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The Seekable iterator.
Beispiel #1 Basic usage
This example demonstrates creating a custom SeekableIterator, seeking to a position and handling an invalid position.
<?php
class MySeekableIterator implements SeekableIterator {
private $position = 0;
private $array = array(
"first element",
"second element",
"third element",
"fourth element"
);
public function seek($position) {
$this->position = $position;
if (!$this->valid()) {
throw new OutOfBoundsException("invalid seek position ($position)");
}
}
/* Methods required for Iterator interface */
public function __construct() {
$this->position = 0;
}
public function rewind() {
$this->position = 0;
}
public function current() {
return $this->array[$this->position];
}
public function key() {
return $this->position;
}
public function next() {
++$this->position;
}
public function valid() {
return isset($this->array[$this->position]);
}
}
try {
$it = new MySeekableIterator;
echo $it->current(), "\n";
$it->seek(2);
echo $it->current(), "\n";
$it->seek(1);
echo $it->current(), "\n";
$it->seek(10);
} catch (OutOfBoundsException $e) {
echo $e->getMessage();
}
?>
Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:
first element third element second element invalid seek position (10)
Better method:
<?php
$class = 'SeekableIterator';
$findingMethod = 'seek'; // have to be lower chars
$methods = get_class_methods($class);
foreach( $methods as $pVal )
if ( $findingMethod == strtolower($pVal) ) {
echo 'This class has method seek().';
break;
}
}
?>
Best method: http://php.net/manual/en/function.method-exists.php
This example show how to check if some class has method seek() (or another method).
<?php
$class = 'SeekableIterator';
$findingMethod = 'seek'; // have to be lower chars
$methods = get_class_methods($class);
for($i = 0, $ii = count($methods); $i < $ii; $i++){
$sl = strtolower($methods[$i]);
$lowermethods[$i] = $sl;
}
if(in_array($findingMethod,$lowermethods))
echo 'This class has method seek().';
?>
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