0bc07.php

来自「介绍PHP5的给类型函数应用」· PHP 代码 · 共 68 行

<?php
// Declare a new class that implements Iterator, that will allow for more
// natural iteration over Arrays with key access
class KeyArrayIterator implements Iterator {
	// Declare a property to hold the actual data array
	protected $data;
	
	// Now make our constructor
	public function __construct($v) {
		// Just store this into our protected storage
		$this->data = $v;
	}
	
	// Ok, we need to declare 'rewind' as part of the implementing Iterator
	public function rewind() {
		// Well the data is still an array, so use the array function:
		return reset($this->data);
	}
	
	// To implement Iterator, declare 'next' which moves the pointer forward
	public function next() {
		// Again, since an array, just use the array function
		return next($this->data);
	}
	
	// To implement Iterator, we need a 'valid', Whether the pointer is valid
	public function valid() {
		// Use the array 'current' function to check if we are at a valid
		// point in the array or not.
		return (current($this->data) === false) ? false : true;
	}
	
	// Now we also need 'key' that returns just a key for this entry.
	public function key() {
		// Just use the arrays build in 'key' function to do this
		return key($this->data);
	}
	
	// Finally define 'current', the real meat of this object
	public function current() {
		// Current needs to return the current entry.  However we want
		// this to really return an object that contains both value
		// and key, therefore let's do just this:
		return new KeyArrayItem(key($this->data), current($this->data));
	}
}

// Now we need to define the KeyArrayItem class that we used in the
// current function of our Iterator.
class KeyArrayItem {
	// First of all, declare properties to hold the data:
	public $key;
	public $value;
	
	// Now make a constructor that will accept these two data points
	public function __construct($k, $v) {
		// Just save them
		$this->key = $k;
		$this->value = $v;
	}
	
	// Now as one last thing, define a __toString method that will return
	// just the value portion if the object is accessed in a direct manner
	public function __toString() {
		return (string) $this->value;
	}
}
?>