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<?php
/** @file filteriterator.inc
* @ingroup SPL
* @brief class FilterIterator
* @author Marcus Boerger
* @date 2003 - 2009
*
* SPL - Standard PHP Library
*/
/**
* @brief Abstract filter for iterators
* @author Marcus Boerger
* @version 1.1
* @since PHP 5.0
*
* Instances of this class act as a filter around iterators. In other words
* you can put an iterator into the constructor and the instance will only
* return selected (accepted) elements.
*
* The only thing that needs to be done to make this work is implementing
* method accept(). Typically this invloves reading the current element or
* key of the inner Iterator and checking whether it is acceptable.
*/
abstract class FilterIterator implements OuterIterator
{
private $it;
/**
* Constructs a filter around another iterator.
*
* @param it Iterator to filter
*/
function __construct(Iterator $it) {
$this->it = $it;
}
/**
* Rewind the inner iterator.
*/
function rewind() {
$this->it->rewind();
$this->fetch();
}
/**
* Accept function to decide whether an element of the inner iterator
* should be accessible through the Filteriterator.
*
* @return whether or not to expose the current element of the inner
* iterator.
*/
abstract function accept();
/**
* Fetch next element and store it.
*
* @return void
*/
protected function fetch() {
while ($this->it->valid()) {
if ($this->accept()) {
return;
}
$this->it->next();
};
}
/**
* Move to next element
*
* @return void
*/
function next() {
$this->it->next();
$this->fetch();
}
/**
* @return Whether more elements are available
*/
function valid() {
return $this->it->valid();
}
/**
* @return The current key
*/
function key() {
return $this->it->key();
}
/**
* @return The current value
*/
function current() {
return $this->it->current();
}
/**
* hidden __clone
*/
protected function __clone() {
// disallow clone
}
/**
* @return The inner iterator
*/
function getInnerIterator()
{
return $this->it;
}
/** Aggregate the inner iterator
*
* @param func Name of method to invoke
* @param params Array of parameters to pass to method
*/
function __call($func, $params)
{
return call_user_func_array(array($this->it, $func), $params);
}
}
?>
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