_sleep and _wakeup

[Water Cooler v2]

I didn't understand from this

http://in2.php.net/manual/en/language.oop.magic-functions.php

whether we, the programmer, have to implement _sleep and _wakeup (like
..NET's IDisposable.Dis pose()) or it is done by PHP internally on a
class that uses resources?

[AlexVN]

Re: _sleep and _wakeup

Water Cooler v2 wrote:[color=blue]
> I didn't understand from this
>
> http://in2.php.net/manual/en/languag...-functions.php
>
> whether we, the programmer, have to implement _sleep and _wakeup (like
> .NET's IDisposable.Dis pose()) or it is done by PHP internally on a
> class that uses resources?[/color]

Hi,

__sleep and __wakeup are the methods, that you can implement in your
class. They are just like events that occur before serialization and
after unserialization . Consider this:

class MyClass {
function __sleep() {
echo "__sleep\n" ;
return array();
}
function __wakeup() {
echo "__wakeup\n ";
}
}

$c = new MyClass();
echo "Sleep: ";
$str = serialize($c);
echo "Wakeup: ";
$c1 = unserialize($st r);

The output will be:
Sleep: __sleep
Wakeup: __wakeup

Sincerely,
Alexander
http://www.alexatnet.com/

[Water Cooler v2]

Re: _sleep and _wakeup

Thanks. That answers it. The onus of cleaning up and restoring
"resources" (if the class uses any) is with us, and hence the
implementation of these methods is a way given to us to do that before
serialization and after deserialization .

Thanks, again. :-)

[Chung Leong]

Re: _sleep and _wakeup


Water Cooler v2 wrote:[color=blue]
> Thanks. That answers it. The onus of cleaning up and restoring
> "resources" (if the class uses any) is with us, and hence the
> implementation of these methods is a way given to us to do that before
> serialization and after deserialization .
>
> Thanks, again. :-)[/color]

You misunderstood I'm afraid. IDisposable.Dis pose called, if I remember
my .NET correctly, when an object is garbage collected. __sleep() is
called when an object is serialized--usually at the end of the request
when PHP saves session data to a file. Its main purpose is to let PHP
know what properties within the object should be saved and what
shouldn't be (cached records for instance). The __wakeup() method is
the inverse of that--called when PHP restore data previously stored in
a file into an object.

__destruct() is the closest counter part to IDisposable.Dis pose. You
typically don't need to manually free resources, since PHP will do it
for you at the end of a request.

[Water Cooler v2]

Re: _sleep and _wakeup


Chung Leong wrote:
[color=blue]
> You misunderstood I'm afraid. IDisposable.Dis pose called, if I remember
> my .NET correctly, when an object is garbage collected. __sleep() is
> called when an object is serialized--usually at the end of the request
> when PHP saves session data to a file. Its main purpose is to let PHP
> know what properties within the object should be saved and what
> shouldn't be (cached records for instance). The __wakeup() method is
> the inverse of that--called when PHP restore data previously stored in
> a file into an object.
>
> __destruct() is the closest counter part to IDisposable.Dis pose. You
> typically don't need to manually free resources, since PHP will do it
> for you at the end of a request.[/color]


Thanks, Chung. I'd understood correctly, albeit my anology was rather
amiss.