Best. Groovy. Method. Ever.

Well, maybe not the best method ever... but it's gotta be damn close :) In just a few lines of code I'm doing a lot of really Groovy stuff!

I was looking for a quick and dirty way of converting JSON into some simple groovy objects that I have. The method recursively walks the object hierarchy and then populates corresponding values that are present in the JSON. Enjoy!

  /**
   * Slick way of using reflection to populate value 
   * objects with JSON.  Performs a DEEP copy in order 
   * to populate all of the dependent pogo properties
   *
   * @param obj object to populate - pogo
   * @param json grails.converters.deep.JSON
   * @return the obj param
   */
  protected def populateFromJson(def obj, def json) {
    obj.metaClass.properties.each {metaBeanProperty ->
      if (metaBeanProperty.modifiers == Modifier.PUBLIC) {
        def val = null
        String jsonVal = json[metaBeanProperty.name]
        if (metaBeanProperty.type == String) {
          val = jsonVal
        } else if (Number.isAssignableFrom(metaBeanProperty.type)) {
          if (jsonVal?.isNumber()) val = jsonVal.invokeMethod("to${metaBeanProperty.type.simpleName}", null)
        } else if (metaBeanProperty.type == Date) {
          if (jsonVal) val = Date.parse("yyyy-MM-dd'T'HH:mm:ss'Z'", jsonVal)
        } else if (metaBeanProperty.type == Boolean) {
          if (jsonVal) val = jsonVal.toBoolean()
        } else if (metaBeanProperty.type.name.startsWith("com.mycomp")) { 
          val = populateFromJson(metaBeanProperty.type.newInstance(), json[metaBeanProperty.name])
        }
        obj[metaBeanProperty.name] = val
      }
    }
    return obj
  }