Polymorphism

ATK Howto: Polymorphism Complexity: expert Author: Ivo Jansch <ivo@achievo.org>

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An example of polymorphism is given in a question that was sent to the mailinglist:

> Can I override view/edit action to go to other node? Say I have a node
> called Main which display part of table Main. Edit and View button
> should go to certain nodes based on particular attribute's value in
> node Main.

The best way to accomplish this is to override the link of the edit icon for a record, and have it link to another node instead of the current one.

Try to add the following to your main node:

function recordActions($record, &$actions, &$mraactions)
{
  switch($record[["type"])
  {
    case "fruit": 
      $actions[["edit"] = dispatch_url("yourmodule.fruit", "edit");
      $actions[["view"] = dispatch_url("yourmodule.fruit", "view");
      break;
    case "car":
      $actions[["edit"] = dispatch_url("yourmodule.car", "edit");
      $actions[["view"] = dispatch_url("yourmodule.car", "view");
      break;
    default:
      // do nothing, this will result in the default edit links.
  }
}

If the 'fruit' and 'car' nodes are derived from the 'main' node (which only contains the fields that are both applicable to cars and fruit), this is a very nice way to achieve polymorphism.

Original Poster: Ivo