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<title>The SeekableIterator interface</title>
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</div><hr /><div id="class.seekableiterator" class="reference">
<h1 class="title">The SeekableIterator interface</h1>
<div class="partintro"><p class="verinfo">(PHP 5 >= 5.1.0)</p>
<div class="section" id="seekableiterator.intro">
<h2 class="title">Introduction</h2>
<p class="para">
The Seekable iterator.
</p>
</div>
<div class="section" id="seekableiterator.synopsis">
<h2 class="title">Interface synopsis</h2>
<div class="classsynopsis">
<div class="ooclass"></div>
<div class="classsynopsisinfo">
<span class="ooclass">
<strong class="classname">SeekableIterator</strong>
</span>
<span class="ooclass">
<span class="modifier">extends</span>
<a href="class.iterator.html" class="classname">Iterator</a>
</span>
{</div>
<div class="classsynopsisinfo classsynopsisinfo_comment">/* Methods */</div>
<div class="methodsynopsis dc-description">
<span class="modifier">abstract</span> <span class="modifier">public</span> <span class="type">void</span> <span class="methodname"><a href="seekableiterator.seek.html" class="methodname">seek</a></span>
( <span class="methodparam"><span class="type">int</span> <code class="parameter">$position</code></span>
)</div>
<div class="classsynopsisinfo classsynopsisinfo_comment">/* Inherited methods */</div>
<div class="methodsynopsis dc-description">
<span class="modifier">abstract</span> <span class="modifier">public</span> <span class="type">mixed</span> <span class="methodname"><a href="iterator.current.html" class="methodname">Iterator::current</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">abstract</span> <span class="modifier">public</span> <span class="type">scalar</span> <span class="methodname"><a href="iterator.key.html" class="methodname">Iterator::key</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">abstract</span> <span class="modifier">public</span> <span class="type">void</span> <span class="methodname"><a href="iterator.next.html" class="methodname">Iterator::next</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">abstract</span> <span class="modifier">public</span> <span class="type">void</span> <span class="methodname"><a href="iterator.rewind.html" class="methodname">Iterator::rewind</a></span>
( <span class="methodparam">void</span>
)</div>
<div class="methodsynopsis dc-description">
<span class="modifier">abstract</span> <span class="modifier">public</span> <span class="type">boolean</span> <span class="methodname"><a href="iterator.valid.html" class="methodname">Iterator::valid</a></span>
( <span class="methodparam">void</span>
)</div>
}</div>
</div>
<div class="section" id="seekableiterator.examples">
<div class="example" id="seekableiterator.examples.basic">
<p><strong>Example #1 Basic usage</strong></p>
<div class="example-contents"><p>
This example demonstrates creating a custom <strong class="classname">SeekableIterator</strong>,
seeking to a position and handling an invalid position.
</p></div>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">class </span><span style="color: #0000BB">MySeekableIterator </span><span style="color: #007700">implements </span><span style="color: #0000BB">SeekableIterator </span><span style="color: #007700">{<br /><br /> private </span><span style="color: #0000BB">$position</span><span style="color: #007700">;<br /><br /> private </span><span style="color: #0000BB">$array </span><span style="color: #007700">= array(<br /> </span><span style="color: #DD0000">"first element"</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">"second element"</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">"third element"</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">"fourth element"<br /> </span><span style="color: #007700">);<br /><br /> </span><span style="color: #FF8000">/* Method required for SeekableIterator interface */<br /><br /> </span><span style="color: #007700">public function </span><span style="color: #0000BB">seek</span><span style="color: #007700">(</span><span style="color: #0000BB">$position</span><span style="color: #007700">) {<br /> if (!isset(</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">array</span><span style="color: #007700">[</span><span style="color: #0000BB">$position</span><span style="color: #007700">]) {<br /> throw new </span><span style="color: #0000BB">OutOfBoundsException</span><span style="color: #007700">(</span><span style="color: #DD0000">"invalid seek position (</span><span style="color: #0000BB">$position</span><span style="color: #DD0000">)"</span><span style="color: #007700">);<br /> }<br /><br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position </span><span style="color: #007700">= </span><span style="color: #0000BB">$position</span><span style="color: #007700">;<br /> }<br /><br /> </span><span style="color: #FF8000">/* Methods required for Iterator interface */<br /> <br /> </span><span style="color: #007700">public function </span><span style="color: #0000BB">rewind</span><span style="color: #007700">() {<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position </span><span style="color: #007700">= </span><span style="color: #0000BB">0</span><span style="color: #007700">;<br /> }<br /><br /> public function </span><span style="color: #0000BB">current</span><span style="color: #007700">() {<br /> return </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">array</span><span style="color: #007700">[</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position</span><span style="color: #007700">];<br /> }<br /><br /> public function </span><span style="color: #0000BB">key</span><span style="color: #007700">() {<br /> return </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position</span><span style="color: #007700">;<br /> }<br /><br /> public function </span><span style="color: #0000BB">next</span><span style="color: #007700">() {<br /> ++</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position</span><span style="color: #007700">;<br /> }<br /><br /> public function </span><span style="color: #0000BB">valid</span><span style="color: #007700">() {<br /> return isset(</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">array</span><span style="color: #007700">[</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position</span><span style="color: #007700">]);<br /> }<br />}<br /><br />try {<br /><br /> </span><span style="color: #0000BB">$it </span><span style="color: #007700">= new </span><span style="color: #0000BB">MySeekableIterator</span><span style="color: #007700">;<br /> echo </span><span style="color: #0000BB">$it</span><span style="color: #007700">-></span><span style="color: #0000BB">current</span><span style="color: #007700">(), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /> <br /> </span><span style="color: #0000BB">$it</span><span style="color: #007700">-></span><span style="color: #0000BB">seek</span><span style="color: #007700">(</span><span style="color: #0000BB">2</span><span style="color: #007700">);<br /> echo </span><span style="color: #0000BB">$it</span><span style="color: #007700">-></span><span style="color: #0000BB">current</span><span style="color: #007700">(), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /> <br /> </span><span style="color: #0000BB">$it</span><span style="color: #007700">-></span><span style="color: #0000BB">seek</span><span style="color: #007700">(</span><span style="color: #0000BB">1</span><span style="color: #007700">);<br /> echo </span><span style="color: #0000BB">$it</span><span style="color: #007700">-></span><span style="color: #0000BB">current</span><span style="color: #007700">(), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /> <br /> </span><span style="color: #0000BB">$it</span><span style="color: #007700">-></span><span style="color: #0000BB">seek</span><span style="color: #007700">(</span><span style="color: #0000BB">10</span><span style="color: #007700">);<br /> <br />} catch (</span><span style="color: #0000BB">OutOfBoundsException $e</span><span style="color: #007700">) {<br /> echo </span><span style="color: #0000BB">$e</span><span style="color: #007700">-></span><span style="color: #0000BB">getMessage</span><span style="color: #007700">();<br />}<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output
something similar to:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
first element
third element
second element
invalid seek position (10)
</pre></div>
</div>
</div>
</div>
</div>
<h2>Table of Contents</h2><ul class="chunklist chunklist_reference"><li><a href="seekableiterator.seek.html">SeekableIterator::seek</a> — Seeks to a position</li></ul>
</div>
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