php重载数组操作符
程序员文章站
2022-05-11 20:02:19
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在php中提供了许多接口用于实现一些很特定的功能,比如你想把一个对象当作array使用时,只需要实现ArrayAccess接口,当你想要foreach中能够使用一个对象时,只需要实现Iterator接口,下面给一个例子出来
class BtstoreRoot { /** * 根结点 * @var BtstoreElement */ static $root; } class BtstoreElement implements ArrayAccess, Iterator { /** * 当前所代表的目录 * @var string */ private $dataDir; /** * 当前所代表的数据 * @var array */ private $arrData; /** * 构造函数 * @param string $dataDir * @param array $arrData */ function __construct($dataDir, $arrData) { $this->dataDir = ''; $this->arrData = array (); if (! empty ( $dataDir ) && is_dir ( $dataDir )) { $this->dataDir = $dataDir; } if (! empty ( $arrData )) { $this->arrData = $arrData; } } function __get($key) { if (isset ( $this->arrData [$key] )) { $data = $this->arrData [$key]; if (is_array ( $data ) && ! is_object ( $data )) { $data = new BtstoreElement ( '', $data ); } return $data; } if (! empty ( $this->dataDir )) { $path = $this->dataDir . '/' . $key; if (is_dir ( $path )) { $data = new BtstoreElement ( $path, null ); $this->arrData [$key] = $data; return $data; } if (is_file ( $path )) { $content = file_get_contents ( $path ); $arrData = unserialize ( $content ); $data = new BtstoreElement ( '', $arrData ); $this->arrData [$key] = $data; return $data; } } trigger_error ( "undefined index:$key" ); } function __isset($key) { if (isset ( $this->arrData [$key] )) { return true; } if (file_exists ( $this->dataDir . '/' . $key )) { return true; } return false; } function toArray() { return $this->arrData; } /* (non-PHPdoc) * @see ArrayAccess::offsetExists() */ public function offsetExists($offset) { return $this->__isset ( $offset ); } /* (non-PHPdoc) * @see ArrayAccess::offsetGet() */ public function offsetGet($offset) { return $this->__get ( $offset ); } /* (non-PHPdoc) * @see ArrayAccess::offsetSet() */ public function offsetSet($offset, $value) { trigger_error ( 'offsetSet not implemented by BtstoreElement' ); } /* (non-PHPdoc) * @see ArrayAccess::offsetUnset() */ public function offsetUnset($offset) { trigger_error ( 'offsetUnset not implemented by BtstoreElement' ); } /* (non-PHPdoc) * @see Iterator::current() */ public function current() { return current ( $this->arrData ); } /* (non-PHPdoc) * @see Iterator::next() */ public function next() { return next ( $this->arrData ); } /* (non-PHPdoc) * @see Iterator::key() */ public function key() { return key ( $this->arrData ); } /* (non-PHPdoc) * @see Iterator::valid() */ public function valid() { $data = current ( $this->arrData ); return ! empty ( $data ); } /* (non-PHPdoc) * @see Iterator::rewind() */ public function rewind() { reset ( $this->arrData ); } } /** * 获取一个BtstoreElement对象 * @return BtstoreElement */ function btstore_get() { if (empty ( BtstoreRoot::$root )) { BtstoreRoot::$root = new BtstoreElement ( ScriptConf::BTSTORE_ROOT, null ); } return BtstoreRoot::$root; }