ContextStorage.php

<?php

  /**
   *  Provides storage data of given storage key.
   * 
   * @param $storage_key
   *
   * @return array
   */
  public function getStorage($storage_key) {
    if ($this->hasStorage($storage_key)) {
      return $this->storage[$storage_key];
    }
    return array();
  }

  /**
   *  Checks whether given storage key has data in storage.
   * 
   * @param $storage_key
   *
   * @return bool
   */
  public function hasStorage($storage_key) {
    return !empty($this->storage) && !empty($this->storage[$storage_key]);
  }