1<?php 2 3/** @file filteriterator.inc 4 * @ingroup SPL 5 * @brief class FilterIterator 6 * @author Marcus Boerger 7 * @date 2003 - 2009 8 * 9 * SPL - Standard PHP Library 10 */ 11 12/** 13 * @brief Abstract filter for iterators 14 * @author Marcus Boerger 15 * @version 1.1 16 * @since PHP 5.0 17 * 18 * Instances of this class act as a filter around iterators. In other words 19 * you can put an iterator into the constructor and the instance will only 20 * return selected (accepted) elements. 21 * 22 * The only thing that needs to be done to make this work is implementing 23 * method accept(). Typically this invloves reading the current element or 24 * key of the inner Iterator and checking whether it is acceptable. 25 */ 26abstract class FilterIterator implements OuterIterator 27{ 28 private $it; 29 30 /** 31 * Constructs a filter around another iterator. 32 * 33 * @param it Iterator to filter 34 */ 35 function __construct(Iterator $it) { 36 $this->it = $it; 37 } 38 39 /** 40 * Rewind the inner iterator. 41 */ 42 function rewind() { 43 $this->it->rewind(); 44 $this->fetch(); 45 } 46 47 /** 48 * Accept function to decide whether an element of the inner iterator 49 * should be accessible through the Filteriterator. 50 * 51 * @return whether or not to expose the current element of the inner 52 * iterator. 53 */ 54 abstract function accept(); 55 56 /** 57 * Fetch next element and store it. 58 * 59 * @return void 60 */ 61 protected function fetch() { 62 while ($this->it->valid()) { 63 if ($this->accept()) { 64 return; 65 } 66 $this->it->next(); 67 }; 68 } 69 70 /** 71 * Move to next element 72 * 73 * @return void 74 */ 75 function next() { 76 $this->it->next(); 77 $this->fetch(); 78 } 79 80 /** 81 * @return Whether more elements are available 82 */ 83 function valid() { 84 return $this->it->valid(); 85 } 86 87 /** 88 * @return The current key 89 */ 90 function key() { 91 return $this->it->key(); 92 } 93 94 /** 95 * @return The current value 96 */ 97 function current() { 98 return $this->it->current(); 99 } 100 101 /** 102 * hidden __clone 103 */ 104 protected function __clone() { 105 // disallow clone 106 } 107 108 /** 109 * @return The inner iterator 110 */ 111 function getInnerIterator() 112 { 113 return $this->it; 114 } 115 116 /** Aggregate the inner iterator 117 * 118 * @param func Name of method to invoke 119 * @param params Array of parameters to pass to method 120 */ 121 function __call($func, $params) 122 { 123 return call_user_func_array(array($this->it, $func), $params); 124 } 125} 126 127?>
