在php中提供了許多接口用於實現一些很特定的功能，比如你想把一個對象當作array使用時，只需要實現ArrayAccess接口，當你想要foreach中能夠使用一個對象時，只需要實現Iterator接口，下面給一個例子出來 [php] class BtstoreRoot { /** * 根結點 * @var BtstoreElement */ static $root; } class BtstoreElement implements ArrayAccess, Iterator { /** * 當前所代表的目錄 * @var string */ private $dataDir; /** * 當前所代表的數據 * @var array */ private $arrData; /** * 構造函數 * @param string $dataDir * @param array $arrData */ function __construct($dataDir, $arrData) { $this->dataDir = ''; $this->arrData = array (); if (! emptyempty ( $dataDir ) && is_dir ( $dataDir )) { $this->dataDir = $dataDir; } if (! emptyempty ( $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 (! emptyempty ( $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 ! emptyempty ( $data ); } /* (non-PHPdoc) * @see Iterator::rewind() */ public function rewind() { reset ( $this->arrData ); } } /** * 獲取一個BtstoreElement對象 * @return BtstoreElement */ function btstore_get() { if (emptyempty ( BtstoreRoot::$root )) { BtstoreRoot::$root = new BtstoreElement ( ScriptConf::BTSTORE_ROOT, null ); } return BtstoreRoot::$root; }
