Grails: Dynamically inject service in domain class

Question

I need to inject a service based on domain property, so far I came up with the following:

ApplicationHolder.application.getServiceClass("package.${property}Service").clazz

but loading it this way doesn't inject it's dependent services. Am I doing it wrong?

Answer 1

Yes. Services aren't injected into domain objects. If your domain object needs something for a particular use case, let the service that owns that use case invoke the other service on the domain object's behalf.

Answer 2

New instances will bypass Spring's dependency management; you need to get the configured singleton bean from the application context. Use this instead:

def service = ApplicationHolder.application.getMainContext.getBean("${property}Service")

That assumes that 'property' is the partial bean name for a service, i.e. for FooBarService, the property would have to be 'fooBar'. If it's 'FooBar' then you can use GrailsNameUtils.getPropertyName() to fix it:

import grails.util.GrailsNameUtils

String beanName = GrailsNameUtils.getPropertyName(property) + 'Service'
def service = ApplicationHolder.application.getMainContext.getBean(beanName)

Answer 3

IMHO domain classes shouldn't contain logic at all (apart form the validators).

In my projects I normally create a service for each domain class (e.g. UserService for class User) and I stick all the logic in there, even small bits in pieces that would normally be in the domain class.

I think a lot of programmers coming from Java/C++ world tend to find this ugly, but it suits better the Grails architecture.