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    <p>Like by the name of the class alone (<code>NoRewindIterator</code>), <a href="http://php.net/NoRewindIterator" rel="nofollow noreferrer">the manual has</a> the following wording in specific:</p> <blockquote> <p>NoRewindIterator - This iterator cannot be rewound.</p> </blockquote> <p>And for the concrete method:</p> <blockquote> <p>NoRewindIterator::rewind() - Prevents the rewind operation on the inner iterator.</p> </blockquote> <p>This implies that the <code>Iterator::rewind()</code> method is not passed through to the inner iterator. Tests also show this, here is a simple one I've been running (code of all iterators not part of PHP are in the <a href="https://github.com/hakre/Iterator-Garden" rel="nofollow noreferrer">Iterator Garden</a>):</p> <pre><code>$iterator = new RangeIterator(1, 1); $debug = new DebugIteratorDecorator($iterator); $noRewind = new NoRewindIterator($debug); echo "first foreach:\n"; foreach ($noRewind as $value) { echo "iteration value: $value\n"; } </code></pre> <p>In this code, the debug-iterator prints (echoes) iteration information on the fly:</p> <pre><code>first foreach: Iterating (RangeIterator): #0 valid() Iterating (RangeIterator): #0 parent::valid() is TRUE Iterating (RangeIterator): #0 current() Iterating (RangeIterator): #0 parent::current() is 1 iteration value: 1 Iterating (RangeIterator): #1 next() Iterating (RangeIterator): #1 after parent::next() Iterating (RangeIterator): #1 valid() Iterating (RangeIterator): #1 parent::valid() is FALSE </code></pre> <p>As this shows, <code>$iterator-&gt;rewind()</code> is never called.</p> <p>This also makes sense for the same reasons given in a related question: <a href="https://stackoverflow.com/q/2458955/367456"><em>Why must I rewind IteratorIterator</em></a>. The <code>NoRewindIterator</code> extends from <code>IteratorIterator</code> and <em>different</em> to it's parent class, the <code>getInnerIterator()</code> method returns an <code>Iterator</code> and not a <code>Traversable</code>.</p> <p>This change allows you to initialize the rewind when you need to:</p> <pre><code>echo "\n\$calling noRewind-&gt;getInnerIterator()-&gt;rewind():\n"; $noRewind-&gt;getInnerIterator()-&gt;rewind(); echo "\nsecond foreach:\n"; foreach ($noRewind as $value) { echo "iteration value: $value\n"; } </code></pre> <p>Exemplary debug output again:</p> <pre><code>$calling noRewind-&gt;getInnerIterator()-&gt;rewind(): Iterating (RangeIterator): #0 rewind() Iterating (RangeIterator): #0 after parent::rewind() second foreach: Iterating (RangeIterator): #0 valid() Iterating (RangeIterator): #0 parent::valid() is TRUE Iterating (RangeIterator): #0 current() Iterating (RangeIterator): #0 parent::current() is 1 iteration value: 1 Iterating (RangeIterator): #1 next() Iterating (RangeIterator): #1 after parent::next() Iterating (RangeIterator): #1 valid() Iterating (RangeIterator): #1 parent::valid() is FALSE </code></pre> <p>Knowing about these details then does allow to create a <code>OneTimeRewindIterator</code> for example:</p> <pre><code>/** * Class OneTimeRewindIterator */ class OneTimeRewindIterator extends NoRewindIterator { private $didRewind = FALSE; public function rewind() { if ($this-&gt;didRewind) return; $this-&gt;didRewind = TRUE; $this-&gt;getInnerIterator()-&gt;rewind(); } } </code></pre>
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    1. POWhen does the NoRewindIterator rewind the inner Iterator?
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