LazyMembers.inc

<?php

/**
 * @file
 *
 */
module_load_include('inc', 'php_lib', 'Members');

/**
 * Lazy Member.
 */
class LazyMember {

  /**
   * A valid argument for call_user_func.
   * 
   * @var mixed
   */
  protected $function;
  /**
   * 
   * 
   * @var mixed
   */
  protected $parameters;
  /**
   * The result from the function.
   * 
   * @var mixed
   */
  protected $value;
  /**
   * Has the value 
   * 
   * @var boolean
   */
  public $dirty;

  /**
   *
   * @param mixed $function
   * @param object $owner 
   */
  public function __construct($function, $parameters = NULL) {
    $this->function = $function;
    $this->parameters = $parameters;
    $this->value = NULL;
    $this->dirty = true;
  }

  /**
   * 
   */
  public function __invoke() {
    if ($this->dirty) {
      $this->value = call_user_func($this->function, $this->parameters);
      $this->dirty = false;
    }
    return $this->value;
  }

}

/**
 *  Lazy Members.
 */
class LazyMembers extends Members {

  /**
   *
   * @var array
   */
  protected $functions;

  /**
   * Create a LazyMembers object.
   * 
   * @param array $members
   * @param array $params 
   */
  public function __construct(array $members, array $params = NULL) {
    parent::__construct($members, $params);
  }

  /**
   * Checks to see if a member is lazy.
   * 
   * @param string $name 
   * @return boolean
   */
  public function isLazy($name) {
    return $this->exists($name) && ($this->values[$name] instanceof LazyMember);
  }

  /**
   * Set the member is as dirty.
   * 
   * @param string $name 
   */
  public function setDirty($name) {
    if ($this->isLazy($name)) {
      $this->values[$name]->dirty = true;
    }
  }

  /**
   * Get a value for the given member if it exists.
   * 
   * Return NULL if the member doesn't exist or isn't set.
   * 
   * @param string $name
   * @return mixed 
   */
  public function __get($name) {
    if ($this->isLazy($name)) {
      return $this->values[$name]();
    }
    else if ($this->exists($name)) {
      return $this->values[$name];
    }
    return NULL;
  }

  /**
   * Set the value for the given member if it exists.
   * 
   * Note that this doesn't create a new element.
   * 
   * @param string $name
   * @param mixed $value 
   */
  public function __set($name, $value) {
    if ($this->has($name) && !$this->isLazy($name)) {
      $this->values[$name] = $value;
    }
  }

}