note 61744 modified in language.references.spot by danbrown
| From: | danbrown@php.net | Date: | Tue, 08 Feb 2011 12:26:30 +0000 |
| Subject: | note 61744 modified in language.references.spot by danbrown | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-176770@lists.php.net to get a copy of this message | ||
One may check reference to any object by simple operator==( object). Example:
<?php
class A {}
$oA1 = new A();
$roA = & $oA1;
echo "roA and oA1 are " . ( $roA == $oA1 ? "same" : "not same") .
"<br>";
$oA2 = new A();
$roA = & $roA2;
echo "roA and oA1 are " . ( $roA == $oA1 ? "same" : "not same") .
"<br>";
?>
Output:
roA and oA1 are same
roA and oA1 are not same
Current technique might be useful for caching in objects when inheritance is used and only base part
of extended class should be copied (analog of C++: oB = oA):
<?php
class A {
/* Any function changing state of A should set $bChanged to true */
public function isChanged() { return $this->bChanged; }
private $bChanged;
//...
}
class B extends A {
// ...
public function set( &$roObj) {
if( $roObj instanceof A) {
if( $this->roAObj == $roObj &&
$roObj->isChanged()) {
/* Object was not changed do not need to copy A part of B */
} else {
/* Copy A part of B */
$this->roAObj = &$roObj;
}
}
}
private $roAObj;
}
?>
--was--
One may check reference to any object by simple operator==( object). Example:
class A {}
$oA1 = new A();
$roA = & $oA1;
echo "roA and oA1 are " . ( $roA == $oA1 ? "same" : "not same") .
"<br>";
$oA2 = new A();
$roA = & $roA2;
echo "roA and oA1 are " . ( $roA == $oA1 ? "same" : "not same") .
"<br>";
Output:
roA and oA1 are same
roA and oA1 are not same
Current technique might be useful for caching in objects when inheritance is used and only base part
of extended class should be copied (analog of C++: oB = oA):
class A {
/* Any function changing state of A should set $bChanged to true */
public function isChanged() { return $this->bChanged; }
private $bChanged;
//...
}
class B extends A {
// ...
public function set( &$roObj) {
if( $roObj instanceof A) {
if( $this->roAObj == $roObj &&
$roObj->isChanged()) {
/* Object was not changed do not need to copy A part of B */
} else {
/* Copy A part of B */
$this->roAObj = &$roObj;
}
}
}
private $roAObj;
}
http://php.net/manual/en/language.references.spot.php