title: Are Grails getDirtyPropertyNames and getPersistentValue supported by MongDB?
body: <p>I am using Grails version 2.4.2 and MongoDB 2.6
  Created a Domain class Foo</p>
  
  <pre><code>class Foo {
    String slug
    String name
    String toString(){
      "${name}"
    }
    static constraints = {
      name blank: false
    }
    @Override
    def beforeUpdate(){
    if(isDirty("slug"){
      println "beforeUpdate() current value is  " +  this.slug
      println "original property names that were changed = " +     this.getDirtyPropertyNames()
      println "original value = " + this.getPersistentValue("slug")
    } 
   }
  }
  </code></pre>
  
  <p>I created a FooController with scaffolding</p>
  
  <pre><code>class FooController{
    static scaffold = true
  }
  </code></pre>
  
  <p>I run the app and create a new foo enter a <em>name</em> field and a <em>slug</em> field value  then update the <em>slug</em> field</p>
  
  <p><strong>Are these methods supported by MongoDB?</strong>
  <a href="http://grails.github.io/grails-doc/2.4.x/ref/Domain%20Classes/getPersistentValue.html" rel="nofollow">getPersistentValue</a>
  <a href="http://grails.github.io/grails-doc/2.4.x/ref/Domain%20Classes/getDirtyPropertyNames.html" rel="nofollow">getDirtyPropertyNames</a></p>