Re: dynamicaly append method to class - workaround for aggregate_methods()

[Jochem Maas <jochem@xxxxxxxxxxxxx>]

Karel Kozlik schreef:
>  Hello list!
> 
> I am using in my application dynamic method appending to class with
> aggregate_methods() function. But this function is no more aviable in
> php5 and runkit extension seems not to be maintained any more. So I
> would like to replace it with something more common (__call method or so).
> 
> Just to describe the situation (simplified). There is one common class
> containing some common functions:
> 
> class DataLayer{
> 
>     function add_method($method){
>         aggregate_methods($this, "DataLayer_".$method);
>     }
> 
>     function common_funct_foo(){
>         ...
>     }
> 
>     function common_funct_bar(){
>         ...
>     }
> }
> 
> 
> And there is hundreds of data manipulation methods (defined within
> separate classes) which could call common functions. E.g.:
> 
> 
> class DataLayer_get_items{
>     function get_items(){
>         $this->common_funct_foo();
>         return something;
>     }
> }
> 
> And they could also call other dynamicaly added methods:
> 
> class DataLayer_update_attr{
>     function update_attr(){
>         $this->get_items();
>         $this->common_funct_bar();
>         return;
>     }
> }
> 
> All the stuff is used e.g. in this way:
> 
> $data = new DataLayer();
> $data->add_method('get_items');
> $data->add_method('update_attr');
> $data->update_attr();
> 
> 
> 
> Now the question is whether is it possible to somehow replace
> functionality of add_method() without aggregate_methods() or
> runkit_class_adopt(). And _WITHOUT_ need to change the hundreds of
> DataLayer_* classes. The change should be only in the main DataLayer class.
>  I was thinking about __call() method, but I do not know how to deal
> with the $this in dynamicaly appended functions. I need somehow make to
> $this in these functions reference to instance of DataLayer class.

__call() will allow you to do this, although you will need php5.3:

<?php

class DataLayer_update_attr
{
    function update_attr()
    {
        echo __METHOD__, "\n";

        $this->common_funct_bar();
        $this->get_items();

        return;
    }
}


class DataLayer
{
    function common_funct_foo() { echo __METHOD__, "\n"; /* ... */ }
    function common_funct_bar() { echo __METHOD__, "\n"; /* ... */ }

    function __call($method, $args)
    {
        $class = "DataLayer_{$method}";

        echo __METHOD__, " ... trying {$class}::{$method}()\n";

        if (!class_exists($class, true)) // trigger autoload
            throw new Exception("buddy we don't have a $class, so $method is not callable");

        $class::$method();
    }
}

$d = new DataLayer;
$d->update_attr();

?>
----- output ------

[22:11:16] jochem::~/test > ~/src/php5.3-200808312030/sapi/cli/php -n -f ./class_agg.php
DataLayer::__call ... trying DataLayer_update_attr::update_attr()
DataLayer_update_attr::update_attr
DataLayer::common_funct_bar
DataLayer::__call ... trying DataLayer_get_items::get_items()

Fatal error: Uncaught exception 'Exception' with message 'buddy we don't have a DataLayer_get_items, so get_items is not
callable' in /Users/jochem/test/class_agg.php:30
Stack trace:
#0 [internal function]: DataLayer->__call('get_items', Array)
#1 /Users/jochem/test/class_agg.php(11): DataLayer->get_items()
#2 /Users/jochem/test/class_agg.php(32): DataLayer_update_attr->update_attr()
#3 [internal function]: DataLayer->__call('update_attr', Array)
#4 /Users/jochem/test/class_agg.php(37): DataLayer->update_attr()
#5 {main}
  thrown in /Users/jochem/test/class_agg.php on line 30


> 
> Any ideas?
> 
> many thanks,
> Karel
> 
> 


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