public function get_collection_params() {
    $types    = array();
    $subtypes = array();

    foreach ( $this->search_handlers as $search_handler ) {
      $types[]  = $search_handler->get_type();
      $subtypes = array_merge( $subtypes, $search_handler->get_subtypes() );
    }

    $types    = array_unique( $types );
    $subtypes = array_unique( $subtypes );

    $query_params = parent::get_collection_params();

    $query_params['context']['default'] = 'view';

    $query_params[ self::PROP_TYPE ] = array(
      'default'     => $types[0],
      'description' => __( 'Limit results to items of an object type.' ),
      'type'        => 'string',
      'enum'        => $types,
    );

    $query_params[ self::PROP_SUBTYPE ] = array(
      'default'           => self::TYPE_ANY,
      'description'       => __( 'Limit results to items of one or more object subtypes.' ),
      'type'              => 'array',
      'items'             => array(
        'enum' => array_merge( $subtypes, array( self::TYPE_ANY ) ),
        'type' => 'string',
      ),
      'sanitize_callback' => array( $this, 'sanitize_subtypes' ),
    );

    $query_params['exclude'] = array(
      'description' => __( 'Ensure result set excludes specific IDs.' ),
      'type'        => 'array',
      'items'       => array(
        'type' => 'integer',
      ),
      'default'     => array(),
    );

    $query_params['include'] = array(
      'description' => __( 'Limit result set to specific IDs.' ),
      'type'        => 'array',
      'items'       => array(
        'type' => 'integer',
      ),
      'default'     => array(),
    );

    return $query_params;
  }