Forms

Task


Quantities
• 1700++ Tables
• 19500++ Columns
• 300++ Forms

Task
• Find abstractions


Quantities
• 1700++ Tables
• 19500++ Columns
• 300++ Forms

Task
• Find abstractions
• Simplify code

@SuppressWarnings("serial")
@Entity
Entity
@Table(name = "BUCHUNGSKREISE_F")
BUCHUNGSKREISE_F
public class BuchungskreiseF extends AbstractEntity implements Serializable {

@SuppressWarnings("unused")
@Id
Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "bkrIdSeq")
@SequenceGenerator(name = "bkrIdSeq", sequenceName = "BKR_SEQ", allocationSize = 1)
BKR_SEQ
@Column(name = "BKR_ID", nullable = false
BKR_ID false)
private Long bkrId
bkrId;

public Long getBkrId() {
return bkrId;
}

public void setBkrId(final Long bkrId) {
this.bkrId = bkrId;
}

@Column(name = "KONTO_NR", nullable = false length = 45
KONTO_NR false, 45)
private String kontoNr;
kontoNr

public String getKontoNr() {
return kontoNr;
}

public void setKontoNr(final String kontoNr) {
String oldValue = this.kontoNr;
this.kontoNr = kontoNr;
firePropertyChangeEvent("kontoNr", oldValue, this.kontoNr);
}

External DSL for Entities

entity BuchungskreiseF
(id=bkrId sequenceName=BKR_SEQ) {

String kontoNr (notNull, length=45)

Long rgNrBkrIdentiﬁkator (notNull, length=1)

String referenzcodeKontoNr (notNull, length=45)

}




String kontoNr

Long rgNrBkrIdentiﬁkator

String referenzcodeKontoNr

}


BUCHUNGSKREISE_F


String kontoNr
RG_NR_BKR_IDENTIFIKATOR

Long rgNrBkrIdentiﬁkator

String referenzcodeKontoNr

}


Validation

addValidator(new Validator<Institutionen>() {
@Override
public ValidationResult validate(final Institutionen institution) {
final ValidationResult result = new ValidationResult();
if (institution != null
&& institution.getEsrNr() != null
&& !CheckUtils.checkPcKontoNrPruefziffer(
Long.parseLong(institution.getEsrNr())) {
result.add(new SimpleValidationMessage(
getResourceMap().getString("validation.esr.msg"),
Severity.ERROR, getModel(Institutionen.DESC.esrNr())));
}
return result;
}
});


Framework-Code

@Override
}
return result;
}
});


Framework-Code
Nullpointer abfragen

@Override
}
return result;
}
});


Framework-Code
Static imports

@Override
}
return result;
}
});


Framework-Code
Static imports
Bibliotheks Methoden deﬁnieren und benutzen
@Override
error("validation.esr.msg", desc.esrNr());
}
return result;
}
});


Internal DSL with Java
@Check
void checkEsrMsg() {
if (!checkKontoNrPruefziffer(parseLong(_this.getEsrNr())))
error("validation.esr.msg",desc.esrNr());
}

• JUnit-like
• Ignore Nullpointer-Exceptions


Future Plans

Eclipse Helios


Eclipse Helios
• Model Index


Eclipse Helios
• Model Index
• Grammar Mixins


Eclipse Helios
• Model Index
• Grammar Mixins
• Base Language


Eclipse Helios
• Model Index
• Grammar Mixins
• Base Language
• UI Features


Eclipse Helios
• Model Index
• Grammar Mixins
• Base Language
• UI Features
• Documentation


Thank you very much for listening

Visit the project’s web site :
www.xtext.org

Copyright 2009 by itemis


Thank you very much for listening

Visit the project’sWebinar :
Xtext web site
www.xtext.org19:00
Tomorrow
http://live.eclipse.org/node/705

Copyright 2009 by itemis


Textual Modeling Framework Xtext

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