Java DSLs with Xtext
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This document discusses using Xtext to create domain-specific languages (DSLs) for Java. It describes how Xtext allows defining a DSL grammar and then generates Java code from that DSL. This includes inferring models from the DSL that map to Java classes and methods. Xtext also supports integrating DSLs with Java typesystems and other Java elements.
![Model Inference
Class Customer
entity Customer {
name: String Field name
address: Address
purchasedItems: Item* Method getName
double sales() {
purchasedItems
returnType String
.map[price]
.reduce[a,b|a+b]
} Method setName
}
parameter name
type String
Mittwoch, 27. März 13](https://image.slidesharecdn.com/dslsforjava-130327123619-phpapp02/85/Java-DSLs-with-Xtext-15-320.jpg)
![Model Inference
entity Customer {
name: String
address: Address
purchasedItems: Item*
double sales() { Method sales
purchasedItems
.map[price] returnType double
.reduce[a,b|a+b]
}
body Expression
}
Mittwoch, 27. März 13](https://image.slidesharecdn.com/dslsforjava-130327123619-phpapp02/85/Java-DSLs-with-Xtext-16-320.jpg)
![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
]
]
}
}
Mittwoch, 27. März 13](https://image.slidesharecdn.com/dslsforjava-130327123619-phpapp02/85/Java-DSLs-with-Xtext-17-320.jpg)
Java DSLs with Xtext
- 1. Java DSLs with Xtext Jan Koehnlein Mittwoch, 27. März 13
- 2. Mittwoch, 27. März 13
- 3. Mittwoch, 27. März 13
- 4. 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; } } Mittwoch, 27. März 13
- 5. @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; } } Mittwoch, 27. März 13
- 6. Domain-Specific Languages Mittwoch, 27. März 13
- 7. DSL Java entity Customer { @Entity name: String public class Customer implements Serializable { @Id address: Address private String name; purchase: Item* 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) Code public Address getAddress() { } return address; public void setAddress(Address address) { Generation this.address = address; } @ManyToMany public List<Item> getPurchase() { return purchase; } public void setPurchase(List<Item> items) { this.purchase = purchase; } } Mittwoch, 27. März 13
- 8. ? Methods Logic Arithmetics Behavior Mittwoch, 27. März 13
- 9. entity Customer { name: String address: Address purchase: Item* double sales() { double result = 0.0; for(Item item: purchase) result += item.getPrice(); return result; } } Mittwoch, 27. März 13
- 10. Expressions Complex Syntax Typesystem Compiler / Interpreter Mittwoch, 27. März 13
- 11. Integration Patterns Manually written code Generated code Mittwoch, 27. März 13
- 12. Reusable powerful expression library language Java‘s Typesystem Access to Java-elements Compile to Java Code Mittwoch, 27. März 13
- 13. DSLs for Java Mittwoch, 27. März 13
- 14. grammar inheritance Grammar (Parser, Lexer) Linker Type System JvmModel MyLanguage Interpreter / Advanced Editor Eclipse Integration Debugger JvmModelInferrer Mittwoch, 27. März 13
- 15. Model Inference Class Customer entity Customer { name: String Field name address: Address purchasedItems: Item* Method getName double sales() { purchasedItems returnType String .map[price] .reduce[a,b|a+b] } Method setName } parameter name type String Mittwoch, 27. März 13
- 16. Model Inference entity Customer { name: String address: Address purchasedItems: Item* double sales() { Method sales purchasedItems .map[price] returnType double .reduce[a,b|a+b] } body Expression } Mittwoch, 27. März 13
- 17. 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 ] ] } } Mittwoch, 27. März 13
- 18. The 7 Languages Scripting Language DSL for MongoDB Http Routing Language Templates Language DSL for Guice Build Language Tortoise Mittwoch, 27. März 13
- 19. Find more at www.eclipse.org/Xtext/7languages.html Mittwoch, 27. März 13