Php/docs/classobj.examples

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Examples

In this example, we first define a base class and an extension of the class. The base class describes a general vegetable, whether it is edible or not and what is its color. The subclass Spinach adds a method to cook it and another to find out if it is cooked.

Example #1 classes.inc

<?php// base class with member properties and methodsclass Vegetable {   var $edible;   var $color;   function __construct($edible, $color="green")   {       $this->edible = $edible;       $this->color = $color;   }   function is_edible()   {       return $this->edible;   }   function what_color()   {       return $this->color;   }} // end of class Vegetable// extends the base classclass Spinach extends Vegetable {   var $cooked = false;   function __construct()   {       parent::__construct(true, "green");   }   function cook_it()   {       $this->cooked = true;   }   function is_cooked()   {       return $this->cooked;   }} // end of class Spinach?>

We then instantiate 2 objects from these classes and print out information about them, including their class parentage. We also define some utility functions, mainly to have a nice printout of the variables.

Example #2 test_script.php

<pre><?phpinclude "classes.inc";// utility functionsfunction print_vars($obj){foreach (get_object_vars($obj) as $prop => $val) {    echo "\t$prop = $val\n";}}function print_methods($obj){$arr = get_class_methods(get_class($obj));foreach ($arr as $method) {    echo "\tfunction $method()\n";}}function class_parentage($obj, $class){if (is_subclass_of($GLOBALS[$obj], $class)) {    echo "Object $obj belongs to class " . get_class($GLOBALS[$obj]);    echo ", a subclass of $class\n";} else {    echo "Object $obj does not belong to a subclass of $class\n";}}// instantiate 2 objects$veggie = new Vegetable(true, "blue");$leafy = new Spinach();// print out information about objectsecho "veggie: CLASS " . get_class($veggie) . "\n";echo "leafy: CLASS " . get_class($leafy);echo ", PARENT " . get_parent_class($leafy) . "\n";// show veggie propertiesecho "\nveggie: Properties\n";print_vars($veggie);// and leafy methodsecho "\nleafy: Methods\n";print_methods($leafy);echo "\nParentage:\n";class_parentage("leafy", "Spinach");class_parentage("leafy", "Vegetable");?></pre>

One important thing to note in the example above is that the object $leafy is an instance of the class Spinach which is a subclass of Vegetable, therefore the last part of the script above will output:

   [...]
Parentage:
Object leafy does not belong to a subclass of Spinach
Object leafy belongs to class spinach, a subclass of Vegetable