07c08-1.php

介绍PHP5的给类型函数应用

<?php
// Define a class that will store values for any property it is given.
class Data_Holder {
    // The data storage array
    private $data = array();

    // A method to set any variable passed to this object.  
    // Store it in the array
    public function __set($name, $value) {
        $this->data[$name] = $value;
    }
    
    // A method to return any values that are set:
    public function __get($name) {
        if (isset($this->data[$name])) { return $this->data[$name]; }
    }

    // A method that will allow 'isset' to work on these variables
    public function __isset($name) {
        return isset($this->data[$name]);
    }
    
    // Finally a method to allow 'unset' calls to work on these variables
    public function __unset($name) {
        unset($this->data[$name]);
    }
}

// Create a data holding object & store some data in it:
$data = new Data_Holder();
$data->name = 'Francesca';

// Now echo the value out to see that the __get method is working:
echo "<p>The data value of 'name' is {$data->name}</p>";

// Now unset the value, and then use isset to ensure that it happened.
unset($data->name);
echo '<p>The value is ', isset($data->name) ? '' : 'not ', 'set.</p>';
?>