php man page for seekableiterator

SEEKABLEITERATOR(3)							 1						       SEEKABLEITERATOR(3)

The SeekableIterator interface

INTRODUCTION
	The Seekable iterator.

INTERFACE SYNOPSIS
       SeekableIterator

       SeekableIteratorextends
       Iterator

       Methods

       o abstractpublic void SeekableIterator::seek (int  $position)

       Inherited methods

       o abstractpublic mixed Iterator::current (void  )

       o abstractpublic scalar Iterator::key (void  )

       o abstractpublic void Iterator::next (void  )

       o abstractpublic void Iterator::rewind (void  )

       o abstractpublic boolean Iterator::valid (void  )

       Example #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;

		  private $array = array(
		      "first element",
		      "second element",
		      "third element",
		      "fourth element"
		  );

		  /* Method required for SeekableIterator interface */

		  public function seek($position) {
		    if (!isset($this->array[$position])) {
			throw new OutOfBoundsException("invalid seek position ($position)");
		    }

		    $this->position = $position;
		  }

		  /* Methods required for Iterator interface */

		  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(), "
";

		  $it->seek(2);
		  echo $it->current(), "
";

		  $it->seek(1);
		  echo $it->current(), "
";

		  $it->seek(10);

	      } catch (OutOfBoundsException $e) {
		  echo $e->getMessage();
	      }
	      ?>

	      The above example will output something similar to:

	      first element
	      third element
	      second element
	      invalid seek position(10)

PHP Documentation Group 												       SEEKABLEITERATOR(3)