Page 230 - Beginning PHP 5.3

Part II: Learning the Language
$testObject = new MyClass;
echo isset( $testObject- > banana ) . “ < br / > ”; // Displays “” (false)
echo isset( $testObject- > testBanana ) . “ < br / > ”; // Displays “1” (true)

__unset() is called when the calling code attempts to delete an invisible property with PHP ’ s
unset() function. It shouldn ’ t return a value, but should do whatever is necessary to “ unset ” the
property (if applicable):

class MyClass {

public function __unset( $propertyName ) {
echo “Unsetting property ‘$propertyName’ < br / > ”;
}
}

$testObject = new MyClass;

unset( $testObject- > banana ); // Displays “Unsetting property ‘banana’”
__callStatic() works like __call() , except that it is called whenever an attempt is made to call an
invisible static method. For example:
class MyClass {

public static function __callStatic( $methodName, $arguments ) {
echo “Static method ‘$methodName’ called with the arguments: < br / > ”;
foreach ( $arguments as $arg ) {
echo “$arg < br / > ”;
}
}
}

MyClass::randomMethod( “apple”, “peach”, “strawberry” );
This code produces the following output:
Static method ‘randomMethod’ called with the arguments:
apple
peach
strawberry

Using Inheritance to Extend the

Power of Objects

So far, all the classes you ’ ve created have been self - contained. However, objects get really interesting
when you start using inheritance. Using this technique, you can create classes — known as child
classes — that are based on another class: the parent class . A child class inherits all the properties and

methods of its parent, and it can also add additional properties and methods.

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