<?php
/**
* This file contains examples on using multiCache
*/
require_once('multiCache.php');
$cache = &new multiCache();
/**
* First the most simple example with simple variables:
*/
echo "<h2>multiCache example1:</h2>\n";
$a = 1;
echo "new \$a value: 1<br>";
$cache->add('myType', 'a', $a);
echo "a = $a<br>";
$a = 2;
echo "new \$a value: 2<br>";
echo "a = $a<br>";
echo "a in cache: ".$cache->find('myType', 'a')."<br>";
$b = &$cache->find('myType', 'a');
echo "b = $b<br>";
$b = 3;
echo "new \$b value: 3<br>";
echo "a = $a<br>";
echo "b = $b<br>";
echo "a in cache: ".$cache->find('myType', 'a')."<br>";
echo "<br><i>end of multiCache example 1</i><hr>\n";
/**
* A more complex example on how to use multiCache with objects.
* Situation: we have two fighter spaceships (SF-1 & SF-2) in our galaxy
* (Milky Way) and we need to transfer one spaceship to another nearest galaxy
* - Andromeda.
*/
echo "<h2>multiCache example2:</h2>\n";
class spaceShip
{
var $model;
var $name;
var $galaxy;
/**
* Constructor method - called only every new object.
*/
function spaceShip($model, $name, $galaxy_name)
{
// first we load cache as internal parameter for convenience.
$this->cache = &$GLOBALS['cache'];
// We check if our object already exists in cache:
// · get_class($this) returns 'spaceShip' - type of entity in cache
// · $model.':'.$name is the unique key for this object
if (!$mcId = $this->cache->exists(get_class($this), $model.':'.$name))
{
// If the object doesn't exist in cache, we create a copy of it in cache
// the copy should call method 'mcConstruct' (which is the real
// constructor) on itself.
$mcId = $this->cache->add(get_class($this), $model.':'.$name, $this, 'mcConstruct', array($model, $name, $galaxy_name));
}
// Now we certainly have a copy of the object in cache.
// So we have to link current object's parameters to cache object's
// parameters:
$this->model = &$this->cache->data[$mcId]->model;
$this->name = &$this->cache->data[$mcId]->name;
// We create parameters that are objects themselves separately.
// This is because we can't link to the cache objects parameters that are
// objects or we'll get a reference to reference - an empty object, that
// will not be linked to the cache objects parameter.
$this->galaxy = &new galaxy($galaxy_name);
return ($this);
} // end of constructor
/**
* Constructor method that is only called for the object copy in cache
*/
function mcConstruct($model, $name, $galaxy_name)
{
// We fill parameters with correct values:
$this->model = $model;
$this->name = $name;
$this->galaxy = &new galaxy($galaxy_name);
// We also place the spaceship in the galaxy.
$this->galaxy->ships[$this->name] = $this;
}
/**
* This method transfers spaceship from one galaxy to another.
*/
function hyperspaceJump($galaxy_name)
{
unset($this->galaxy->ships[$this->name]);
$this->galaxy = &new galaxy($galaxy_name);
$this->galaxy->ships[$this->name] = $this;
}
/**
* The ship reports its model, name and galaxy it's in:
*/
function report()
{
echo "<HR>Ship $this->name reporting:<BR>
Model: $this->model<BR>
Location: ".$this->galaxy->name."<HR>";
}
} // end of class spaceShip
class galaxy
{
var $name;
var $ships;
/**
* Galaxy constructor - the situation is the same as with the ship.
*/
function galaxy($name)
{
$this->cache = &$GLOBALS['cache'];
// The unique key for the galaxy is it's name:
if (!$mcId = $this->cache->exists(get_class($this), $name))
{
$mcId = $this->cache->add(get_class($this), $name, $this, 'mcConstruct', array($name));
}
$this->name = &$this->cache->data[$mcId]->name;
$this->ships = &$this->cache->data[$mcId]->ships;
return ($this);
}
/**
* Constructor function used for the object copy in cache.
*/
function mcConstruct($name)
{
$this->cache = &$GLOBALS['cache'];
$this->name = $name;
$this->ships = array();
}
function report()
{
echo "<bR>Ships in galaxy $this->name:<bR>";
foreach ($this->ships as $ship)
{
echo $ship->model." model ship ".$ship->name."<BR>\n";
}
}
} // end of class galaxy
// We create two fighters:
$fighter1 = &new spaceShip('fighter', 'SF-1', 'Milky Way');
$fighter2 = &new spaceShip('fighter', 'SF-2', 'Milky Way');
// We create two galaxies. Actually 'Milky Way' will find itself in cache so
// $galaxy1 and $fighter1->galaxy are the same.
$galaxy1 = &new galaxy('Milky Way');
$galaxy2 = &new galaxy('Andromeda');
// FIghter #1 jumps from one galaxy into another:
$fighter1->hyperspaceJump('Andromeda');
// Now let's see the results:
$fighter1->report();
$fighter2->report();
$galaxy1->report();
$galaxy2->report();
/**
* END COMMENTS ON EXAMPLE 2:
* The whole procedure seems rather complicated, doesn't it?
* The point is that PHP references is a mysterious and complicated thing.
* multiCache allows accessing the cached object from it's constructor by
* simply creating a copy of it, but keeping the internal parameters linked.
* I borrowed the idea from [email protected] comment in the PHP
* manual on page:
* "References inside the constructor"
* http://lt.php.net/manual/en/language.oop.newref.php
* If you'll find this class helpfull - please let me know :]
*
* >>> Emilis 2002-08-20
*/
echo "<br><i>end of multiCache example 2</i><hr>\n";
?>
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