laravel/system/validation/rule.php

<?php namespace System\Validation;

use System\Lang;

abstract class Rule {

	/**
	 * The attributes being validated by the rule.
	 *
	 * @var array
	 */
	public $attributes;

	/**
	 * The validation error message.
	 *
	 * @var string
	 */
	public $message;

	/**
	 * The error type. This is used for rules that have more than
	 * one type of error such as Size_Of and Upload_Of.
	 *
	 * @var string
	 */
	public $error;

	/**
	 * Create a new validation Rule instance.
	 *
	 * @param  array      $attributes
	 * @return void
	 */
	public function __construct($attributes)
	{
		$this->attributes = $attributes;
	}

	/**
	 * Run the validation rule.
	 *
	 * @param  array  $attributes
	 * @param  array  $errors
	 * @return void
	 */
	public function validate($attributes, &$errors)
	{
		foreach ($this->attributes as $attribute)
		{
			$this->error = null;

			if ( ! $this->check($attribute, $attributes))
			{
				$message = Message::get($this, $attribute);

				// -------------------------------------------------------------
				// Make sure the error message is not duplicated.
				//
				// For example, the Nullable rules can add a "required" message.
				// If the same message has already been added we don't want to
				// add it again.
				// -------------------------------------------------------------
				if ( ! array_key_exists($attribute, $errors) or ! is_array($errors[$attribute]) or ! in_array($message, $errors[$attribute]))
				{
					$errors[$attribute][] = $message;
				}
			}
		}
	}

	/**
	 * Set the validation error message.
	 *
	 * @param  string  $message
	 * @return Rule
	 */
	public function message($message)
	{
		$this->message = $message;
		return $this;
	}

}