ValueContainer.php

<?php

/*
 * This file is part of the Assetic package, an OpenSky project.
 *
 * (c) 2010-2013 OpenSky Project Inc
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace Assetic\Extension\Twig;

use Assetic\ValueSupplierInterface;

/**
 * Container for values initialized lazily from a ValueSupplierInterface.
 *
 * @author Christophe Coevoet <stof@notk.org>
 */
class ValueContainer implements \ArrayAccess, \IteratorAggregate, \Countable {
  private $values;
  private $valueSupplier;
  public function __construct(ValueSupplierInterface $valueSupplier) {
    $this->valueSupplier = $valueSupplier;
  }
  public function offsetExists($offset) {
    $this
      ->initialize();
    return array_key_exists($offset, $this->values);
  }
  public function offsetGet($offset) {
    $this
      ->initialize();
    if (!array_key_exists($offset, $this->values)) {
      throw new \OutOfRangeException(sprintf('The variable "%s" does not exist.', $offset));
    }
    return $this->values[$offset];
  }
  public function offsetSet($offset, $value) {
    throw new \BadMethodCallException('The ValueContainer is read-only.');
  }
  public function offsetUnset($offset) {
    throw new \BadMethodCallException('The ValueContainer is read-only.');
  }
  public function getIterator() {
    $this
      ->initialize();
    return new \ArrayIterator($this->values);
  }
  public function count() {
    $this
      ->initialize();
    return count($this->values);
  }
  private function initialize() {
    if (null === $this->values) {
      $this->values = $this->valueSupplier
        ->getValues();
    }
  }

}