gistfile1.groovy

//This code iterates a nested Map/List structure and converts any Date objects it finds into
// String equivalents.
//def data = [:] - data is some complex nested Map/List data structure
UnwelcomeVisitor.traverse( data, [
  visitMap: { key, value -> 
    if ( value instanceof Date ) value = value.toString()
    value
  },
  visitList: { entry ->
    if ( entry instanceof Date ) entry = entry.toString()
    entry
  }
] )