Call onAfterRender and change default model without error

[Brown, Berlin [GCG-PFS]]

I tried to do the following below but I got an error could not update
component hierarchy.
WicketMessage: Cannot modify component hierarchy after render phase has
started (page version cant change then anymore)

Is there an event method (like onAfterRender) that I could use without
error?

Component: 
 
onBeforeRender() {
  ... 
  this.setDefaultModel(...);
}
 
onAfterRender() {
  this.setSetDefaultModel(...);
}
 
Berlin Brown (POL)