dependency injection: conditional - spring

Question

This is an extremely simplified example of something I'm already doing in Grails:
// this can be a service or normal class
public abstract class Person {
public final String introduceSelf() {
return "Hi, I'm " + getFullName()
}
protected abstract String getFullName()
}
// Service
class AlexService extends Person {
protected String getFullName() {
return "Alex Goodman"
}
}
// Service
class BobService extends Person {
protected String getFullName() {
return "Bob Goodman"
}
}
// Service
class CarlService extends Person {
protected String getFullName() {
return "Carl Goodman"
}
}
// Controller
class IntroduceController {
def alex
def bob
def carl
def index() {
if(params.person == "a")
render alex.introduceSelf()
if(params.person == "b")
render bob.introduceSelf()
if(params.person == "c")
render carl.introduceSelf()
}
}
I'm looking for more object oriented way of doing it, something like:
// Controller
class IntroduceController {
def person
def index() {
// inject a proper person in a more object oriented way
render person.introduceSelf()
}
}
Can you suggest how to achieve this in a more object-oriented/dynamic way?

Answer 1

You can write a person bean definition in grails-app/conf/spring/resources.groovy file. For example:
beans = {
person(BobService)
}
For more information, check this: http://grails.org/doc/latest/guide/spring.html#springdslAdditional

Answer 2

class IntroduceController {
def grailsApplication
def index() {
def person = grailsApplication.mainContext.getBean( params.person )
person.doSomething()
}
}
You must make sure, that your services' names correspond to params.person value, params.person = 'bob' would work, params.person = 'b' would not