title: How to query a collection of inherited object for a particular object type in grails?
body: <p>I have a this model : </p>
  
  <pre><code>class Question{
    Set components
    static hasMany = [components: QuestionComponent]
  }
  
  class QuestionComponent{
    static belongsTo = Question
  }
  
  class QuestionComponentStatus extends QuestionComponent{
  
  }
  class QuestionComponentOther extends QuestionComponent{
  
  }
  </code></pre>
  
  <p>I want to get only QuestionComponentStatus from Set components : </p>
  
  <p>questionInstance.components. ?</p>
  
  <p>Thanks a lot</p>