Home | MySQL Russian Manual | MySQL Manual | Apache HTTP Server Rus Documentation | Apache HTTP Server Documentation | downloads | faq

search for in the  Language: Russian

Predefined Interfaces
PHP Manual

The ArrayAccess interface

Introduction

Interface to provide accessing objects as arrays.

Interface synopsis

ArrayAccess
ArrayAccess {
/* Methods */
abstract public boolean offsetExists ( mixed $offset )
abstract public mixed offsetGet ( mixed $offset )
abstract public void offsetSet ( mixed $offset , mixed $value )
abstract public void offsetUnset ( mixed $offset )
}

Example #1 Basic usage

<?php
class obj implements arrayaccess {
    private $container = array();
    public function __construct() {
        $this->container = array(
            "one"   => 1,
            "two"   => 2,
            "three" => 3,
        );
    }
    public function offsetSet($offset, $value) {
        $this->container[$offset] = $value;
    }
    public function offsetExists($offset) {
        return isset($this->container[$offset]);
    }
    public function offsetUnset($offset) {
        unset($this->container[$offset]);
    }
    public function offsetGet($offset) {
        return isset($this->container[$offset]) ? $this->container[$offset] : null;
    }
}

 $obj = new obj;

 var_dump(isset($obj["two"]));
var_dump($obj["two"]);
unset($obj["two"]);
var_dump(isset($obj["two"]));
$obj["two"] = "A value";
var_dump($obj["two"]);

 ?>

The above example will output something similar to:

bool(true)
int(2)
bool(false)
string(7) "A value"

Table of Contents

Predefined Interfaces
PHP Manual
User Contributed Notes
ArrayAccess
max at flashdroid dot com
06-Apr-2010 01:49
Objects implementing ArrayAccess may return objects by references in PHP 5.3.0.

You can implement your ArrayAccess object like this:

    class Reflectable implements ArrayAccess {

        public function set($name, $value) {
            $this->{$name} = $value;
        }

        public function &get($name) {
            return $this->{$name};
        }

        public function offsetGet($offset) {
            return $this->get($offset);
        }

        public function offsetSet($offset, $value) {
            $this->set($offset, $value);
        }

        ...

    }

This base class allows you to get / set your object properties using the [] operator just like in Javascript:

    class Boo extends Reflectable {
        public $name;
    }

    $obj = new Boo();
    $obj['name'] = "boo";
    echo $obj['name']; // prints boo
Cintix
29-Oct-2009 09:32
To take full advantages of all array features with ArrayAccess, then you would need to implements Countable and Iterator

Like this.

<?php

 class ArrayOfColorModel implements ArrayAccess, Iterator, Countable {
    private $container = array();

    public function __construct() {
    }

    public function offsetSet($offset,$value) {
         if ($value instanceof ColorModel){
            if ($offset == "") {
                $this->container[] = $value;
            }else {
                $this->container[$offset] = $value;
            }
        } else {
            throw new Exception("Value have to be a instance of the Model ColorModel");
        }
    }

    public function offsetExists($offset) {
     return isset($this->container[$offset]);
    }

    public function offsetUnset($offset) {
        unset($this->container[$offset]);
    }

    public function offsetGet($offset) {
        return isset($this->container[$offset]) ? $this->container[$offset] : null;
    }

    public function rewind() {
        reset($this->container);
    }

    public function current() {
        return current($this->container);
    }

    public function key() {
        return key($this->container);
    }

    public function next() {
        return next($this->container);
    }

    public function valid() {
        return $this->current() !== false;
    }   

    public function count() {
     return count($this->container);
    }

}

 ?>

Now you can using it like any other array.

<?php
   
   $array = new ArrayOfColorModel();
   foreach ($array as $model) {
        var_export($model);
   }

   // OR

   for($i=0;$i<count($array);$i++){
        var_export($array[$i]);
   }

 ?>
AryehGregor+php-comment at gmail dot com
09-Jan-2009 01:33
Note that at least in PHP 5.1, objects implementing ArrayAccess cannot return objects by reference.  See http://bugs.php.net/bug.php?id=34783 .  If you have code like

<?php
$x = &$y[0];
 ?>

then this will (as far as I can tell) *always* fail unless $y is a real array -- it cannot work if $y is an object implementing ArrayAccess.  If your offsetGet() function returns by reference, you get the fatal error "Declaration of MyClass::offsetGet() must be compatible with that of ArrayAccess::offsetGet()".  If you try to have it return by value, however, you get the (contradictory) fatal error "Objects used as arrays in post/pre increment/decrement must return values by reference", at least in my version of PHP.

It is therefore not possible to take arbitrary code dealing with arrays and try to substitute an object of your own for an array, even if all of the normal array functions didn't fail as well (which they do, or at least some of them).
 

 
credits | contact