ToStringObject.php

<?php

namespace App\Model;


class ToStringObject {

  private $data;
  private $primaryKey;

  public function __construct(array $data, string $primaryKey) {
    $this->data = $data;
    if (!array_key_exists($primaryKey, $data)) {
      throw new \ValueException('Primary key is not in data');
    } 
    $this->primaryKey = $primaryKey;
  }

  public function __set($name, $value) {
    $this->data[$name] = $value;
  }

  public function __get($name) {
    if (array_key_exists($name, $this->data)) {
      return $this->data[$name];
    }

    $trace = debug_backtrace();
    trigger_error(
        'Undefined property via __get(): ' . $name .
        ' in ' . $trace[0]['file'] .
        ' on line ' . $trace[0]['line'],
        E_USER_NOTICE);
    return null;
  }

  public function __isset($name) {
      return isset($this->data[$name]);
  }

  public function __unset($name) {
      unset($this->data[$name]);
  }

  public function __toString() {
    return (string) $this->data[$this->primaryKey];
  }
}