named-constructor.php

<?php

namespace AnrDaemon;

class Xxx
implements \JsonSerializable, \Serializable
{
  public static function createFromState(array $state)
  {
    $self = new static();

    $self->params = array_replace($self->params, array_intersect_key($state, $self->params));
    $self->repair();

    return $self;
  }

  public static function createFromJson(/*TODO:PHP7 string */$json)
  {
    $state = json_decode($json, true);
    if(json_last_error() !== JSON_ERROR_NONE)
      throw new Exceptions\InvalidObjectStateException(json_last_error_msg(), json_last_error());
    if(!is_array($state))
      throw new Exceptions\InvalidObjectStateException("Saved state must be an array or an object");

    return static::createFromState($state);
  }

  public function saveState()
  {
    return $this->params;
  }

// Magic

  private function __construct()
  {
    // Stuff that shouldn't happen out of context
  }

  public static function __set_state(array $state)
  {
    return static::createFromState($state['params']);
  }

// JsonSerializable

  public function jsonSerialize()
  {
    return (object)$this->params;
  }

// Serializable

  public function serialize()
  {
    return serialize($this->params);
  }

  public function unserialize($state)
  {
    $self = static::createFromState(unserialize($state));
    $this->params = $self->params;
  }
}