PHP implements a simple log processing class

<?php
//以下为日志


interface ILogHandler
{
	public function write($msg);
	
}


class CLogFileHandler implements ILogHandler
{
	private $handle = null;
	
	public function __construct($file = &#39;&#39;)
	{
		$this->handle = fopen($file,&#39;a&#39;);
	}
	
	public function write($msg)
	{
		fwrite($this->handle, $msg, 4096);
	}
	
	public function __destruct()
	{
		fclose($this->handle);
	}
}


class Log
{
	private $handler = null;
	private $level = 15;
	
	private static $instance = null;
	
	private function __construct(){}


	private function __clone(){}
	
	public static function Init($handler = null,$level = 15)
	{
		if ( ! self::$instance instanceof self ) {
			self::$instance = new self();
			self::$instance->__setHandle($handler);
			self::$instance->__setLevel($level);
		}
		return self::$instance;
	}
	
	
	private function __setHandle($handler){
		$this->handler = $handler;
	}
	
	private function __setLevel($level)
	{
		$this->level = $level;
	}
	
	public static function DEBUG($msg)
	{
		self::$instance->write(1, $msg);
	}
	
	public static function WARN($msg)
	{
		self::$instance->write(4, $msg);
	}
	
	public static function ERROR($msg)
	{
		$debugInfo = debug_backtrace();
		$stack = "[";
		foreach($debugInfo as $key => $val){
			if(array_key_exists("file", $val)){
				$stack .= ",file:" . $val["file"];
			}
			if(array_key_exists("line", $val)){
				$stack .= ",line:" . $val["line"];
			}
			if(array_key_exists("function", $val)){
				$stack .= ",function:" . $val["function"];
			}
		}
		$stack .= "]";
		self::$instance->write(8, $stack . $msg);
	}
	
	public static function INFO($msg)
	{
		self::$instance->write(2, $msg);
	}
	
	private function getLevelStr($level)
	{
		switch ($level)
		{
		case 1:
			return &#39;debug&#39;;
		break;
		case 2:
			return &#39;info&#39;;	
		break;
		case 4:
			return &#39;warn&#39;;
		break;
		case 8:
			return &#39;error&#39;;
		break;
		default:
				
		}
	}
	
	protected function write($level,$msg)
	{
		if(($level & $this->level) == $level )
		{
			$msg = &#39;[&#39;.date(&#39;Y-m-d H:i:s&#39;).&#39;][&#39;.$this->getLevelStr($level).&#39;] &#39;.$msg."\n";
			$this->handler->write($msg);
		}
	}
}

?>

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