Setting Default Function Param in Constructor

Sorry, still new to OO.

I'm working with CodeIgniter but this question is basically just PHP OO.

I have a class file with a bunch of functions that do a 开发者_JAVA技巧similar thing:

function blah_method($the_id=null)
{                   
        // if no the_id set, set it to user's default
        if(!isset($the_id)){
            $the_id = $this->member['the_id'];          
        } 

Now, Instead of doing that on every method in this class, can I set this up in the constructor? so that I can still pass in $the_id explicitly, to overide it but otherwise it always just defaults to $this->member['the_id'];

What's the most elegant way of doing that?

How about passing all your initialising data to the constructor as an array?

public function __construct(array $settings) {

    // if 'the_id' has not been passed default to class property.
    $the_id = isset($settings['the_id']) ? $settings['the_id'] : $this->member['the_id']; 
    // etc
}

I think the most elegant way would be to extend the arrayobject class and to override the offset method which is called if you try to access a property which is not set. Then you can just return or set what you need there and forget the construct.

you can do this:

class A {

    private $id = null;
    public function __construct($this_id=null){
        $this->id = $this_id;
    }

    public function _method1(){
        echo 'Method 1 says: ' . $this->id . '<br/>';
        return "M1";
    }

    public function _method2($param){
        echo 'Method 2 got param '.$param.', and says: ' . $this->id . '<br/>';
        return "M2";
    }
    public function __call($name, $args){
        if (count($args) > 0) {
            $this->id = $args[0];
            array_shift($args);
        }
        return (count($args) > 0)
            ? call_user_func_array(array($this, '_'.$name), $args)
            : call_user_func(array($this, '_'.$name));
    }
}

$a = new A(1);
echo $a->method1() . '<br>';
echo $a->method2(2,5) . '<br>';

of course it's ugly and will cause you some mess if you have more optional variables in the functions...

btw, the output is:

Method 1 says: 1
M1
Method 2 got param 5, and says: 2
M2