SplFixedArray::valid
I have two things to note about SplObjectStorage:
#1: A reference to the object itself is stored (not just a hash to compare against the object) and it must be removed before the object is destroyed and the destructor is executed.
#2: SplObjectStorage::rewind() MUST be called to initiate the iterator and before SplObjectStorage::current() will return an object (and I think the only way to retrieve an object?) rather than automatically starting at the first element as I expected it to, like an array for example. This assumption is based on SplObjectStorage::current() returning NULL until SplObjectStorage::rewind() is called once the objects are contained. As a note, always use REWIND before iterating through or fetching objects.
<?php
class foo {
public function __destruct() {
print("--- DESTRUCTOR FIRED!!<br />\r\n");
}
}
# Create object and storage
$bar = new foo();
$s = new SplObjectStorage();
# Rewind early just as a test
$s->rewind();
# attach the object
$s->attach($bar, array('test'));
# Unset the object; destructor does NOT fire
unset($bar);
print("Object has been unset<br />\r\n");
# First demonstrate that REWIND must be called to initialize the iterator
$obj = $s->current();
var_dump($obj);
print("- Note the NULL (from \$s->current())<br />\r\n");
# Initialize, and then detach the current (and only) object
$s->rewind();
$s->detach( $s->current() );
# The destructor should NOW execute
?>
Output:
Object has been unset
NULL - Note the NULL (from $s->current())
--- DESTRUCTOR FIRED!!
The SplObjectStorage class
Introduction
The SplObjectStorage class provides a map from objects to data or, by ignoring data, an object set. This dual purpose can be useful in many cases involving the need to uniquely identify objects.
Class synopsis
SplObjectStorage
/* Methods */
}Examples
Example #1 SplObjectStorage as a set
<?php
// As an object set
$s = new SplObjectStorage();
$o1 = new StdClass;
$o2 = new StdClass;
$o3 = new StdClass;
$s->attach($o1);
$s->attach($o2);
var_dump($s->contains($o1));
var_dump($s->contains($o2));
var_dump($s->contains($o3));
$s->detach($o2);
var_dump($s->contains($o1));
var_dump($s->contains($o2));
var_dump($s->contains($o3));
?>
The above example will output:
bool(true) bool(true) bool(false) bool(true) bool(false) bool(false)
Example #2 SplObjectStorage as a map
<?php
// As a map from objects to data
$s = new SplObjectStorage();
$o1 = new StdClass;
$o2 = new StdClass;
$o3 = new StdClass;
$s[$o1] = "data for object 1";
$s[$o2] = array(1,2,3);
if (isset($s[$o2])) {
var_dump($s[$o2]);
}
?>
The above example will output:
array(3) {
[0]=>
int(1)
[1]=>
int(2)
[2]=>
int(3)
}
Table of Contents
- SplObjectStorage::addAll — Adds all objects from another storage
- SplObjectStorage::attach — Adds an object in the storage
- SplObjectStorage::contains — Checks if the storage contains a specific object
- SplObjectStorage::count — Returns the number of objects in the storage
- SplObjectStorage::current — Returns the current storage entry
- SplObjectStorage::detach — Removes an object from the storage
- SplObjectStorage::getInfo — Returns the data associated with the current iterator entry
- SplObjectStorage::key — Returns the index at which the iterator currently is
- SplObjectStorage::next — Move to the next entry
- SplObjectStorage::offsetExists — Checks whether an object exists in the storage
- SplObjectStorage::offsetGet — Returns the data associated with an object
- SplObjectStorage::offsetSet — Associates data to an object in the storage
- SplObjectStorage::offsetUnset — Removes an object from the storage
- SplObjectStorage::removeAll — Removes objects contained in another storage from the current storage
- SplObjectStorage::rewind — Rewind the iterator to the first storage element
- SplObjectStorage::serialize — Serializes the storage
- SplObjectStorage::setInfo — Sets the data associated with the current iterator entry
- SplObjectStorage::unserialize — Unserializes a storage from its string representation
- SplObjectStorage::valid — Returns if the current iterator entry is valid
add a note
User Contributed NotesSplObjectStorage
randallgirard at hotmail dot com
14-Dec-2009 08:01
14-Dec-2009 08:01