PHP ignores __set method inside class

Question

I am creating a class with several input checks, and I decided to place them inside the __set method (I'm not sure if this is the correct form, since I have limited OOP experience). This seems to work fine, throwing the correct errors when invalid values ​​are passed from outside the class. However, if the variable is changed inside the class, the _ _set method seems to be ignored by alltogether.

Any insight would be greatly appreciated.

//RESULT::::::::::::::::::::::::::::::: // PASS: Testing : hello // PASS: Testing exception handling // __SET: Setting b to 123 // PASS: Testing with valid value: 123 // FAIL: Testing exception handling World2 <?php class Test { public $a; private $b; function __set( $key, $val ) { switch( $key ) { case 'b': if( !is_numeric( $val ) ) throw new Exception("Variable $b must be numeric"); break; } echo ( "__SET: Setting {$key} to {$val}<br/>" ); $this->$key = $val; } function __get( $key ) { return $this->$key; } function bMethod() { $this->b = "World2"; } } $t = new Test(); //testing a try { $t->a = "hello"; echo "PASS: Testing $a: {$t->a}<br/>"; } catch( Exception $e) { echo "FAIL: Testing $a"; } //testing b try { $t->b = "world"; echo "FAIL: Testing $b exception handling<br/>"; } catch( Exception $e ){ echo "PASS: Testing $b exception handling<br/>"; } //testing b with valid value try { $t->b = 123; echo "PASS: Testing $b with valid value: {$t->b}<br/>"; } catch( Exception $e) { echo "FAIL: Testing $b"; } //bypassing exception handling with method try { $t->bMethod("world"); echo "FAIL: Testing $b exception handling {$t->b}<br/>"; } catch( Exception $e ) { echo "PASS: Testing $b exception handling<br/>"; } 

Answer 1

Read the __set definition: "__set () is fired when writing data to inaccessible members." Inaccessible here inaccessible. From inside the class, all members are accessible and __set bypasses. Overloading

Answer 2

The documentation in php documentation says:

__ get () is used to read data from inaccessible members.

So you can do something like:

 <?php class Test { private $_params = array(); function __set( $key, $val ) { ... $this->_params[$key] = $val; } function __get( $key ) { if (isset($this->_params[$key])) return $this->$key; throw Exception("Variable not set"); } ... }