Question

I have an application where it needs to instantiate only one object, I was thinking of Singleton, but before I jump in to that, I was thinking of dependency injection. What I would like to do is, to instantiate the object and setAttribute to ServletContext in Bootstrap.groove and use the object in every controller. My understanding would be that bootstrap will be called just once during the application lifetime? Could I do that?

Answer 1

You can define singleton beans in resources.groovy

beans = {
    myBean(my.company.MyBeanImpl) {
        singleton true
    }
}

then in your controllers

class ExampleController {
     def myBean
}

All documented here: http://www.grails.org/doc/latest/guide/14.%20Grails%20and%20Spring.html