<?php
 
class fwValidationChain
{
 
  public function __construct ()
  {
    $this -> rules = array ();
    $this -> logger = new fwLogger ();
  }
 
  public function addRule ( ruleInterface $rule )
  {
    $this -> rules [] = $rule;
 
  }
 
  public function runChain ( fwDataSpace $dataspace )
  {
    $return = true;
    foreach ( $this -> rules AS $rule )
    {
      $return = $rule -> isSatisfied ( $dataspace, $this -> logger ) && $return;
 
    }
    return $return; 
  }
 
}
 
 
interface ruleInterface
{
  public function isSatisfied ( fwDataSpace $datasource, fwLogger $logger );
 
}
 
class NotEmptyRule implements ruleInterface
{
  private $fieldnames;
 
  private $errormessage;
 
  public function __construct ( $errormessage, $fieldname )
  {
    $parameters = func_get_args();
    $this -> errormessage = array_shift( $parameters );
    $this -> fieldnames = $parameters;
 
  }
 
 
  public function isSatisfied ( fwDataSpace $dataspace, fwLogger $logger )
  {
    $return = true;
    foreach ( $this -> fieldnames AS $fieldname )
    {
      if ( $dataspace -> get ( $fieldname ) === false OR strlen ( $dataspace -> get ( $fieldname ) ) <= 0 )
      {
        $logger -> addMessage ( $fieldname, $this -> errormessage );
        $return = false; 
      } 
    }
    return $return;
  } 
}
 
class fwDataSpace
{
 
  public function __construct ( &$values = false )
  {
    if ( $values !== false )
    {
      $this -> values = $values;
    } 
  } 
 
  public function set ( $key, $value )
  {
    $this -> values [ $key ] = $value;
 
  }
 
  public function get ( $key )
  {
    return ( isset ( $this -> values [$key]  ) ) ? $this -> values [$key] : false;
 
  }
}
 
 
class fwLogger
{
  private $messages;
 
  public function __construct ()
  {
    $this -> messages = array ();
 
  }
 
  public function addMessage ( $fieldname, $message )
  {
    $this -> messages [$fieldname] [] = sprintf ( $message, $fieldname );
 
  }
 
 
  public function getMessages ()
  {
    return $this -> messages; 
  }
   
}
 
 
/**
* Model class User.
**/
class User
{
  public function __construct ()
  {
    $this -> validationChain = new fwValidationChain ();
    $this -> validationChain -> addRule ( new NotEmptyRule ( '%s mag niet leeg zijn.', 'foo', '' ) );
 
  }
 
 
  public function save ()
  {
    /*  Ik heb nog geen dataspace (die komt uit een fwRequest, maar dat heb ik even weggelaten),
    zo'n dataspace kan POST, GET, SESSION, COOKIE, ENV of gewoon userdefined zijn */
    $post = array ( 'foo' => 'Test', 'bar' => 'kip' );
    $dataspace = new fwDataSpace ( $post );
 
    if ( $this -> validationChain -> runChain ( $dataspace ) === false )
    {
      return false;
 
    }
    else
    {
      /* Hier zou bijvoorbeeld een save() van een ORM of ActiveRecordBase aangeroepen kunnen worden. */
      return true;
    } 
  } 
}
 

$user = new User ();
if ( $user -> save () === true )
{
  echo '\o/';
}
else
{
  echo ':(';
}
?>