class - Grails initialization of classes -

i have question initialization wiith groovy/grails. when have following class, sinstance doesn't passed sservice initialization.

class {      string sinstance     string app     string dbinstance      sservice s = new sservice(sinstance:sinstance, app:app) } 

sservice class:

class sservice {      string sinstance     string app  public getsinstance{     return sinstance     } } 

this returns null, where

class {      string sinstance     string app     string dbinstance  public initializesservice{     sservice s = new sservice(sinstance:sinstance, app:app)     } } 

returns sinstance variable sservice class.

why , how can have sservice object initialized class constructor?

you can't this:

class {      string sinstance     string app     string dbinstance      sservice s = new sservice(sinstance:sinstance, app:app) } 

the problem when creating instance of sservice, sinstance has not been initialized yet. if want pass sinstance constructor of other class within class, going have after sinstance has been assigned value, method called after constructed.

edit:

trying clarify comments below:

class {     string sinstance     string app     string dbinstance      void anymethod() {         // work long have initialized sinstance         sservice s = new sservice(sinstance:sinstance, app:app)     } } 

depending on trying do, maybe in direction:

class {     string sinstance     string app     string dbinstance     sservice s      void initializes() {         if(s == null) {             // work long have initialized sinstance             s = new sservice(sinstance:sinstance, app:app)         }     } } 

or:

class {     string sinstance     string app     string dbinstance     sservice theservice      sservice gettheservice() {         if(theservice == null) {             // work long have initialized sinstance             theservice = new sservice(sinstance:sinstance, app:app)         }         theservice     }      def somemethodwhichusestheservice() {         gettheservice().dosomethingtoit()     } }