数组式访问(ArrayAccess)接口
提供像访问数组一样访问对象的能力的接口。
接口摘要
ArrayAccess {
/* 方法 */
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 )
}
实现接口
class obj implements arrayaccess {
private $container = array();
public function __construct() {
$this->container = array(
"one" => 1,
"two" => 2,
"three" => 3,
);
}
public function offsetSet($offset, $value)
{
if (is_null($offset)) {
$this->container[] = $value;
} else {
$this->container[$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;
}
}
运行输出
$obj = new obj;
var_dump(isset($obj["two"])); # bool(true)
var_dump($obj["two"]); # int(2)
unset($obj["two"]);
var_dump(isset($obj["two"])); # bool(false)
$obj["two"] = "A value";
var_dump($obj["two"]); # string(7) "A value"
$obj[] = 'Append 1';
$obj[] = 'Append 2';
$obj[] = 'Append 3';
print_r($obj);
obj Object
(
[container:obj:private] => Array
(
[one] => 1
[three] => 3
[two] => A value
[0] => Append 1
[1] => Append 2
[2] => Append 3
)
)