La classe Errors que propose le framework ICanBoogie est une classe générique qui permet la collecte de messages d'erreur. Une instance est en général partagée par plusieurs composants pour collecter les erreurs qui peuvent survenir durant un processus, par exemple entre l'opération, le validateur du formulaire et le validateur du modèle lors de la mise à jour d'un enregistrement. Les erreurs peuvent être générales (pour tout un processus) ou associées à un identifiant comme celui d'un champ de formulaire.

Le reste de l'article se trouve sur mon blog : Collecter des messages d'erreur

La classe se trouve sur GitHub et voici son code actuel :

/*
 * This file is part of the ICanBoogie package.
 *
 * (c) Olivier Laviale <[email protected]>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace ICanBoogie;

class Errors implements \ArrayAccess, \Countable, \Iterator
{
	protected $errors=array(null => array());

	/**
	 * Checks if an error is defined for an attribute.
	 *
	 * Example:
	 *
	 * $e = new Errors();
	 * $e['username'] = 'Funny username';
	 * var_dump(isset($e['username']);
	 * #=> true
	 * var_dump(isset($e['password']);
	 * #=> false
	 *
	 * @return boolean true if an error is defined for the specified attibute, false otherwise.
	 *
	 * @see ArrayAccess::offsetExists()
	 */
	public function offsetExists($attribute)
	{
		return isset($this->errors[$attribute]);
	}

	/**
	 * Returns error messages.
	 *
	 * Example:
	 *
	 * $e = new Errors();
	 * var_dump($e['password']);
	 * #=> null
	 * $e['password'] = 'Invalid password';
	 * var_dump($e['password']);
	 * #=> 'Invalid password'
	 * $e['password'] = 'Ugly password';
	 * var_dump($e['password']);
	 * #=> array('Invalid password', 'Ugly password')
	 *
	 * @return string|array|null Return the global error messages or the error messages attached
	 * to an attribute. If there is only one message a string is returned, otherwise an array
	 * with all the messages is returned. null is returned if there is no message defined.
	 *
	 * @see ArrayAccess::offsetGet()
	 */
	public function offsetGet($attribute)
	{
		if (empty($this->errors[$attribute]))
		{
			return null;
		}

		$messages = $this->errors[$attribute];

		return count($messages) > 1 ? $messages : current($messages);
	}

	/**
	 * Adds an error message.
	 *
	 * Example:
	 *
	 * $e = new Errors();
	 * $e['password'] = 'Invalid password';
	 * $e[] = 'Requires authentication';
	 *
	 * @param string|null attribute If null, the message is considered as a general error message
	 * instead of an attribute messge.
	 * @param string message The error message.
	 *
	 * @see ArrayAccess::offsetSet()
	 */
	public function offsetSet($attribute, $message)
	{
		$this->errors[$attribute][] = $message;
	}

	/**
	 * Removes error messages.
	 *
	 * @param string|null attribute If null, general message are removed, otherwise the message
	 * attached to the attribute are removed.
	 *
	 * @see ArrayAccess::offsetUnset()
	 */
	public function offsetUnset($attribute)
	{
		unset($this->errors[$attribute]);
	}

	/**
	 * Returns the number of errors defined.
	 *
	 * Example:
	 *
	 * $e = new Errors();
	 * $e['username'] = 'Funny user name';
	 * $e['password'] = 'Weak password';
	 * $e['password'] = 'should have at least one digit';
	 * count($e);
	 * #=> 3
	 *
	 * @see Countable::count()
	 */
	public function count()
	{
		$n = 0;

		foreach ($this->errors as $errors)
		{
			$n += count($errors);
		}

		return $n;
	}

	private $i;
	private $ia;

	public function current()
	{
		return $this->ia[$this->i][1];
	}

	public function next()
	{
		++$this->i;
	}

	public function key()
	{
		return $this->ia[$this->i][0];
	}

	public function valid()
	{
		return isset($this->ia[$this->i]);
	}

	public function rewind()
	{
		$this->i = 0;
		$ia = array();

		foreach ($this->errors as $attribute => $errors)
		{
			foreach ($errors as $error)
			{
				$ia[] = array($attribute, $error);
			}
		}

		$this->ia = $ia;
	}

	/**
	 * Iterates through errors using the specified callback.
	 *
	 * Example:
	 *
	 * $e = new Errors();
	 * $e['username'] = 'Funny user name';
	 * $e['password'] = 'Weak password';
	 *
	 * $e->each
	 * (
	 *     function($attribute, $message)
	 *     {
	 *         echo "$attribute => $message<br />";
	 *     }
	 * );
	 *
	 * @param mixed $callback
	 */
	public function each($callback)
	{
		foreach ($this->errors as $attribute => $errors)
		{
			foreach ($errors as $error)
			{
				call_user_func($callback, $attribute, $error);
			}
		}
	}

	/**
	 * Clears the errors.
	 */
	public function clear()
	{
		$this->errors = array(null => array());
	}
}