SplQueue::dequeue
(PHP 5 >= 5.3.0)
SplQueue::dequeue — Dequeues a node from the queue
Description
Dequeues value from the top of the queue.
Note:
SplQueue::dequeue() is an alias of SplDoublyLinkedList::shift().
Parameters
This function has no parameters.
Return Values
The value of the dequeued node.
Коментарии
If the queue is empty, dequeue() will raise an 'RuntimeException' with message 'Can't shift from an empty datastructure'.<?php
$q = new SplQueue();
$q->setIteratorMode(SplQueue::IT_MODE_DELETE);
$q->enqueue('item 1');
$q->enqueue('item 2');
$q->enqueue('item 3');
$q->dequeue();
$q->dequeue();
foreach ($q as $item) {
echo $item;
}
//Result: item 3
$q->dequeue(); //Fatal error: Uncaught exception 'RuntimeException'
//with message 'Can't shift from an empty datastructure'
?>
I just thought this was a fun and interesting way for lining up method calls and then calling them back-to-back. Might be useful as a basis for a transactional execution class or something.
<?php
$q = new SplQueue();
$q->setIteratorMode(SplQueue::IT_MODE_DELETE);
$q->enqueue(array("FooBar", "foo"));
$q->enqueue(array("FooBar", "bar"));
$q->enqueue(array("FooBar", "msg", "Hi there!"));
foreach ($q as $task) {
if (count($task) > 2) {
list($class, $method, $args) = $task;
$class::$method($args);
} else {
list($class, $method) = $task;
$class::$method();
}
}
class FooBar {
public static function foo() {
echo "FooBar::foo() called.\n";
}
public static function bar() {
echo "FooBar::bar() called.\n";
}
public static function msg($msg) {
echo "$msg\n";
}
}
?>
Results:
FooBar::foo() called.
FooBar::bar() called.
Hi there!
I just thought this was a fun and interesting way for lining up method calls and then calling them back-to-back. Might be useful as a basis for a transactional execution class or something.
<?php
$q = new SplQueue();
$q->setIteratorMode(SplQueue::IT_MODE_DELETE);
$q->enqueue(array("FooBar", "foo"));
$q->enqueue(array("FooBar", "bar"));
$q->enqueue(array("FooBar", "msg", "Hi there!"));
foreach ($q as $task) {
if (count($task) > 2) {
list($class, $method, $args) = $task;
$class::$method($args);
} else {
list($class, $method) = $task;
$class::$method();
}
}
class FooBar {
public static function foo() {
echo "FooBar::foo() called.\n";
}
public static function bar() {
echo "FooBar::bar() called.\n";
}
public static function msg($msg) {
echo "$msg\n";
}
}
?>
Results:
FooBar::foo() called.
FooBar::bar() called.
Hi there!