framework/caching/Cache.php
public function get($key)
    {
        $key = $this->buildKey($key);
        $value = $this->getValue($key);
        if ($value === false || $this->serializer === false) {
            return $value;
        } elseif ($this->serializer === null) {
            $value = unserialize($value);
        } else {
            $value = call_user_func($this->serializer[1], $value);
        }
        if (is_array($value) && !($value[1] instanceof Dependency && $value[1]->isChanged($this))) {
            return $value[0];
        }

        return false;
    }
public function get($key)
    {
        $key = $this->buildKey($key);
        $value = $this->getValue($key);
        if ($value === false || $this->serializer === false) {
            return $value;
        } elseif ($this->serializer === null) {
            $value = unserialize($value);
        } else {
            $value = call_user_func($this->serializer[1], $value);
        }
        if (is_array($value) && !($value[1] instanceof Dependency && $value[1]->isChanged($this))) {
            return $value[0];
        }

        return false;
    }
Retrieves a value from cache with a specified key.
@param mixed $key a key identifying the cached value. This can be a simple string or
a complex data structure consisting of factors representing the key.
@return mixed the value stored in cache, false if the value is not in the cache, expired,
or the dependency associated with the cached data has changed.