class FieldByClassEnhancer

FieldByClassEnhancerTest.php in drupal/core/vendor/symfony-cmf/routing/Symfony/Cmf/Component/Routing/Tests/Enhancer/FieldByClassEnhancerTest.php

class FieldByClassEnhancer implements RouteEnhancerInterface {

  /**
   * @var string field for the source class
   */
  protected $source;

  /**
   * @var string field to write hashmap lookup result into
   */
  protected $target;

  /**
   * @var array containing the mapping between a class name and the target value
   */
  protected $map;

  /**
   * @param string $source the field name of the class
   * @param string $target the field name to set from the map
   * @param array  $map    the map of class names to field values
   */
  public function __construct($source, $target, $map) {
    $this->source = $source;
    $this->target = $target;
    $this->map = $map;
  }

  /**
   * If the source field is instance of one of the entries in the map,
   * target is set to the value of that map entry.
   *
   * {@inheritDoc}
   */
  public function enhance(array $defaults, Request $request) {
    if (isset($defaults[$this->target])) {

      // no need to do anything
      return $defaults;
    }
    if (!isset($defaults[$this->source])) {
      return $defaults;
    }

    // we need to loop over the array and do instanceof in case the content
    // class extends the specified class
    // i.e. phpcr-odm generates proxy class for the content.
    foreach ($this->map as $class => $value) {
      if ($defaults[$this->source] instanceof $class) {

        // found a matching entry in the map
        $defaults[$this->target] = $value;
        return $defaults;
      }
    }
    return $defaults;
  }

}