On Mon, Oct 20, 2008 at 1:07 PM, Christoph Boget
<christoph.boget@xxxxxxxxx> wrote:
> Ok, so why isn't this working as (I, at the very least) expected?
>
> class singleTon
> {
> private static $thisObj = NULL;
> private $thisProp = NULL;
>
> public function __construct()
> {
> echo 'singleTon::__construct()<br>';
> if( !is_null( singleTon::$thisObj ))
> {
> echo '$thisObj already set. returning it...<br>';
> return singleTon::$thisObj;
> }
> singleTon::$thisObj = $this;
> }
>
> public static function singleton()
> {
> echo 'singleTon::singleton()<br>';
> if( is_null( singleTon::$thisObj ))
> {
> $retval = new singleTon();
> }
> return singleTon::$thisObj;
>
> }
>
> public function setThisProp( $sVal )
> {
> $this->thisProp = $sVal;
> }
>
> public function getThisProp()
> {
> return $this->thisProp;
> }
> }
>
> $one = singleTon::singleton();
> $one->setThisProp( 'Joe' );
> echo '$one->getThisProp();: [' . $one->getThisProp() . ']<br>';
> echo '$one: [<pre>' . var_export( $one, TRUE ) . '</pre>]<br>';
> $two = new singleTon();
> echo '$two->getThisProp();: [' . $two->getThisProp() . ']<br>';
> $two->setThisProp( 'Bob' );
> echo '$two: [<pre>' . var_export( $two, TRUE ) . '</pre>]<br>';
> echo '$one->getThisProp();: [' . $one->getThisProp() . ']<br>';
> echo '$two->getThisProp();: [' . $two->getThisProp() . ']<br>';
> echo '$one->getThisProp();: [' . $one->getThisProp() . ']<br>';
>
> I would have thought that both $one and $two would be referencing the
> same object but they aren't. Apart from making the constructor
> private, is there any way I can ensure that there is ever only one
> instance of an object?
>
> thnx,
> Christoph
>
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>
>
Look at http://us3.php.net/manual/en/language.oop5.patterns.php for a
working singleton example.
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