Gradle call constructor on extension - gradle

Question

I am writing a custom plugin for Gradle. I want to be able to have:
serviceDependencies {
service name: 'service1', version: '1.0'
service name: 'service2', version: '1.1'
}
In my Plugin implementation (in Java) I have:
public void apply(final Project project) {
project.getExtensions().create("serviceDependencies", Services.class);
project.getExtensions().create("service", Service.class);
}
And Service.java:
public class Service {
private String name;
private String version;
public Service(final String name, final String version) {
this.name = name;
this.version = version;
}
public String getName() {
return this.name;
}
public void setName(final String name) {
this.name = name;
}
public String getVersion() {
return this.version;
}
public void setVersion(final String version) {
this.version = version;
}
}
When I try use this plugin I get:
java.lang.IllegalArgumentException: Could not find any public constructor for class com.xxx.xxx.Service_Decorated which accepts parameters [].
This still happens when I remove serviceDependencies/Services.java from the picture.
If I remove the Service constructor or remove the arguments.
org.gradle.internal.metaobject.AbstractDynamicObject$CustomMessageMissingMethodException: Could not find method service() for arguments [{name=service1, version=1.0}] on root project ...
Obviously my pojo is being decorated, but not quite with the correct constructor. How can I get the constructor to work how I want in my build.gradle script?
A second and independent question is what should Services.java look like?

Answer 1

I would only register one extension for serviceDependencies {} that exposes functions to register your services:
public class Services {
void service(String name, String version) { /* new Service(...) */ }
}
project.getExtensions().create("serviceDependencies", Services.class);
This would allow Java, Kotlin and Groovy consumer to do something like:
serviceDependencies {
service 'service1', '1.0'
service 'service2', '0.1'
}
Then if you want to support Groovy named arguments you'd need to add:
public class Services {
void service(String name, String version) { /* new Service(...) */ }
void service(Map<String, String> namedArguments) {
service(namedArguments.get("name"), namedArguments.get("version"))
}
}
This would allow Groovy consumers to do:
serviceDependencies {
service name: 'service1', version: '1.0'
service name: 'service2', version: '0.1'
}