ID: 30958
Updated by: [EMAIL PROTECTED]
Reported By: schaa101 at tech dot nhl dot nl
-Status: Open
+Status: Closed
Bug Type: Class/Object related
Operating System: Windows XP Pro SP2
PHP Version: 5.0.2
Previous Comments:
------------------------------------------------------------------------
[2004-12-16 05:47:31] rampant at gmail dot com
If error_reporting(E_ALL) is set, you will see that instead of setting
$this in a singleton, $this is set in the Main class. Here is the
notice:
Notice: Undefined property: Main::$instance in
C:\eclipse\workspace\tmote\tmp_singles.php on line 12
Where line 12 is:
if( $this->instance == null )
Replacing $this->instance with self::$instance and
private $instance = null;
with,
private static $instance = null;
Will make the code behave as expected.
------------------------------------------------------------------------
[2004-12-02 12:16:30] schaa101 at tech dot nhl dot nl
<?php
class Singleton1
{
private $instance = null;
private function __Construct()
{ }
public function & GetInstance()
{
if( $this->instance == null )
$this->instance = new Singleton1();
return $this->instance;
}
public function Write( $message )
{
print "Singleton1 - " . $message;
}
}
class Singleton2
{
private $instance = null;
private function __Construct()
{ }
public function & GetInstance()
{
if( $this->instance == null )
$this->instance = new Singleton2();
return $this->instance;
}
public function Write( $message )
{
print "Singleton2 - " . $message;
}
}
class Main
{
public function __Construct()
{
Singleton1::GetInstance()->Write( "Singleton1" );
echo "<br/>";
Singleton2::GetInstance()->Write( "Singleton2" );
}
}
new Main();
?>
------------------------------------------------------------------------
[2004-12-02 11:09:30] schaa101 at tech dot nhl dot nl
Description:
------------
When you use 2 singletons, the second singeleton also returns the
instance of the first.
If you change the name of the variables, that store the instance of the
singleton class, inside the singletons and make them both unique, the
problem is solved though.
Reproduce code:
---------------
http://klaas.fiskaaf.com/singleton-bug.rar
or try
http://klaas.fiskaaf.com/singleton-bug.zip
Expected result:
----------------
Singleton1 - Singleton1
Singleton2 - Singleton2
Actual result:
--------------
Singleton1 - Singleton1
Singleton1 - Singleton2
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=30958&edit=1
