RE: PHP object communication
| From: | Tim Ward | Date: | Thu, 25 Oct 2001 10:03:46 +0000 |
| Subject: | RE: PHP object communication | ||
| Groups: | php.general | ||
| Request: | Send a blank email to php-general+get-72237@lists.php.net to get a copy of this message | ||
If you want access to error functions within the db class it must either
extend the error class or have an error object within it. Either ...
Class DB extends Error
{ ...
}
Class Core extends DB
{ ...
}
or
Class DB
{ var $error;
...
function DB() // constructor
{ ...
$this->error = new Error();
}
...
}
Class Core
{ var $db;
var error;
function Core() // constructor
{ ...
$this->db = new DB();
$this->error = new Error();
...
}
}
at the end of the day, both these are ways of getting around the
lack of multiple inheritance
Tim Ward
----------
From: ad@m.beecher.net [SMTP:ad@m.beecher.net]
Sent: 24 October 2001 22:45
To: php-general@lists.php.net
Subject: PHP object communication
Not coming from a programming background, I'm going to have
difficulty
explaining this one... :)
I would like to handle an entire application through one object,
which in
turn contains objects. I only recently "got" classes though, and I
don't
fully understand if what I want to do is possible, or if I'm going
about it
the wrong way. Consider:
<?php
// All of these will be in separate files.
// The first two are separated simply because
// I want to keep my include files small.
class Config {
// Base config class.
// Just contains data.
}
class Core extends Config {
// Base application class.
// Just contains methods.
}
class Error {
// Error handler.
}
class DB {
// Database handler.
}
?>
Tying the first two together is no problem, I can just extend the
Config
class. However I would like to incorporate the third and fourth as
objects
inside the main object:
<?
// In fact these would be instantiated (is that the
// right word?) inside the Core class.
$Core = new Core;
$Core->Error = new Error;
$Core->DB = new DB
?>
This is fine when working in the main application, or in the $Core
object,
but where I get stuck is with communication between the $Core->Error
and
$Core->DB objects. Say for example that within the DB class I
encountered an
error, and wanted to talk to the Error object - I /could/ do this:
<?
class DB {
var $Error;
function DB() {
global $Core;
$this->Error = $Core->Error;
}
}
?>
But if I extend the application later and add a bunch of new
classes, it
means I have to do the same for each object I add. I get the
impression that
I might be able to do this with references, but I can't get a handle
on them
for the life of me. Can someone explain?
Sorry for the lengthy post.
Thanks,
adam