3 files changed, 991 insertions, 0 deletions
diff --git a/framework/Data/TMemCache.php b/framework/Data/TMemCache.php
new file mode 100644
index 00000000..73eec99f
--- /dev/null
+++ b/framework/Data/TMemCache.php
@@ -0,0 +1,268 @@
+<?php
+/**
+ * TMemCache class file
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Revision: $  $Date: $
+ * @package System.Data
+ */
+
+/**
+ * TMemCache class
+ *
+ * TMemCache implements a cache application module based on {@link http://www.danga.com/memcached/ memcached}.
+ *
+ * TMemCache can be configured with the Host and Port properties, which
+ * specify the host and port of the memcache server to be used.
+ * By default, they take the value 'localhost' and 11211, respectively.
+ * These properties must be set before {@link init} is invoked.
+ *
+ * The following basic cache operations are implemented:
+ * - {@link get} : retrieve the value with a key (if any) from cache
+ * - {@link set} : store the value with a key into cache
+ * - {@link add} : store the value only if cache does not have this key
+ * - {@link replace} : store the value only if cache has this key
+ * - {@link delete} : delete the value with the specified key from cache
+ * - {@link flush} : delete all values from cache
+ *
+ * Each value is associated with an expiration time. The {@link get} operation
+ * ensures that any expired value will not be returned. The expiration time can
+ * be specified by the number of seconds (maximum 60*60*24*30)
+ * or a UNIX timestamp. A expiration time 0 represents never expire.
+ *
+ * By definition, cache does not ensure the existence of a value
+ * even if it never expires. Cache is not meant to be an persistent storage.
+ *
+ * Also note, there is no security measure to protected data in memcache.
+ * All data in memcache can be accessed by any process running in the system.
+ *
+ * To use this module, the memcache PHP extension must be loaded.
+ *
+ * Some usage examples of TMemCache are as follows,
+ * <code>
+ * $cache=new TMemCache;  // TMemCache may also be loaded as a Prado application module
+ * $cache->init(null);
+ * $cache->add('object',$object);
+ * $object2=$cache->get('object');
+ * </code>
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Revision: $  $Date: $
+ * @package System.Data
+ * @since 3.0
+ */
+class TMemCache extends TComponent implements IModule, ICache
+{
+	/**
+	 * @var boolean if the module is initialized
+	 */
+	private $_initialized=false;
+	/**
+	 * @var Memcache the Memcache instance
+	 */
+	private $_cache=null;
+	/**
+	 * @var string a unique prefix used to identify this cache instance from the others
+	 */
+	private $_prefix=null;
+	/**
+	 * @var string host name of the memcache server
+	 */
+	private $_host='localhost';
+	/**
+	 * @var integer the port number of the memcache server
+	 */
+	private $_port=11211;
+	/**
+	 * @var string ID of this module
+	 */
+	private $_id='';
+
+	/**
+	 * Destructor.
+	 * Disconnect the memcache server.
+	 */
+	public function __destruct()
+	{
+		if($this->_cache!==null)
+			$this->_cache->close();
+		parent::__destruct();
+	}
+
+	/**
+	 * Initializes this module.
+	 * This method is required by the IModule interface. It makes sure that
+	 * UniquePrefix has been set, creates a Memcache instance and connects
+	 * to the memcache server.
+	 * @param IApplication Prado application, can be null
+	 * @param TXmlElement configuration for this module, can be null
+	 * @throws TConfigurationException if memcache extension is not installed or memcache sever connection fails
+	 */
+	public function init($application,$config)
+	{
+		if(!extension_loaded('memcache'))
+			throw new TConfigurationException('memcache_extension_required');
+		$this->_cache=new Memcache;
+		if($this->_cache->connect($this->_host,$this->_port)===false)
+			throw new TInvalidConfigurationException('memcache_connection_failed');
+		if($application instanceof IApplication)
+			$this->_prefix=$application->getUniqueID();
+		$this->_initialized=true;
+	}
+
+	/**
+	 * @return string id of this module
+	 */
+	public function getID()
+	{
+		return $this->_id;
+	}
+
+	/**
+	 * @param string id of this module
+	 */
+	public function setID($value)
+	{
+		$this->_id=$value;
+	}
+
+	/**
+	 * @return string host name of the memcache server
+	 */
+	public function getHost()
+	{
+		return $this->_host;
+	}
+
+	/**
+	 * @param string host name of the memcache server
+	 * @throws TInvalidOperationException if the module is already initialized
+	 */
+	public function setHost($value)
+	{
+		if($this->_initialized)
+			throw new TInvalidOperationException('memcache_host_unchangeable');
+		else
+			$this->_host=$value;
+	}
+
+	/**
+	 * @return integer port number of the memcache server
+	 */
+	public function getPort()
+	{
+		return $this->_port;
+	}
+
+	/**
+	 * @param integer port number of the memcache server
+	 * @throws TInvalidOperationException if the module is already initialized
+	 */
+	public function setPort($value)
+	{
+		if($this->_initialized)
+			throw new TInvalidOperationException('memcache_port_unchangeable');
+		else
+			$this->_port=TPropertyValue::ensureInteger($value);
+	}
+
+	/**
+	 * Retrieves a value from cache with a specified key.
+	 * @return mixed the value stored in cache, false if the value is not in the cache or expired.
+	 */
+	public function get($key)
+	{
+		return $this->_cache->get($this->generateUniqueKey($key));
+	}
+
+	/**
+	 * Stores a value identified by a key into cache.
+	 * If the cache already contains such a key, the existing value and
+	 * expiration time will be replaced with the new ones.
+	 *
+	 * Note, avoid using this method whenever possible. Database insertion is
+	 * very expensive. Try using {@link add} instead, which will not store the value
+	 * if the key is already in cache.
+	 *
+	 * @param string the key identifying the value to be cached
+	 * @param mixed the value to be cached
+	 * @param integer the expiration time of the value,
+	 *        0 means never expire,
+	 *        a number less or equal than 60*60*24*30 means the number of seconds that the value will remain valid.
+	 *        a number greater than 60 means a UNIX timestamp after which the value will expire.
+	 * @return boolean true if the value is successfully stored into cache, false otherwise
+	 */
+	public function set($key,$value,$expire=0)
+	{
+		return $this->_cache->set($this->generateUniqueKey($key),$value,0,$expire);
+	}
+
+	/**
+	 * Stores a value identified by a key into cache if the cache does not contain this key.
+	 * Nothing will be done if the cache already contains the key.
+	 * @param string the key identifying the value to be cached
+	 * @param mixed the value to be cached
+	 * @param integer the expiration time of the value,
+	 *        0 means never expire,
+	 *        a number less or equal than 60*60*24*30 means the number of seconds that the value will remain valid.
+	 *        a number greater than 60 means a UNIX timestamp after which the value will expire.
+	 * @return boolean true if the value is successfully stored into cache, false otherwise
+	 */
+	public function add($key,$value,$expiry=0)
+	{
+		return $this->_cache->add($this->generateUniqueKey($key),$value,0,$expire);
+	}
+
+	/**
+	 * Stores a value identified by a key into cache only if the cache contains this key.
+	 * The existing value and expiration time will be overwritten with the new ones.
+	 * @param string the key identifying the value to be cached
+	 * @param mixed the value to be cached
+	 * @param integer the expiration time of the value,
+	 *        0 means never expire,
+	 *        a number less or equal than 60*60*24*30 means the number of seconds that the value will remain valid.
+	 *        a number greater than 60 means a UNIX timestamp after which the value will expire.
+	 * @return boolean true if the value is successfully stored into cache, false otherwise
+	 */
+	public function replace($key,$value,$expiry=0)
+	{
+		return $this->_cache->replace($this->generateUniqueKey($key),$value,0,$expire);
+	}
+
+	/**
+	 * Deletes a value with the specified key from cache
+	 * @param string the key of the value to be deleted
+	 * @return boolean if no error happens during deletion
+	 */
+	public function delete($key)
+	{
+		return $this->_cache->delete($this->generateUniqueKey($key));
+	}
+
+	/**
+	 * Deletes all values from cache.
+	 * Be careful of performing this operation if the cache is shared by multiple applications.
+	 */
+	public function flush()
+	{
+		return $this->_cache->flush();
+	}
+
+	/**
+	 * Generates a unique key based on a given user key.
+	 * This method generates a unique key with the memcache.
+	 * The key is made unique by prefixing with a unique string that is supposed
+	 * to be unique among applications using the same memcache.
+	 * @param string user key
+	 * @param string a unique key
+	 */
+	protected function generateUniqueKey($key)
+	{
+		return md5($this->_prefix.$key);
+	}
+}
+
+?>
+\ No newline at end of file
diff --git a/framework/Data/TSqliteCache.php b/framework/Data/TSqliteCache.php
new file mode 100644
index 00000000..8d59b035
--- /dev/null
+++ b/framework/Data/TSqliteCache.php
@@ -0,0 +1,277 @@
+<?php
+/**
+ * TSqliteCache class file
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Revision: $  $Date: $
+ * @package System.Data
+ */
+
+/**
+ * TSqliteCache class
+ *
+ * TSqliteCache implements a cache application module based on SQLite database.
+ *
+ * The database file is specified by the DbFile property. This property must
+ * be set before {@link init} is invoked. If the specified database file does not
+ * exist, it will be created automatically. Make sure the database file is writable.
+ *
+ * The following basic cache operations are implemented:
+ * - {@link get} : retrieve the value with a key (if any) from cache
+ * - {@link set} : store the value with a key into cache
+ * - {@link add} : store the value only if cache does not have this key
+ * - {@link replace} : store the value only if cache has this key
+ * - {@link delete} : delete the value with the specified key from cache
+ * - {@link flush} : delete all values from cache
+ *
+ * Each value is associated with an expiration time. The {@link get} operation
+ * ensures that any expired value will not be returned. The expiration time can
+ * be specified by the number of seconds (maximum 60*60*24*30)
+ * or a UNIX timestamp. A expiration time 0 represents never expire.
+ *
+ * By definition, cache does not ensure the existence of a value
+ * even if it never expires. Cache is not meant to be an persistent storage.
+ *
+ * Do not use the same database file for multiple applications using TSqliteCache.
+ * Also note, cache is shared by all user sessions of an application.
+ *
+ * To use this module, the sqlite PHP extension must be loaded. Sqlite extension
+ * is no longer loaded by default since PHP 5.1.
+ *
+ * Some usage examples of TSqliteCache are as follows,
+ * <code>
+ * $cache=new TSqliteCache;  // TSqliteCache may also be loaded as a Prado application module
+ * $cache->setDbFile($dbFilePath);
+ * $cache->init(null);
+ * $cache->add('object',$object);
+ * $object2=$cache->get('object');
+ * </code>
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Revision: $  $Date: $
+ * @package System.Data
+ * @since 3.0
+ */
+class TSqliteCache extends TComponent implements IModule, ICache
+{
+	/**
+	 * name of the table storing cache data
+	 */
+	const CACHE_TABLE='cache';
+	/**
+	 * extension of the db file name
+	 */
+	const DB_FILE_EXT='.db';
+	/**
+	 * maximum number of seconds specified as expire
+	 */
+	const EXPIRE_LIMIT=2592000;  // 30 days
+
+	/**
+	 * @var boolean if the module has been initialized
+	 */
+	private $_initialized=false;
+	/**
+	 * @var SQLiteDatabase the sqlite database instance
+	 */
+	private $_db=null;
+	/**
+	 * @var string the database file name
+	 */
+	private $_file=null;
+	/**
+	 * @var string id of this module
+	 */
+	private $_id='';
+
+	/**
+	 * Destructor.
+	 * Disconnect the db connection.
+	 */
+	public function __destruct()
+	{
+		$this->_db=null;
+		parent::__destruct();
+	}
+
+	/**
+	 * Initializes this module.
+	 * This method is required by the IModule interface. It checks if the DbFile
+	 * property is set, and creates a SQLiteDatabase instance for it.
+	 * The database or the cache table does not exist, they will be created.
+	 * Expired values are also deleted.
+	 * @param IApplication Prado application, can be null
+	 * @param TXmlElement configuration for this module, can be null
+	 * @throws TConfigurationException if sqlite extension is not installed,
+	 *         DbFile is set invalid, or any error happens during creating database or cache table.
+	 */
+	public function init($application,$config)
+	{
+		if(!function_exists('sqlite_open'))
+			throw new TConfigurationException('sqlitecache_extension_required');
+		if($this->_file===null)
+			throw new TConfigurationException('sqlitecache_filename_required');
+		$error='';
+		if(($fname=Prado::getPathOfNamespace($this->_file,self::DB_FILE_EXT))===null)
+			throw new TConfigurationException('sqlitecache_dbfile_invalid',$this->_file);
+		if(($this->_db=new SQLiteDatabase($fname,0666,$error))===false)
+			throw new TConfigurationException('sqlitecache_connection_failed',$error);
+		if(($res=$this->_db->query('SELECT * FROM sqlite_master WHERE tbl_name=\''.self::CACHE_TABLE.'\' AND type=\'table\''))!=false)
+		{
+			if($res->numRows()===0)
+			{
+				if($this->_db->query('CREATE TABLE '.self::CACHE_TABLE.' (key CHAR(128) PRIMARY KEY, value BLOB, serialized INT, expire INT)')===false)
+					throw new TConfigurationException('sqlitecache_table_creation_failed',sqlite_error_string(sqlite_last_error()));
+			}
+		}
+		else
+			throw new TConfigurationException('sqlitecache_table_creation_failed',sqlite_error_string(sqlite_last_error()));
+		$this->_initialized=true;
+		$this->_db->query('DELETE FROM '.self::CACHE_TABLE.' WHERE expire<>0 AND expire<'.time());
+	}
+
+	/**
+	 * @return string id of this module
+	 */
+	public function getID()
+	{
+		return $this->_id;
+	}
+
+	/**
+	 * @param string id of this module
+	 */
+	public function setID($value)
+	{
+		$this->_id=$value;
+	}
+
+	/**
+	 * @return string database file path (in namespace form)
+	 */
+	public function getDbFile()
+	{
+		return $this->_file;
+	}
+
+	/**
+	 * @param string database file path (in namespace form)
+	 * @throws TInvalidOperationException if the module is already initialized
+	 */
+	public function setDbFile($value)
+	{
+		if($this->_initialized)
+			throw new TInvalidOperationException('sqlitecache_dbfile_unchangeable');
+		else
+			$this->_file=$value;
+	}
+
+	/**
+	 * Retrieves a value from cache with a specified key.
+	 * @return mixed the value stored in cache, false if the value is not in the cache or expired.
+	 */
+	public function get($key)
+	{
+		$sql='SELECT serialized,value FROM '.self::CACHE_TABLE.' WHERE key=\''.md5($key).'\' AND (expire=0 OR expire>'.time().')';
+		if(($ret=$this->_db->query($sql))!=false && ($row=$ret->fetch(SQLITE_ASSOC))!==false)
+			return $row['serialized']?Prado::unserialize($row['value']):$row['value'];
+		else
+			return false;
+	}
+
+	/**
+	 * Stores a value identified by a key into cache.
+	 * If the cache already contains such a key, the existing value and
+	 * expiration time will be replaced with the new ones.
+	 *
+	 * Note, avoid using this method whenever possible. Database insertion is
+	 * very expensive. Try using {@link add} instead, which will not store the value
+	 * if the key is already in cache.
+	 *
+	 * @param string the key identifying the value to be cached
+	 * @param mixed the value to be cached
+	 * @param integer the expiration time of the value,
+	 *        0 means never expire,
+	 *        a number less or equal than 60*60*24*30 means the number of seconds that the value will remain valid.
+	 *        a number greater than 60 means a UNIX timestamp after which the value will expire.
+	 * @return boolean true if the value is successfully stored into cache, false otherwise
+	 */
+	public function set($key,$value,$expire=0)
+	{
+		$serialized=is_string($value)?0:1;
+		$value1=sqlite_escape_string($serialized?Prado::serialize($value):$value);
+		if($expire && $expire<=self::EXPIRE_LIMIT)
+			$expire=time()+$expire;
+		$sql='REPLACE INTO '.self::CACHE_TABLE.' VALUES(\''.md5($key).'\',\''.$value1.'\','.$serialized.','.$expire.')';
+		return $this->_db->query($sql)!==false;
+	}
+
+	/**
+	 * Stores a value identified by a key into cache if the cache does not contain this key.
+	 * Nothing will be done if the cache already contains the key.
+	 * @param string the key identifying the value to be cached
+	 * @param mixed the value to be cached
+	 * @param integer the expiration time of the value,
+	 *        0 means never expire,
+	 *        a number less or equal than 60*60*24*30 means the number of seconds that the value will remain valid.
+	 *        a number greater than 60 means a UNIX timestamp after which the value will expire.
+	 * @return boolean true if the value is successfully stored into cache, false otherwise
+	 */
+	public function add($key,$value,$expire=0)
+	{
+		$serialized=is_string($value)?0:1;
+		$value1=sqlite_escape_string($serialized?Prado::serialize($value):$value);
+		if($expire && $expire<=self::EXPIRE_LIMIT)
+			$expire=time()+$expire;
+		$sql='INSERT INTO '.self::CACHE_TABLE.' VALUES(\''.md5($key).'\',\''.$value1.'\','.$serialized.','.$expire.')';
+		return @$this->_db->query($sql)!==false;
+	}
+
+	/**
+	 * Stores a value identified by a key into cache only if the cache contains this key.
+	 * The existing value and expiration time will be overwritten with the new ones.
+	 * @param string the key identifying the value to be cached
+	 * @param mixed the value to be cached
+	 * @param integer the expiration time of the value,
+	 *        0 means never expire,
+	 *        a number less or equal than 60*60*24*30 means the number of seconds that the value will remain valid.
+	 *        a number greater than 60 means a UNIX timestamp after which the value will expire.
+	 * @return boolean true if the value is successfully stored into cache, false otherwise
+	 */
+	public function replace($key,$value,$expire=0)
+	{
+		$serialized=is_string($value)?0:1;
+		$value1=sqlite_escape_string($serialized?Prado::serialize($value):$value);
+		if($expire && $expire<=self::EXPIRE_LIMIT)
+			$expire=time()+$expire;
+		$sql='UPDATE '.self::CACHE_TABLE.' SET value=\''.$value1.'\', serialized='.$serialized.',expire='.$expire.' WHERE key=\''.md5($key).'\'';
+		$this->_db->query($sql);
+		$ret=$this->_db->query('SELECT serialized FROM '.self::CACHE_TABLE.' WHERE key=\''.md5($key).'\'');
+		return ($ret!=false && $ret->numRows()>0);
+	}
+
+	/**
+	 * Deletes a value with the specified key from cache
+	 * @param string the key of the value to be deleted
+	 * @return boolean if no error happens during deletion
+	 */
+	public function delete($key)
+	{
+		$sql='DELETE FROM '.self::CACHE_TABLE.' WHERE key=\''.md5($key).'\'';
+		return $this->_db->query($sql)!==false;
+	}
+
+	/**
+	 * Deletes all values from cache.
+	 * Be careful of performing this operation if the cache is shared by multiple applications.
+	 */
+	public function flush()
+	{
+		return $this->_db->query('DELETE FROM '.self::CACHE_TABLE)!==false;
+	}
+}
+
+?>
+\ No newline at end of file
diff --git a/framework/Data/TXmlDocument.php b/framework/Data/TXmlDocument.php
new file mode 100644
index 00000000..f8ba5dc2
--- /dev/null
+++ b/framework/Data/TXmlDocument.php
@@ -0,0 +1,446 @@
+<?php
+/**
+ * TXmlElement, TXmlDocument, TXmlElementList class file
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Revision: $  $Date: $
+ * @package System.Data
+ */
+
+/**
+ * TXmlElement class.
+ *
+ * TXmlElement represents an XML element node.
+ * You can obtain its tagname, attributes, text between the openning and closing
+ * tags via the TagName, Attributes, and Value properties, respectively.
+ * You can also retrieve its parent and child elements by Parent and Elements
+ * properties, respectively.
+ *
+ * TBD: xpath
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Revision: $  $Date: $
+ * @package System
+ * @since 3.0
+ */
+class TXmlElement extends TComponent
+{
+	/**
+	 * @var TXmlElement parent of this element
+	 */
+	private $_parent=null;
+	/**
+	 * @var string tagname of this element
+	 */
+	private $_tagName;
+	/**
+	 * @var string text enclosed between openning and closing tags of this element
+	 */
+	private $_value;
+	/**
+	 * @var TXmlElementList list of child elements of this element
+	 */
+	private $_elements=null;
+	/**
+	 * @var TMap attributes of this element
+	 */
+	private $_attributes=null;
+
+	/**
+	 * Constructor.
+	 * @param string tagname for this element
+	 */
+	public function __construct($tagName)
+	{
+		parent::__construct();
+		$this->setTagName($tagName);
+	}
+
+	/**
+	 * @return TXmlElement parent element of this element
+	 */
+	public function getParent()
+	{
+		return $this->_parent;
+	}
+
+	/**
+	 * @param TXmlElement parent element of this element
+	 */
+	public function setParent($parent)
+	{
+		$this->_parent=$parent;
+	}
+
+	/**
+	 * @return string tagname of this element
+	 */
+	public function getTagName()
+	{
+		return $this->_tagName;
+	}
+
+	/**
+	 * @param string tagname of this element
+	 */
+	public function setTagName($tagName)
+	{
+		$this->_tagName=$tagName;
+	}
+
+	/**
+	 * @return string text enclosed between opening and closing tag of this element
+	 */
+	public function getValue()
+	{
+		return $this->_value;
+	}
+
+	/**
+	 * @param string text enclosed between opening and closing tag of this element
+	 */
+	public function setValue($value)
+	{
+		$this->_value=$value;
+	}
+
+	/**
+	 * @return boolean true if this element has child elements
+	 */
+	public function getHasElement()
+	{
+		return $this->_elements!==null && $this->_elements->getCount()>0;
+	}
+
+	/**
+	 * @return boolean true if this element has attributes
+	 */
+	public function getHasAttribute()
+	{
+		return $this->_attributes!==null && $this->_attributes->getCount()>0;
+	}
+
+	/**
+	 * @return string the attribute specified by the name, null if no such attribute
+	 */
+	public function getAttribute($name)
+	{
+		if($this->_attributes!==null)
+			return $this->_attributes->itemAt($name);
+		else
+			return null;
+	}
+
+	/**
+	 * @return TXmlElementList list of child elements
+	 */
+	public function getElements()
+	{
+		if(!$this->_elements)
+			$this->_elements=new TXmlElementList($this);
+		return $this->_elements;
+	}
+
+	/**
+	 * @return TMap list of attributes
+	 */
+	public function getAttributes()
+	{
+		if(!$this->_attributes)
+			$this->_attributes=new TMap;
+		return $this->_attributes;
+	}
+
+	/**
+	 * @return TXmlElement the first child element that has the specified tagname, null if not found
+	 */
+	public function getElementByTagName($tagName)
+	{
+		if($this->_elements)
+		{
+			foreach($this->_elements as $element)
+				if($element->_tagName===$tagName)
+					return $element;
+		}
+		return null;
+	}
+
+	/**
+	 * @return TList list of all child elements that have the specified tagname
+	 */
+	public function getElementsByTagName($tagName)
+	{
+		$list=new TList;
+		if($this->_elements)
+		{
+			foreach($this->_elements as $element)
+				if($element->_tagName===$tagName)
+					$list->add($element);
+		}
+		return $list;
+	}
+
+	/**
+	 * @return string string representation of this element
+	 */
+	public function toString($indent=0)
+	{
+		$attr='';
+		if($this->_attributes!==null)
+		{
+			foreach($this->_attributes as $name=>$value)
+				$attr.=" $name=\"$value\"";
+		}
+		$prefix=str_repeat(' ',$indent*4);
+		if($this->getHasElement())
+		{
+			$str=$prefix."<{$this->_tagName}$attr>\n";
+			foreach($this->getElements() as $element)
+				$str.=$element->toString($indent+1)."\n";
+			$str.=$prefix."</{$this->_tagName}>";
+			return $str;
+		}
+		else if($this->getValue()!=='')
+		{
+			return $prefix."<{$this->_tagName}$attr>{$this->_value}</{$this->_tagName}>";
+		}
+		else
+			return $prefix."<{$this->_tagName}$attr />";
+	}
+}
+
+/**
+ * TXmlDocument class.
+ *
+ * TXmlDocument represents a DOM representation of an XML file.
+ * Besides all properties and methods inherited from {@link TXmlElement},
+ * you can load an XML file or string by {@link loadFromFile} or {@link loadFromString}.
+ * You can also get the version and encoding of the XML document by
+ * the Version and Encoding properties.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Revision: $  $Date: $
+ * @package System
+ * @since 3.0
+ */
+class TXmlDocument extends TXmlElement
+{
+	/**
+	 * @var string version of this XML document
+	 */
+	private $_version;
+	/**
+	 * @var string encoding of this XML document
+	 */
+	private $_encoding;
+
+	/**
+	 * Constructor.
+	 * @param string version of this XML document
+	 * @param string encoding of this XML document
+	 */
+	public function __construct($version='1.0',$encoding='')
+	{
+		parent::__construct('');
+		$this->setversion($version);
+		$this->setEncoding($encoding);
+	}
+
+	/**
+	 * @return string version of this XML document
+	 */
+	public function getVersion()
+	{
+		return $this->_version;
+	}
+
+	/**
+	 * @param string version of this XML document
+	 */
+	public function setVersion($version)
+	{
+		$this->_version=$version;
+	}
+
+	/**
+	 * @return string encoding of this XML document
+	 */
+	public function getEncoding()
+	{
+		return $this->_encoding;
+	}
+
+	/**
+	 * @param string encoding of this XML document
+	 */
+	public function setEncoding($encoding)
+	{
+		$this->_encoding=$encoding;
+	}
+
+	/**
+	 * Loads and parses an XML document.
+	 * @param string the XML file path
+	 * @throws TIOException if the file fails to be opened.
+	 */
+	public function loadFromFile($file)
+	{
+		if(($str=file_get_contents($file))!==false)
+			$this->loadFromString($str);
+		else
+			throw new TIOException('xmldocument_file_read_failed',$file);
+	}
+
+	/**
+	 * Loads and parses an XML string.
+	 * The version and encoding will be determined based on the parsing result.
+	 * @param string the XML string
+	 */
+	public function loadFromString($string)
+	{
+		$doc=new DOMDocument();
+		$doc->loadXML($string);
+
+		$this->setEncoding($doc->encoding);
+		$this->setVersion($doc->version);
+
+		$element=$doc->documentElement;
+		$this->setTagName($element->tagName);
+		$this->setValue($element->nodeValue);
+		$elements=$this->getElements();
+		$attributes=$this->getAttributes();
+		$elements->clear();
+		$attributes->clear();
+		foreach($element->attributes as $name=>$attr)
+			$attributes->add($name,$attr->value);
+		foreach($element->childNodes as $child)
+		{
+			if($child instanceof DOMElement)
+				$elements->add($this->buildElement($child));
+		}
+	}
+
+	/**
+	 * Saves this XML document as an XML file.
+	 * @param string the name of the file to be stored with XML output
+	 * @throws TIOException if the file cannot be written
+	 */
+	public function saveToFile($file)
+	{
+		if(($fw=fopen($file,'w'))!==false)
+		{
+			fwrite($fw,$this->saveToString());
+			fclose($fw);
+		}
+		else
+			throw new TIOException('xmldocument_file_write_failed',$file);
+	}
+
+	/**
+	 * Saves this XML document as an XML string
+	 * @return string the XML string of this XML document
+	 */
+	public function saveToString()
+	{
+		$version=empty($this->_version)?' version="1.0"':' version="'.$this->_version.'"';
+		$encoding=empty($this->_encoding)?'':' encoding="'.$this->_encoding.'"';
+		return "<?xml{$version}{$encoding}?>\n".$this->toString(0);
+	}
+
+	/**
+	 * Recursively converts DOM XML nodes into TXmlElement
+	 * @param DOMXmlNode the node to be converted
+	 * @return TXmlElement the converted TXmlElement
+	 */
+	private function buildElement($node)
+	{
+		$element=new TXmlElement($node->tagName);
+		$element->setValue($node->nodeValue);
+		foreach($node->attributes as $name=>$attr)
+			$element->getAttributes()->add($name,$attr->value);
+		foreach($node->childNodes as $child)
+		{
+			if($child instanceof DOMElement)
+				$element->getElements()->add($this->buildElement($child));
+		}
+		return $element;
+	}
+}
+
+
+/**
+ * TXmlElement class.
+ *
+ * TXmlElement represents an XML element node.
+ * You can obtain its tagname, attributes, text between the openning and closing
+ * tags via the TagName, Attributes, and Value properties, respectively.
+ * You can also retrieve its parent and child elements by Parent and Elements
+ * properties, respectively.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Revision: $  $Date: $
+ * @package System
+ * @since 3.0
+ */
+class TXmlElementList extends TList
+{
+	/**
+	 * @var TXmlElement owner of this list
+	 */
+	private $_o;
+
+	/**
+	 * Constructor.
+	 * @param TXmlElement owner of this list
+	 */
+	public function __construct(TXmlElement $owner)
+	{
+		parent::__construct();
+		$this->_o=$owner;
+	}
+
+	/**
+	 * @return TXmlElement owner of this list
+	 */
+	protected function getOwner()
+	{
+		return $this->_o;
+	}
+
+	/**
+	 * Overrides the parent implementation with customized processing of the newly added item.
+	 * @param mixed the newly added item
+	 */
+	protected function addedItem($item)
+	{
+		if($item->getParent()!==null)
+			$item->getParent()->getElements()->remove($item);
+		$item->setParent($this->_o);
+	}
+
+	/**
+	 * Overrides the parent implementation with customized processing of the removed item.
+	 * @param mixed the removed item
+	 */
+	protected function removedItem($item)
+	{
+		$item->setParent(null);
+	}
+
+	/**
+	 * This method is invoked before adding an item to the map.
+	 * If it returns true, the item will be added to the map, otherwise not.
+	 * You can override this method to decide whether a specific can be added.
+	 * @param mixed item to be added
+	 * @return boolean whether the item can be added to the map
+	 */
+	protected function canAddItem($item)
+	{
+		return ($item instanceof TXmlElement);
+	}
+}
+
+?>
+\ No newline at end of file