Java DSLs with Xtext

Java DSLs with Xtext

Jan Koehnlein

Mittwoch, 27. März 13

public class Customer implements Serializable {

private String name; private Address address; private List<Item> purchase;

public String getName() { return name; } public void setName(String name) { this.name = name; }

public Address getAddress() { return address; } public void setAddress(Address address) { this.address = address; } public List<Item> getPurchase() { return purchase; } public void setPurchase(List<Item> items) { this.purchase = purchase; }}


@Entity public class Customer implements Serializable { @Id private String name; private Address address; private List<Item> purchase;

public String getName() { return name; } public void setName(String name) { this.name = name; } @Column(name="ADDR", nullable=false) public Address getAddress() return address; } public void setAddress(Address address) { this.address = address; } @ManyToMany public List<Item> getPurchase() { return purchase; } public void setPurchase(List<Item> items) { this.purchase = purchase; }}


http://www.objectdb.com/api/type/Column#




Domain-Specific Languages


@Entity public class Customer implements Serializable { @Id private String name; private Address address; private List<Item> purchase;

public String getName() { return name; } public void setName(String name) { this.name = name; } @Column(name="ADDR", nullable=false) public Address getAddress() { return address; } public void setAddress(Address address) { this.address = address; } @ManyToMany public List<Item> getPurchase() { return purchase; } public void setPurchase(List<Item> items) { this.purchase = purchase; }}

entity Customer { name: String address: Address purchase: Item*}

CodeGeneration

DSL Java






Methods Logic

ArithmeticsBehavior ?


entity Customer { name: String address: Address purchase: Item* double sales() { double result = 0.0; for(Item item: purchase) result += item.getPrice(); return result; }}


Typesystem

Compiler / Interpreter

Complex Syntax

Expressions


Integration Patterns

Generatedcode

Manually writtencode


Reusable powerful expression library language

Java‘s Typesystem

Compile to Java Code

Access to Java-elements


DSLs for

JavaMittwoch, 27. März 13

Type System

Interpreter /

Debugger

Grammar (Parser, Lexer)Linker

Advanced Editor

Eclipse IntegrationJvm

Model

MyLanguage

grammar inheritance

JvmModelInferrer


Model Inference

entity Customer { name: String address: Address purchasedItems: Item* double sales() { purchasedItems .map[price] .reduce[a,b|a+b] }}

Class Customer

parameter name

returnType String

Field name

Method getName

Method setName

type String


Model Inference

entity Customer { name: String address: Address purchasedItems: Item* double sales() { purchasedItems .map[price] .reduce[a,b|a+b] }}

returnType double

Method sales

body Expression


class ScriptingJvmModelInferrer extends AbstractModelInferrer { @Inject extension JvmTypesBuilder

def dispatch void infer(Script script, IJvmDeclaredTypeAcceptor acceptor, boolean isPreIndexingPhase) {

acceptor.accept(script.toClass('MyClass')).initializeLater [

// the class gets one main method members += script.toMethod(

'main', script.newTypeRef(Void::TYPE)) [

parameters += script.toParameter("args", script.newTypeRef(typeof(String))

.addArrayTypeDimension) static = true varArgs = true // Associate the script as the body of the main method body = script ] ] }}


The 7 LanguagesScripting Language

Http Routing Language

Templates Language

DSL for Guice

Build Language

Tortoise

DSL for MongoDB


www.eclipse.org/Xtext/7languages.html

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Java DSLs with Xtext

Technology

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