var ctx = Packages.org.springframework.web.context.ContextLoader.getCurrentWebApplicationContext();
var behaviourFilter = ctx.getBean("policyBehaviourFilter");

// -----------------------------------------------------------------

function findAndReplaceAttribute(query, attribute, value) {
  nodes = search.luceneSearch(query);
  
  for each(var node in nodes) {
      logger.log("Changing property "+attribute+" from value '"+ node.properties[attribute]+"' of node " + node.nodeRef + " to value '"+value+"'");
      behaviourFilter.disableBehaviour(node.nodeRef);
      node.properties[attribute] = value;
      node.save();
  }
}

// -----------------------------------------------------------------

var oldUser = "oldusername", newUser = "newusername";

findAndReplaceAttribute("+@cm\\:modifier:" + oldUser, "cm:modifier", newUser);
findAndReplaceAttribute("+@cm\\:creator:"  + oldUser, "cm:creator",  newUser);
findAndReplaceAttribute("+@cm\\:owner:"    + oldUser, "cm:owner",    newUser);