seekableiterator(3) [php man page]

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)

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ARRAYACCESS(3)								 1							    ARRAYACCESS(3)

The ArrayAccess interface

INTRODUCTION

	Interface to provide accessing objects as arrays.

INTERFACE SYNOPSIS

       ArrayAccess

       ArrayAccess

       Methods

       o abstractpublic boolean ArrayAccess::offsetExists (mixed  $offset)

       o abstractpublic mixed ArrayAccess::offsetGet (mixed  $offset)

       o abstractpublic void ArrayAccess::offsetSet (mixed  $offset, mixed  $value)

       o abstractpublic void ArrayAccess::offsetUnset (mixed  $offset)

       Example #1

	      Basic usage

	      <?php
	      class obj implements ArrayAccess {
		  private $container = array();

		  public function __construct() {
		      $this->container = array(
			  "one"   => 1,
			  "two"   => 2,
			  "three" => 3,
		      );
		  }

		  public function offsetSet($offset, $value) {
		      if (is_null($offset)) {
			  $this->container[] = $value;
		      } else {
			  $this->container[$offset] = $value;
		      }
		  }

		  public function offsetExists($offset) {
		      return isset($this->container[$offset]);
		  }

		  public function offsetUnset($offset) {
		      unset($this->container[$offset]);
		  }

		  public function offsetGet($offset) {
		      return isset($this->container[$offset]) ? $this->container[$offset] : null;
		  }
	      }

	      $obj = new obj;

	      var_dump(isset($obj["two"]));
	      var_dump($obj["two"]);
	      unset($obj["two"]);
	      var_dump(isset($obj["two"]));
	      $obj["two"] = "A value";
	      var_dump($obj["two"]);
	      $obj[] = 'Append 1';
	      $obj[] = 'Append 2';
	      $obj[] = 'Append 3';
	      print_r($obj);
	      ?>

	      The above example will output something similar to:

	      bool(true)
	      int(2)
	      bool(false)
	      string(7) "A value"
	      obj Object
	      (
		  [container:obj:private] => Array
		      (
			  [one] => 1
			  [three] => 3
			  [two] => A value
			  [0] => Append 1
			  [1] => Append 2
			  [2] => Append 3
		      )

	      )

PHP Documentation Group 													    ARRAYACCESS(3)

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seekableiterator(3) [php man page]

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