PHP properties with get/set functions

Question

One of the handy features of other languages is the ability to create get and set methods for properties. In trying to find a good way to duplicate this functionality in PHP, I stumbled across this: http://www.php.net/manual/en/language.oop5.magic.php#98442

Here is my breakdown of that class:

<?php

class ObjectWithGetSetProperties {

    public function __get($varName) {
        if (method_exists($this,$MethodName='get_'.$varName)) {
            return $this->$MethodName();
        } else {
            trigger_error($varName.' is not avaliable .',E_USER_ERROR);
        }
    }

    public function __set($varName,$value) {
        if (method_exists($this,$MethodName='set_'.$varName)) {
            return $this->$MethodName($value);
        } else {
            trigger_error($varName.' is not avaliable .',E_USER_ERROR);
        }
    }

}

?>

My plan was to extend this class and define the appropriate get_someproperty() and set_someproperty() in this extended class.

<?php
class SomeNewClass extends ObjectWithGetSetProperties {
    protected $_someproperty;
    public function get_someproperty() {
        return $this->_someproperty;
    }
}
?>

The trouble is, the base class of ObjectWithGetSetProperties is unable to see my method get_someproperty() in SomeNewClass. I always get the error, "key is not available".

Is there any way to resolve this, allowing the base class of ObjectWithGetSetProperties to work, or will I have to create those __get() and __set() magic methods in each class?

Answer 1

Try is_callable instead. Example code-fragment:

<?php
date_default_timezone_set("America/Edmonton");
class A {
    protected $_two="goodbye";
    protected $_three="bye";
    protected $_four="adios";
    public function __get($name) {
        if (is_callable(array($this,$m="get_$name"))) {
            return $this->$m();
        }
        trigger_error("Doh $name not found.");
    }
    public function get_two() {
        return $this->_two;
    }
}
class B extends A {
    protected $_one="hello";
    protected $_two="hi";
    protected $_three="hola";
    public function get_one() {
        return $this->_one;
    }
    public function get_two() {
        return $this->_two;
    }
    public function get_three() {
        return $this->_three;
    }
    public function get_four() {
        return $this->_four;
    }
}

$a=new a();
echo $a->one."<br />";//Doh one not found.
echo $a->two."<br />";//goodbye
echo $a->three."<br />";//Doh three not found.
echo $a->four."<br />";//Doh four not found.
$b=new b();
echo $b->one."<br />";//hello
echo $b->two."<br />";//hi
echo $b->three."<br />";//hola
echo $b->four."<br />";//adios
?>

(Updated to show where B overrides A)

Answer 2

In your example, you'll need to declare the $_someproperty property, like this

class SomeNewClass extends ObjectWithGetSetProperties {
    protected $_someproperty;
    public function get_someproperty() {
        return $this->_someproperty;
    }
}

Answer 3

That's not well documented (some mentions in the comments), but method_exists() really only checks for method presence in the current class.

But you can use is_callable() instead. It also verifies that the method not only exists, but is indeed allowed to be invoked:

 if (  is_callable(array($this, $varName))  ) {
     ...

Answer 4

<form  id="fname" method="post">
    <textarea name="sms" id="messageText"></textarea>
    <input type="submit" name="smsbut"  value="sms"/>
</form> 
<script>
    $(document).ready(function() {
        $("#fname").submit(function()
        {
            var sms = $('#messageText').val();
            $.ajax(
                    {
                        type: "POST",
                        url: "sms.php/?id=<?php echo $_SESSION['id']; ?>",
                        data: {userSms: sms},
                        dataType: "json",
                        success: function(result)
                        {
                            if (result["error"] != undefined)
                            {

                            }
                            else if (result["success"] != undefined)
                            {
                                $('#messageText').val("");
                                location.reload();
                            }
                        }
                    });
            return false;
        });
    });
</script>